Chapter 4: Beauty

4.1 How to achieve a high level of beauty in the built environment

The New European Bauhaus (NEB) paradigm (COM, 2021a) identifies, within the dimension of Beauty, two primary requirements for the built environment: ensuring an adequate quality of experience for the users and presenting a pleasant level of aesthetics and style that transcends functionality. This revisits the principles of Vitruvian tradition, wherein architecture was regarded as a reflection of nature, and where aesthetic quality (venustas), stability (firmitas) and utility (utilitas) stood as its fundamental attributes.

Research indicates that the aesthetic component of the Beauty dimension is a desirable element of the human living environment (Coburn et al., 2017). In the past, the prevailing view was that the visual aspect of beauty in architecture results from the perfect construction of a building, being a function of the proportions of the parts and their relationship to the whole. In this approach, beauty could be “measured”. Changes in the definition of aesthetic quality were brought by modern empiricism, which assumed that since we are born without innate ideas about beauty, we can only judge it based on our own experiences — pleasure or lack thereof. Some empiricists believed that its evaluation could only be subjective, while others pointed out that it could be treated in universal terms, since people have common experiences that influence their judgements (Tatarkiewicz, 1980).

In the past century, beauty as an aesthetic category has lost its importance. In the wave of modernism, there was a paradigm shift in architecture ('form follows function'), and the discussion of beauty was also hampered by postmodern anti-aesthetics concepts. Since the 1990s, the academic discourse has called for a 'reclaiming' of beauty, even though this is often seen as an ideological statement, usually conservative. However, aesthetics is neither an ideological nor a political issue, even though it may relate to the local values and cultural ideals of a community (van Damme, 1996). Aesthetics concerns the relationship between object and subject in a particular situation or environment (Sartwell, 2004). Aesthetic quality is a kind of matching function between form and its context. Moreover, it is nowadays presented as one of the conditions for human wellbeing, and even as an element necessary for the health and survival of our species. This underscores the necessity for a comprehensive evaluation of these aspects within a common unified dimension. 

There is a need to draw the attention of designers to issues of beauty in the built environment and to support solutions that go hand in hand with EU policies. Achieving beauty in the built environment should be a conscious pursuit and an explicitly declared objective of place-making, planning or building (European Commission, 2021b). This is inherently related to the preservation of cultural heritage, including rediscovery of history of architecture and places that feel familiar, or places that are in harmony with the natural world. The same protection and care should be extended to unique places and forms that appeal to people’s creativity and imagination (COM, 2021b).

Today, various models for the aesthetic quality of architecture and the built environment are identified. This is characterised by the coexistence of traditional architecture and new building styles, depending on the region, available technology, and climatic conditions. As a result, European modern and historical architecture is characterised by a desirable diversity that should be enhanced and protected. At the same time, we are witnessing and contributing to a paradigm shift in the creation of living spaces. The contemporary approach emphasises sustainable design, environmental protection, supporting local communities, and satisfying aesthetics. There is an increasing use of local, natural building materials, greater attention to the material and cultural surroundings, and a concern to perpetuate the heritage for future generations of Europeans. Human beings remain the focus of architects’ and planners’ attention, but modern science is creating new tools to assess their wellbeing, including aesthetics.

Built heritage should be enhanced or preserved and contemporary design should take into account the sense of place and the characteristics of natural and cultural heritage, open landscapes, sites and buildings, including their context. Context in relation to the New European Bauhaus refers to the built and non-built environment and landscape in terms of scale, typology and materiality, while sense of place encompasses the local character, unique identity and distinctiveness of a place and the attachment of people to that place (European Commission, 2021b). Beauty, context and sense of place are essential criteria for high-quality Baukultur within the Davos Baukultur Quality System. Importantly, places with high-quality Baukultur, well embedded in their built and natural context, encourage people’s emotional response to the place by building a positive relationship with it. A crucial part of such context is an overall sensory experience, in which a sense of place is built with understanding of the relationship between objects, spaces and people, enhancing user satisfaction and quality of life (SFoC, 2021).

Assessing and improving beauty in an all-encompassing and integrated way within the built environment and place-making projects require taking into account all the characteristics, connections and phenomena of a geographically defined area in which a place – a single building or a larger unit such as an industrial area or a village – is embedded. In other words, the relation of a place to its surroundings is required at any scale over time. It is, thus, crucial that contemporary design activities consider the sensory perception of the place – visual, acoustic, tactile and olfactory impressions – and that the project solutions foster the creation of a strong sense of place and offer high performance landscapes and sites as places to live, work and recreate. This is expected to provide aesthetic enjoyment, encourage identification and familiarity, contributing to increase the attractiveness for residents and tourists, going beyond the artistic dimension to produce a positive impact on wellbeing of the inhabitants/users of buildings and spaces.

Beyond addressing the aesthetic, psychological and cultural needs of the people in their relationship with the surrounding built environment, setting functional and technical requirements is essential to ensure the high-quality and liveability of projects and spaces for everyone and for the long term. Thus, Beauty is further strongly concerned with two objectives connected to the quality of experience. 

The first one seeks to enhance within the built environment the comfort, wellbeing, health and safety of users, regardless of age, ability or background, in normal operational conditions and in face of potential natural and man-made hazards. The built environment is exposed to various hazards that can cause extensive damage, resulting in substantial economic losses and, in extreme cases, loss of lives. Within this first objective, it is crucial to reduce the impact of such hazards by ensuring a comprehensive assessment of the risks and adopting adequate solutions to mitigate them, enhance preparedness and functionality retention, minimise the operation disruptions and allow a swift recovery process following the emergency. However, threats to users are not only posed by disasters. Significant background noise from external and internal sources of airborne, impact noise and noise from services, poor perceived thermal comfort, and inadequate quality and composition of natural and artificial lighting may compromise overall physical, mental and social wellbeing of the users. On the other hand, design solutions that integrate opportunities for physical movement to prevent sedentary behaviour or physical inactivity may improve user health and productivity. Finally, a further reduction of risk to people and enhancement of their wellbeing stem from a design that ensures the ease of use and operation for all, to the greatest extent possible, irrespective of their cognitive, physical, and sensory abilities.

The second objective aims to achieve high environmental performance through a circular use of construction products, beyond the expected service life, while integrating rigorous decision-making into the procurement and design processes. Within this objective, the integration of emerging and disruptive strategies and methods for data acquisition, automation, and digital information and analysis into the design and delivery activities is encouraged. Such integration may serve as a driver of enhanced quality of the products as well as increased safety of the actors involved in the construction and optimised allocation and consumption of resources. Furthermore, high-quality design, construction and management practices are promoted. This includes favouring more durable elements and components, adopting design solutions capable of accommodating changes in needs or market conditions and facilitating disassembly for reuse and recycling, to retain the highest utility and value of construction products over time. Responsible sourcing of construction products during procurement and efficient material use are integral to this objective. Such efforts are anticipated to reduce both mass and carbon embodied into buildings, mitigate consumption of resources and minimise waste production. Achieving these goals necessitates active involvement from all actors, namely design teams and contractors, with proven suitability to pursue professional activities, economic and financial standing, technical and professional ability as well as extensive experience with certification, design, construction and/or management of buildings and living spaces with improved environmental performance.

4.2 Assessment targets to achieve

To ensure that a high level of beauty is achieved eleven assessment targets are identified, each addressing key concerns in the evaluation process.

4.2.1   Integration of emerging technologies

Digital technologies have emerged as enablers of enhanced customer experience, quality, competitiveness, transparency, safety, resource efficiency and productivity (Baldini et al., 2019; ECSO, 2021). Therefore, their integration across key sectors of the economy is expected to actively contribute to sustainable development, by introducing novel production processes. In particular, the European Union has taken proactive steps towards the digital transformation of the construction sector. This sector is currently one of the least digitalised in the economy, characterised by a low adoption rate of innovative systems and methodologies. Furthermore, considerable variability in market maturity and technology readiness across different disciplines and stakeholders is present throughout the entire building lifecycle and supply chain (Papadonikolaki et al., 2022). Full scale digitalisation of the construction sector is expected to yield annual global savings up to 20% across diverse stages of the building lifecycle (Baldini et al., 2019). This digital transformation is expected to optimise production and generate new business models, replacing some existing jobs while creating new ones. This shift is fostered by manual labour automation, digitalisation of processes and coordination of tasks and activities (van der Heijden, 2023). A significant impact within the construction sector is also anticipated in terms of safety. Digital technologies have the potential to drastically enhance worker safety by reducing the likelihood of errors, supporting training initiatives and skills development, and minimising or replacing human involvement in heavy physical labour, operations in hazardous environments and repetitive tasks (Trask and Linderoth, 2023). To this end, the establishment of a secure environment that facilitates the safe interaction and coexistence of human operators and robots in construction sites is a key enabler (Baldini et al., 2019). Finally, the Smart Building, Infrastructure and City paradigm is leveraging digitalisation and big data revolution to enhance resilience and performance of built assets.

The commitment of Member State policymakers to digitalisation is evident through the implementation of active measures to foster this transformation. Support mechanisms include grants, loans and equity investments as well as the provision of technical assistance and platforms dedicated to skills development and knowledge transfer. Furthermore, the widespread adoption of e-services, for purposes ranging from data storage and sharing to streamlining administrative and bureaucratic procedures, plays a pivotal role in facilitating the digital transition (ECSO, 2021).

Three categories of emerging technologies for the Architectural Engineering and Construction (AEC) sector have been identified (Baldini et al., 2019; ECSO, 2021):

• Data acquisition: sensors, internet of things (IoT), 3D scanning.
• Automating processes: robotics, 3D printing, drones.
• Digital information and analysis: building information modelling (BIM), virtual/augmented reality (VR), artificial intelligence (AI), digital twins.

Some of the above technologies are more relevant for construction or operational phases of the building lifecycle, while the present self-assessment method focuses on promoting their integration into decision-making and processes at the design phase.

4.2.2   High-quality design and delivery

The organisation, qualification and experience of the actors involved in the design, construction operation, maintenance and deconstruction of a built asset significantly influence the quality of design and delivery and the final performance of projects. Therefore, the Public Procurement Directive (Directive, 2014) define a set of criteria for contract awarding that emphasises competences and expertise required of the involved parties. The use of these criteria should be expanded in procurement processes to enhance competitiveness and quality. The European Union has been actively promoting this transition by advocating for strategic plans for green and circular procurement, as well as introducing voluntary or mandatory criteria for selection. These initiatives aim to address a prevailing trend where more than 50% of the procurement procedures in the public sector adopt the lowest price as the award criterion (European Commission, 2017b). Green Public Procurement (GPP) extends beyond the Public Procurement Directive (PPD) criteria, specifically targeting goods, services and works with high environmental impact. GPP promotes the procurement of products that reduce this impact and minimise waste throughout their life cycle, compared to non-green alternatives with the same primary functions that may otherwise be selected (COM, 2008). Similarly, a circularity-driven approach to procurement shifts the focus from short-term needs to long-term consequences of each purchase (European Commission, 2017a). The positive impact of sustainable procurement transcends environmental benefits and encompasses social and economic dimensions (ISO, 2017c).

In this perspective, procurement serves as a catalyst for fostering responsible production and consumption patterns. Markets for environmentally friendly products and services can be created or expanded by raising awareness and driving demand for ‘greener’ goods. Green markets, in turn, are expected to incentivise innovative businesses and solutions, including smart and clean technologies. Therefore, the attention is not only directed towards the competencies of the involved parties but also towards the characteristics of the products (COM, 2008). Moreover, sustainable procurement aims to promote ethical behaviour across its supply chains, avoiding bias and prejudice in decision-making, providing equal opportunities, identifying and preventing violations of the rule of law, and respecting internationally recognised human rights (ISO, 2017c). To achieve this ethical behaviour in production, purchase and consumption, ensuring a transparent, legal and responsible material sourcing is essential. All organisations should be committed to continually improve their practices, avoiding complicity with wrongful acts and taking responsibility for the actions and decisions made.

Although the aforementioned criteria for green and circular procurement have been developed with a focus on public procurement, they can equally inform private procurement practices, since the principles of responsible production, consumption, and ethical sourcing are relevant and beneficial across both domains (COM, 2008).

Finally, transition to a more circular economy implies promoting sufficiency, thus preventing excessive and unnecessary material consumption. The quality of design can be assessed in terms of efficient use of materials aiming at doing more with fewer resources. Ensuring, by design, the long-term resource efficiency throughout the building life cycle is a primary goal highlighted by the Level(s) framework (Dodd et al., 2021a). BS 8895 series (BSI, 2013a, 2015a, 2019) outlines material-efficient processes, key tasks, team members and their responsibilities, outputs specific to each work stage, along with supporting guidance and tools. Examples of suitable design measures for material efficiency can include:

• Increasing the utilisation factor of structural members.
• Designing to standard material dimensions to reduce offcuts and waste on site.
• Removing redundant materials from the design.
• Using materials that can be recycled and/or reused at the end of their service life.
• Making use of recycled and/or reclaimed materials.
• Designing for deconstruction and material reuse.
• Using prefabricated elements where appropriate to reduce material waste.
• Consider using an ‘exposed thermal mass’ design strategy to reduce finishes.
• Avoiding overspecification of predicted loads.
• Using lightweight structural design strategies.
• Making use of bespoke structural elements to reduce overall material use.
• ‘Rationalisation’ of structural elements.
• Optimising the foundation design to reduce embodied environmental impact.

Some of these measures, such as recycling, reuse, use of standard components and offsite construction are evaluated within other assessment targets of the Beauty dimension (e.g. Sections 4.2.1, 4.2.6) as well as in the Sustainability dimension (e.g. Sections 3.2.6, 3.2.9). The remaining main aspects are addressed within the present target.

4.2.3   Resilience of the built environment

Since 2004, over 3.3 billion people worldwide have been either injured, killed or left homeless due to natural disasters (CRED, 2024). In the EU, from 1980 to 2020, natural hazards affected nearly 50 million people and have cost Member States on average EUR 12 billion per year (World Bank, 2021). Recent years have seen an increasing trend in the number of disasters, fuelled by increasing urbanisation and environmental degradation that results in higher exposure of people and assets to natural hazards. With climate change expected to bring more extreme weather events and sea level rise, the severity of natural hazards is projected to increase, and with it the potential for higher losses in future disaster events. Growing political instability, geopolitical tensions and diversification of hostile groups, result in the potential for increased terrorist threats (NIC, 2023). Several global policies and directives have been issued to support measures for reducing risk from natural and man-made disasters. The most important is the Sendai Framework (UNDRR, 2015) which was issued by the UN General Assembly following the 2015 Third UN World Conference on Disaster Risk Reduction (WCDRR). The Sendai framework presents a paradigm for understanding and managing systemic risk from natural, human-made, technological, environmental and biological hazards (UNDRR, 2015). It advocates that disaster risk reduction must be at the core of economic, social and environmental policy at all levels. It also recognises the link between disaster risk reduction and sustainability, highlighting that disasters can set back sustainable development goals as they undermine poverty eradication and magnify inequality (IRDR, 2014). The Sendai framework therefore calls for the substantial reduction of disaster risk and losses in lives, livelihoods and health, as well as in economic, physical, social, cultural and environmental assets of persons, businesses, communities and countries. The framework recognises that the state authorities have the primary role to reduce disaster risk, though this responsibility should be shared with other stakeholders including regional authorities and the private sector (UNDRR, 2015).

Achieving resilience under extreme events involves effective prevention, mitigation, preparedness, response and recovery. In the construction sector, the focus has traditionally been on the adoption of modern building codes for hazard resistance. This is an important part of the mitigation component of resilience, but project design can contribute to disaster response and recovery also, through the provision of means of evacuation, access for emergency services, and the preservation of functionality. Moreover, for a project to be inclusive for its users, measures need to be taken towards enhancing preparedness through training and drills, and organisational steps can be taken to promote faster restoration of services.

4.2.4   Health and wellbeing

The target addresses the design of indoor environment to promote physical, social and mental health and wellbeing. Time spent indoors accounts for roughly 90% of daily life (Fitwel, 2020). The quality, amenities and design of indoor environments are strongly linked to individual health outcomes and productivity.

According to the Environmental noise guidelines for the European region (WHO, 2018), environmental noise features among the top environmental hazards to physical and mental health and wellbeing, with a substantial associated burden of disease in Europe (WHO, 2011; Hänninen et al., 2014). In many cities across the EU, over 50% of the population (approximately 200 million people) are exposed to road noise levels above 55 dB day-evening-night level (L_den), which is above the recommended values by WHO (Kantor et al., 2021). Railway and aircraft noise affect a lower proportion of the EU population (approximately 50 million people), but both are significant sources of local noise pollution. Under the European Green Deal (COM, 2019), the EU has committed to achieve a zero-pollution ambition for a toxic-free environment. The 2021 zero pollution action plan 5 sets a specific target of reducing the number of people chronically disturbed by transport noise by 30% in 2030 as compared to 2017 (Directive, 2002). It is therefore widely recognised that providing a healthy acoustic environment is important. 

External noise transmission into indoor areas is not the only source of noise discomfort. Indoor sources of noise also need to be considered in design. Most commonly, target indoor background noise levels and reverberation times are key metrics used to provide an appropriate acoustic environment within an enclosed space. Background noise (or ambient noise) must be calculated from external and internal sources of airborne, impact noise and noise from services (e.g. HVAC), considering the absorptive and reflective characteristics of façades, structural components and partitions. Reverberation times, indicate the suitability of sound transmission and speech intelligibility. They depend on the frequency of the noise as well as the absorptive properties of surfaces and fitting materials. The target values of these and other parameters adopted to define acoustic environments, vary with the use of the space, its type and level of occupancy, and with the needs of people using the space.

The quality and composition of lighting directly affects people’s ability to conduct tasks within a space. Moreover, lighting has also been shown to affect mental wellbeing and physical health. This is because humans’ circadian rhythm is linked to the natural day-night cycle, and the body requires periods of both light and darkness. Light exposure can affect people’s moods, symptoms of depression, and rates of healing (WELL v2, IWBI, 2020). Appropriate illumination and visual contrasts also contribute to the information needed for wayfinding and for safety (IWBI, 2020). It is therefore important to design and implement a holistic lighting strategy that combines natural and artificial lighting to provide visual acuity, comfort, physical and mental health, and contributes to wayfinding and safety. Such a strategy must account for the diverse needs of occupants of different ages and abilities.

Thermal comfort is defined as “the condition of mind that expresses satisfaction with the thermal environment and is assessed by subjective evaluation” (ASHRAE, 2023). Thermal discomfort strongly influences user wellbeing and productivity as it affects alertness, moods, motivation and focus (Lamb and Kwok, 2016). Thermal comfort is subjective with gender, age, and climatic conditions, all affecting perceived thermal comfort (Nicol and Humphreys, 2002). The location and typology of the building along with outdoor climate and season also influence thermal comfort of occupants (Frontczak and Wargocki, 2011). Since a unique design for thermal environment will not suit all people, designers should aim for a thermal performance of projects that is comfortable for as many people as possible (IWBI, 2020). Devices for regulating thermal comfort can help adjust the environment to individual needs. Thermal comfort is important throughout the year, hence, as a rule, both heating and cooling must be considered.

A large proportion of the EU housing stock cannot provide adequate levels of thermal comfort because of a combination of a lack of insulation, poor quality windows, cold bridging through the building fabric, high levels of air infiltration and inadequate or poorly maintained heating systems (Dodd et al., 2021e). Attempts to provide better thermal comfort can result in large energy consumption in heating and cooling. Thermal comfort is also linked to indoor air quality as both are strongly influenced by the HVAC system used. It is important that design for thermal comfort is considered together with design for better indoor air quality and lower energy consumption (see Sections 3.2.1, 3.2.2 and 3.2.5 in Sustainability).

In 2022, globally, 7.2% and 7.6% of all-cause and cardiovascular disease deaths, respectively, were attributable to physical inactivity, with the proportions of non-communicable diseases (e.g. hypertension, dementia) due to physical inactivity equal to 1.6% and 8.1%, respectively (Katzmarzyk et al., 2022). Despite wide knowledge of the health benefits of regular exercise, over a quarter of the adult population do not meet the current public health guidelines for physical activity (Guthold et al., 2018). Modern desk-based learning and working environments also promote sedentary behaviour. Sedentary behaviour is different from physical inactivity and is characterised as very low-intensity, low-effort activities, such as sitting, and has distinct health outcomes, including higher incidences of obesity, cardiovascular risks and premature mortality (Saunders et al., 2020). A recent study (Santos et al., 2023) evaluated that 500 million new cases of preventable non-communicable diseases would occur globally by 2030 if the prevalence of physical inactivity does not change, with direct health-care costs of EUR 480 billion. This is preventable, and it is critical that future projects promote more active living by integrating opportunities for physical movement into their designs. Several recommendations exist along these lines, such as the Active Design guidance (Sport England, 2023; Sport England and BREEAM, 2019), and the WELL Movement concept (IWBI, 2020).

4.2.5   Accessibility

Accessibility is a fundamental human right (United Nations, 2007), and is defined in the context of the built environment as “adjusting every detail of the built space to (accommodate) a large and varied group of potential users, with a focus on details of importance in relation to cognitive, physical and sensory abilities” (Andersson and Skehan, 2016). 87 million people with disabilities are reported to live in the EU (European Commission, 2021a). According to the World Health Organization, around 16% of the world's population has a disability, which equates to over 1.3 billion people worldwide (WHO, 2023). In March 2021, the European Commission adopted the ‘Strategy for the rights of persons with disabilities 2021-2030’ (European Commission, 2021a), which builds on a previous strategy (COM, 2010) and aims to improve the lives of persons with disabilities in Europe and around the world. The provision of dignified and non-discriminatory accessibility is a part of this strategy. It should be noted that ‘disabilities’ are considered as comprising long-term physical, mental, intellectual or sensory impairments, which are often invisible (in line with Article 1 of United Nations, 2007). Included in physical impairments are reduced physical strength, dexterity and mobility that are associated with ageing. Population ageing is a demographic trend that has been apparent for several decades in Europe, with the number of people aged 65 and over projected to increase from the 2019 value of 90 million to 130 million by 2050 (Eurostat, 2020). This process is driven by low fertility rates and increasing life expectancy, which has significant implications for society and the economy.

Making the built environment accessible is widely recognised as having a significant social benefit. However, other benefits co-exist. Firstly, consideration of the specific needs and requirements of users allows the identification and mitigation of hazards and risks, thus contributing to user safety (European Committee for Standardisation, CEN, 2021b). Secondly, significant economic benefits have been highlighted in the literature (Terashima and Clark, 2021). Accessible design can improve access to information and communication, improve efficiency, and reduce barriers to employment and career advancement, ultimately increasing productivity of people in society. Moreover, developers and building owners will benefit from user satisfaction and increased productivity, resulting in higher visitor rates, social branding opportunities, broadening markets, and lower renovation and operation costs (Steinfeld and Smith, 2012).

Achieving accessibility of the built environment requires consideration of a wide set of human abilities and characteristics, which may be conflicting at times. Achieving accessibility for all is therefore not simple. Several design movements have put forward approaches for accessible design. Amongst these, Universal Design is widely acknowledged and involves the design of products, environments, programmes and services to be usable by all people, to the greatest extent possible, without the need for adaptation or specialised design (Centre for Excellence in Universal Design, 1997). The Universal Design approach is based on seven principles: simple and intuitive use; flexibility in use; size and space for approach and use; perceptible information; low physical effort; tolerance for error; equitable use. These concepts run through the EN 17210 performance standard (CEN, 2021b), which was developed to aid implementation of the UN Convention on the Rights of Persons with Disabilities (United Nations, 2007) in Europe (COM, 2010). This performance standard and the associated technical report (CEN, 2021c) are described in Section 4.7, and are used in Section 4.8 as key references. 

It would be beneficial to all projects to consider universal design principles in every design element, with consideration of its intended use and contribution to the project accessibility and functionality. In the context of the NEB self-assessment method, the design elements considered most important are those that contribute to ease of circulation, safe and intuitive wayfinding, and ease of use and operation of all amenities within the project boundaries.

4.2.6   Service life

Service life maximisation aims to ensure that buildings and products are designed to retain their utility and value over time. The current economy is dominated by a linear take-make-use-dispose principle, in which half of total greenhouse gas (GHG) emissions and most than 90% of biodiversity loss and water stress come from resource extraction and processing (COM, 2020). In particular, the construction sector generates over 35% of total waste in the EU, is responsible for about 50% of all extracted materials, and produces GHG emissions equal to 5-12% of total national emissions (COM, 2020). Most of the environmental impacts relate to the production and construction of structures and façades (Dodd et al., 2021c). As an alternative, circular economy has gained much attention. Circularity pursues a restorative and regenerative model that reduces single-use and premature obsolescence, decoupling economic growth and resource consumption and fostering the implementation of sustainable development goals (Ellen MacArthur Foundation, 2015; Murray et al., 2017; Schroeder et al., 2019; Dokter et al., 2021). The European Commission has proposed a Circular Economy Action Plan, as one of the main building blocks of the European Green Deal, to foster this systematic shift towards a climate-neutral, resource-efficient and competitive economy (COM, 2020). Responding to it, many EU Member States have adopted proactive implementation strategies. 

A main goal of circular economy is to guarantee that products retain their highest utility, as well as their embedded environmental and economic value, over time (Ellen MacArthur Foundation, 2015; Webster, 2015; Nußholz, 2017; Reike et al., 2018; COM, 2020). Circular economy involves ensuring durability, maintainability, and repairability of products, maximising the value of the resources invested in their production. However, to ensure that such long-lasting products are not disposed before the end of their service life, designing buildings that are more easily adapted and upgraded to suit uncertain and fast-evolving future scenarios is essential. Flexible and adaptable systems can accommodate to changing household, personal and business circumstances, variations in the overall demand or conversions in the use. Design for adaptability and renovation does not simply address the capability of load bearing elements to sustain increased actions due to change in use or height and mass of the building. It also aims at facilitating future modification of the layout, and repurposing of internal spaces. Service and equipment distribution and their ease of replacement are additional critical aspects, as they typically pose a major barrier to change in use or changes in fuel or input energy sources (Dodd et al., 2021c). 

Although adaptability may be more compelling for non-residential buildings, in residential buildings specific drivers of adaptability, like starting a family, ageing and changes in circumstances that lead to reduced mobility, alternative requirements for living spaces with different cultures upon changing tenure, as well as the need for suitable home working environments should be properly addressed (Dodd et al., 2021c). Some requirements for adaptability may be fulfilled by universal design principles (ISO, 2020), which are evaluated within the accessibility assessment target of the Beauty dimension (Section 4.2.5). 

Circularity is further promoted by design for disassembly, deconstruction and reuse. Deconstruction principles and good practices comprise (ISO, 2020) independence, avoidance of unnecessary treatments and finishes, simplicity and standardisation. The ease of access to materials, components or connectors of an assembly, and the possibility of disassembling without the use of specialised equipment, causing negligible or no damage, is essential to prevent unnecessary waste during deconstruction. Leaving connections exposed, visible and accessible, with necessary room on all sides to operate them, is a way of promoting ease of disassembly for reuse. Moreover, elements with a minimum number and type of components, parts and materials are in general easier to handle and disassemble, reducing the necessary tools and techniques. Similarly, standardisation ensures that well-established and repetitive techniques can be used for the deconstruction and increases the likelihood of a larger demand for reuse (ISO, 2020; Dodd et al., 2021d).

Additionally, the circular economy model favours the use of renewable resources, the minimisation of hazardous materials and the integration of higher proportions of recycled and recovered content. Other targets within the present self-assessment method are concerned with these circular economy-related measures, namely Section 3.2.9 in Sustainability.

It has been estimated that decisions made at the design phase determine more than 80% of the environmental impact of products (COM, 2020). Therefore, promoting design practices that extend the service life of buildings, components, parts or materials, and foster reuse is an essential step of the paradigm shift towards the circularity model. This effort is expected to reduce embodied life cycle impacts and resource consumption, extending the functional use that can be obtained from the initial investment of resources (Dodd et al., 2021c, d).

4.2.7   High-level aesthetic acceptance

The experience of architecture and space by observers and users is possible thanks to the human sensory system. Although human perception is multisensory in nature, the dominant sense is vision, which means that people tend to perceive their surroundings primarily through images. Studies show that between one third and more than half of the cerebral cortex is involved in the processing of visual information, 12% in the processing of tactile information, about 3% in the processing of auditory information, and less than 1% is responsible for the processing of olfactory and gustatory information (Eberhard, 2007). Nevertheless, there is a growing awareness of the interconnectedness between the senses and their influence on how we perceive the built environment.

To achieve a high level of aesthetics in the built environment, the creation of buildings and spaces with desirable visual qualities and a positive impact on the sensory and cognitive user experience should be reinforced. Visual qualities are based on universal values identified by interdisciplinary architecture research and widely accepted realisation practices. Formal qualities include order, contrast, transparency and novelty, and their appropriate compilation has a positive impact on visual richness. Beauty is also associated with pleasant sensory experiences for users that go beyond a sense of comfort, defined by interior temperature, light intensity, ergonomics, and basic functionality, as assessed by the target of health and wellbeing (Section 4.2.4). Research on human sensory perception describes the process of interaction between the environment and the observer through cognitive, emotional as well as physiological responses influencing spatial behaviour. We have become accustomed to giving priority to visual judgements and perception in evaluations of the built environment, somehow building up its superiority over auditory, olfactory, or tactile impressions. However, it has been proven that there is a close relationship between multisensory architectural and spatial experiences and the wider wellbeing of users has been identified (Spence, 2020). Aesthetic experience is concerned with combining feelings of pleasure and satisfaction in a coherent and complete way, and it is intended to engage with all senses through a variety of architectural means. Material and technological innovations can enrich the sensory experience and provide interactive and engaging stimulation, but do not determine the overall value of the aesthetic experience of architecture (Mallgrave, 2018). The intellectual and emotional factor of the perception of spaces and buildings is not less important. The cognitive aspects enrich the aesthetic experience and thus support a beautiful built environment.

4.2.8   Spatial coherence in planning and design

The concept of coherence is based on a spatial quality that results from the complex interactions among various elements within an urban structure. Urban space quality relies on morphological interactions, with strong connections at lower scales forming module-like units such as streets and blocks. These lower-level modules connect with higher-level ones to form a coherent space within a larger context (Salingaros, 2000). Spatial coherence in urban design is central to the design of successful and vibrant cities. Integrating spatial interventions into the urban pattern while preserving local identity improves the overall quality of the urban fabric, contributing to a sense of place and fostering a lasting connection between people and their environment. It is also of great importance that the designed interventions address challenges and opportunities in a way that considers the interconnectedness and interdependence of regions and localities. Efforts in this direction are important for the promotion of a more balanced and sustainable territorial development (Rodríguez-Pose, 2018).

4.2.9   Preservation of natural and cultural heritage

Heritage embodies the accumulated creative achievements of the past, and its preservation represents a responsibility of contemporary society. The recognition and maintenance of heritage should be integral to any development strategy, ensuring its relevance for future generations amidst the ongoing changes of the present. Given the emotional connection between people and their environment, a sense of place is an important factor in motivating people to act on behalf of their heritage and context (SFoC, 2021). However, achieving a high level of aesthetics in the built environment does not just mean protecting built heritage, but also integrating its substance and values in planning and building. Ensuring a high-quality urban environment is essential for the cultural vitality, economic development, and social welfare of cities and regions (UNESCO, 2005).

The landscape plays an important role in enhancing the quality of life and contributes to the cultural heritage of regions. It is a product of the interaction of natural and human factors, shaping local cultures and contributing to the European identity (Council of Europe, 2005). Historic urban landscapes, as representations of landscapes in historic areas, carry traces of current and past social expressions. These areas, including their surroundings, should be seen coherently, with a specific character deriving from the interaction of their parts. Contemporary architecture, when integrated into historic environments, should encompass planned interventions such as new buildings, extensions, and conversions, all contributing to the management of the historic urban landscape.

4.2.10   Genius loci and sense of belonging

The sense of belonging, a cultural motivation that drives human collaboration in creative efforts, is closely tied to the establishment and development of settlements in specific places that have profound meaning and significance. This connection extends beyond communities to encompass monuments, works of art, and historical cities. Significance, as an intangible quality that is sustained by material resources and environmental context, indicates the importance of recognising and preserving heritage. Genius loci emphasises that new developments must respect the existing urban fabric and preserve its qualities and characteristics, so that the place remains recognised for its heritage value over generations. The aim is to maintain the spirit or essence of a place, by recognising and preserving its characteristic features, emotional identity (elements with deeper meanings and emotional connections for its inhabitants), and other aspects within a natural or constructed environment (Norberg-Schulz, 1980; Garnham, 1985; Jackson, 1994). Hereby environment pertains to the ambiance shaped by human activities within a structure and its surrounding natural landscape. Work on a specific space should commence with a thorough examination and consideration of the unique spirit that characterises that place. By employing a sensitive adaptation process (Fusco Girard and Vecco, 2019), the genius loci of an existing building and place can be safeguarded.

4.2.11   Aesthetic perception of buildings and spaces

The target addresses the understanding of aesthetic perception of buildings and spaces through comparison to actual styles and tendencies. In architecture, the concept of style is widely used as a typological tool, the result of critical reflection focused on establishing similarities between buildings. In this context, it provides a useful indicator of coherence in the built environment. It is worth recalling, however, that contemporary architectural practices and theories react vividly to changing economic, social and political conditions and are both global and local disciplines. Their susceptibility to change, as well as the lack of universally recognised aesthetic canons and rules, makes it difficult to propose a unique stylistic and formal typology of trends present in contemporary architecture. Regardless of the style, it is possible to identify certain characteristics of a building/space such as unity, order, contrast, transparency and novelty that provide users with a positive visual and aesthetic experience. The arbitrary support of a chosen style can be seen as exclusionary (Hopkins, 2014). Therefore, existing building assessment standards do not use references to any particular style, but one can find references to the idea of biophilic design. The WELL v2 Building Standard (IWBI, 2020) uses biophilic design as a qualitative and quantitative metric. The qualitative metric must incorporate nature, natural patterns, and nature interaction within and outside of the building. For the quantitative portion, projects must have outdoor and indoor biophilia, as well as water features. The Living Building Challenge standard identifies the need to seek solutions in architectural design to intentionally incorporate nature into the fabric of buildings through environmental features, light, natural shapes and forms (MHCLG, 2020).

4.3 Selection criteria and list of KPIs

The NEB dimension of Beauty is strongly multidisciplinary and encompasses various and multifaceted approaches to achieve the set targets (Section 4.2) and to analyse the main aesthetic and quality of experience values. Hence, the first phase of the development of the method has involved identifying the most important areas of the Beauty dimension. The focus areas have been mapped selecting key definitions to establish a conceptual framework, along with guiding questions, formulated to define relevant aspects to be rated and assessed. 

In addressing these questions, a thorough review of existing policies, standards, guidelines, codes and well-established rating frameworks has been undertaken, leading to the identification of a comprehensive set of criteria and thresholds. Defining clear and measurable criteria to objectively assess aesthetic requirements has proven particularly challenging. Indicators and thresholds have been carefully selected to surpass national regulatory standards, aiming for best practices within the defined targets. This process initially yielded numerous potential indicators, which were subsequently rationalised, harmonised and condensed into a more manageable set by resolving duplications, interlinkages and overlaps among candidate indicators, including those from other NEB dimensions. The identification of these indicators has represented a pivotal step within the procedural framework. This set underwent testing on different case studies encompassing varying scales, contexts and project types. The results of these tests informed a second selection of indicators, which focused on their relevance, applicability and effectiveness.

This second stage has led to the final development of key performance indicators (KPIs), each one comprehensively evaluating a specific assessment target by combining interlinked indicators and metrics. The selection or exclusion of indicators was guided by their readiness and maturity, as well as their alignment with the NEB ambitions (European Commission, 2022). To this end, indicators were categorised as currently established and used within academia and industry, emerging indicators expected to be used in the near future, or novel ones which require more research to be regularly applied in the far future. Moreover, the ambitions of the NEB dimension of Beauty have been duly considered, namely to (i) (re)activate the qualities of a given context while contributing to physical and mental wellbeing, (ii) connect different places and people and foster a sense of belonging through meaningful collective experiences, and (iii) integrate new enduring cultural and social values through creation (European Commission, 2022). The final set of indicators underwent meticulous review and validation. The entire process has reflected a commitment to evidence-based development, ensuring that the developed KPIs are relevant, accepted, credible, easy to use, and robust, providing a structured framework for evaluating aesthetic and quality of experience aspects across diverse scenarios.

As a result of this process, the following key performance indicators have been developed for self-assessment within the Beauty (B) dimension:

B.1 Digitalisation in construction: the extent to which disruptive technologies are adopted, with a specific focus on the establishment of a collaborative working environment and the integration of digital technologies, premanufacturing and automation.

B.2 Quality of design and delivery: the extent to which high environmental performance and project quality are ensured through the engagement of actors with relevant experience and competencies, the responsible procurement of certified products, and the optimisation of the quantity of sourced materials.

B.3 Improving building resilience to extreme events: the extent to which the design considers the different natural and man-made hazards to which the project may be exposed, including the effects of climate change, ensuring that the building and its components are designed to resist them and that preparedness measures are taken to foster more effective emergency management and rapid restoration of project functionality post-disaster.

B.4 Ensuring occupant health, comfort and wellbeing: the extent to which the project design provides a healthy environment with adequate visual, thermal and acoustic comfort, supporting and promoting physical, social and mental health, and in which the users can easily cater to their needs, have a meaningful experience and thrive. 

B.5 Improving accessibility of the built environment for everyone: the extent to which the project space is adjusted to a large and varied group of potential users regardless of their ability or background, enabling non-discriminatory accessibility and movement through, around and between spaces, conveying spatial information to support the identification and comprehension of the environment and presenting easily usable and operable elements.

B.6 Maximising durability and service life: the extent to which the service life of building elements and components is maximised through the selection of durable products, the implementation of design considerations that accommodate substantial changes in user requirements and needs, and the promotion of ease of disassembly, reuse and recycling.

B.7 Ensuring high level of aesthetic acceptance of buildings and spaces: the extent to which the design solutions support and promote a positive sensory experience, both visual and non-visual, allowing acceptance of architecture and space and leading to support for the social, cognitive and emotional development of users. 

B.8 Providing spatial coherence in planning and design: the extent to which the project fits into its context, integrating the spatial transformation into its built and non-built environment, creating harmony, unity, and order, preserving, reusing or adapting existing spaces, including open ones, and ensuring compatibility with the surrounding setting.

B.9 Improving preservation of cultural and natural heritage: the extent to which cultural and natural heritage within the context of projects, including traditional cultivated landscapes and original, historic urban green areas, are protected and preserved for the benefit of present and future generations, maintaining their authentic character and visual integrity by adopting solutions that are aligned with best conservation principles, respectful of the heritage value and minimally invasive.

B.10 Maintaining genius loci and improving sense of belonging: the extent to which the emotional bond and attachment among community members is nurtured and the unique spirit of the place is identified and preserved, encompassing its characteristic features, the authenticity of the built and non-built environment, as well as all associated interactions and sense of identity, within the context of projects.

B.11 Understanding aesthetic perception of buildings and spaces through comparison to actual styles and tendencies in art and architecture: the extent to which the project including buildings and spaces presents clear distinctive features that allow categorisation according to specific styles and tendencies, based on their common linguistic form and cultural context, and features that provide users with a positive visual and aesthetic experience.

The KPIs together with the associated indicators and indicator weights (w_B.i.j) are provided in Table 47. The same table presents also the field of application and consideration of indicators according to the project classification based on scale, type, main use and relevance to cultural heritage. 

Additional information on each KPI is provided in Sections 4.4–4.14, including the rationale, background, calculation method, main actors involved, and input data needed for the evaluation. The calculation method addresses the evaluation of indicator scores, KPI scores and KPI performances classes according to Sections 2.2.1 and 2.2.2.

Table 47. Key performance indicators (KPIs) within Beauty.

¹        Although minimum KPI scores are not prescribed in the NEB self-assessment method, it is highly recommended that all KPIs reach the Acceptable performance class. 

²        In the case of renovation projects, the evaluation of KPIs B.1, B.2, B.3, B.4, B.5 and B.6 overall focuses on the specific aspects of buildings and spaces that are affected by the proposed intervention works. However, when indicators and/or metrics address aspects that are not altered by the renovation works, their evaluation should consider the as-built state (i.e. condition before the intervention is set).

³        Yes: Indicator applicable only to cultural heritage; No: Indicator non-applicable to cultural heritage; Not affected: Indicator applicable irrespective of cultural heritage.

⁴        The assessment should focus on representative building attributes within the neighbourhood or urban scale project. The user may assess a building that can represent on average the different attributes (or integrates the most dominant ones) within the project. Alternatively, the user may perform multiple assessments corresponding to distinct building designs representative of the building stock. In the latter case, the indicator score is estimated as a weighted average, with the weights obtained from the relative occurrence of each building design (in terms of number of buildings, built area, or other features).

⁵        Additional conditions apply.

⁶        In the case of B.9, users must decide utilising either indicators B.9.1 and B.9.2, or indicator B.9.3, based on whether cultural heritage buildings/spaces are legally protected or not.

Source: JRC.

The KPI performance class scores (PCS) assigned to all KPIs of the Beauty dimension, as a function of the attained KPI performance class and KPI score (Section 2.2.3), are provided in Figure 46.

Figure 46. KPI performance class scores (PCS) in the Beauty dimension.

Source: JRC.

The Beauty dimension score (B) (Section 2.2.4) is evaluated according to Equation (125). The number of the considered KPIs (m) within the equation depends on the project classification according to scale, type and main use (reported in Table 47). 

(125)

A variable weight (w_B.i), reported in Table 48, is assigned to indicators, selectively modifying the weight provided in Equation (126).

(126)

Table 48. Beauty key performance indicator weights.

Source: JRC.

The Beauty dimension performance class is assessed considering the dimension score and dimension thresholds according to Figure 47.

Figure 47. Beauty performance classes and thresholds.

Source: JRC.

Most indicators and thus KPIs in the Beauty dimension are designed to be implemented at all project spatial scales, types and main uses (Table 47). 

The evaluation of several indicators and/or metrics is affected by the project classification in terms of both project scale and type. When a project, classified into the neighbourhood or urban scale, involves several buildings with distinct design characteristics, thus likely leading to different indicator scores for each of them, the evaluation of the relevant indicator shall be carried out by identifying representative samples of buildings with similar design features. For each of them, a separate assessment shall be conducted. The overall average indicator score characterising the neighbourhood/urban-scale project is provided by weighting the evaluation of each specific typology by its relevance (e.g., number of occurrences) within the whole project. In the case of renovation projects, the assessment focuses on the specific aspects of buildings and spaces that are affected by the proposed intervention works. However, when indicators and/or metrics address aspects that are not altered by the renovation, their evaluation should consider the as-built state (i.e. condition before the intervention is set). 

On a few occasions, apart from the project classification (scale, type, use), some additional conditions apply for the implementation of an indicator. For example, B.2.3 is applicable when new floor systems are constructed either in newbuild or renovation projects (e.g. as part of the interventions works. Accordingly, the indicator is omitted in renovation projects that do not intervene in the floor system. When a renovation project, classified into the neighbourhood or urban scale, includes buildings with modified floor systems and buildings without such modifications, the two cases must be assessed separately, as two distinct projects. This is the same approach as the one followed when a neighbourhood/urban scale project includes both types (newbuild, renovation) and/or uses (residential, non-residential) (Section 2.3.2). In all these cases the project should be assessed as multiple ones addressing separately the different classes (e.g. newbuild and residential; newbuild and non-residential; renovation and residential; renovation and non-residential) at the scale of the complete project.

Context influences B.3 regarding the definition of the hazards expected to affect the buildings. Specifically, the assessment is governed by the combination of hazard characterisation and hazard resistant design which has the most significant negative impact on performance. Context further affects the renovation of heritage buildings in B.9, for which alternative formulations are provided depending on whether statutory protection is enforced or not.

4.4 Digitalisation in construction (B.1)

4.4.1   Description and assessment

Under Digitalisation in construction KPI (B.1) the following indicators are assessed:

• Collaboration and information sharing (B.1.1): the extent to which the adopted information management processes establish a collaborative working environment and foster the integration of digital technologies.
• Premanufacturing and automation (B.1.2): the extent to which construction adopts premanufacturing and preassembly processes, and pursues automation.

B.1 score is evaluated as follows:

(127)

The first indicator (B.1.1) measures the level of digitalisation and coordination among all stakeholders from conceptual design phases to construction, operation, and deconstruction. B.1.1 is strongly related to the implementation of BIM practices. BIM is likely the most used digital technology in the construction sector. Its consistent application is expected to produce positive returns on investment, with reduction of overall projects costs and significant optimisation of time, resources allocation and waste production (ECSO, 2021). Moreover, BIM solutions play an important role in facilitating the integration of additional disruptive technologies and methodologies. These include VR/AR, data-model integration and IoT, digital twinning, parametric and generative design as well as other AI-assisted tasks, across the lifecycle of the building. These methods can help architects, engineers, and construction professionals to significantly streamline the design process and reduce resource consumption (Fonseca Arenas and Shafique, 2023; Guignone et al., 2023). Therefore, the integration of these methods within the design and management processes is positively evaluated.

The second indicator (B.1.2) places emphasis on advancing automation, fostering materials innovation and promoting efficiencies from off-site, near-site, and on-site premanufacturing and preassembly. These initiatives are anticipated to drive greater efficiency and yield more consistent, defect-free outcomes by standardising products as well as prioritising repeatable, digitally aligned, manufacturing-oriented methods over labour-focused approaches. However, the indicator does not aim to exclude traditional craft-based methods which constitute an important legacy of European cultural and constructive tradition and may add intrinsic value to the building. The proposed metric serves as a proxy for evaluating the extent of integration into the project of technologies collected under the term of Modern Methods of Construction (MMC), as defined within the framework established by the UK Ministry of Housing, Communities & Local Government (MHCLG, 2019).

Figure 48 provides B.1 KPI thresholds adopted in the self-assessment method.

Figure 48. B.1 performance classes and thresholds.

Source: JRC.

The KPI and its two indicators are designed to be implemented at all project scales, types and main uses (Table 47). The assessment of B.1.1 requires the identification of the main methods and technologies integrated within the project, therefore, it is not affected by the project classification (i.e. scale, type main use).

In the case of B.1.2, the evaluation is conducted through estimation of the costs for the complete Bill of Quantities (BoQ) and Materials (BoM) (Donatello et al., 2021) including manufacturing, logistic, transportation, site labour and preliminaries. To make and manage a harmonised estimate and classification of BoQ and BoM during the design stage, the Level(s) inventory template (Donatello et al., 2021) may be adopted. B.1.2 evaluation is affected by the project scale and type.

When a project, classified into the neighbourhood or urban scale, involves several buildings with distinct design characteristics, thus likely leading to different indicator scores for each of them, the evaluation of B.1.2 shall be carried out by identifying representative samples of buildings with similar design features. For each of these representative building designs, a separate assessment should be performed. The overall indicator score for B.1.2 is then estimated as a weighted average of the separate assessment scores, with the weights obtained from the relative occurrence of each building design.

For renovation projects, there are no significant alterations in the assessment compared to newbuild projects. B.1.1 addresses the level of collaboration among actors and the integration of other digital methods and technologies in the renovation project design. In B.1.2, the estimation of the construction costs for premanufacturing and automation indicator comprises manufacturing and installation of new elements, components, parts and materials, but also alterations and deconstruction of existing elements.

The evaluation of the KPI is expected to be performed by the design team, comprising architects, structural engineers and service engineers, potentially seeking the advice of product manufacturers, and main and specialist contractors to identify emerging technologies that are beneficial to the project and produce a correct estimate of costs. The evaluation requires the identification and collection of the building design plans, architectural and structural design drawings, service plans, BoQ and BoM for the whole building(s) or the renovated section of the building(s).

4.4.2   Collaboration and information sharing (B.1.1)

The collaboration and information sharing indicator is evaluated through a dimensionless score, which varies between 0 and 100 based on the BIM maturity stages outlined in PAS 1192-2 (BSI, 2013b) and the ISO 19650-1 (ISO, 2018c). This indicator measures the level of sophistication of the information management processes and the extent to which they establish a collaborative working environment.

As the size and level of complexity of a project grows, the number of involved parties increases. This includes, but is not limited to, clients, owners, operators and managers of the built asset, the design team, construction team and manufacturers delivering the projects, policymakers, regulators, investors, insurers and other external parties (ISO, 2018c). During the whole lifecycle of an asset, these actors produce, exchange and use asset and project information in different forms and with distinct purposes but with a particular order. Digitalisation of such information has been a key driver of collaboration and coordination among distinct disciplines involved in constructing or managing a project (Baldini et al., 2019). Information models are containers of such structured (e.g. geometry, schedules and databases) and unstructured digitalised information (e.g. documents, videos and sounds) related to the delivery phase (i.e. design, construction and commissioning) and operational phase (i.e. operations and maintenance) (ISO, 2018c).

Upon achieving full collaboration or full integration, the indicator rewards the inclusion of disruptive technologies within the design and management processes. The scores are assigned according to the rationale presented in Table 49. The sum of the points cannot exceed 100.

Table 49. B.1.1 score.

¹        If no metric value is satisfied in a single or multiple selection, the assigned score is zero (0).

Source: JRC.

Within the NEB framework, a project characterised by a low collaboration is considered low performing. This is, for instance, when there is no sharing of digital information resulting in the production of non-interoperable or paper-based documents. A low BIM maturity (i.e. BIM stage 1) is achieved when digital 2D and 3D information is generated by the individual parties and disciplines but is managed separately by all involved actors. In the case of low BIM maturity, partial collaboration is obtained with a limited exchange of data through the adoption of an online shared repository as a common data environment. 

A medium BIM maturity (i.e. BIM stage 2) corresponds to a full collaboration across disciplines and specialities. The adopted information management processes are tailored to the specifics of the project and promote a strong collaborative working environment in which the production and exchange of data are coordinated between the parties. Not all the stakeholders operate on the same model. However, information produced through distinct discipline-based software, with different levels of interoperability, is exchanged in common file formats, producing a unified federate model compliant with the ISO 19650-1 (ISO, 2018c). This is stored in a single online shared repository, accessible, editable and maintained by all involved parties.

High BIM maturity (i.e. BIM stage 3) is a level in which deep collaboration among all project stakeholders is achieved through full integration of information into a single common shared model, which is centrally stored in a cloud-based environment. The structured database systems of the model are accessible, interrogable, and editable by all project participants, allowing them to work on and modify it simultaneously and in real time. This fully integrated information management process seamlessly follows the evolution of the project across each phase of its lifecycle, including design and construction, refurbishment, operations and maintenance.

Enhanced information management processes where agreed methods are adopted to produce standardised information with predetermined form, quality and delivery schedule, are expected to be beneficial to all involved parties, building a collaborative working environment (BSI, 2013b). Establishing a collaborative environment does not require additional work in terms of information generation and transfer, but implies mutual understanding and trust, as well as a high level of standardisation of the processes to ensure consistent and timely deliverables. Once effectively implemented, this approach ensures a beneficial reduction and anticipation of risks, in terms of costs, mistakes, delays and disputes among actors (BSI, 2013b; ISO, 2018c). BIM stands as the foremost method for generating and managing information models in the current market practices. BIM goes beyond the mere graphical description of the asset (BIM 3D) by incorporating layers of non-graphical information. This comprehensive approach facilitates scheduling and planning across all phases of the lifecycle, encompassing construction, operations, maintenance, and deconstruction. Furthermore, BIM extends its functionality to include the management of activities, costs, supply chains, energy and other critical resource consumption (Sacks et al., 2020). Therefore, higher BIM maturity is expected to result in an optimized quantity of generated information, tailored to specific uses and goals, to increase the reuse of this information and to mitigate the risk of data loss, inconsistencies and misinterpretations.

BIM has been shown to play a pivotal role in fostering the digital transformation of the construction sector, through the integration of other digital methods and technologies such as VR/AR, data-model integration and IoT, digital twinning, parametric and generative design. Recent developments highlight a clear shift away from static BIM models to digital twins that can help improve construction efficiency and reduce maintenance through virtual and augmented reality and IoT integration for continuous monitoring (Tuhaise et al., 2023). Digital twins can be employed to improve the quality and speed of decision-making, while significantly reducing errors. This enables rapid iterations and adjustments, resulting in innovative and refined designs. Digital twins can also help to identify and rectify errors early in the design phase, preventing costly mistakes and rework during construction and operation. By creating a real-time, virtual counterpart, digital twins provide a platform for rigorous analysis and simulation, enabling designers to assess the performance of construction materials and components under various conditions. This approach helps to identify potential flaws before they manifest in the physical world, leading to more robust construction practices and anticipating maintenance needs, which allows for timely corrections and mitigations (Opoku et al., 2021). An additional promising ability that digital twinning offers is dynamic life-cycle evaluation supported by past and present information. This allows an accurate end-of-life assessment that could be a key enabler for Circular Economy through component reuse (De Wolf et al., 2024; Brütting et al., 2019).

Parametric design and optimisation techniques are powerful tools to facilitate performance-based design as well as unlock innovative engineering and architectural solutions (Frangedaki et al., 2023). Through parametric design, a set of parameters and constraints can be varied enabling the rapid generation of diverse what-if scenarios that may lead to improved solutions in terms of key performance metrics (e.g. structural integrity, energy efficiency, and functionality) and may unlock innovative design concepts. Novel methods are emerging that make use of machine learning to reduce the computational time required for performance evaluation and behaviour prediction (Maureira et al., 2021; Asgarkhani et al., 2024), as well as mining and learning geometric and other key features that can be systematically encoded using knowledge graphs for the generation of new architectural and structural design (As et al., 2018; Płoszaj-Mazurek et al., 2020; Hayashi and Ohsaki, 2020). These approaches are particularly useful in conceptual design enabling AEC actors (e.g. architects, engineers) to focus on high-level performance targets (as defined in Section 4.2) that require an interdisciplinary and holistic approach.

Figure 49 shows the indicator thresholds used to link indicator scores with performance classes for B.1.1. While these thresholds and performance classes are not directly applied in the evaluation of KPI and dimension scores and performance classes, they are included here to assist users in determining appropriate performance levels for specific project aspects and to offer clear guidance on their improvement.

Figure 49. B.1.1 indicative performance classes and thresholds.

Source: JRC.

4.4.3   Premanufacturing and automation (B.1.2)

The premanufacturing and automation indicator is quantitatively evaluated through the premanufactured value (PMV_a) of the assessed project (Cast, 2021). This dimensionless score varies between 0 and 100, for an increasing number of processes that are not executed on the final location on site. Despite its simplicity, PMV_a has proven to be a good metric to quantify the trade-off between innovative and traditional processes, thus, it has been included into the UK Construction Sector Deal’s 2018 Implementation Plan as a primary measure for improvement in the construction industry (Cast, 2021).

PMV_a is calculated as the ratio of the premanufactured product and material cost (PMC) to the gross construction cost (GCC), expressed as a percentage.

(128)

PMC comprises the cost of raw material, manufacturing (including factory overhead, running, labour, plant and equipment cost), logistic and transportation of components to site. GCC comprises PMC, preliminaries (from main contractor and sub-contractors) and on-site labour costs (Cast, 2021; CLC, 2018). In GCC, non-construction cost, such as marketing, is not considered. ‘Preliminaries’ comprise items and expenses necessary to fulfil the terms of the contract that are not allocated to a specific building element or component, such as cost associated with management, staff, site establishment, utility supplies, security, safety and control, insurances, bonds, guarantees and warranties (CLC, 2018). Premanufacturing processes may be conducted off-site, near-site or even on-site, as long as controlled conditions are ensured. As the design evolves from conceptual to detailed, the PMV_a calculation may become more accurate, increasing the availability, granularity and reliability of the data (Jansen van Vuuren and Middleton, 2020). Upon the final definition of the BoQ and BoM, the PMV_a can be further broken down for the specific elements, components, parts and materials (Cast, 2021).

Increasing PMV_a in a project, thus reducing site labour and preliminaries intensity, is expected to enhance efficiency, predictability of the outcomes, productivity, quality, performance, speed, health and safety, while reducing waste, site overheads, cost, time and community disruption (Cast, 2021). Although no established methodologies exist to measure the level of construction automation, PMV_a is considered an informative metric. Indeed, following the definitions of the MMC (MHCLG, 2019), structural and non-structural additive manufacturing, away from or even at the final location on site, is considered a controlled manufacturing process whose costs should be included in PMC. Whereas, innovative site-based construction techniques and robot-assisted operations, although falling outside main premanufacturing categories, improve site-based processes, reducing material wastage, site labour, supervision and overhead cost, thus leading to a higher PMV_a (Cast, 2021; MHCLG, 2019). 

In the construction sector, the use of computer-controlled machinery for additive manufacturing, laser cutting and 3D printing of buildings, elements and components is still premature. However, these technologies hold significant potential for offering greater geometric flexibility while improving quality and speed of completion (Baldini et al., 2019). Their evolution is strongly linked with robotics, which boasts a wide-ranging scope, especially in construction, maintenance and deconstruction phases (ECSO, 2021). The advancement of robotics has facilitated the portability of machinery and devices capable of executing various operations on-site, such as welding, casting, bricklaying, assembly or disassembly, either autonomously or under direct operator control (ECSO, 2021). Similarly to additive manufacturing, their adoption remains relatively limited, however, it is steadily increasing (ECSO, 2021).

Performance thresholds for PMV_a may vary depending on the project scale. While some degree of onsite construction is typically required, such as for foundations, achieving complete automation and standardisation of processes is often hindered by the inherent diversity of products within the construction sector (Baldini et al., 2019). Experience in school projects, provided a qualitative three-level rating system with the medium class expected to have a PMV_a above 50% and the high class exceeding 70% (Jansen van Vuuren and Middleton, 2020). A study on residential houses, categorised in low (5 storeys or fewer), mid (6 to 9 storeys) and high rise (10 storeys or above), indicates an expected baseline PMV_a of 40%, and demonstrated that the implementation of premanufacturing processes and automation enables the attainment of target PMV_a values ranging from 55% to 60%, independently of the building category (Cast, 2021). Following this rationale, the indicator for premanufacturing and automation (B.1.2) is evaluated from PMV_a, according to Equation (129), which results in scores of B.1.2 = 40 for PMV_a = 40%, and B.1.2 = 100 for PMV_a ≥ 80%.

(129)

Figure 50 shows the indicator thresholds used to link indicator scores with performance classes for B.1.1. While these thresholds and performance classes are not directly applied in the evaluation of KPI and dimension scores and performance classes, they are included here to assist users in determining appropriate performance levels for specific project aspects and to offer clear guidance on their improvement.

Figure 50. B.1.2 indicative performance classes and thresholds.

Source: JRC.

4.4.4   Example (B.1)

In the following example a newbuild project type for residential main use is considered. The assessment is carried out at the building scale and no listed cultural heritage is affected by the project. During the delivery phase, the design team, comprising the architect, structural engineer and service engineers, focus on ensuring spatial coordination of the components realised off-site, simplifying their specification and manufacturing processes and preventing conflicts during assembly. Additionally, in collaboration with contractors and manufactures, the design team pursue an optimised planning and scheduling of the main construction processes, in terms of logistic, transportation and installation of premanufactured products as well as site labour. To achieve this, each party develops specific discipline models that are then integrated into a master model hosted in a shared common data environment. This full collaboration entails B.1.1 = 50. 

As shown in Table 50, the total capital cost for the housing project is EUR 3 000 000. Of this cost, 33% is labour cost, and 18% contractor preliminary cost. Premanufactured cost is estimated to be 49% of the capital cost, due to the off-site production in a controlled factory environment for the columns, beams and floor slabs for the structural system, and external walling products, which are all assembled on-site. This value of PMV_a corresponds to B.1.2 = 54. Accordingly, B.1 score is equal to 54 (Equation (127)), which corresponds to the Acceptable performance class (Figure 48) and a performance class score of 40 (Figure 46).

Table 50. Example of B.1 evaluation.

¹        Transformation of the indicator score to an indicator performance class is indicative and not required by the self-assessment method to estimate KPI and dimension scores and performance classes.

Source: JRC.

4.5 Quality of design and delivery (B.2)

4.5.1   Description and assessment

Under Quality of design and delivery KPI (B.2), the following indicators are assessed:

• Competencies of design team and contractors (B.2.1): the extent to which the project team has relevant skills and experience in delivering improved environmental performance and quality.
• Responsible material sourcing (B.2.2): the extent to which purchased construction products contribute to lower levels of negative environmental, economic and social impact.
• Compliance with material efficiency opportunities (B.2.3): the extent to which the design achieves more efficient use of material resources in structural elements.

In the general case when all indicators are considered, B.2 score is evaluated as follows:

(130)

The first indicator (B.2.1) focuses on the competencies necessary to deliver an environmentally improved product. With respect to the requirements in a standard tender process, this criterion values experience in specific technical areas relevant to the sustainability of the final outcomes. This includes expertise in managing technical innovations and utilising multi-criteria green/sustainability or resilience certification schemes, given their increasing prevalence. A competent team is expected to select and specify solutions that align with environmental criteria. The criterion does not aim to exclude companies with less experience and rather encourages their participation in projects with high environmental performance requirements. The goal is to balance risks and foster the project success by ensuring that design and construction teams comprise experienced professionals.

The second indicator (B.2.2) shifts the focus from the procurement of services to the procurement of goods. It promotes the specification and purchase of products with responsible sourcing certification over similar products without certification. Embedding ecological aspects in procurement policies and practices is expected to contribute to sustainable development (ISO, 2017c) and this indicator measures the commitment of the involved organisations to the principles of responsible sourcing.

The third indicator (B.2.3) evaluates whether a project is overdesigned by assessing the quantity of sourced materials in structural elements, thus promoting the optimisation and reduction of embodied resources. Load-bearing systems typically contain an important part of the mass and carbon embodied into the building, which is becoming more relevant also in terms of carbon emissions due to the improvement in the reduction of operational carbon (Röck et al., 2020). Therefore, this indicator provides an evaluation of the structural resource use intensity in the adopted design solutions. To simplify the quantification of this indicator, only floor systems are considered since they typically embody most of the building mass (van der Lugt et al, 2023) and are subjected to well-known loading conditions that are not significantly affected by exogenous factors. 

Figure 51 provides the B.2 KPI thresholds adopted in the self-assessment method.

Figure 51. B.2 performance classes and thresholds.

Source: JRC.

The KPI and its three indicators are designed to be implemented at all project scales, types and main uses (Table 47). The assessment of B.2.1 requires the identification of the main actors involved in the delivery and operational phases, therefore, it is not affected by the project classification (i.e. scale, type main use). B.2.2 and B.2.3 are evaluated from an estimation of the BoQ and BoM for the whole building (B.2.2) and the floor systems (B.2.3). To make and manage a harmonised estimate and classification of BoQ and BoM during the design stage, the Level(s) inventory template (Donatello et al., 2021) may be adopted. B.2.2 and B.2.3 evaluation is affected by the project scale and type.

For renovation projects, there are no significant alterations in the assessment compared to newbuild projects for B.2.2 that focuses on new products sourced for the proposed works. For renovation projects, B.2.3 is evaluated only when changes are made to the floor systems. Accordingly, when renovation projects do not include alterations to the floor system, B.2.3 is omitted according to Equation (131).

(131)

When a project, classified into the neighbourhood or urban scale, involves several buildings with distinct design characteristics, thus likely leading to different indicator scores for each of them, the evaluation of B.2.2 and B.2.3 shall be carried out by identifying representative samples of buildings with similar design features. For each of these representative building designs, a separate assessment should be performed. The overall score per indicator is then estimated as a weighted average of the separate assessment scores, with the weights obtained from the relative occurrence of each building design (in terms of number of buildings, built area, or other features). For example, when a neighbourhood/urban project includes multiple floor system types, B.2.3 is separately calculated for each system and the overall indicator score is determined as a weighted average of the different floor system scores, with the weights based on the area of each floor type as a percentage of the total gross internal floor area.

When a renovation project, classified into the neighbourhood or urban scale, includes buildings with modified floor systems and buildings without such modifications, the two cases must be assessed separately, as two distinct projects. This is the same approach as the one followed when a neighbourhood/urban scale project includes both types (newbuild, renovation) and/or uses (residential, non-residential) (Section 2.3.2). In all these cases the project should be assessed as multiple ones addressing separately the different classes (e.g. newbuild and residential; newbuild and non-residential; renovation and residential; renovation and non-residential) at the scale of the complete project.

The evaluation of the indicators is conducted by the design team, comprising architects, structural engineers, and service engineers, potentially seeking the advice of product manufacturers, main and specialist contractors, to ensure the traceability of products and materials across their supply chains (B.2.2) or identify feasible alternatives to optimise the design of the floor systems (B.2.3).

The assessment requires the identification and collection of the building design plans, architectural and structural design drawings, service plans, BoQ and BoM for the whole building or the renovated section of the building. For B.2.1, the CVs of the involved parties, official declarations and information related to relevant contracts in the previous years may be necessary to the self-assessor to carry out the indicator quantification.

4.5.2   Competencies of design team and contractors (B.2.1)

The competencies of design team and contractors indicator (B.2.1) is evaluated through a dimensionless score, varying between 0 and 100, based on the PPD (Directive, 2014) and the GPP (COM, 2008) project team competency criteria. The GPP criteria have been defined for office building design, construction and management; however, they are considered hereafter as generally applicable to any building type.

This indicator seeks to ensure that all parties involved in the delivery phase (i.e. design, construction and commissioning), and operational phase (i.e. operations and maintenance), have relevant competencies and experience in each of the technical areas that are relevant to their contractual obligations. Following the GPP approach, four main actors are considered separately due to their distinct roles, differences in the contractual relationships and required competencies: (i) project manager, (ii) architect, consultant and/or design team, (iii) main contractor and specialist contractors, (iv) design, build and operate (DBO) contractors and property developers. 

The qualitative requirements for contract awarding envisaged by the PPD are categorised as: (i) suitability to pursue the professional activity, (ii) economic and financial standing, (iii) technical and professional ability. The evaluation of these qualitative requirements within a tender procedure is a complex task, often entrusted to a panel with sufficient knowledge and experience to assess competing contractors effectively. Moreover, specific criteria and minimum requirements may be set by national legislation, depending on the size and characteristics of the projects. Therefore, for the scope of the self-assessment tool, a simplified procedure is proposed.

The suitability to pursue the professional activity of any party involved is evaluated with membership in national professional or trade registers. A list of relevant registers and corresponding declarations and certificates is provided in Annex XI of the Directive on public procurement (Directive, 2014).

Requirements concerning economic and financial standing aim to ensure that actors have the necessary economic and financial capacity to execute the contract. The combined capacity of the actors involved is demonstrated, for self-assessment purposes, through a turnover ratio (i.e. ratio of the annual revenue to the expected annual contract value) at least unitary for the three financial years previous to the contract. Moreover, the actors should be protected against third-party claims through an appropriate level of professional risk indemnity insurance. On the other hand, technical and professional ability ensures that actors have adequate human and technical resources and experience to perform the contract to an appropriate quality standard. Combined compliance of the parties involved with these requirements is achieved by holding satisfactory experience of at least four works of a similar size, nature and complexity performed in the five previous years. Project similarity is evaluated in terms of the percentage of the estimated project value. Additionally, an adequate average annual manpower employed in the previous years and specific tools, plant and other technical equipment are necessary and at least one member of the project management or design team must have at least seven years of experience in delivering similar projects. 

GPP shifts the focus of the assessment from the three classes of requirements to more environmentally related factors, defining two increasing levels of ambition. The core criteria aim to optimise the trade-off between capacity and economic investments, since the inclusion of green criteria typically entails higher upfront costs compared to standard solutions. Comprehensive criteria, instead, aim at higher innovation goals and more competencies are required. According to GPP, the actors should have relevant competencies and experience in each of the areas that are listed in Table 51, excluding the ones that are not relevant to the specific contract.

Table 51. Competencies and experience required of the main actors involved.

Source: Adapted from Dodd et al. (2016).

In the case of design and build contracts, the design team employed should be assessed under the design team criteria. Additionally, when the DBO contractors or property developers operate as facility managers of the building, they shall have certified experience, such as ISO 50001 (ISO, 2018a) or equivalent, in implementing energy management systems (Dodd et al., 2016).

Given the aforementioned PPD and GPP criteria, the scores are assigned according to the rationale indicated in Table 52. The sum of the points cannot exceed 100. For the assessment, the presence in the project team of actors who meet any one of the exclusion rules defined in Directive (2014) automatically results in a value of 0 for the indicator. 

Table 52. B.2.1 score.

¹        If no metric value is satisfied in a single or multiple selection, the assigned score is zero (0).

Source: JRC.

Figure 52 shows the indicator thresholds used to link indicator scores with performance classes for B.2.1. While these thresholds and performance classes are not directly applied in the evaluation of KPI and dimension scores and performance classes, they are included here to assist users in determining appropriate performance levels for specific project aspects and to offer clear guidance on their improvement.

Figure 52. B.2.1 indicative performance classes and thresholds.

Source: JRC.

4.5.3   Responsible material sourcing (B.2.2)

The responsible material sourcing indicator is quantitatively evaluated as the percentage of construction products from traceable and certified sources. Thus, the indicator varies between 0 and 100. The indicator aims at lowering the levels of negative environmental, economic and social impact, across the supply chain of products, including extraction, processing and manufacture, adopting sustainable development principles and practices in the provision, procurement and traceability of construction materials and components.

To eliminate the use of construction products originating from non-legal sources, a prerequisite of this indicator is that all components, parts and materials integrated in the building must be legally sourced. Failing to meet this requirement leads to a score equal to zero. This is particularly relevant for wood and wood-based products used permanently in the building, and temporarily during construction (e.g. formwork materials). These must be legally harvested and traded as demonstrated through certification schemes, such as those of the Forest Stewardship Council (FSC), the Programme for the Endorsement of Forest Certification (PEFC), the Forest Law Enforcement Governance and Trade (FLEGT), the European Union Timber Regulations (EUTR) or equivalent. Additional certificates may be needed in case of endangered species according to the Convention on International Trade in Endangered Species (CITES) (Dodd et al., 2016).

The BRE Environmental and Sustainability standard (BRE, 2016) provides a comprehensive framework for the assessment of sustainability aspects in the management and procurement practices of an organisation, defining a set of criteria with increasing performance levels. In the current absence of a European standardised method, an approach based on the supply chain management requirements reported in the BRE standard is adopted here as a transitional strategy for the assessment of the responsible material sourcing.

Based on the adopted approach, the assessment is conducted following the identification of the relevant building elements, components, parts, and materials, together with their respective quantities. Within the elements of BoQ, products are identified that are traceable through the supply chain and have an environmental management system in place. Quantities can be measured according to masses, volumes, or values, depending on the most appropriate measure for the assessed product. Consistency is crucial, and when the evaluation aims at driving the decision-making regarding multiple design solutions, the same measure should be consistently adopted in all alternatives.

In the self-assessment tool, products to be considered traceable and responsibly sourced require organisations involved at each stage of their supply chain, including raw material extraction and primary material production, to be certified by an accredited organisation according to ISO 9001 (ISO, 2024b). Moreover, such products must present an environmental management system certified by an accredited organisation according to standards such as ISO 14001 (ISO, 2024a), EU Eco-Management and Audit Scheme (EMAS), FSC and PEFC for wood and wood-based products, among others. Products and materials that are directly reused, fulfil responsible sourcing criteria even without a certification, whereas recycled and recovered ones require a certification for the reprocessing operations. In some cases, it is not possible to ensure the traceability across all the supply chain. In these cases, a possible future improvement of the assessment method consists in considering a different weight depending on the possibility of defining the certification of all or only the major aspects of processing, as currently adopted by some of the BREEAM ([1]) certification schemes.

Recommended thresholds for the percentage of construction products from responsible sourcing may depend on local, regional and/or national market factors (considering the scale of the project). Referring to wood and wood-based materials, GPP sets 25% as an easily achievable target and 70% as a more ambitious goal for public authorities (Dodd et al., 2016). The BRE Environmental and Sustainability standard (BRE, 2016), instead, sets three increasing levels at 60%, 75% and 90%. Considering these sources, Figure 53 shows the indicator thresholds used to link indicator scores with performance classes for B.2.2 in the NEB self-assessment method. While these thresholds and performance classes are not directly applied in the evaluation of KPI and dimension scores and performance classes, they are included here to assist users in determining appropriate performance levels for specific project aspects and to offer clear guidance on their improvement.

Figure 53. B.2.2 indicative performance classes and thresholds.

Source: JRC.

[1]        https://breeam.com.

4.5.4   Compliance with material efficiency opportunities (B.2.3)

The compliance with material efficiency opportunities is quantitatively evaluated through a dimensionless score, based on the material weight per floor area, which is denoted as g (kN/m²). This ratio serves as a measure of ‘lightness’ of structures and anthropogenic (technosphere) mass flows. 

Specifically, the assessment of B.2.3 focuses on the horizontal structural systems of buildings (i.e. beams and slabs). The influence of foundations, columns and walls is omitted. The design of these structural components depends significantly on a multitude of exogenous factors such as soil properties, ground water levels and expected actions, which would make the evaluation impractical. Importantly, floor slabs typically embody most of the building mass, estimated between 55 and 65% (van der Lugt et al, 2023), and thus offer a prime opportunity for resource optimisation. In addition, the design of floor systems, in most cases is based on established and well-known loading conditions that are not significantly affected from exogenous factors. Floor slabs are integral components of the structure, providing support for occupants, furnishings, and equipment. However, conventional floor slab designs may result in excessive material use, particularly in buildings with large spans or irregular shapes. 

B.2.3 indicator aims at the adoption and implementation of strategies to ensure a reduction of material use in the horizontal structural elements. This, in turn, has a beneficial impact in terms of carbon emissions, resource consumption and energy embodied in the building. The estimation of embodied GHG emission into products and processes across the whole life cycle of the building is covered by S.3.2 indicator in the Sustainability dimension, complementing this indicator towards the efficient use of materials and resources.

Preliminary benchmarks have been collected from recent studies (Hart et al., 2021; Svatoš-Ražnjević et al., 2022; Belizario-Silva et al., 2024), which focused on the evaluation of superstructure systems for a variety of material options. Additional information was taken from a survey of 518 buildings (De Wolf et al., 2020), which reports material use intensity considering different structural systems. Since the identified thresholds are not well established, an independent investigation has been conducted for the development of this indicator.

According to this investigation, material usage estimation was carried out for reinforced concrete, timber, and composite floor slabs. Selected construction technologies for each construction material are briefly described in Table A. 1. The selection was based on the degree of maturity of the construction technology, ease of construction and common use in practice. 

A multi-span sample area (28 · 21 m = 588 m²) and two different layouts for supports were considered, as illustrated in Figure 54. For reinforced concrete and composite slabs, spans of 7 · 7 m and 7 · 14 m were considered, respectively, while for timber slabs, the spans were reduced to 6 · 6 m and 6 · 12 m in line with existing construction technologies and good design practice (Schneider et al., 2024). For each construction technology, the slab self-weight along with additional permanent (g₂) and imposed loads (q) were estimated. Loading scenarios with g₂ + q ranging from 4 to 7 kN/m² were considered as lower and upper bounds respectively, complying with the design prescriptions of Eurocode 1 – Part 1-1-1 (CEN, 2002a) for most residential and commercial buildings. Assumptions for the material properties were made for each slab configuration. The material designation intends not only to ensure effectiveness for each floor construction technology, but also reflect a typical implementation, avoiding material classes addressed to special structures. A minimum storey height of 2.6 m and a minimum structural fire resistance class of R60 (CEN, 2002b) were considered for all combinations of material, support layout and construction technologies.

Figure 54. Slab support layout: (a) A · B = 7 · 14 m for reinforced concrete and composite systems and A · B = 6 · 12 m for timber systems; (b) A · B = 7 · 7 m for reinforced concrete and composite systems and A · B = 6 · 6 m for timber systems.

(a)

(b)

Source: JRC.

The investigation resulted in detailed maps of floor slab self-weight versus the employed construction technology and main span, as presented in the box plot of Figure 55 for reinforced concrete, Figure 56 for timber, and Figure 57 for composite floor systems. The floor slab cross-sections are detailed in Table A. 1.

Figure 55. Structural resource intensity for concrete slabs (C25/30, C50/60).

Self-weight g [kN/m²]

Source: JRC

Figure 56. Structural resource intensity for timber slabs (C24, GL24h, GL28h, LVL).

Self-weight g [kN/m²]

Volume / Area [m³ / m²]

Source: JRC

Figure 57. Structural resource intensity for composite slabs (concrete C25/30, C50/60; steel S235, S355; timber C24, GL24h).

Self-weight g [kN/m²]

Source: JRC

For timber floor slabs, a metric of material volume per floor area (in m³/m²) is added as a secondary vertical axis, since it is commonly used in practice. However, B.2.3 score for self-assessment is based on the self-weight g. The conversion to material volume per floor area is approximate, considering a density of timber equal to 415 kg/m³ that is the average value of C24 timber (350 kg/m³) and laminated veneer lumber (LVL) (480 kg/m³). 

For composite floor slabs, a homogenisation coefficient (a) was employed to convert the weight contribution of other materials to concrete-equivalent values. For a generic material, the homogenisation coefficient is given as:

(132)

where, E and ρ are the Young’s modulus and density, respectively, for a generic material (i) and concrete (c). Referring to the materials considered in this investigation, for concrete-timber composites, a takes values in the range of 1.9–2.5. The lower value was obtained using C50/60 concrete and LVL, while the upper value using C25/30 concrete and C24 timber. For concrete-steel composites, a takes values in the range of 1.8–2.2. Lower and upper bounds were obtained using C50/60 and C25/30 concrete, respectively. The steel Young’s modulus and density did not vary with the considered steel grades (i.e. S235 and S355). The concrete specific weight was set to 25 kN/m³ regardless of the class.

From the carried-out investigation, it is possible to identify lower and upper bounds of the slab self-weight g for each material, denoted as g_lb and g_ub, respectively. These correspond to the value of the performance classes Excellent and Low indicated in Table 53. 

Table 53. Performance classes expressed in material weight g in kN/m² for concrete, timber and composite floor systems.

Source: JRC.

The score of B.2.3 is evaluated using a linear interpolation between the bounds, according to Equation (133). Lower and upper score bounds are B.2.3_lb = 30 and B.2.3_ub = 80, whereas the slab weight bounds are indicated in Table 53 for each considered material (g_lb, g_ub). Figure 55–Figure 57 may provide a range of g values as a function of the slab construction technology, main span and material at the early stages of design to evaluate alternative design solutions and improve the indicator score.

(133)

The indicator score bounds have been chosen so that the application of standard practice is expected to result in the Acceptable performance class (Figure 58). Thoughtful design choices in the support distribution and floor shapes enable efficient material use, when common and economical construction technologies are adopted. On the other hand, when programmatic and architectural choices favour large spans for functional reasons (i.e. to improve circulation, daylight penetration, etc.), high performance structural solutions become essential to minimise material consumption.

Higher performance classes can be achieved by employing more advanced design workflows that include parametric design and structural optimisation. Among innovative construction technologies that have a good potential are functionally graded concrete slabs, i.e. slabs with optimised gradient of porosity obtained by placing mineral void formers in the cross-section (Schmeer and Sobek, 2018). This can be thought of as an optimised variant of a voided biaxial slab using mineral void formers, which facilitates recycling compared to conventional solution using plastic void formers (Nigl et al., 2022). This technology has been applied to the design of the foundation and basement slabs of the new Large-scale Construction Robotics Laboratory (LCRL) at the University of Stuttgart (Haufe et al., 2024).

Vaulted floor systems (Hawkins et al., 2019) and rib-stiffened funicular floor systems (Rippmann et al., 2018) are innovative solutions that draw on experience of Gothic master builders, comprising double curved shells and post-tensioned ties between the slab corners to sustain the horizontal thrusts. These solutions are being reconsidered thanks to digital fabrication methodologies that ease construction feasibility of systems characterised by a more complex geometry than conventional flat slabs. Material savings exceeding 50% have been reported compared to conventional flat slabs (Liew et al., 2017).

An emerging approach to structural design involves the strategic integration of sensors and mechanical actuators to design structural systems that can counteract actively the effect of loads. The effect of actuation can be employed to redirect the stress from critically loaded components and reduce deformations. This approach is particularly effective for stiffness-governed design problems, e.g. tall and slender buildings, and long-span floor systems and bridges. Numerical and experimental tests have demonstrated that well-designed adaptive structures, including floor systems, can achieve material and associated emission savings exceeding 50%, compared to equivalent optimised passive solutions (Blandini et al., 2022; Reksowardojo et al., 2024; Senatore and Wang, 2024).

In the box plot map of Figure 55, emerging technologies for concrete slabs are reported on the right side of the dashed line. For vaulted floor systems, values are adapted from a structural design developed by ARUP and Laing O’Rourke on a 9 · 9 m layout (Scott, 2022). The adaptive ribbed slab is an experimental design developed at the University of Stuttgart that uses active tendons integrated in the ribs to counteract the effect of superimposed dead and live load (Reksowardojo et al., 2024). Further information about these systems is given in Table A. 1.

Figure 58 shows the indicator thresholds used to link indicator scores with performance classes for B.2.3. While these thresholds and performance classes are not directly applied in the evaluation of KPI and dimension scores and performance classes, they are included here to assist users in determining appropriate performance levels for specific project aspects and to offer clear guidance on their improvement.

Figure 58. B.2.3 indicative performance classes and thresholds.

Source: JRC.

4.5.5   Example (B.2)

In the following example a renovation project type for non-residential main use is considered, namely the structural design of a new multi-span 28.0 · 21.0 m concrete slab for an existing office building. The assessment is carried out at the building scale and no listed cultural heritage is affected by the project. A project team involved in the structural design of a multi-span 28.0 · 21.0 m concrete slab for an office building consists of the following members: (i) project manager; (ii) architect; (iii) civil engineer; (iv) main contractor.

All the parties are qualified to pursue the professional activity, as demonstrated by their enrolment in national professional or trade registers. The economic and financial standing is demonstrated through a ratio of the annual revenue of the involved parties to their annual contract value higher than one, in the last three years. Moreover, the parties are protected by professional risk indemnity insurances with an appropriate liability limit to provide coverage against claims for loss or damage in the specific current work. The technical and professional capacity of the team is demonstrated through participation in the previous five years in more than four works of the same nature and complexity and with values equal or greater than the value of the current project. Finally, the project manager has more than ten years of experience in delivering similar projects. These criteria are considered sufficient in the self-assessment to satisfy the PPD criteria (Directive, 2014) for both the design team (+25) and contractors (+25). Moreover, the project manager satisfies the comprehensive GPP criteria (+30), having experience in the design of environmentally efficient buildings, as demonstrated by works delivered in the previous five years, expertise in LCA analysis, and certification in well-established multicriteria rating schemes. Other members do not have any specific demonstrable competencies in green technologies, design or construction. Considering this consortium, B.2.1 equals 25 + 25 + 30 = 80 (corresponding to Excellent performance according to Figure 52).

Initially, the team designs a uniaxial slab (Design alternative 1, in Table 54). The slab is supported on beams and has spans of 7.0 and 14.0 m having a layout of column support as shown in Figure 54a. The design is carried out considering a permanent additional load of g₂ = 2.0 kN/m² and an imposed live load of q = 3.0 kN/m². The design results in 300 m³ of concrete, expected to be cast in place. 

60% of concrete (in terms of volume), including recycled materials, is purchased from organisations with a certificated environmental management system. Accordingly, B.2.2 score is equal to 60 (corresponding to a Good performance class according to Figure 53). The design solution is estimated to require a concrete usage per unit area of g = 12.7 kN/m². Using Equation (133), B.2.3 score is given by:

(134)

(achieving Low performance, according to Figure 58). From Equation (130), B.2 score is given by:

(135)

which corresponds to a Low performance class (Figure 51) and a performance class score PCS_B2 = 0 (Figure ).

Then, the project team designs a second configuration (shown in Figure 54b), characterised by a point-supported flat slab with a 7.0 · 7.0 m column grid. For this configuration, the expected volume of concrete reduces to 150 m³. Considering the same percentages of responsibly sourced materials, B.2.2 is kept as 60, whereas the concrete usage per unit area reduces to g = 6.3 kN/m², corresponding to a B.2.3 score of 57 (thus, a Good performance class). Combining the three indicator values, B.2 scores is equal to 65, corresponding to an Acceptable performance class and a performance class score PCS_B2 = 40. 

The flat slab solution with reduced column spacing performs well, however, the developer perceives a potential value decrease due to a lower space flexibility. The project team designs a third alternative solution with a bidirectional voided slab on 7.0 · 14.0 m bays (configuration shown in Figure 54a). Compared to the first solution, the expected volume of concrete reduces to 188 m³ (-37%), with a material usage of g = 8 kN/m², corresponding to a B.2.3 score of 43. Keeping the same sourcing requirements for indicator B.2.2, B.2 score is found equal to 59, which corresponds to an Acceptable performance class and a performance class score PCS_B.2 = 40.

Table 54. Example of B.2 evaluation.

¹        Transformation of the indicator score to an indicator performance class is indicative and not required by the self-assessment method to estimate KPI and dimension scores and performance classes.

Source: JRC.

4.6 Improving building resilience to extreme events (B.3)

4.6.1   Description and assessment 

The Resilience to extreme events KPI (B.3) looks to evaluate the extent to which the project is resilient to the multiple hazards that can affect it, through the use of three indicators: 

• Hazard characterisation (B.3.1): evaluates the reliability of the hazard estimates used in the project design, for all hazards that may affect the project.
• Hazard resilient design (B.3.2): evaluates the reliability of the approach used for the hazard resistant design of structural systems, and what measures are implemented by the design to limit damage and promote rapid recovery.
• Consequence mitigation (B.3.3): extent to which the project design implements measures in place to mitigate the consequences of extreme hazards on functionality and on the user community.

To evaluate B.3, the assessor must first identify which hazards can affect the project. In the NEB self-assessment method, the man-made hazards of fire and blast are considered, together with the following natural hazards: wind, floods (riverine and coastal), earthquakes, landslides, volcanic ash and tsunami. Volcanic hazards other than ashfall are not considered, as it is not safe, nor cost effective, to design buildings to resist other volcanic hazards, such as lahars. For the selected natural hazards, established methods for hazard intensity calculation and numerous hazard maps can be sourced in codes of practice and the global literature. Design codes and/or guidelines exist for design against the chosen hazards, even if not in all countries.

Table 55. Identification of hazards affecting the project.

Source: JRC.

B.3.1 and B.3.2 indicators are evaluated separately for each hazard according to adherence with best-practice design guidance, and beyond best-practice standards and guidance. B.3.3 is hazard independent and includes aspects of community and organisational preparedness, evacuation as well as considerations of project function continuity post hazard event. B.3 and the associated indicators can take values between 0 and 100. B.3 score is evaluated according to Equation (136):

(136)

Equation (136) differs from the general form of Equation (2) with regard to the calculation of the first two indicators. Specifically, the values of B.3.1 and B.3.2 that enter Equation (136), correspond to the hazard (h) (among the n considered hazards of Table 55) that minimises the sum of the two indicators:

(137)

Finally, the performance class of B.3 is assessed, according to the thresholds in Figure 59.

Figure 59. B.3 performance classes and thresholds.

Source: JRC.

The KPI and its indicators are designed to be implemented at all project scales, types and main uses (Table 47). The KPI is influenced by the context regarding the identification of hazards expected to affect the projects. The assessment of B.3.1, B.3.2 and B.3.3 is affected by the project scale and type.

When a project, classified into the neighbourhood or urban scale, involves several buildings with distinct design characteristics, thus likely leading to different indicator scores for each of them, the evaluation of B.3.1, B.3.2 and B.3.3 shall be carried out by identifying representative samples of buildings with similar design features. For each of these representative building designs, a separate assessment should be performed. The overall score per indicator is then estimated as a weighted average of the separate assessment scores, with the weights obtained from the relative occurrence of each building design.

For renovation projects, the assessment focuses on the specific aspects of the building and spaces that are affected by the proposed renovation works. However, when indicators and/or metrics address an aspect that has not been altered by the renovation, their evaluation should consider the as-built state (i.e. condition before the intervention is set), as this contributes to the building resilience to extreme events. 

The evaluation of the indicators within B.3 KPI is conducted by the design team, comprising architects, engineers and service engineers, seeking the advice of specialist engineers in hazard-resilient design, device manufacturers, main and specialist contractors. The assessment requires the following information to be identified and collected:

• Standards, guidelines and certification scheme documents, as well as any national standards relevant to hazard resilient design. International building codes and standards may need to be sourced if national codes and standards do not exist for a hazard deemed relevant to the project.
• Hazard maps and past hazard event footprints, for identification of hazards of relevance to the project site.
• Detailed information on the procedures followed by the design and engineering team for determining the hazard intensities at the site of the project.
• Detailed information on the design approach followed for the hazard-resilient design of the project.
• Plans of services and information on any back-up systems for water, electricity, gas, their capacity and location.
• Detailed plans of the buildings including information on storage of hazardous materials where relevant.
• Details of insurance policies for insuring against damage from hazards.
• Information on evacuation training of staff and users of the project, evacuation plans and drills.

4.6.2   Hazard characterisation (B.3.1)

The hazard characterisation indicator (B.3.1) evaluates the reliability of the hazard estimates used in the project design, for all hazards that may affect the project. 

A value of B.3.1 is evaluated for each hazard i, among the n identified to be of relevance to the project (Table 55). These hazard-specific indicator values, B.3.1_i, are retained for use in the calculation of B.3. The score for each B.3.1_i cannot exceed 100. On some occasions, next to the metrics of the indicator, a “non-applicable” option exists, so that users can indicate that the specific metric is not relevant to the project attributes. If the non-applicable option is selected (when available), the full metric score should be considered in the evaluation of the indicator score, to avoid penalising a project due to non-relevant aspects. 

Indicative performance classes for the indicator scores are provided in Figure 60. While these thresholds and performance classes are not directly applied in the evaluation of KPI and dimension scores and performance classes, they are included here to assist users in determining appropriate performance levels for specific project aspects and to offer clear guidance on their improvement.

Figure 60. B.3.1 indicative performance classes and thresholds.

Source: JRC.

Table 56 to Table 62 provide the score evaluation of B.3.1_i score for all hazards. For natural hazards, the indicator B.3.1 focuses on the reliability of the estimated hazard intensity measure (IM) for the project. An IM is defined as a measurable characteristic of the hazard that can be used to calculate the forces and actions for the project engineering design. For example, wind speed is an IM, as it is a measurable characteristic of wind and is used in the calculation of pressures acting on structural components. Codes of practice can define one or more IM values for design, each associated with a different mean recurrence interval (MRI) (also called return period). MRI is representative of the average time between occurrences of the IM value at a site. Hence, a high MRI value corresponds to a rare hazard occurrence and a high IM value. Building codes use MRI to set limit states (or performance levels) for the design of buildings with different occupancy and importance. At a minimum, they define a high MRI (and associated IM) for the ultimate limit state design of a building. More commonly, modern hazard-related building codes recommend the explicit consideration of multiple limit-states and hence define multiple MRIs for the design (Fardis, 2013). For example, in Europe, Model Code 2010 (fib, 2012), EN 1998-1 (CEN, 2004) and draft of the next generation of Eurocode 8–Part 1, respectively define 4, 3 and 4 limit states for design against earthquake hazards. In the case of European building codes, some flexibility can be included to allow each EU member state to define the minimum number of limit states to be explicitly checked. Designers can, however, choose to adopt more performance levels than the minimum number defined in their national code. The number of limit states used in the project is relevant to the reliability of the hazard resilient design (i.e. to B.3.2, where design for more limit states results in a more reliable performance of the project against the hazard). However, as a consistent approach is used for estimating IM values at different MRI, the number of limit states used in the design is not relevant in the evaluation of hazard reliability.

In the design of a project, use of a single hazard event scenario for the determination of IM value (i.e. a deterministic hazard assessment) is not recommended, as it ignores the multiple hazard sources that may affect the project, and hence does not allow a reliable MRI to be associated with the IM value. For most hazard types, probabilistic hazard maps exist that provide IM estimates for given MRI values. These are based on probabilistic hazard assessments that account for multiple sources of aleatory and epistemic uncertainty in the IM estimation. Most modern codes of practice include such hazard maps, which are commonly developed by national entities, such as geological surveys or meteorological offices. 

In general, an Acceptable performance class for B.3.1_i can be achieved if the project design adopts hazard IM estimates derived from code-based hazard maps, e.g. seismic zonation and wind speed maps. However, for some hazards, such as floods, landslides, volcanic ash and tsunami, probabilistic hazard maps may not be available in building codes, as national building codes may not include these hazards in standard design practice. In such cases, probabilistic hazard maps from national entities or from reputable academic literature may be used in designs, leading to an Acceptable performance class. It should be noted that although probabilistic hazard assessment techniques are well-established for some hazards (e.g. earthquakes and wind), they are less well developed for other hazards (e.g. tsunami and landslides). Hence, the use of multiple deterministic hazard scenarios obtained from reputable scientific studies may also be adopted in the absence of any reliable probabilistic hazard studies. However, in the case of design for special structures (e.g. those with high occupancy, those used as evacuation shelters, or those providing critical services in the aftermath of a hazard event) the development of a bespoke probabilistic hazard assessment is desired. 

For all hazards considered, higher indicator scores are obtained where bespoke data and hazard models are used in the IM evaluation. In the case of bespoke hazard models, it is expected that the topographical, bathymetric or urban arrangement features that are likely to increase the hazard intensity at a site are accounted for in the IM calculation. If they are not, a lower score will be obtained. Neglecting, in the IM calculation, specific mitigation measures (e.g. coastal defence, enhanced landslide drainage, etc.) in surrounding areas that may reduce the hazard intensity at the project site, is conservative. Hence, this is not included as part of the B.3.1_i scoring criteria. 

Physics-based models of the hazard can be used to develop probabilistic hazard assessments, and usually are used to simulate the value of an IM at a project site, the IM time history, and other characteristics of the hazard (e.g. other IMs). These physics-based models take different forms for the different hazard types. For example, for landslide hazard assessment, physics-based models are based on simple mechanical laws used to describe the physical processes leading to the landslide event and the resulting landslide characteristics (Pardeshi et al., 2013).

If the effects of climate change are likely to increase the hazard, then they should also be accounted for in the IM calculation to ensure the resulting design is resilient to future climate scenarios. A higher indicator score is therefore achieved if the IM estimates include climate change effects. Climate change projections are used as input to hazard models for floods and wind (e.g. Zscheischler et al., 2018). The Intergovernmental Panel on Climate Change (IPCC) publishes various scenarios for the Earth’s future climate and associated effects. The IPCC scenarios are widely used by the global climate change research community and are defined based on possible future trends in GHG emissions. IPCC presents the latest version of these scenarios, which include, for example: (i) the ‘ambitious’ scenario, with a climate policy aimed at reducing GHG, resulting in emissions declining to net zero by about 2075, and becoming negative after that (RCP2.6 or SSP1-2.6 scenarios in IPCC, 2022), (ii) the ’transition‘ scenario, with a climate policy aimed at stabilising GHG emissions, characterised by a slight rise in emissions before they decline after 2050, but do not reach net zero by 2100 (RCP 4.5 or SSP2-4.5 scenarios in IPCC, 2022), and (iii) The ‘business-as-usual’ scenario, whereby emissions rise steadily, doubling by 2050 and more than triple by the end of the century (RCP 8.5 scenario in IPCC, 2022. These scenarios of emissions provide the input parameters to large scale climate models (e.g. atmosphere-ocean general circulation models, see for example Wigley and Raper, 2001). The climate models are then downscaled to provide finer resolution data for IM assessment at the project site. The downscaling can be carried out either by using empirical relationships between global and regional climate models, or by using higher resolution regional climate models with boundary conditions taken from the larger scale models (Fowler et al., 2007). The downscaled models are used to simulate values for dynamic weather variables, from which the IMs are determined. The simulation is repeated at different time steps in the future (commonly up to 50 or 100 years in the future), to generate frequency exceedance curves for the IM (Cremen et al., 2022).

Extreme hazards can impact a project at the same time as other common hazard effects. Accounting for these in the design is important for the consideration of the full range of scenarios in the resilience assessment. A number of key guidelines, standards, databases and other indicator systems have been consulted to form the basis of B.3.1 indicator. These include ASCE (2020, 2022, 2023b), BAT-ADAPT (OID, 2020), Building Resilience Index (International Finance Corporation, 2023), European Soil Data Centre ([1]), FEMA (2007, 2011b, 2013, 2020), Florida Building Code (International Code Council, 2020), Government of Netherlands (2020), NASA global landslide catalog (NASA, 2019), REDi Floods (ARUP, 2023), REDi Extreme windstorms (ARUP, 2022).

In the case of the man-made hazards, designing for fire and blast does not necessarily require a reliable estimate of the hazard intensity. Instead, design approaches focus on promoting hazard avoidance, providing hazard containment, and limiting the likelihood of progressive failure within structures. In the evaluation of B.3, the values of B.3.1 for blast and fire should take on the same value as the scores achieved for B.3.2 for the respective hazards (Table 62).

Table 56. B.3.1 score for wind hazard.

¹        If the non-applicable option is selected (when available), the full metric score is considered in the evaluation of the indicator score.

²        For windborne debris, simplified methods in codes of practice can be used to assess possible impacts.

Source: JRC.

Table 57. B.3.1 score for flood (coastal and riverine) hazard.

¹        Water-borne debris hazard assessment in Urban environment can be conducted as per ASCE/SEI 7-22 Supplement 2 (ASCE, 2023a) section 5.3.9.1.2, FEMA 543 (FEMA, 2007), FEMA P-55 (FEMA, 2011b), or other simplified approach.

Source: JRC.

Table 58. B.3.1 score for earthquake hazard.

Source: JRC.

Table 59. B.3.1 score for landslide hazard.

Source: JRC.

Table 60. B.3.1 score for volcanic ash hazard.

Source: JRC.

Table 61. B.3.1 score for tsunami hazard.

¹        Both the Energy Gradeline Analysis in ASCE/SEI 7-22 chapter 6, and numerical inundation models can take into account any amplifying effects of inundation from topography.

Source: JRC.

Table 62. B.3.1 score for fire and blast.

Source: JRC.

[1]        https://esdac.jrc.ec.europa.eu.

4.6.3   Hazard resilient design (B.3.2)

The hazard resilient design indicator (B.3.2) evaluates the reliability of the approach used for the hazard resistant design of structural systems, and what measures are implemented by the design to limit damage and promote rapid recovery. Indicative performance classes for the indicator scores are provided in Figure 61. While these thresholds and performance classes are not directly applied in the evaluation of KPI and dimension scores and performance classes, they are included here to assist users in determining appropriate performance levels for specific project aspects and to offer clear guidance on their improvement. A value of B.3.2 is evaluated for each hazard (i), among the n identified to be of relevance to the project (Table 55). The scoring system for each considered hazard is presented in Table 63 to Table 70, and the score for each B.3.2_i cannot exceed 100. On some occasions, next to the metrics of the indicator, a “non-applicable” option exists, so that users can indicate that the specific metric is not relevant to the project attributes. If the non-applicable option is selected (when available), the full metric score should be considered in the evaluation of the indicator score, to avoid penalising a project due to non-relevant aspects.

Figure 61. B.3.2 indicative performance classes and thresholds.

Source: JRC.

Unlike some rating systems (e.g. Building Resilience Index for wind, International Finance Corporation, 2023), the design in the NEB method is not assessed against its performance under a recommended value of IM. Instead, scoring for the hazard resilient design indicator refers either to the national code of practice and/or international best practice code used for the project design. The indicator first seeks to evaluate whether and how the project meets or exceeds the performance criteria set out in the code. As stated in Section 4.6.2, many modern hazard-related building codes are performance-based and recommend that the performance of the project is checked at multiple hazard intensity values, each corresponding to a different MRI value (Fardis, 2013). For example, a code may specify that a building should sustain no damage to its structural elements when subjected to an IM value that occurs very frequently (i.e. at low MRI), and that collapse is avoided for IM values that occur very infrequently (i.e. MRI is very high). The use of performance-based design allows for a more tailored approach, whereas it is needed where prescriptive guidance is not available (e.g. for special structures), and it allows implementation of new technologies. The minimum MRI values associated with each limit state can be defined differently for structures with different functions, importance and occupancy. For example, for a given performance objective, the MRI value assigned to a hospital (which should remain operational after an extreme hazard event) is higher than for a normal residential building. As a consequence, hospitals must satisfy the same limit states as residential buildings, but at higher hazard IM values. 

In the case of European building codes, some flexibility is included to allow each EU member state to define the minimum number of limit states to be explicitly checked but life-safety performance must always be checked. Non-compliance with the minimum performance checks stated within national hazard codes (or best international practice if a national code does not exist) results in a score of zero being assigned to B.3.2. Designers can choose to adopt more limit states than the minimum number defined in their national code. This results in a higher indicator score as multiple performance checks result in a more reliable and predictable structural performance, but not a more resilient structure. Higher scores for B.3.2 are also achieved when more advanced, state-of-the-art methodologies are used to design the structural components against the hazard, again providing greater reliability in the structural performance.

To this point, performance-based codes that set minimum (prescriptive) MRI for each performance objective included in the code, have been discussed. However, a designer, in consultation with a client and users, may also decide to set higher performance objectives for their project than those required by the code for the use, occupancy and importance of their project. Design to higher hazard levels will result in a reduction in structural and non-structural damage, facilitating faster recovery of functionality post-hazard event, and hence is given a higher indicator score. Higher scores are also achieved for projects that explicitly consider the safety of non-structural components and mechanical, electrical and plumbing (MEP) system performance. These measures reduce the loss of life during a hazard event and allow the rapid restoration of functionality after a hazard event.

The EU currently does not have a Europe-wide building code for flooding. National building design codes for flood resilience are typically prescriptive, with few allowing performance-based design. ASCE/SEI 7-22 Supplement 2, Table C5.3-4 (ASCE, 2023a) provides flood performance objectives for buildings with different occupancies and importance. It also provides guidance on how to design against foundation scour and flood debris impact. The difficulty of excluding water from the building envelope is recognised in most flood building codes, which allow for two design philosophies to be followed: (i) flood resistance in the case of small water depths and velocities, where water is kept out of the building by the building elements, and (ii) flood resilience, where some flood resistance is provided, but the water is allowed to enter the building. In the latter case, the design criteria aim to minimise the damage to building materials, services and contents. Guidance for the latter is provided by BS 85500 (BSI, 2015b) and Draft BS 85500 (BSI, 2024), which is used as a reference for the B.3.2 score development for these enhanced design features.

In the case of landslide hazards, it is highlighted that it is not typically cost effective nor are there accepted guidelines for designing to directly resist landslide hazards. The best means of achieving landslide resilience is to site the project on stable ground/slopes that are not susceptible to land sliding. However, with growing urbanisation and pressure on land, the built environment expands into areas with low to moderate landslide hazard. In these cases, according to AGS (2000), several actions can be taken to improve landslide resilience. These do not necessarily involve interventions on the structure, but instead involve intervening to stabilise the landslide, erect defensive barriers, as well as set up monitoring and warning systems. These elements therefore constitute the indicator metrics in the case of landslides. 

Similar to the case of landslides, there are no building codes or widely accepted guidelines for the design against volcanic ash. However, it is recognised that projects may be sited in areas where volcanic ash may fall, as ash can be transported large distances from the volcano. Volcanic ash is very heavy when wet, corrosive, it can conduct electricity and be harmful to health. Most existing guidance on ashfall vulnerability focus on the collapse of buildings under the weight of ash, which has a density up to 2000 kg/m³ when wet (Blong et al., 2017). Some aspects of roof design can help reduce the accumulation of volcanic ash (USGS, 2024), whereas other resilience enhancing measures involve keeping ash out of interiors and protecting HVAC and sensitive equipment. The scoring criteria for resilience to volcanic ash are based on these features.

In the case of tsunami hazards, although no European building code exists, there are two international building codes in Japan and USA for the design of structures of critical importance, essential facilities or structures that act as vertical evacuation towers. The ASCE/SEI 7-22 chapter 6, Tsunami loads and effects (ASCE, 2022), is taken as reference for the development of B.3.2 indicator for tsunami. Additionally, insights from tsunami engineering research are included to provide enhanced design criteria for the evaluation.

Currently, the Eurocodes contain specific parts that deal with the fire resistance of structures. A performance-based approach is possible in the general framework of the Eurocodes, however, is not provided in detail. According to a recent review, Athanasopoulou et al. (2023) shows that fire safety and design regulations vary across EU member states, and that prescriptive methods of design for fire safety in buildings are largely prevalent in practice, even if a performance-based approach is allowed. ISO 23932-1 (ISO, 2018b) presents a performance-based framework for fire safety engineering. It provides significant flexibility to the designer to set the performance objectives (amongst which life-safety is mandatory), and guidance is provided on how this could be done in TR 16576 (ISO, 2017b), which draws on international practice. However, according to Athanasopoulou et al. (2023), the fire engineering community needs further standardisation of several equations and approaches for setting performance criteria. The UK Building Regulations Approved Document B – Fire safety (DLUHC, 2019) is a state-of-art document that provides practical guidance to meeting the technical requirements involved in achieving different performance criteria, for most common buildings and occupancy types. It does not provide information on the fire scenarios to be used, which are part of national regulations. This key reference is used as the basis for the indicator evaluation. 

In terms of blast loading, EN 1991-1-7 (CEN, 2006) prescribes the need to design for an internal explosion in projects where gas is burned or regulated, or where explosive material such as explosive gases, or liquids forming explosive vapour or gas are stored or transported. The standard requires the structure to be designed to resist progressive collapse resulting from an internal explosion, in accordance with EN 1990, section 4.4 and annex E (CEN, 2023a). However, an overall approach for design under blast external loads is missing from the standard (Karlos and Solomos, 2013). When blast is from external sources/terrorist attack, the most effective means of protecting a structure is to deter the attack or keep the explosive as far away as possible by maximising the standoff distance. These can be achieved through heightened security and the placing of physical barriers, like bollards or large planters, between the road and the building (Cormie et al., 2020). Apart from avoiding progressive collapse, a number of design features can be implemented to help disperse the blast pressures, and the structure can be ‘hardened’ to absorb the energy of the attack and to protect valuable assets (Cormie et al., 2020). In the case of blast loading, performance criteria can be set for different blast scenarios (e.g. per ASCE, 2011), where a blast scenario has a defined type and weight of explosive, which is triggered in a specific location outside or within the project boundary. Multiple scenarios should be looked at with a variety of devices that befit the use and size of the building. These scenarios should be chosen as the most probable for the site; e.g. Karlos and Solomos (2013) – table 3 provide maximum charge weights per measure of transportation. The score of B.3.2 for blast is drawn from several sources of literature and international guidance.

Aspects of resilience can be achieved through the provision of redundancy. For example, ensuring that progressive collapse does not occur in the case that one structural element is severely damaged by wind- or water-borne debris, or that the safety of evacuation routes is not compromised if the active protection systems (like sprinklers) fail in case of fire. Aspects of redundancy that affect the design of structural and non-structural components are therefore included in B.3.2 evaluation. 

Consideration of climate change effects will typically result in a higher IM value for the project design. Given that this level of IM might happen in the future, its consideration in design will result in a more reliable future performance, as well as an enhanced resilience in the short term. However, the inclusion of climate change effects on hazard characterisation is already part of B.3.1 score (hazard characterisation), and therefore not included in B.3.2.

Development of B.3.2 has been guided by a number of key building codes, standards, guidelines and indicator systems, namely: AGS (2000), ASCE (2020, 2022, 2023a, b), Building Resilience Index (International Finance Corporation, 2023), Cormie et al. (2020), Draft prEN 1998-1-1 (CEN, 2022), Draft prEN 1998-1-2 (CEN, 2023b), FEMA P-424 (FEMA, 2010), FEMA 426/BIPS-06 (FEMA, 2011a), ISO 23932-1 (ISO, 2018b), Karlos and Solomos (2013), REDi Extreme windstorms (ARUP, 2022), TR 16576 (ISO, 2017b), REDi Floods (ARUP, 2023), UK Building Regulations Approved Document B – Fire Safety (DLUHC, 2019).

Table 63. B.3.2 score for resilience to wind hazard.

¹        If the non-applicable option is selected (when available), the full metric score is considered in the evaluation of the indicator score.

Source: JRC.

Table 64. B.3.2 score for resilience to flood hazard.

¹        If the non-applicable option is selected (when available), the full metric score is considered in the evaluation of the indicator score.

Source: JRC.

Table 65. B.3.2 score for resilience to earthquake hazard.

¹        If the non-applicable option is selected (when available), the full metric score is considered in the evaluation of the indicator score.

Source: JRC.

Table 66. B.3.2 score for resilience to landslide hazard.

Source: JRC.

Table 67. B.3.2 score for resilience to volcanic ash hazard.

¹        If the non-applicable option is selected (when available), the full metric score is considered in the evaluation of the indicator score.

Source: JRC.

Table 68. B.3.2 score for resilience to tsunami hazard.

¹        If the non-applicable option is selected (when available), the full metric score is considered in the evaluation of the indicator score.

Source: JRC.

Table 69. B.3.2 score for resilience to fire hazard.

¹        If the non-applicable option is selected (when available), the full metric score is considered in the evaluation of the indicator score.

²        The metric can only be considered non-applicable if the building being assessed is not a non-residential building >30m in height.

³        For this metric, external walls of a building include anything located within any space forming part of the wall, any decoration or other finish applied to any external (but not internal) surface forming part of the wall, any windows and doors in the wall (DLUHC, 2019).

Source: JRC.

Table 70. B.3.2 score for resilience to blast hazard.

¹        If the non-applicable option is selected (when available), the full metric score is considered in the evaluation of the indicator score.

²        Progressive collapse can be checked according to EN 1990, section 4.4 and annex E (CEN, 2023a), or equivalent standard.

³        The metric can be marked as non-applicable only where a building has load bearing walls with no cladding.

Source: JRC.

4.6.4   Consequence mitigation (B.3.3)

This consequence mitigation indicator (B.3.3) evaluates the extent to which the project design has measures in place to mitigate the consequences of extreme natural hazards on functionality and on the user community. The indicator focuses on design aspects that promote survivability (i.e. the availability of early warning) and on measures that can be taken to restore project functionality rapidly after a hazard event (e.g. availability of back-up systems). It is noted that dimensioning of spaces and signage for safe evacuation and emergency communication are considered in the indicator B.5.1 Ease of circulation (Section 4.8.2), and therefore not included here.

B.3.3 is evaluated independently of hazard type, as the integrated metrics are relevant to consequence mitigation from all natural and man-made hazards. Indicative performance classes for the B.3.3 scores are provided in Figure 62. While these thresholds and performance classes are not directly applied in the evaluation of KPI and dimension scores and performance classes, they are included here to assist users in determining appropriate performance levels for specific project aspects and to offer clear guidance on their improvement. The indicator evaluation is presented in Table 71 and the score B.3.3 cannot exceed 100. On some occasions, next to the metrics of the indicator, a “non-applicable” option exists, so that users can indicate that the specific metric is not relevant to the project attributes. If the non-applicable option is selected (when available), the full metric score should be considered in the evaluation of the indicator score, to avoid penalising a project due to non-relevant aspects.

Figure 62. B.3.3 indicative performance classes and thresholds.

Source: JRC.

Table 71. B.3.3 score.

¹        If the non-applicable option is selected (when available), the full metric score is considered in the evaluation of the indicator score.

²        The emergency plan should account for the arrival time of wind, tsunami and other hazard events, and account for the characteristics of each hazard.

³        Amongst other items, the business continuity plan should include plans for project cleanup and repair, prioritised restoration of different utilities and services in light of functional recovery.

Source: JRC.

4.6.5   Example (B.3)

The example case study is a newly built high school (non-residential main use) in southern Italy. The assessment is carried out at the building scale and no listed cultural heritage is affected by the project. The school building is a three-storey high reinforced concrete moment resisting frame. A sketch of the school and its ground floor plan are presented in Figure 63. Each floor contains four classrooms with a capacity of 30 children per class. A central staircase provides access to all floors and is located in the central bay of the school. Infill walls are made of unreinforced masonry, and large windows line the back and front of each classroom.

Figure 63. Sketch (left) and ground floor plan (right) of a fictitious high school in Southern Italy, used as an example for B.3 indicator evaluation.

Source: JRC.

From hazard maps available from the National Institute of Geophysics and Volcanology in Italy (INGV), it is observed that the school is sited in an area prone to earthquakes and tsunami, but far enough inland from the coastline (1 km) and any waterways, thus, it is not prone to coastal or riverine flooding. It is also not prone to either landslides or volcanic ash. It is prone to wind, fire and blast hazards.

Table 72. Identification of hazards affecting the project.

Source: JRC.

The first part of the evaluation involves obtaining a score for the hazard characterisation indicator (B.3.1_i) for wind, earthquake and tsunami.

The wind map from the Italian National Annex to Draft prEN 1991-1-4 (CEN, 2021f) is used for the wind design. The school is sited in wind zone 3, which is associated with a fundamental value of the basic wind speed of 27 m/s. According to the code, the basic wind speed corresponds to the characteristic 10-minute mean wind velocity at a height of 10 m above ground level, with an annual probability of being exceeded of 0.02 (MRI = 50 years). This is used to calculate a basic wind velocity of 28 m/s and 30.3 m/s for MRIs of 100 and 500 years, respectively, using equation 6.1 in the Draft prEN 1991-1-4 (using the shape parameter depending on the coefficient of variation of the extreme-value distribution k = 0.2, and the exponent n = 0.5). The code is applied for the wind design of the school building, with wind actions on structures and structural elements determined considering both external and internal wind pressures. No wind tunnel test is carried out for the structure, as it is low-rise and is sited in a semi-rural area. 

In the case of earthquake hazard, the latest approved Italian earthquake hazard map is accessed via a GIS platform on INGV website. The map shows the probabilistic seismic hazard and has been derived using more than one ground motion prediction equation. The map provides peak ground acceleration (PGA) values for eight MRI values for any location on the Italian territory. The values of PGA for the school location are plotted against MRI to develop a hazard curve. The earthquake engineering design of the school employs performance checks according to Draft prEN 1998-1-2, table 4.3 (CEN, 2023b) performance criteria, which state that for a school (building class CC3-a) the following performance objectives should be considered: Damage Limitation limit state for MRI = 125 years; Significant Damage limit state for MRI = 700; Near Collapse limit state for MRI = 2500. The hazard curve is used to estimate the PGA values for these MRIs; PGAs are found equal to 0.18g, 0.25g and 0.33g for the three MRI values in increasing order. A 3D finite element model of the school is built, and non-linear static analysis is adopted to analyse, design and check the structure performance under the three earthquake intensity levels. 

For the tsunami hazard, a recent study (Basili et al, 2018) conducted as part of a large European Union funded project called TSUMAPS-NEAM, produced a probabilistic tsunami hazard map for the North-eastern Atlantic, Mediterranean and Connected Seas ([1]). This map provides the maximum inundation height at the coastline nearest the school to be 1.78 m for MRI = 2500 years. The NASA Sea level projection tool ([2]) () is used to source a sea level rise projection of 0.31 m for the SSP2-4.5 scenario at mid century. This is added to the coastal inundation height to become 2.09 m. As only one projection is used, the enhanced criteria score for use of the three projections of climate change is not met. A transect of the topography between the coastline and the school location is found and the Energy Gradeline Analysis of ASCE/SEI 7-22 chapter 6 (ASCE, 2022), is carried out. This results in a tsunami inundation depth prediction of 1.67 m at the site of the school. The waterborne debris impact is designed as per ASCE/SEI 7-22.

The values of B.3.1 for blast and fire are considered equal to the relevant for B.3.2 values for the respective hazards.

The scores for the hazard characterisation indicator (B.3.1) for wind, earthquake and tsunami hazards are provided in Table 73, Table 74 and Table 75, respectively.

Table 73. Example of B.3.1 evaluation for wind hazard.

¹        If the non-applicable option is selected (when available), the full metric score is considered in the evaluation of the indicator score.

²        For windborne debris, simplified methods in codes of practice can be used to assess possible impacts.

Source: JRC.

Table 74. Example of B.3.1 evaluation for earthquake hazard.

Source: JRC.

Table 75. Example of B.3.1 evaluation for tsunami hazard.

¹        Both the Energy Gradeline Analysis in ASCE/SEI 7-22 chapter 6, and numerical inundation models can take into account any amplifying effects of inundation from topography.

Source: JRC.

Subsequently, the scores of the hazard resilient design indicator (B.3.2_i) are evaluated for wind, earthquake, tsunami, fire and blast.

In the case of wind, the Eurocodes are followed using Nationally Determined Parameters for Italy. Wind design is carried out for the ultimate and serviceability limit states. The same finite element model created for the school building to conduct the seismic design, is adopted to check the wind design. In the model, the infill panels are modelled for in-plane resistance through an equivalent strut approach. Enhanced performance criteria are not used beyond the prescriptions of the code for school structures. The design is checked with respect to EN 1990, section 4.4 and annex E (CEN, 2023a) for progressive collapse, if one column is damaged, and is found to be sufficiently robust (redundant). The windows in the school are large, and are wind rated. There is no chimney in the school, and the parapet walls along the external walkways at the ground and first floor are not reinforced.

For the earthquake resilient design, as stated above, three performance objectives are checked explicitly, and a non-linear static procedure is adopted for the structural analysis. The developed finite element model meets the guidelines of Draft prEN 1998-1-1, section 6.2 (CEN, 2022) and includes the infill walls in the modelling. Enhanced performance criteria are not used beyond the prescriptions of the code for school structures. No damping devices or base-isolation is adopted in the design due to economic constraints. Separation joints are not provided between the infill walls and the surrounding structural elements. The infills and other main non-structural components are not designed or reinforced to limit their damage. HVAC ducting in ceilings is restrained so as not to cause damage to ceiling tiles in the case of ground shaking. Bookcases and heavy furniture are fixed to walls or floors to avoid their toppling in an earthquake event. Flexible gas piping is implemented across the school.

The school governing board wants the school to act as a vertical evacuation tower, to facilitate the evacuation of the school children in the case of tsunami. Hence, the school design is conducted in adherence with ASCE/SEI 7-22 (ASCE, 2022) requirements. Only the collapse limit state is checked for the 2500-year tsunami inundation depth of 1.67 m (see above). The same 3D finite element model is adopted to conduct a variable depth pushover analysis. Out-of-plane failure of the infill walls is calculated from yield line theory, and the effect of their breaking is simulated in the pushover loading histories (see Del Zoppo et al. 2021). The global capacity of the school under tsunami loading exceeds the demand load calculated from the inundation height calculated per ASCE/SEI 7-22, chapter 6, Load Case 2. Hence, the structure satisfies the global checks. However, the component checks show that the shear capacity of the columns needs to be enhanced. Additional shear reinforcement is added throughout the ground floor columns such that the component check is also satisfied. No separation is provided between the infill panels and surrounding frame, and the infills are not specifically designed to breakaway. However, in the analysis, it is observed that they do collapse out-of-plane during the tsunami inundation, as the panels consist of weak material, resulting in a reduction of load on the structural elements. The school does not have living areas. All important equipment that might be damaged when wet is located above the second floor of the building. This includes the boiler.

The school is designed for fire in accordance with the current fire code in Italy (Ministry of the Interior, 2023). This code sets out performance objectives in relation to the importance and function of the building. The school falls in Category IV of the code, and should provide fire resistance such that limited damage to the structure is evident after the fire event. The fire is characterised by a standard fire curve (Section S.2.7 of the code), and to achieve the Damage Limitation limit state, deflections of loaded structural elements must be limited to 1/100 of the member length during the fire. Compartmentalisation is required such that there is no fire spread beyond the originating classroom, and doors and windows must not allow smoke transmission. However, each classroom has a floor area that is 18.1% (i.e. >15%) of the total floor area of one storey. Fire load is calculated per Section S.2.9 of the code from knowledge of the compartment size and combustibles contained. For the fire resistance, the European Standards are used, e.g. EN 13501-2 (CEN, 2023c). The EN standard is prescriptive and results in fire resistance of elements and doors that exceed the requirements of Table B4 in UK Building Regulations Approved Document B (DLUHC, 2019). The lining material requirements of UK Approved Document Bare satisfied. No sprinkler system is installed. The evacuation route is the central staircase of the building, which is only partially surrounded by reinforced concrete walls and does not provide the level of evacuation route protection specified in the UK Approved Document B (DLUHC, 2019). The only cavity is the roof space, and that qualifies as an extensive cavity, according to Section 9 of UK Approved Document B (DLUHC, 2019) as it has a dimension that exceeds 20 m. To achieve fire safety, the cavity needs to be divided up with cavity barriers, but such a measure has not been applied. Openings made by utilities in fire-separating elements are protected, but the ducts are not. The external walls are made of masonry infill, therefore, they exceed the requirement that external wall material should have a density of 300 kg/m³ or more, which, when tested to BS 476-11 (BSI, 1982), does not flame, and causes a rise in temperature on the furnace thermocouple not exceeding 20°C. The school does not have a basement. The school is in a semi-rural area and at significant distance from any neighbouring building. Moreover, the boundaries of the school walls ensure no future construction is within 30 m of the school building. Thus, fire in the building cannot spread fire to adjacent buildings. All appliances have certification and are installed by qualified professionals. No hazardous substances are kept on the premises due to the presence of children.

In the blast loading design, internal explosions have not been accounted for as there is no kitchen area in the school and no stored gas. The school has a security and safeguarding system in place which makes it extremely difficult for students to bring in any weapon or for someone external to enter the school perimeter. There is a perimeter fence that surrounds the building at a 20m distance from the school footprint. Only scenarios of terrorist attack are considered applicable, with a minimum standoff distance of 20 m. Several scenarios of blast are considered. The worst case is a 100 kg TNT detonation at ground level. An empirical method is used for the design against blast loading. This assumes that the blast detonates at a distance of 20 m, and will apply a uniform pressure across the front of the building. Design charts like those of Unified Facilities Criteria (US Army Corps of Engineers et al., 2008) can be used to calculate the parameters of the blast pressure time history on each façade of the building and at roof level. More details of the calculation approach are available in Karlos and Solomos (2013). In the indicator evaluation, robustness against progressive collapse from damage to an external member is scored (see earlier). The design against blast only considers the collapse performance, and hence is not following a performance-based design. A safety factor of 20% is not applied to the charge weight, and a single degree of freedom approach is considered to check component resistance to the blast load. Accordingly, the design ensures that under the considered blast loading the structure will not collapse. Enhanced design criteria regarding the shape of the building are not met. Significant glazing above minimum needs is provided to maximise light in the classrooms. The floor slab is connected to the frame fully and can sustain reverse loading. The cladding (infill) spans the height of the floor and is also connected to the slabs above and below. Glazing is not made of laminated glass.

The scores for the hazard resilient design indicator (B.3.2) for wind, earthquake, tsunami, fire and blast hazards are provided in Table 76–Table 80.

Table 76. Example of B.3.2 evaluation for resilience to wind hazard.

¹        If the non-applicable option is selected (when available), the full metric score is considered in the evaluation of the indicator score.

Source: JRC.

Table 77. Example of B.3.2 evaluation for resilience to earthquake hazard.

¹        If the non-applicable option is selected (when available), the full metric score is considered in the evaluation of the indicator score.

Source: JRC.

Table 78. Example of B.3.2 evaluation for resilience to tsunami hazard.

¹        If the non-applicable option is selected (when available), the full metric score is considered in the evaluation of the indicator score.

Source: JRC.

Table 79. Example of B.3.2 evaluation for resilience to fire hazard.

¹        If the non-applicable option is selected (when available), the full metric score is considered in the evaluation of the indicator score.

²        The metric can only be considered non-applicable if the building being assessed is not a non-residential building >30m in height.

³        For this metric, external walls of a building include anything located within any space forming part of the wall, any decoration or other finish applied to any external (but not internal) surface forming part of the wall, any windows and doors in the wall (DLUHC, 2019).

Source: JRC.

Table 80. Example of B.3.2 evaluation for resilience to blast hazard.

¹        If the non-applicable option is selected (when available), the full metric score is considered in the evaluation of the indicator score.

²        Progressive collapse can be checked according to EN 1990, section 4.4 and annex E (CEN, 2023a), or equivalent standard.

³        The metric can be marked as non-applicable only where a building has load bearing walls with no cladding.

Source: JRC.

Finally, the consequence mitigation indicator (B.3.3) is evaluated. In terms of hazard warnings, the school is within earshot of tsunami warning towers and is also equipped with fire alarms. The location is not susceptible to landslides and so there is no need for a warning. Through the Italian Civil Protection and police, respectively, the school receives warnings of severe weather conditions and any terrorist threats. An emergency response plan for terrorist or gunman attack is present in the school, and teachers are trained on what to do in such events. Fire alarm and evacuation drills take place once a month, and tsunami evacuation practice to upper floors in the schools is practiced once a year. Automatic shutdown systems are not in place for utilities. Emergency lighting for evacuation routes is not provided. There are four classrooms with 30 children each at each storey. There are also two teachers on average per storey. Hence, from Table 3.3 of UK Approved Document B (DLUHC, 2019), the stair width for phased evacuation should be a minimum of 1.20 m wide. Considering the plan in Figure 63, this requirement is met. Sufficient fire hydrants and access is provided by the design to fire fighters. No fire shaft is however present. The school has an arrangement with a nearby school that in case of shut down, the other school will host the children such that education continuity can be ensured. The school is not insured against natural hazards. The school has a back-up generator and water tank on site that can provide 48 hours of independence from the grid. However, it does not have gas storage on site, access to off grid services or a pre-arranged priority of service agreement with local utility companies. The teachers have access to a satellite phone, which is provided to the school as a precaution by the local council. Finally, the security system can function if there is loss of energy, but no fast reboot system is put in place for the school computing systems. The evaluation of B.3.3 is shown in Table 81.

Table 81. Example of B.3.3 evaluation.

¹        If the non-applicable option is selected (when available), the full metric score is considered in the evaluation of the indicator score.

²        The emergency plan should account for the arrival time of wind, tsunami and other hazard events, and account for the characteristics of each hazard.

³        Amongst other items, the business continuity plan should include plans for project cleanup and repair, prioritised restoration of different utilities and services in light of functional recovery.

Source: JRC.

Having evaluated the scores for each indicator, the indicator values are used to calculate the key performance indicator score for B.3 (Table 82). B.3. score corresponds to an Acceptable performance class and a performance class score PCS_B.3 = 40 (Figure 46).

Table 82. Example of B.3 evaluation.

Source: JRC.

[1]        http://ai2lab.org/tsumapsneam/interactive-hazard-curve-tool/.

[2]        https://sealevel.nasa.gov/ipcc-ar6-sea-level-projection-tool.

4.7 Ensuring occupant health, comfort and wellbeing (B.4)

4.7.1   Description and assessment

The Ensuring occupant health, comfort and wellbeing KPI (B.4) looks to evaluate the extent to which the project design provides a healthy environment which supports and promotes physical, social and mental health, and in which the users can easily cater to their needs, have a meaningful experience and thrive. 

Four main areas of project design that have been linked to occupant health, comfort and wellbeing are considered within B.4:

• Indoor acoustic environment (B.4.1): extent to which harmful or intrusive noises are prevented and the users are provided with a healthy and productive acoustic environment.
• Lighting environment (B.4.2): extent to which natural and artificial lighting systems support health, wellbeing, orientation, safety and the ability to conduct tasks, for all users.
• Thermal comfort (B.4.3): extent to which the design caters for the thermal comfort of diverse users.
• Promotion of physical movement (B.4.4): extent to which opportunities for physical movement are integrated into the project.

B.4 score is evaluated according to Equation (138).

(138)

Each indicator is evaluated with a score between 0-100 and a corresponding indicative performance class (indicator class is provided just to guide users but not used further in the evaluation of KPIs and dimensions), according to adherence with best-practice design guidance, and beyond best-practice standards and guidance that are typically voluntary. The performance class of the B.4 key performance indicator is assessed according to the thresholds in Figure 64.

Figure 64. B.4 performance classes and thresholds.

Source: JRC.

The KPI and its indicators are designed to be implemented at all project scales, types and main uses (Table ). The assessment of B.4.1, B.4.2, B.4.3 and B.4.4 is affected by the project scale and type.

When a project, classified into the neighbourhood or urban scale, involves several buildings with distinct design characteristics, thus likely leading to different indicator scores for each of them, the evaluation of the indicators shall be carried out by identifying representative samples of buildings with similar design features. For each of these representative building designs, a separate assessment should be performed. The overall score per indicator is then estimated as a weighted average of the separate assessment scores, with the weights obtained from the relative occurrence of each building design.

For renovation projects, the assessment focuses on the specific aspects of the building and spaces that are affected by the proposed renovation works. However, when indicators and/or metrics address an aspect that has not been altered by the renovation, their evaluation should consider the as-built state (i.e. condition before the intervention is set), as this affects the user health, comfort and wellbeing.

The definition of the B.4 KPI and indicators draws heavily upon of the following key standards, certification schemes and guidance documents: CEN (2021b), IWBI (2020), Fitwel (2020), PAS 6463 (BSI, 2022) and Level(s) (Dodd et al., 2021e, f, g).

EN 17210 (CEN, 2021b) is a European standard adopted by the 34 member countries of the European Committee for Standardisation. The main goal of the standard is to contribute to the implementation of the UN Convention on the Rights of Persons with Disabilities in Europe (COM, 2010). EN 17210 (CEN, 2021b) is a performance standard, and aims to provide the basic, minimum functional requirements and recommendations for the design, construction, refurbishment or adaptation, and maintenance of an accessible and usable built environment, including guidance on outdoor pedestrian and urban areas. Although adherence to this standard is mandatory for publicly funded projects in the EU, the scope of NEB extends its use to privately funded projects. Hence, in many of the indicators within B4, EN 17210 is adopted in the definition of the Acceptable performance class.

As a performance standard, EN 17210 provides design direction without limiting to a prescribed metric, which allows for greater flexibility for implementation across countries and without the risk of conflicting with other existing standards. National standards or regulations may be used to determine the technical performance criteria and specifications to fulfil the functional requirements of EN 17210. However, if national standards or regulations standards are insufficient or lacking, the supplementary technical reports TR 17621 (CEN, 2021c) and TR 17622 (CEN, 2021a), provide the necessary information on how to meet the performance standard. As the technical performance criteria set out in these reports are typically more stringent than those in most national standards and regulations, compliance with TR 17621 and TR 17622 is adopted in the definition of the Good performance class in many of the indicators within B.4. 

WELL v2 (IWBI, 2020) and Fitwel (2020) are two of the few certification schemes that focus on the health and wellbeing of occupants and users. Both define design features and metrics for achieving specific health and wellbeing goals in projects. A number of design features and associated metrics in WELL and Fitwel are adopted in the definition of the Good and Excellent performance classes in the indicators within B.4. Although WELL requires an on-site assessment as part of its certification process, only those metrics that can be evaluated at the design stage are considered here. Both the WELL and Fitwel standards are continuously updated as new research findings are published. Hence, in the evaluation of B.4, the latest versions of these standards should be used. 

PAS 6463 (BSI, 2022) provides guidance on the design of the built environment to include the needs of people who experience sensory/neurological processing differences. Such needs are often excluded from existing design standards, and are not fully incorporated in current certification schemes. PAS 6463 aims to help with the design, creation or management of intuitive environments which readily accommodate the neurological variations in the way people perceive, process and organise sensory information, received through hearing, sight, touch, smell or movement. The guidance provided PAS 6463 contributes to the definition are drawn of the Good and Excellent classes for indicators within B.4.

The evaluation of the indicators in B.4 is conducted by the design team, comprising architects, structural engineers and service engineers, potentially seeking the advice of product manufacturers, and main and specialist contractors. The assessment requires the following information to be identified and collected:

• Standards, guidelines and certification scheme documents, as well as any national standards relevant to acoustic, lighting, thermal comfort and active design.
• Information of the project location and orientation, and relevant maps of pedestrian areas, cycle lanes and public transportation.
• Project design plans, architectural and structural design drawings, service plans, (especially lighting and HVAC).
• Plans for the use of different areas of the project, with identification of regularly occupied individual and multi-occupant spaces.
• Information on the type of users and their needs.
• Information of sources of noise outside and inside the building and estimates of their values.
• Characteristics of internal finishes (ceiling, walls, flooring), and manufacturer information regarding the reflectance and acoustic performance of materials.
• Manufacturer information regarding acoustic insulation of the envelope and façades, and regarding any mechanical systems (HVAC) used for cooling or heating.
• Information on provided amenities, with particular focus on those related to physical activity.

4.7.2   Indoor acoustic environment (B.4.1)

The Indoor acoustic environment indicator (B.4.1) evaluates the extent to which the project design provides users with a healthy and productive acoustic environment, that is void of harmful or intrusive noise, and which supports speech intelligibility. The evaluation of the indicator score is summarised in Table 83, based on compliance with best practice standards and beyond best-practice guidance that specifically address users with diverse abilities. The indicator score cannot exceed 100. On some occasions, next to the metrics of the indicator, a “non-applicable” option exists, so that users can indicate that the specific metric is not relevant to the project attributes. If the non-applicable option is selected (when available), the full metric score should be considered in the evaluation of the indicator score, to avoid penalising a project due to non-relevant aspects.

Figure 65 shows indicator thresholds adopted to associate the indicator score to an indicator performance class. While these thresholds and performance classes are not directly applied in the evaluation of KPI and dimension scores and performance classes, they are included here to assist users in determining appropriate performance levels for specific project aspects and to offer clear guidance on their improvement.

Table 83. B.4.1 score.

¹        If the non-applicable option is selected (when available), the full metric score is considered in the evaluation of the indicator score.

Source: JRC.

Figure 65. B.4.1 indicative performance classes and thresholds.

Source: JRC.

Excessive noise seriously harms human health and interferes with people’s daily activities at school, at work, at home and during leisure time. Many health consequences of exposure to excessive noise have been identified, such as sleep disturbance, cardiovascular and psychophysiological issues, performance reduction and changes in social behaviour (WHO, 2011). The importance of protecting citizens from noise is recognised in European policy, with Directive (2002) on the assessment and management of environmental noise. Typically, noise problems that affect health and wellbeing within an indoor space result from (Dodd et al., 2021g; IWBI, 2020):

• Too much noise outside the building entering the space (typically this includes noise from air traffic, rail, road traffic congestion, industrial works and processes, construction, public works etc.).
• Too much noise from activities adjacent to the space, including:
  • Airborne noise (generated in the air and transmitted by air, such as sounds from speech, radio, television etc. in adjacent spaces or buildings).
  • Impact noise (generated by physical interaction with the building structure causing it to vibrate. Examples include footfall, exercise or mechanical equipment vibration that can create uncomfortable environments for occupants located nearby).
• Too much noise from service equipment or occupants in the space itself (e.g. sound from HVAC equipment, appliances and other occupants).
• Lack of sound control and inappropriate reverberation times (see later definition) in the space.

Even when not at harmful levels, too much noise may affect speech intelligibility and can be distracting, reducing functionality, productivity and enjoyment of spaces. An acoustic environment where all users can distinguish essential sounds (primary sounds) from general background noise (ambient noise other than primary sounds) is essential. In particular, people with hearing and cognitive impairments, can have difficulties in making out sounds and words in noisy environments (CEN, 2021b). 

Evaluation of the appropriateness of an indoor acoustic environment depends on the use, occupancy type and level of the space being designed, as well as a number of interacting design features, including sound isolation provided by façades and partitioning elements (e.g. walls and floors), surface shapes and finishing materials, indoor acoustic design and noise and vibration mitigation of service equipment. EN 17210 (CEN, 2021b) sets out performance objectives for indoor acoustic environments considering all these aspects, and specifically considers speech transmission and intelligibility. This standard is considered best-practice for acoustic environment design. Non-compliance with this performance standard results in an indicator score of 0 (indicative of Low performance in Figure 65).

An Acceptable performance class is based (at a minimum) on compliance with EN 17210 using national guidelines. A performance class exceeding the Acceptable can be achieved by demonstrating compliance with the EN 17210 performance criteria, using the material and element specifications as well as threshold values of acoustic environment metrics as defined in TR 17621 (CEN, 2021c) (or alternative national guidance that provides equal or more stringent criteria than TR 17621 for all aspects of the acoustic design). 

Higher indicator scores can also be achieved by implementing selected relevant guidance and thresholds in WELL v2 (IWBI, 2020) and PAS 6463 (BSI, 2022) that ensure acoustic comfort for people with diverse abilities and neurodiversity. These include more stringent values for background noise, the use of dedicated artificial sound to uniformly increase speech privacy between occupied spaces (i.e. sound masking), and provision of enhanced user control over noise. 

To characterise the level of noise from external sources, the Level(s) approach (Dodd et al., 2021g) for the evaluation of the noise levels at the façade of a building may be used. Level(s) state that the yearly average noise level (with a daily penalty distribution) or the maximum noise level can be estimated according to the calculation method described in Annex II of Directive (2002).

Background noise levels combine noise penetration from outside and inside sources of noise. Several acoustic software models exist for the prediction of indoor noise levels. Alternatively, predictions may be based on the sound insulation properties of the façades and reverberation times of the receiving rooms using a building element approach (e.g. ISO 12354-3, ISO, 2017a).

Thresholds of background noise levels are defined differently in the reference standards for different occupancy and uses of the space. Hence, at design stage, it is necessary to map the likely uses of the different spaces within a project. The WELL v2 (IWBI, 2020) certification system proposes the following five acoustic categories for spaces: 

• Loud zone: includes areas intended for loud equipment or activities (e.g. mechanical rooms, AV/IT closets, kitchens, fitness rooms, social spaces, recreational rooms, music rooms).
• Quiet zone: includes areas intended for concentration, wellness, rest, study and/or privacy (e.g. restorative spaces, lactation rooms, nap rooms).
• Mixed zone: includes areas intended for learning, collaboration and/or presentation (e.g. auditoriums, classrooms, breakout spaces).
• Circulation zone: includes occupiable areas not intended for regular occupancy (e.g. hallways, egress, atria, stairs, lobbies)
• Not applicable zones: includes other areas without significant sources of sound (e.g. storage rooms, janitor rooms, coat closets) that are not regularly occupied.

Key parameters adopted by the referenced standards and guidelines for determining the acoustic environment and speech intelligibility of a space, are the reverberation time (T) and speech transmission index (STI). 

The reverberation time (T) is the time, in seconds (sec), that would be required for the sound pressure level to decrease by 60 dB after the sound source has stopped. The reverberation time is strongly dependent on the frequency of the sound and the absorptive properties of the materials in the space assessed. As stated in Level(s), the chosen frequency range for the reverberation time is often in 1/1 octave bands of 125 or 250Hz to 4kHz for rooms where people work, rest or stay for more than a few minutes (Dodd et al., 2021g). For rooms where people simply pass through, like hallways and staircases, the frequency range in octave bands is often 500Hz to 2kHz (Dodd et al., 2021g). The sound absorption of the room can be characterised by the equivalent absorbing area (A_eq) of the room. The reverberation time (T), and the equivalent sound absorption area (A_eq), can be estimated using EN 12354-6 (CEN, 2003), based on volume and sound absorption data. The latter can be estimated from material specifications, or from standards and guidelines (e.g. absorption coefficients for common surfaces in buildings and for objects are provided in Annex B and C of EN 12354-6, respectively). 

The speech transmission index (STI) is described in IEC 60268-16 (IEC, 2020) and quantifies the transmission of the speech signal between a speaker and a listener. This can be evaluated using various available acoustic environment planning software. 

Threshold (or ranges of) values for T and STI are included in national guidance in accordance with the use and occupancy type and level of the space being assessed. Such threshold values may be used to achieve the performance levels required by EN 17210 (CEN, 2021b). Alternatively, the typically more demanding threshold values set out in TR 17621 (CEN, 2021c) and WELL v2 (IWBI, 2020) may be used to increase the acoustic environment indicator score.

4.7.3   Lighting environment (B.4.2) 

The Lighting environment indicator (B.4.2) evaluates the extent to which the project adopts a natural and artificial lighting system that supports health, wellbeing, orientation, safety and the ability to conduct tasks, for all users. 

The evaluation of the indicator score is summarised in Table 84, based on compliance with best practice standards and beyond best-practice guidance that specifically address users with diverse abilities. The indicator score cannot exceed 100. On some occasions, next to the metrics of the indicator, a “non-applicable” option exists, so that users can indicate that the specific metric is not relevant to the project attributes. If the non-applicable option is selected (when available), the full metric score should be considered in the evaluation of the indicator score, to avoid penalising a project due to non-relevant aspects. 

Figure 66 shows indicator thresholds adopted to associate the indicator score to an indicator performance class. While these thresholds and performance classes are not directly applied in the evaluation of KPI and dimension scores and performance classes, they are included here to assist users in determining appropriate performance levels for specific project aspects and to offer clear guidance on their improvement.

Table 84. B.4.2 score.

¹        If the non-applicable option is selected (when available), the full metric score is considered in the evaluation of the indicator score.

²        If the section of EN 17210 does not apply to the project (i.e. non-applicable is selected), then as long as all other stated sections are complied with, then the project is deemed to be in compliance with EN 17210.

Source: JRC.

Figure 66. B.4.2 indicative performance classes and thresholds.

Source: JRC.

Key factors to provide visual conditions to support visual tasks, orientation and safety, include: level of illumination of horizontal and vertical surfaces, limitation of glare from a light source or reflections, uniformity and luminance distribution, direction of lighting and shading, and colour. EN 17210 (CEN, 2021b) sets out performance objectives for lighting related criteria in several sections of the standard, covering both indoor and external lighting. These relate to how lighting contributes to wayfinding, safety and the lighting needs of different users to conduct visual tasks. Approaches to the reduction of glare are provided, and the standard promotes users being able to adjust lighting environments. Moreover, EN 17210 promotes the consultation with users to identify their needs for the lighting environment.

The EN 17210 standard is considered best-practice currently for lighting environment design. Non-compliance with this performance standard results in an indicator score of 0 (indicative of Low performance in Figure 66).

An Acceptable performance class is based (at a minimum) on compliance with EN 17210 using national guidelines. A performance class exceeding Acceptable can be achieved by demonstrating compliance with the EN 17210 using metrics as defined in TR 17621 (CEN, 2021c) (or alternative national that provides equal or more stringent criteria than TR 17621 for all aspects of the lighting environment design). 

Higher indicator scores can also be achieved by implementing selected relevant guidance and thresholds in WELL v2 (IWBI, 2020), PAS 6463 (BSI, 2022) and Fitwel (2020). These consider lighting environments for people with diverse abilities and neurodiversity. They include even more stringent values for minimum light levels provided for various tasks, but specifically aim to promote the use of lighting systems (natural and artificial) that contribute to physical and mental wellbeing. 

For compliance with EN 17210 (CEN, 2021b), TR 17621 (CEN, 2021c) calls upon a number of other standards. In particular, EN 13201-2 (CEN, 2015a) — Road Lighting — is called upon for outdoor lighting. This standard defines lighting performance objectives on the basis of lighting classes, which are based on the type of vehicle and road/pathway type. Highlighted lighting classes include class P and HS which are for pedestrians and pedal cyclists on footways and cycleways etc. The SC class is an additional class for use in high crime areas, where public lighting is needed for the identification of people. Calculation approaches for meeting the performance objectives are provided in EN 13201-3 (CEN, 2015b).

A space is considered to provide adequate daylight if a target illuminance (Ē) level is achieved across a fraction of the reference plane within a space for at least half of the daylight hours. The reference plane of the space is located 0.85 m above the floor, unless otherwise specified (EN 17037, CEN, 2021e). The adequacy of daylight provision to an interior space can be calculated as per EN 17037 section 5.1.3, using a method based on daylight factors (Method 1), or through simulation (Method 2). Annex A in EN 17037, provides the minimum target illuminances (and corresponding daylight factors) for spaces with different uses, that can be adopted to determine the appropriateness of the lighting. It is noted that many standards and guidelines adopt daylight factors as proxies for illuminance (e.g. Active House Alliance, 2020). However, calculating daylight factors (Method 1) requires complex repetition of calculations, and thus generally undertaken using a professional lighting design software.

For indoor artificial lighting TR 17621 (CEN, 2021c) calls upon EN 12464-1: (CEN, 2021g) for the lighting of workplaces, which specifies requirements for lighting solutions for most indoor workplaces and their associated areas in terms of quantity and quality of illumination. This standard defines minimum illuminance levels (Ē_min) and uniformity of illuminance (U_o) for different space uses. It also provides guidance on ranges of surface reflectance to achieve good illuminance and contribute to room brightness. Again, professional lighting calculation software may be used for the illuminance calculation.

Glare is a negative sensation caused by bright areas with sufficiently greater luminance than the luminance to which the eyes are adapted, producing annoyance, discomfort or loss in visual performance and visibility (EN 17037, CEN, 2021e). The perception of glare is dependent on the luminance distribution in the field of view and is therefore strongly dependent on the spatial position and the line of sight of the occupant. A simplified approach to consider glare is the daylight glare probability (DGP) presented in EN 14501 (CEN, 2021d). DGP is used to assess protection from daylight glare in spaces where the activities are comparable to reading, writing or using display devices, and where the occupants are not able to choose position and viewing direction. For determination of glare from artificial lighting instead, the methodology defined in CIE 117 (CIE, 1995) may be used. This uses the unified glare rating (UGR) as a measure of potential discomfort glare experienced by an occupant in interior lighting spaces.

4.7.4   Thermal comfort (B.4.3)

The thermal comfort indicator (B.4.3) evaluates the extent to which the design caters for the thermal comfort of diverse users. The evaluation of the indicator score is summarised in Table 85, based on compliance with the best-practice standard WELL v2 (IWBI, 2020) that specifically accounts for users with diverse abilities. The indicator score cannot exceed 100. On some occasions, next to the metrics of the indicator, a “non-applicable” option exists, so that users can indicate that the specific metric is not relevant to the project attributes. If the non-applicable option is selected (when available), the full metric score should be considered in the evaluation of the indicator score, to avoid penalising a project due to non-relevant aspects. Figure 67 shows indicator thresholds adopted to associate the indicator score to an indicator performance class. While these thresholds and performance classes are not directly applied in the evaluation of KPI and dimension scores and performance classes, they are included here to assist users in determining appropriate performance levels for specific project aspects and to offer clear guidance on their improvement. 

Measuring thermal comfort in buildings typically involves assessing people’s levels of comfort relative to several parameters describing the environment (e.g. air temperature, relative humidity and air velocity). These in turn depend on project design features such as site location and project orientation with respect to the sun and prevailing winds, building envelope materials and design, use of natural ventilation, use of shading, and use of heating and cooling systems, amongst others. The feeling of comfort, however, is subjective, and depends on people’s physiology, the activity they are doing and what they are wearing. There is therefore no one-fits-all solution, and the aim in designing for thermal comfort is not to ensure thermal comfort for all, but rather to provide a baseline satisfaction for the largest number of people while providing people some level of thermal control to adjust their thermal comfort level where possible. It is also important to note the connection between provision of indoor thermal comfort and energy use. Over 80% of the energy used in EU households in 2022 was for heating, cooling and hot water (Eurostat, 2024). Hence, energy consumption must be considered in addition to the provision of thermal comfort in design (see 3.4 in Sustainability chapter).

One of the most used parameters to evaluate thermal comfort is the predicted mean vote (PMVo), which was developed by the American Society of Heating, Refrigerating and Air-conditioning Engineers (ASHRAE). The parameter uses the fact that human body temperature is maintained at optimum levels (37 degrees) through heat exchange between the human body and the environment by convection, radiation, and evaporation (ASHRAE, 2023). PMVo relates the imbalance between the actual heat flow from the body into a given environment and the heat flow required for optimum comfort. PMVo is evaluated through a set of semi-empirical equations, and is supposed to represent the mean response of a large group of people according to the ASHRAE 55 thermal sensation scale (ASHRAE, 2023). The ASHRAE 55 scale has seven comfort ratings, ranging from hot (PMVo = 3) to cold (PMVo = –3), with a comfortable environment deemed to be one where PMVo values lie between –1 and 1. PMVo is one of the parameters adopted in WELL v2 (IWBI, 2020) T01 criterion, which in turn provides the threshold for the Acceptable performance class in B.4.3.

Table 85. B.4.3 score.

Source: JRC.

Figure 67. B.4.3 indicative performance classes and thresholds.

Source: JRC.

4.7.5   Promotion of physical movement (B.4.4)

The Promotion of physical movement indicator (B.4.4) evaluates the extent to which the design encourages physical movement where there are such opportunities. The evaluation of the indicator score is summarised in Table 86, based on guidance provided as part of the WELL v2 Movement (IWBI, 2020), which aims to promote movement, foster physical activity and active living and discourage sedentary behaviour, by creating and enhancing opportunities through living spaces where we spend our lives. WELL v2 (IWBI, 2020) also specifically addresses users with diverse abilities. The indicator score cannot exceed 100. On some occasions, next to the metrics of the indicator, a “non-applicable” option exists, so that users can indicate that the specific metric is not relevant to the project attributes. If the non-applicable option is selected (when available), the full metric score should be considered in the evaluation of the indicator score, to avoid penalising a project due to non-relevant aspects. Figure 68 shows indicator thresholds adopted to associate the indicator score to an indicator performance class. While these thresholds and performance classes are not directly applied in the evaluation of KPI and dimension scores and performance classes, they are included here to assist users in determining appropriate performance levels for specific project aspects and to offer clear guidance on their improvement. 

The design requirements of WELL v2 (IWBI, 2020) and Fitwel (2020) included in B.4.4 promote circulation in the inside and outside of buildings, and provide opportunities for reducing sedentary behaviour through appropriate furnishings, also promoting better posture.

Table 86. B.4.4 score.

¹        If the non-applicable option is selected (when available), the full metric score is considered in the evaluation of the indicator score.

²        Effort should be made to provide stairs as close as possible to the lifts, to reduce separation and provide a similar journey for people using the stairs and people using the lifts. Lifts should be easy to locate with appropriate wayfinding and signage. It should be ensured that any enhanced feature of the stair, such as music, artwork or game, does not create a safety hazard, disturbance or distraction to users who may be negatively impacted.

Source: JRC.

Figure 68. B.4.4 indicative performance classes and thresholds.

Source: JRC.

4.7.6   Example (B.4)

A four-storey residential building is to be designed (newbuild project type) in an urban area of Lisbon, Portugal. The assessment is carried out at the building scale and no listed cultural heritage is affected by the project. The building has a plan of 23.5 m by 23.5 m. The building has a symmetrical and identical repeated floor plan on each floor, with each façade made up of 5 rooms (i.e. 16 perimeter rooms, as corner rooms have two façades). The building is composed of a reinforced concrete frame with façades made of double brickwork with air cavity. A central lift and stairwell are located at the centre of the building plan.

External sources of noise mainly include road traffic. On average, 10 000 vehicles per day use the residential roads around the building, with 10% being heavy vehicles. 15% of the daytime traffic is on average using the roads at night. The A-weighted long-term average sound pressure levels for the day, night and evening are calculated in octave bands according to Annex II of Directive (2002). The estimated outdoor free field sound pressure level is calculated as 50 dB. The sound pressure level 2 m from the façade of the building is found to be 53 dB. 

The formulation in equation E.2 of ISO 12354-3 (ISO, 2017a) is used to evaluate the indoor sound pressure level, standardised to 0.5 sec reverberation time. This value is calculated from the standardised level difference of the façade as per equation 4 of ISO 12354-3, which in turn is evaluated from estimates of the sound reduction index of the façade and the receiving room size. The building is composed of a reinforced concrete frame with façades made of double brickwork with air cavity, with surface mass of 400 kg/m². A typical room along the centre of the façade of the building has a volume of 50 m³, a façade of 11.3 m², and contains a 4.5 m² window with double glazing that is partially openable, with an acoustically treated air inlet located above the window. Sound reduction indices for each façade element are adopted from ISO 12354-3 and the calculation procedure shown in example G.1 of ISO 12354-3 is followed. This results in a standardised level difference of the façade of 29 dB and hence an indoor sound pressure level of 24 dB (i.e. = 53 – 29). The room is equipped with a mechanical ventilation system that produces an additional 10 dB of background noise, resulting in a total of 34 dB background noise. This is considered low and meets the criteria of TR 17621 (CEN, 2021c). It also lies below the threshold for maximum background noise for dwellings stated in WELL v2 (IWBI, 2020).

The reverberation time is calculated as per equation 5 of EN 12354-6 (CEN, 2003). Considering the 50 m³ room used in the above example, it has usable dimensions (length, width, height) of 4.42 m, 4.70 m and 2.40 m. The floors and ceilings are made of concrete and the walls of plastered brick. There is one window (as previously described) and a door of height and width equal to 2.04 m and 0.93 m, respectively. The floor has a soft layer with a depth of greater than 10mm. The values for the absorption of materials are obtained from Annex B of EN 12354-6 and the total equivalent absorption area is calculated as per section 4.3 in EN 12354-6, considering an empty room. This is shown in Table 87 for the frequency of 1000 Hz, resulting in a reverberation time of 1 sec. This does not meet the requirements in WELL v2 SO4 (IWBI, 2020). However, the STI is also calculated using an acoustic environment planning software, resulting in compliance with the values provided in TR 17621 (CEN, 2021c).

Table 87. Calculation of equivalent absorption area for a typical room.

Source: JRC.

The calculation is repeated for all rooms and spaces in the building plan and compliance with EN 17210 (CEN, 2021b) using the criteria of TR 17621 (CEN, 2021c) is demonstrated. Interior walls meet the sound transmission class values in WELL v2 (IWBI, 2020) S03 Part 1. The noise reduction coefficient (NRC) rating (WELL v2 S05) is calculated as the arithmetic average of the absorption coefficients at 250, 500, 1000, and 2000 Hz octave bands (obtained for the used materials from Annex B of EN 12354-6, CEN, 2003), rounded to the nearest multiple of 0.05. For the ceilings of the typical room, which is made of concrete, NRC is 0.014 (which rounded to the nearest non-zero 0.05, is 0.05). Although, this falls below any of the recommended values for WELL v2 (IWBI, 2020) S05, as the building is residential, composed of dwelling units, WELL v2 (IWBI, 2020) S04, S05 and S06 do not apply, and these criteria are given full scores. An approximate impact insulation class (IIC) rating of 75 is obtained from Warnock (1999) for concrete floors with carpet and underlay, and is seen to comply with the requirements of WELL v2 Impact noise management – Part 1 (IWBI, 2020). No enhanced audio devices are used in the building (hence, no compliance with the WELL v2 (IWBI, 2020) S08 requirements). Finally, individual control for noise is provided throughout the building by allowing users to switch extractor fans on or off and close windows or ventilator panels when noise comes from the street. 

B.4.1 score is evaluated in Table 88 (corresponding to Excellent performance for this indicator). 

Table 88. Example of B.4.1 evaluation.

¹        If the non-applicable option is selected (when available), the full metric score is considered in the evaluation of the indicator score.

Source: JRC.

The adequacy of the lighting environment is checked with respect to EN 17210 clause 15.1 Lighting (CEN, 2021b) for the typical 50 m³ room. The 4.5 m² window for this specific room is south-facing and is equipped with blinds that have an electric control. The room is used as a bedroom with a home office space, and equipped with 8 LED lights with colour temperature of 2000 k, spaced in a symmetrical grid evenly across the ceiling. The lights are dimmable, make no noise when dimmed and extra light fixtures are available, meeting the WELL v2 L09 Occupant lighting control criteria – Parts 1 and 2 (IWBI, 2020), as well as PAS 6463 (BSI, 2022). The reflectance of the white painted concrete ceiling, brick walls and carpeted floor are 0.6, 0.3 and 0.2, respectively. These are close but outside the recommended ranges specified in EN 12464-1 (CEN, 2021g).

Considering the room dimensions, a grid of 0.5 m is used for the daylight and artificial illuminance calculation. A lighting calculation software is adopted to calculate the daylight factor for the grid and the illuminance due to artificial light for this grid, considering lighting positions and surface reflectance. The adopted tool used ray tracing to perform all lighting calculations. 

Daylight factors ranging between 4.3% and 4.9% are calculated across the room. The target daylight illuminance is obtained from EN 17037 table A.2 (CEN, 2021e) as 750 lx, which according to EN 17037 table A.3 for Lisbon requires the daylight factor higher than 4.1%. As all values of daylight factor exceed this minimum value, the illuminance is deemed adequate according to TR 17621 (CEN, 2021c). WELL v2 L01 Light exposure (IWBI, 2020) requires a minimum illuminance of 205 lx over 30% of the floor area for 50% of the daylit hours of the year. This is deemed to be satisfied, as the 16 rooms that run along the façade of the building have a floor area of 315 m² (i.e. 4.2m · 4.7 m · 16.0 m) and make up 57% of the area of each floor. Hence, more than 30% of the regularly occupied rooms are within a 6 m distance to envelope glazing at each floor. Moreover, the envelope glazing is equal to 90m² (4.5m² · 5 · 4) which corresponds to 16% of the regularly occupied floor area (552 m² per floor), which in turn exceeds the 7% threshold set in WELL v2 (IWBI, 2020). These values satisfy WELL v2 L01 Options 1-3, L05 Part 1 Tier 1, and L06 Tier 1.

EN 12464-1, clause 7 (CEN, 2021g) provides minimum requirements for the maintained illuminance (Ē_m) and minimum illuminance uniformity (U_o) depending on the tasks and/or activities being performed in the space. The following minimum values are obtained from Clause 7.3 table 34 Ref. No. 34.2 Writing, typing, reading, data processing: Ē_m = 500 lx, U = 0.6. As the room may be used by people who have a below normal visual capacity, and who will work in the space for long periods of time, an enhanced minimum Ē_m of 1000 lx is required. The provided artificial light provides illuminance in the range 1300–1500 lx, and the lighting uniformity is 0.8. The lighting system therefore meets the lighting provision requirements of TR 17621 (CEN, 2021c). The WELL v2 L07 minimum uniformity threshold is exceeded (IWBI, 2020), a lighting automation system is not used, and horizontal and vertical luminance contrast ratios are no more than 10:1 between adjacent independently controlled zones, meaning that this WELL v2 (IWBI, 2020) criterion is satisfied.

The blinds used on the window have a low light transmittance and meet the criteria of Class 3 performance according to table E.3 in EN 14501 (CEN, 2021d). According to this standard, this has a ‘good effect’ on glare control, night privacy, visual contact with the outside and daylight utilisation, with no light perceived at incident light levels higher than or equal to 30 000 lx. The daylight glare probability (DGP) is calculated according to EN 17037 (CEN, 2021e) to be between 0.35 and 0.40, which according to table E.1 in EN 14501 (CEN, 2021d) results in glare being perceived but being mostly not disturbing.

For the artificial lighting, the unified glare rating (UGR) tabular method detailed in CIE 117 (CIE, 1995) and in CIE 190 (CIE, 2010) is adopted. UGR is found equal to 17, which is below the maximum limit of 19 stated in table 34 of section 7.3 (CIE, 2010). However, this value is higher than the maximum value of 16 specified in WELL v2 L04 criterion (IWBI, 2020). The colour rendering quality of the lighting also does not meet the criteria of WELL v2 L08 criterion.

The calculation is repeated for each room in the building, considering their specific use, natural and artificial lighting system. It is found that all rooms meet the lighting requirements of EN 17210 (CEN, 2021b) according to the approach and thresholds stated in TR 17621 (CEN, 2021c). Moreover, lighting in the corridors, passageways, lifts, entrances and lifts are similarly found to comply with TR 17621. Lighting in kitchens and bathroom areas comply with the Illuminating Engineering Society (IES) Lighting application standard (IES, 2020), meeting the criteria for WELL v2 L02 criterion for dwelling units (IWBI, 2020).

B.4.2 score is evaluated in Table 89 (corresponding to Good performance for this indicator). For this building, a reduction in glare from artificial lighting could increase the score such that it would reach the Excellent performance class.

Table 89. Example of B.4.2 evaluation.

¹        If the non-applicable option is selected (when available), the full metric score is considered in the evaluation of the indicator score.

²        If the section of EN 17210 does not apply to the project (i.e. non-applicable is selected), then as long as all other stated sections are complied with, then the project is deemed to be in compliance with EN 17210.

Source: JRC.

Thermal comfort is calculated for the typical 50 m³ room. The room is mechanically ventilated and equipped with central heating.

The first parameter to calculate is the predicted mean vote (PMVo). Assuming limited activity inside the residence, the rate of metabolic energy production (M) is assumed equal to 58.2 Watt/m² and the rate of mechanical work (W) is zero. The mean radiant temperature (T_mr) is the uniform temperature of an imaginary black enclosure in which radiant heat transfer from a person equals the radiant heat transfer in the actual enclosure. The value of T_mr can be calculated from knowledge of the temperature of each surface in a room and the position of a person relative to the surfaces, following the approach in ASHRAE 55 (ASHRAE, 2023). In this example, T_mr is estimated equal to 23 ^OC. The water vapour pressure equals 1.419 kPa and the user is assumed fully clothed. The speed of air, circulating throughout the building space, is 0.1 m/s. This results in a PMVo of –0.202 (comfortable environment). PMVo is calculated for all spaces in the building, and it is observed that PMVo values between +0.5 and –0.5 exist for more than 90% of the regularly occupied spaces. Hence WELL v2 (IWBI, 2020) T01 – Part 1 is satisfied.

The typical room is equipped with a thermostat which can be used to regulate the temperature. The room forms a thermal zone, as do the other rooms on the floorplan with similar layout and area. The room floor area is less than the 60.4 m² limit for thermal zone definitions in WELL v2 T03 criterion (IWBI, 2020).

At least 50% of the regularly occupied project area is heated and cooled with radiant panels, but these do not cover at least half of the wall to which they are attached. Hence, WELL v2 (IWBI, 2020) T05 criterion is satisfied.

The relative humidity in moist air is the ratio of partial vapor pressure to air pressure. The room relative humidity is modelled with computational fluid dynamics (CFD) software, and is found to be 35% for 98% of all business hours of the year. Moreover, the mechanical ventilation system has the capability of maintaining relative humidity between 30% and 45% at all times, by adding or removing moisture from the air. The operable window in the typical room can open to allow greater ventilation, and instructions for the window operation are provided. These conditions meet the criteria of WELL v2 (IWBI, 2020) T07 and T08 criteria.

60% of pedestrian pathways and building entrances are shaded for more than half of daylight hours each day by awnings. An outdoor seating area and children’s play area are provided near the building. 50% of their area is shaded by tree canopies. These conditions comply with WELL v2 (IWBI, 2020) T09 – Part 1.

The score of B.4.3 is evaluated in Table 90 (corresponding to Excellent performance for this indicator).

Table 90. Example of B.4.3 evaluation.

Source: JRC.

The promotion of physical movement indicator is calculated next, considering the typical 50 m³ room of the building example. As previously mentioned, the room is used as a bedroom and home office. The latter is equipped with a docking station for a laptop, which includes an external keyboard, mouse, adjustable laptop stand and an external monitor. The workstation can be adjusted by the user to work both in a seated and standing position, and the associated workstation chair is also adjustable in height with an adjustable seat pan and backrest angle. Being a home office, the user is not required to stand for 50% or more of their work hours. These design features are provided for all the home office rooms in the building, hence, they meet the WELL v2 criteria for V02 Ergonomic workstation design – Parts 1-4, and V07 Active Furnishings with Tier 2 requirements (IWBI, 2020).

The residential building has a central staircase that is open to all residents of the building and services all occupiable floors. Each apartment door opens onto the stairwell platform. The staircase is decorated with artwork depicting images of nature, and the staircase has a light level of 200 lx. At each floor, signage is located that promotes people to take the stairs rather than the elevator. These design features meet the WELL v2 (IWBI, 2020) criteria for V03 circulation network – Parts 1-3.

The building is located in an urban part of Lisbon, within a 200 m walk distance of an existing cycling network, and an existing bus network that operates frequent trips on weekdays and weekends. All streets within 400 m of the building have continuous raised sidewalks and cycle lanes on both sides of the road, and a vehicular speed limit of 20km/h. Street segments intersect each other every 30m on average. Exterior building walls facing the pedestrian network incorporate windows on the first floor. A bike room is located on the ground floor of the building that can accommodate one bicycle from each flat. The bike room is equipped with a cupboard containing bike maintenance tools that are free for residents to use. Moreover, adjacent to the bike room there is a shower room and changing room with five lockers for use by residents. These design features meet the WELL v2 criteria for V04 Facilities for active occupants – Parts 1-2, and V05 Site planning and selection – Parts 1 and 2 (IWBI, 2020).

Although a children’s playground is provided onsite, a dedicated fitness facility for residents is not provided by the design, and although residents have access to nearby gyms these are at a cost. Hence, the project does not meet criteria WELL v2 V08 Part 1 (but does meet V08 Part 2) and obtains a zero score for this criterion. The building also does not have a multi-purpose room available to residents, and hence does not meet the Fitwel (2020) criterion. 

The score for B.4.4 is evaluated in Table 91 (corresponding to Excellent performance for this indicator). Having evaluated the scores for each indicator, B.4 is calculated in Table 92, corresponding to an excellent KPI performance class. 

Table 91. Example of B.4.4 evaluation.

¹        If the non-applicable option is selected (when available), the full metric score is considered in the evaluation of the indicator score.

²        Effort should be made to provide stairs as close as possible to the lifts, to reduce separation and provide a similar journey for people using the stairs and people using the lifts. Lifts should be easy to locate with appropriate wayfinding and signage. It should be ensured that any enhanced feature of the stair, such as music, artwork or game, does not create a safety hazard, disturbance or distraction to users who may be negatively impacted.

Source: JRC.

Table 92. Example of B.4 evaluation.

¹        Transformation of the indicator score to an indicator performance class is indicative and not required by the self-assessment method to estimate KPI and dimension scores and performance classes.

Source: JRC.

4.8 Improving accessibility of the built environment for everyone (B.5)

4.8.1   Description and assessment

The Physical Accessibility for Everyone KPI (B.5) evaluate the extent to which the project design provides ease of physical access in terms of three indicators:

• Ease of circulation (B.5.1): extent to which movement of different users through, around and between spaces and environments is enabled without barriers and without compromise to their safety and experience.
• Safe wayfinding (B.5.2): extent to which the design conveys spatial information to users to help them identify and comprehend the various elements within the environment around them.
• Usability and operation (B.5.3): extent to which the design is usable and operable by all users, regardless of their abilities or background.

B.5 score is evaluated according to Equation (139).

(139)

Each indicator is evaluated with a score between 0-100 and a corresponding indicative performance class (indicator class is provided just to guide users but not used further in the evaluation of KPIs and dimensions), according to adherence with best-practice design guidance, and beyond best-practice standards and guidance that are typically voluntary. The performance class of the B.5 key performance indicator is assessed according to the thresholds in Figure 69.

Figure 69. B.5 performance classes and thresholds.

Source: JRC.

The KPI and its indicators are designed to be implemented at all project scales, types and main uses (Table ). The assessment of B.5.1, B.5.2 and B.5.3 is affected by the project scale and type.

When a project, classified into the neighbourhood or urban scale, involves several buildings with distinct design characteristics, thus likely leading to different indicator scores for each of them, the evaluation of the indicators shall be carried out by identifying representative samples of buildings with similar design features. For each of these representative building designs, a separate assessment should be performed. The overall score per indicator is then estimated as a weighted average of the separate assessment scores, with the weights obtained from the relative occurrence of each building design.

For renovation projects, the assessment focuses on the specific aspects of the building and spaces that are affected by the proposed renovation works. However, when indicators and/or metrics address an aspect that has not been altered by the renovation, their evaluation should consider the as-built state (i.e. condition before the intervention is set), as this contributes to the accessibility of the built environment.

The evaluation of the indicators within B.5 is conducted by the design team, comprising architects and service engineers, potentially seeking the advice of product manufacturers, and main and specialist contractors. The assessment requires the following information to be identified and collected:

• Standards, guidelines and certification scheme documents, as well as any national standards relevant to universal design and design for disabilities.
• Information of the project location and relation to roads, pedestrian areas, cycle lanes and public transportation.
• Project design plans, architectural and structural design drawings, service plans.
• Plans for the use of different areas of the project, with identification of regularly occupied individual and multi-occupant spaces.
• Information on the type of users and their needs.
• Characteristics of internal finishes (ceiling, walls, flooring), and manufacturer information regarding the light reflectance value (LRV) of surfaces and finishes.
• Specifications of doors, handles, handrails, toilets, sinks, seating, furniture and other fixings.
• Details on design, specifications and placement of controls and switches.
• Plans and information on the location of signage and its visual and tactile characteristics.
• Information on means of delivery and content of acoustic messaging and cues in the design.

4.8.2   Ease of circulation (B.5.1)

The Ease of circulation indicator (B.5.1) evaluates the extent to which the project design enables the movement of different users through, around and between spaces and environments without barriers and without compromise to their safety and experience. It focuses on evaluation of the adequacy of entrances, horizontal circulation (e.g. across a building floor) and vertical circulation (i.e. access to other floors). As the provision of adequate circulation comprises numerous design elements, the indicator evaluation is based on compliance with best practice standards and beyond best-practice guidance that specifically addresses users with diverse abilities. 

The evaluation of the indicator score is summarised in Table 93. The indicator score cannot exceed 100. On some occasions, next to the metrics of the indicator, a “non-applicable” option exists, so that users can indicate that the specific metric is not relevant to the project attributes. If the non-applicable option is selected (when available), the full metric score should be considered in the evaluation of the indicator score, to avoid penalising a project due to non-relevant aspects.

Figure 70 shows indicator thresholds adopted to associate the indicator score to an indicator performance class. While these thresholds and performance classes are not directly applied in the evaluation of KPI and dimension scores and performance classes, they are included here to assist users in determining appropriate performance levels for specific project aspects and to offer clear guidance on their improvement.

EN 17210 (CEN, 2021b) sets out performance objectives for safe physical accessibility for different users in several sections of the standard, covering indoor circulation and access to the project from the exterior. Particular care is given to consider the needs of users with mobility impairments, including those using wheelchairs or walking aids. EN 17210 also promotes consultation with users to identify their needs for physical accessibility.

This standard is considered current best-practice. Hence, non-compliance with this performance standard results in an indicator score of zero. An indicative Acceptable performance class for the indicator is based (at a minimum) on compliance with EN 17210 (CEN, 2021b) using national guidelines. A higher indicator score can be achieved by demonstrating compliance with the EN 17210 performance criteria using the specifications included in TR 17621 (CEN, 2021c) (or alternative national guidance that provides equal or more stringent criteria than TR 17621). Higher indicator scores can also be achieved by implementing enhanced design criteria that have been derived from BS 8300-2 (BSI, 2018; Irish Technical Guidance Document M (DHLGH, 2022), DIN 18040-1 (DIN, 2010) and PAS 6463 (BSI, 2022). The enhanced criteria are grouped into categories according to the area or asset that they relate to in the project design. Each category of enhanced criteria is assigned a maximum score to ensure that an Excellent indicative performance class for B.5.1 cannot be achieved without enhanced design features across the entire project. Accordingly, if either all relevant criteria within a category are satisfied, or all criteria within a category are non-applicable, the maximum score of the category is achieved.

Table 93. B.5.1 score.

¹        If the non-applicable option is selected (when available), the full metric score is considered in the evaluation of the indicator score. If satisfied and non-applicable metrics result in a score higher than the maximum within a category, then the maximum score of the category is applied.

²        If the section of EN 17210 does not apply to the project (i.e. non-applicable is selected), then as long as all other stated sections are complied with, then the project is deemed to be in compliance with EN 17210.

Source: JRC.

Figure 70. B.5.1 indicative performance classes and thresholds.

Source: JRC.

4.8.3   Safe wayfinding (B.5.2) 

The Safe wayfinding indicator (B.5.2) evaluates the extent to which the design conveys spatial information to users to help them identify and comprehend the various elements within the environment around them. This includes spatial information to aid orientation and navigation and use of the space without harm or compromise. In particular it looks at whether: (i) sufficient visual contrast is provided to ensure users can easily identify and comprehend the various elements within the environment, (ii) finishes are safe, clear and void of elements or patterns which may create confusion to users, (iii) signage, information and communication systems provide the necessary information for users to navigate and use the space independently and with confidence, including alternative formats for people with specific needs. As numerous design elements need to be considered, evaluation of this indicator is based on the level of design adherence to best practice and beyond best-practice design guidance that specifically addresses users with diverse abilities. 

The evaluation of the indicator score is summarised in Table 94. The indicator score cannot exceed 100. On some occasions, next to the metrics of the indicator, a “non-applicable” option exists, so that users can indicate that the specific metric is not relevant to the project attributes. If the non-applicable option is selected (when available), the full metric score should be considered in the evaluation of the indicator score, to avoid penalising a project due to non-relevant aspects. Figure 71 shows indicator thresholds adopted to associate the indicator score to an indicator performance class. While these thresholds and performance classes are not directly applied in the evaluation of KPI and dimension scores and performance classes, they are included here to assist users in determining appropriate performance levels for specific project aspects and to offer clear guidance on their improvement.

EN 17210 (CEN, 2021b) sets out performance objectives for safe wayfinding and orientation for different users in several sections. These mainly cover indoor wayfinding and access to the project from the exterior, as well as clarity of signage and messaging. The EN 17210 standard provides design guidance for users of different ages and with physical impairments (e.g. mobility, auditory and visual impairments), and is considered current best-practice. Hence, non-compliance with this performance standard, results in an indicator score of 0. An Acceptable indicative performance class is based (at a minimum), on compliance with EN 17210 using national guidelines. A higher indicator score can be achieved by demonstrating compliance with the EN 17210 performance criteria using the specifications provided in TR 17621 (CEN, 2021c) (or alternative national guidance that provides equal or more stringent criteria than TR 17621). Higher indicator scores can also be achieved by implementing enhanced design criteria that also account for users with neurodiversity, and which derive from BS 8300-2 (BSI, 2018), ISO 19028 (ISO, 2016), NS 11001-1 (NS, 2018) and PAS 6463 (BSI, 2022). The enhanced criteria are grouped into categories according to the area, asset or design feature that they relate to in the project design. Each category of enhanced criteria is assigned a maximum score to ensure that an Excellent indicative performance for B.5.2 cannot be achieved without enhanced design features across the entire project. Accordingly, if either all relevant criteria within a category are satisfied, or all criteria within a category are not applicable, the maximum score of the category is achieved.

Visual contrast is adopted as one of the wayfinding cues in built environment projects. It is defined as the visual perception between one elements of a building (TR 17621). Visual contrast may be obtained by a combination of luminance contrast and colour contrast. Since people with impaired vision can rely only on luminance contrast, this is used in TR 17621 for visual contrast determination. As stated in Annex A of TR 17621, three main methods can be adopted for the estimation of luminance contrast, i.e. the Michelson contrast formula, the Weber contrast formula, and the light reflectance value (LRV) difference. The three methods are not comparable, and the selected method should be used consistently when adhering to the specifications provided in TR 17621. In the B.5.2 enhanced criteria, the LRV difference is used. LRV is defined as the proportion of visible light reflected by a surface at all wavelengths and directions, when illuminated by a light source. The LRV scale ranges from 0, which is a perfectly absorbing surface that could be assumed to be totally black, up to 100, which is a perfectly reflective surface that may be considered as the perfect white (BSI, 2018). For the selection of colours and materials during a planning procedure, the use of LRV is regarded to be appropriate as LRV values may be provided by the supplier of the colour system or can be measured with samples in a laboratory (see BS 8300-2, BSI, 2018 Annex B). The LRV difference is the point difference between the LRV values of two surfaces. Differences less than 20 points may not give adequate visual contrast, even with an illuminance of 200 lx on the surfaces (BSI, 2018).

Table 94. B.5.2 score.

¹        If the non-applicable option is selected (when available), the full metric score is considered in the evaluation of the indicator score. If satisfied and non-applicable metrics result in a score higher than the maximum within a category, then the maximum score of the category is applied.

²        If the section of EN 17210 does not apply to the project (i.e. non-applicable is selected), then as long as all other stated sections are complied with, then the project is deemed to be in compliance with EN 17210.

Source: JRC.

Figure 71. B.5.2 indicative performance classes and thresholds.

Source: JRC.

4.8.4   Usability and operation (B.5.3)

The Usability and operation indicator (B.5.3) evaluates the extent to which the project is usable and operable by all users, regardless of their abilities or background. This indicator focuses on whether the necessary and desired facilities for people with diverse needs available are available, and whether usable and operable elements within the space, such as furnishings, fixtures and fittings, are easy to use and operate by all users. 

The evaluation of the indicator score is summarised in Table 95. The indicator score cannot exceed 100. On some occasions, next to the metrics of the indicator, a “non-applicable” option exists, so that users can indicate that the specific metric is not relevant to the project attributes. If the non-applicable option is selected (when available), the full metric score should be considered in the evaluation of the indicator score, to avoid penalising a project due to non-relevant aspects. Figure 72 shows indicator thresholds adopted to associate the indicator score to an indicator performance class. While these thresholds and performance classes are not directly applied in the evaluation of KPI and dimension scores and performance classes, they are included here to assist users in determining appropriate performance levels for specific project aspects and to offer clear guidance on their improvement.

EN 17210 (CEN, 2021b) sets out performance objectives for usability and operation for different users in several sections, and mainly considers the needs of users of different ages and with physical impairments (e.g. mobility, auditory and visual impairments). The EN 17210 standard is considered current best-practice, and similarly to B.5.1 and B.5.2, non-compliance with it, results in an indicator score of 0. An Acceptable indicative performance class is based (at a minimum) on, compliance with EN 17210 using national guidelines. A higher indicator score can be achieved by demonstrating compliance with the EN 17210 performance criteria using the specifications provided in TR 17621 (CEN, 2021c) (or alternative national guidance that provides equal or more stringent criteria than TR 17621). Higher indicator scores can also be achieved by implementing enhanced design criteria that provide enhanced specifications and address users with neurodiversity. These derive from BS 8300-2 (BSI, 2018), ISO 21542 (ISO, 2021), ONORM B 1600 (ASI, 2017), PAS 6463 (BSI, 2022) and WELL v2 (IWBI, 2020). The enhanced criteria are grouped into categories according to the area, asset or design feature that they relate to in the project design. Each category of enhanced criteria is assigned a maximum score. This is done to ensure that an Excellent performance for B.5.3 cannot be achieved without enhanced design features across the entire project. Accordingly, if either all relevant criteria within a category are satisfied, or all criteria within a category are not applicable, the maximum score of the category is achieved.

Table 95. B.5.3 score.

¹        If the non-applicable option is selected (when available), the full metric score is considered in the evaluation of the indicator score. If satisfied and non-applicable metrics result in a score higher than the maximum within a category, then the maximum score of the category is applied.

²        If the section of EN 17210 does not apply to the project (i.e. non-applicable is selected), then as long as all other stated sections are complied with, then the project is deemed to be in compliance with EN 17210.

Source: JRC.

Figure 72. B.5.3 indicative performance classes and thresholds.

Source: JRC.

4.8.5   Example (B.5)

In this example a renovation project type for non-residential main use is considered. The assessment is carried out at the building scale. A textile factory, built in the 1800s, is sited in Lyon, France. Once at the outskirts of the city, with increasing urban development, it is now sited in a mixed-use area that combines residential and light commercial properties. A two-storey building, part of the textile factory complex, is renovated and transformed into a community facility for performing arts. The building provides the case study for the B.5 evaluation example (Figure 73). The community facility will be used by schools, community groups and charities. The latter includes a charity that promotes performing arts in adults with intellectual limitations or learning disabilities, many with co-occurring physical, visual and hearing impairments. 

On the ground floor, the renovation includes three new studio spaces, each with a specific use: creative workshop studio, dance studio and full theatre rehearsal studio. These branch out from a central community meeting space and a café. The studios form three sides of the central space. The fourth side includes at its centre the main entrance and lobby with a reception desk, two accessible toilets and a stair and lift for accessing the second floor. Female and male changing rooms (containing showers and further toilets) are on both sides of the lobby. The second floor of the building includes two storage rooms, office space with two accessible toilets and a technical studio and sound booth that serves the theatre rehearsal studio. To enhance ease of use, corridors are avoided throughout the renovated building.

Figure 73. Fictitious community centre plans.

Ground floor:

First floor:

Source: JRC.

Ease of circulation (B.5.1) is evaluated according to the metrics of Table 93.

Access, entrances and doors: Most users access the studios by public transportation. Others use door-to-door paratransit service and arrive at a drop-off zone, just beyond the building entrance. A public road runs in parallel to the façade, and is one of the few that intersects the complex of green space and multi-block textile factory buildings. Access from street level to the main entrance is provided via three steps, as well as by a ramp, which leads onto a landing. The landing is 2.50 m wide and 4.00 m in length, exceeding the minimum dimensions needed for wheelchair manoeuvring (CEN, 2021c, section 9.15(b)). The landing is fully covered by a canopy that cantilevers out from the building, providing headroom of 2.20 m. The landing is at the same level with the entrance and main lobby, whereas gratings are provided on the landing in front of the main entrance doors to prevent dirt being brought in. The main entrance comprises automatic sliding doors with a stop mechanism, opearated via a movement sensor or manually by pressing a clearly visible button that is mounted on a post. The sliding doors provide a clear width of 1.50 m and clear height of 2.00 m. A silver-coloured intercom system is provided on the wall at the side of the door at a height of 0.90 m above floor level. An emergency exit is provided in each of the three studios, and each exit provide direct step-free access to the streets, surrounding the building. Emergency exit devices are operated by a horizontal bar. All internal doors (e.g. to the changing rooms, offices, accessible toilets) are 1.00 m wide, except for the internal doors to the studio, which are 1.80 m wide double doors. No risk of crowding is identified. The entrance and door features meet the requirements of EN 17210 (CEN, 2021b) with the specifications of TR 17621 (CEN, 2021c). Enhanced criteria for the entrance doors, internal doors and canopy size are met, but not for the canopy seating area. The enhanced criterion for an automated door is met. As there are no side-hung gates, the related enhanced criterion does not apply. 

Corridors, passageways and other spaces: To enhance ease of use, corridors are avoided in the renovation design. An open space of 2.00 m · 2.00 m is provided in front of the lift for wheelchair manoeuvring. The building is composed of large open spaces in general (i.e. studios and central community meeting area), with most furniture either being on castors (with brakes) or light enough to be re-arranged freely. The central community meeting area and café provide a place of rest in transition between the lobby and studios. The corridors, passageways and other spaces meet the requirements of EN 17210 with the specifications of TR 17621. Enhanced criteria for the minimum turning spaces, avoidance of corridors and spaces of rest are met. The enhanced criterion of minimum unobstructed width of corridor does not apply.

Patios, balconies and terraces: There are none in the case study. 

Ramps, steps and stairs: The only ramp in the project is a straight ramp that provides access from street level to the landing in front of the main entrance. The ramp rise is 0.45 m with a gradient of 1:17 (5.9%) and length of 7.66 m. The ramp clear width is 1.5 m, allows frequent two-way traffic (permitting a walking person and a wheelchair user to pass each other). Two handrails are provided, which extend 0.30 m beyond the end of the ramp at both ends. The ramp is equipped with an upstand at each side of height 0.15 m. A flight of steps (3 steps) is provided in addition to the ramp. These steps have a rise of 0.15 m and a going of 0.30m. An internal staircase exists between the ground and first floor of the building. This is sited adjacent to the lift and has a half turn intermediate landing of 1.70 m depth, located 10 steps up from the ground floor. The internal staircase has an unobstructed width of 1.50 m and surface width of 1.70 m (allowing for handrails), which is adequate for evacuation use. Handrails are provided that are continuous across the stairs and landing, and extend 0.30m horizontally beyond the first and last step of each flight of stairs. The ramps, steps and stairs meet the requirements of EN 17210 considering the specifications of TR 17621. Enhanced criteria for avoiding curved and skewed stairs are met. The enhanced criterion regarding siting of stairs opposite to lifts does not apply, as the stairs are located adjacent to the lift.

Lifts, vertical and inclined lifting platforms, escalators and moving walks: There are no vertical or inclined lifting platforms, escalators or moving walks in the project. A lift is provided to facilitate access between the ground and first storey of the building. The lift has a size of 1.50 m · 2.10 m, which can accommodate one wheelchair and one additional passenger, allowing wheelchair rotation within the car. The lift is large enough to allow use with a stretcher in case of emergency. The lift is not equipped with a small mirror. As previously stated, an open space of 2.00 m · 2.00 m is provided in front of the lift for wheelchair manoeuvring. The lift meets the requirements of EN 17210 considering the specifications of TR 17621. The lift does not meet the enhanced criterion of provision of small mirror in the lift for wheelchair manoeuvring, but it does meet the enhanced criterion for space in front of the lift. The lift meets the enhanced criteria for colour.

Service counters for information, ticketing and reception, waiting and queuing areas: The reception desk, which is 0.80 m high, is directly in front of the main entrance. An open space of 2.50 m · 4.00 m (depth by width) is provided in front of the reception desk and a seating for 4 people is provided adjacent to the entrance. A 0.70 m clear height and 0.30 m recess is provided under the reception desk, at the front, to allow approach from people in wheelchairs. The reception and waiting areas meet the requirements of EN 17210 considering the specifications of TR 17621, and meet both the relevant enhance criteria.

B.5.1 score is in Table 96 (corresponding to Excellent performance for this indicator).

Table 96. Example of B.5.1 evaluation.

¹        If the non-applicable option is selected (when available), the full metric score is considered in the evaluation of the indicator score. If satisfied and non-applicable metrics result in a score higher than the maximum within a category, then the maximum score of the category is applied.

²        If the section of EN 17210 does not apply to the project (i.e. non-applicable is selected), then as long as all other stated sections are complied with, then the project is deemed to be in compliance with EN 17210.

Source: JRC.

Safe wayfinding (B.5.2) is evaluated according to the metrics of Table 94. 

In the community centre for performing arts, safety information includes signage for hazardous areas (including stairs), accessible evacuation routes and fire extinguishers. These are placed at 1.50 m and 2.20 m heights to allow them to be read and seen at a distance, respectively. They are located away from other signage to avoid confusion and have an LRV difference of 60 with respect to surrounding background. Information concerning fire safety and evacuation procedures is provided at all entrances and final emergency exits. Approaches to the entrance ramp and steps from above and below are highlighted with a coloured strip of width equal to 0.10 m that provides a visual contrast with the landing and ramp surfaces (LRV difference of 60 points). At the internal staircase, a visually contrasting line with a width of 0.04 m is provided on the front edge of the going in each step with LRV 80 points, which extends across the width of the step. The LRV value for the step surface is 20 points, thus the LRV difference is 60 points and lies within the accepted range for hazard zones in figure A.3 in TR 17621. All handrails are coloured to have an LRV difference of 30 with respect to the adjacent wall. The handrails are provided with raised Braille script at locations along their length that indicates the direction of fire evacuation. Tactile walking surface indicators (TWSI) with attention patterns (based on ISO 23599, ISO, 2019), and with profile heights of 4mm, rounded edges and LRV differences of 50 points with respect to surrounding surfaces, are used on the landings at the top and bottom of the outdoor steps and ramp. TWSI with similar specifications are also used at the top bottom of each flight of stairs indoors. These TWSI extend the full width of the stairs (and ramp), are set back 0.30 m from the hazard and extend 0.60 m in the perpendicular direction. The café kitchen, a potentially hazardous area, is set behind a door and accessible by a programmed lock system. 

Information for wayfinding includes signage in the reception area that indicates the location of the stairs and lift, changing rooms, toilets, and throughway to the community meeting area and studios, as well as directional signage from the central community meeting area to the studios. Signs are designed for maximum readability; therefore, font, text size, spacing, and alignment are chosen based on their ability to communicate messages clearly and directly. Standard and recognisable symbols, icons and pictograms are used along with text and braille. A consistent terminology is used in all signage, and other visual, acoustic and tactile messaging. The height of the relief of raised tactile letters, figures and graphical symbols is 1 mm. Appropriate lighting is provided for readability of signs. The specifications of TR 17621 sections 6.6 and 6.7 are met. Signs stating arrival at a point of interest are provided. A tactile map 0.5 m high by 0.5 m wide is provided at the reception area on a stand which angles the map at 20 degrees to the horizontal. Audible and visual information is provided through accessible public ICT screens in the reception area and central community meeting space, placed at 1.60 m height. No public ICT screens are placed at higher height. A hearing enhancement system is installed in each of the performance studios.

Important wayfinding features in the project are highlighted through visual contrast complemented by acoustic or tactile cues. Moderate visual contrast is provided between large surface areas (floor, walls and ceilings), with LRV difference between adjoining large surfaces being in the range of 30 to 40 points throughout the building, which meets the TR 17621 requirement of LRV difference equal to or higher than 30 points for large surfaces. The entrance to the building is easily identifiable due to the large canopy. Moreover, the sliding doors of the entrance are transparent and have a white frame (LRV = 83 points) that visually contrasts against the exterior brick (LRV = 30 points) façade of the building (LRV difference = 53 points). The doors have horizontal contrasting markings on the glazing that highlight its presence and indicate where the door opens. Smaller items that enable the use of building elements, such as the intercom at the front entrance and door handles, have an LRV difference equal to or higher than 70 points with respect to adjoining surfaces. A grating is located on the landing in front of main entrance doors. The grating has a length of 2.00 m and slots with mesh width 0.01 m and mesh length 0.02 m. The grating slots are flush with the floor, well drained and run across in the direction of travel, hence they contribute to acoustic orientation. Tactile cues to navigate the space include building textures, which identify the old versus new components of the building and allow users to familiarise themselves with the material representing each area. The central community meeting space walls where the entrances to Studios 1 and 2 are located, are made of brick and dry wall, respectively, with the entry to Studio 3 located to one side of the café kitchen. Internal doors leading to the studios strongly contrast with the surrounding wall in colour and material. 

All floor surfaces are level and flat without irregularities exceeding 5 mm, and made of firm materials that have adequate load-bearing capacity for persons using wheeled mobility devices. Both walls and floors have low reflective properties and are void of patterns. Vivid colours and bold patterns are avoided throughout the project. The stairs are located so that they are not in the direct line of travel. The location of accessible toilets is the same on both floors of the building. Opportunities to preview spaces are provided. The entrance doorway is glazed. All internal doors, except for those leading to toilets and changing rooms, include glazed panels (extending from 0.60 m to 1.70 m above floor level and 0.15 m wide), in order for users to verify whether they intend to enter the space beyond, especially during rehearsals and classes. The lift is glass-encased to support visual orientation. 

The project has a website that provides information about how to get to the building, the internal plan and environment, facilities and provides a virtual tour via a video. Crowding is avoided via bookings.

B.5.2 score is evaluated for the building in Table 97 (corresponding to Excellent performance). Overall, the project meets the specifications of EN 17210 through compliance with TR 17621 requirements. The project meets most of the B.5.2 enhanced criteria. It does not meet the criteria for: signage LRV difference equal to or higher than 70 points, directional signage to be visible from all directions, height of public ICT screens, steps having 70 points LRV difference to the edge of the tread and riser. The project is not a complex visitor destination and is not expected to have crowding. These enhanced criteria are therefore not applicable.

Table 97. Example of B.5.2 evaluation.

¹        If the non-applicable option is selected (when available), the full metric score is considered in the evaluation of the indicator score. If satisfied and non-applicable metrics result in a score higher than the maximum within a category, then the maximum score of the category is applied.

²        If the section of EN 17210 does not apply to the project (i.e. non-applicable is selected), then as long as all other stated sections are complied with, then the project is deemed to be in compliance with EN 17210.

Source: JRC.

Usability and operation (B.5.3) is evaluated according to the metrics of Table 95.

Doors: The main entrance doors have an automatic opening mechanism, triggered by movement or by the pressing of a button. Internal doors have horizontal handles of ‘D-lever’ type, that are 20 mm in diameter, 80 mm long, and located at a height of 0.90 m from the floor and 30mm from the door edge. The inside faces of accessible toilet doors are equipped with horizontal grab bars. All internal doors, including those for WC and changing rooms have a maximum opening force of 20 N and include kick plates. All internal doors are self-closing and have 0.40 m height at the base of the push side of doors. Emergency exit doors are operated by a horizontal bar. 

Windows: The position of the windows in the building is dictated by the original building design. The lower edge of all windows is 1.10 m from the floor, and they extend to 0.50 m from the ceiling height. In the renovation, the location of windows is considered in the space planning, and openable windows are provided at the ground floor in the 3 studios and in the reception area on either side of the main entrance. The pattern of windows is repeated on the first floor, and openable windows are available in the office space, storage rooms and technical studio. No windows are positioned in toilets, the café and central meeting area, changing rooms or stairwell. The windows are equipped with lever handles for manual opening and closing. Moreover, they can be opened through an automated system, with controls for each window placed at 1.00 m height adjacent to the windows and always at a distance more than 0.70 m from any corner. 

Ramps, stairs and lifts: Two powder coated metal handrails are provided along the ramp providing access to the main entrance: one at a height of 0.60 m and the second at 0.90 m from the ramp surface. Similarly, nylon-sleeved steel tube handrails are provided at 0.60 m and 0.90 m above the pitch of the stair and surface of landing for the internal staircase. For both the ramp and staircase, the upper and lower handrails have circular profiles with a diameter of 40 mm and 30mm, respectively. Circular handrails with a diameter of 30 mm are provided at a height of 0.90 m, on two sides of the lift car. A tip-up seat is not provided in the car. Both the landing and car control devices are placed at a height of 0.90 m from the floor level and at a distance of 0.50 m away from any corner. Audio messages are provided in the car to inform users of floor level reached, door opening, and at landing to inform of car arrival. All audible messaging is reproduced via an induction loop system. The area of active part of push buttons in both landing and car is 500mm². Each push button has a diameter of 20 mm and operating force of 2.5 N. Visual contrast is provided between the push buttons, face plate and surroundings. Symbols are provided in relief and braille as an independent feature to tactile figures. 

Furnishings: The seating area in the reception comprises 4 fixed seats with the following features: seat height of 0.42 m, seat depth of 0.40m, backrest height of 0.75 m from the floor and angled 100 degrees to the seat, armrests provided every two seats that are at a height of 0.25 m with no setback from the seat front. The edges of the seat, backrest and armrests are rounded. Along one side of the seats, there is a designated space for wheelchair users to stop. Along the other side of the seats there is a free area for assistance dogs. The number of seats in the reception area are deemed adequate for the space use, considering minimal queuing. Furniture in the central community meeting area comprises a range of seat sizes, heights and shapes, adequate for different users. The seats are lightweight and easy to move. Coffee tables are on castors (with brakes) and can be re-arranged freely. Seats in the office space have adjustable heights, inclinations and armrests. All desks have adjustable heights to allow use whilst seated or standing. Accessible lockers are provided in the changing rooms, but hand dryers and WC flushing system are normal and not low-noise ones. Power outlets are provided throughout the building, and mounted on walls at a height of 0.40 m. Drinking fountains are located in the community central meeting space at 0.70 m above floor level and use a lever-type tap system. Wall-mounted first-aid kits are also provided in the three studios, the reception area and office area. All staff is trained in first-aid administration.

Kitchen area and storage: The arrangement of the kitchen in the café considers users with wheelchairs. The kitchen is u-shaped, with work surfaces and appliances located on three sides, and a clear central space of 1.80m in diameter. A 0.60 m wide and a 1.50 m long clear space of counter (void of appliances or base units) with knee recess is provided. This is adjacent to the main kitchen appliances which have features to facilitate access by users on wheelchairs; for example, the refrigerator and freezer are fitted as separate units on a plinth of height of 0.20 m. Knee space is also provided directly below the hob and sink. The sink is shallow and has a lever-type tap and the hob is insulated below. A smooth transition is provided between the work surface, hob and drainer. Kitchen cupboard doors have a 90-degree opening. The storage rooms on the first floor allow access of wheelchairs.

Facilities for assistance dogs: Assistance dogs are welcomed in the building. A gated area, for them to stay when their owner uses the studios, is provided within the community meeting space, in a corner away from the café and visible by staff. 

Fire extinguishers and alarms: Fire extinguishers and alarms are located in each large space/room in the building (i.e. reception area, community meeting area, studio rooms, office space). Fire extinguishers are mounted at a height of 0.80 m from the floor and are at least 0.60 m away from any corner. Fire alarms are placed near the fire extinguishers, at a height of 1.00 m from the floor level.

Sanitary accommodation: These are provided adjacent to the reception areas and in the changing room at the ground floor. Other (non-accessible) toilet facilities are also provided in the changing room. On the first floor, the plan location of the accessible toilets is the same as for the ground floor. All accessible toilets have 1.00 m width outward opening doors, with D-lever type door handle that also activates the locking mechanism (when pulled upwards), and horizontal pull handle. One of the accessible toilets in the lobby area is designated as a baby changing facility (and hence are larger, to accommodate a 0.50 m by 0.70 m foldable table, nappy bins and other accessories). Each accessible toilet is a corner-type toilet, with a clear manoeuvring space of at least 1.50 m in front of the toilet pan, and lateral, oblique and frontal space for transfer to toilet pan. The accessible toilets have a toilet seat height of 0.45 m and foldable grab rails at 0.65 m height from the floor (i.e. 0.20 m above the toilet seat level). These extend to 0.20 m in front of the toilet pan, have rounded edges and are able to withstand a force of 1.7 kN in any direction. The accessible toilets have a washbasin located at 0.55 m distance from the toilet seat. The washbasin provides a knee space height of 0.70 m above the floor surface and a knee depth of 0.30 m. The child accessible toilets have a toilet seat height of 0.32 m and foldable grab rails at 0.47 m height from the floor. These extend to 0.20 m in front of the toilet pan, have rounded edges and are able to withstand a force of 1.70 kN in any direction. All washbasins have lever-type tap controls. Separate changing room spaces are provided for male and female users, with a breast-feeding room located in the female changing room. The breast-feeding room contains a comfortable chair, one electrical outlet, a microwave for sterilisation, and a user-operated lock with occupancy indicator. The male and female changing rooms have a shower section. Each shower room section contains four separate showers, one of which is accessible. Eight showers are more than sufficient for a building maximum occupancy of 400 people according to WELL v2 (IWBI, 2020) V04 – Part 2. The accessible showers contain a foldable waterproof shower seat able to withstand a force of 1.70 kN in any direction, with fixed vertical and horizontal grab rails for transfer to seat, and clear manoeuvring space of 1.80 m in diameter. A space of 0.90 m width by 1.30 m depth is also provided alongside the seat. 

All design features of the case study project meet the relevant specifications in TR 17621 but do not meet some of the enhanced criteria of B.5.3. The criteria for door opening force and for horizontal bars on wide doors are not achieved. In the latter case, although horizontal grab bars are provided in toilets, they are not on all internal doors (which all exceed 0.85 m in width). The enhanced criterion for handrails in lift cars is not met, nor are the criteria for the kitchen to have 180 degree opening cupboard doors and slide out shelves below the work surface. Minimum distance from control to internal corners is 0.60 m and not 0.70 m. Although all provided controls and switches are intuitive, no additional information is provided for their use. A space for practice of faith and/or contemplation is not provided. Sufficient shower facilities are provided to meet the requirements of WELL v2 (IWBI, 2020) C04 – Part 2. Although a separate breast-feeding room is provided, not all the amenities required by WELL v2 (IWBI, 2020) C09 to be within the breast-feeding room are provided. Hence, this metric is not satisfied. Although the central community meeting space provides an area for distraction and restoration, it only meets 4 of the 5 criteria in Part 1c of WELL v2 (IWBI, 2020) M07. Also, no restorative external space is provided. Hence, the project does not meet this enhanced requirement. The community centre is composed of large spaces but no specific smaller space for retreat is provided within any of these.

B.5.3 score is evaluated in Table 98 (corresponding to Good for this indicator). Addressing any of the design features that do not meet the enhanced criteria, as described above, could increase the score such that it would reach a higher performance class.

Table 98. Example of B.5.3 evaluation.

¹        If the non-applicable option is selected (when available), the full metric score is considered in the evaluation of the indicator score. If satisfied and non-applicable metrics result in a score higher than the maximum within a category, then the maximum score of the category is applied.

²        If the section of EN 17210 does not apply to the project (i.e. non-applicable is selected), then as long as all other stated sections are complied with, then the project is deemed to be in compliance with EN 17210.

Source: JRC.

Having evaluated the scores for each indicator, B.5 is calculated in Table 99, corresponding to an Excellent KPI performance class.

Table 99. Example of B.5 evaluation.

¹        Transformation of the indicator score to an indicator performance class is indicative and not required by the self-assessment method to estimate KPI and dimension scores and performance classes.

Source: JRC.

4.9 Maximising durability and service life (B.6)

4.9.1   Description and assessment

Under the KPI Maximising durability and service life (B.6), a quantitative assessment of the following indicators is provided:

• Durability (B.6.1): Duration of the useful life of the main elements of the building, between necessary refurbishments or renewals.
• Design for adaptability (B.6.2): Extent to which the design of the building allows and accommodates changing user needs and market conditions.
• Design for deconstruction (B.6.3): Extent to which the design of the building facilitates the future disassembly, reuse and recycling of building elements, components, parts and materials.

B.6 score is evaluated according to Equation (140). 

(140)

In the above equation, indicators promote resource efficiency, by ensuring that the service life of elements, components, parts and materials is maximised (B.6.1) and likely extended beyond the useful life of the building (B.6.3) that, at the same time, is renewed, allowing accommodating substantial changes in user requirements and needs (B.6.2). The combined optimisation of these three indicators is essential, as poor performance of one indicator may undermine the efforts to maximise the others. Very durable products that are not easily adaptable to new uses and purposes could go out of fashion or become obsolete, due to user needs or market factors, leading to their disuse before the end of their service life. Similarly, durable products that are not designed for disassembly cannot be adequately reused in new buildings or efficiently recycled. Both scenarios result in unnecessary removal, disposal, new purchase and new construction, making an inefficient use of the energy invested into the long-lasting products.

Each indicator is evaluated with a score between 0-100. The performance class of the B.6 key performance indicator is assessed according to the thresholds in Figure 74. 

Figure 74. B.6 performance classes and thresholds.

Source: JRC.

B.6 and its three indicators are designed to be implemented at the building scale, aggregating the assessment conducted over main spatial, architectural, structural, installation and service design features (B.6.1 and B.6.2) or its complete bill of quantities (BoQ) and materials (BoM) (B.6.3). To make and manage a harmonised estimate and classification of BoQ and BoM during the design stage, the Level(s) inventory template may be adopted (Donatello et al., 2021). B.6.1, B.6.2 and B.6.3 evaluation is affected by the project scale and type.

When a project, classified into the neighbourhood or urban scale, involves buildings with distinct design characteristics, thus likely leading to different indicator scores for each of them, the evaluation shall be carried out by identifying representative samples of buildings with similar design features. For each of these representative building designs, a separate assessment should be performed. The overall score per indicator is then estimated as a weighted average of the separate assessment scores, with the weights obtained from the relative occurrence of each building design.

For renovation projects, the assessment of B.6.1 and B.6.2 focuses on the specific aspects of the building and spaces that are affected by the proposed renovation works. However, when these indicators and/or any of their metrics address an aspect that has not been altered by the renovation, they are assessed considering the as-built state (i.e. condition existing before renovation and still present in the building), as this determines the service life of the building and its elements. The evaluation of B.6.3, instead, should be focused on the complete BoQ and BoM of the elements, components, parts and materials added during the renovation works.

The evaluation of the indicators is conducted by the design team, comprising architects, structural engineers and service engineers, likely seeking the advice of product manufacturers (B.6.1 and B.6.3), property market experts (B.6.2), demolition contractors and waste management experts (B.6.3), energy/sustainability consultants to conduct a life cycle analysis (LCA) or a global-warming potential (GWP) assessment, or experts familiar with the concept of buildings as material banks (BAMB) (Dodd et al., 2021c, d).

The assessment requires the identification and collection of the building design plans, architectural and structural design drawings, service plans, BoQ and BoM for the whole building or the renovated section of the building.

4.9.2   Durability (B.6.1)

The Durability indicator is evaluated through a dimensionless score. In the absence of a European standardised method, an approach based on the CASBEE property appraisal framework (IBEC, 2014) is adopted in the NEB self-assessment method. B.6.1 measures the capability of the building to maximise the interval between refurbishments and renewals. The durability score varies between 0 and 100 and is calculated as the weighted sum of the scores for the expected service life of main building elements including structural materials, interior and exterior finishes, specific building systems (HVAC, water supply and drainage pipe), and major equipment and services. Equal weights are adopted. The scores for the considered building components are reported in Table 100, and are assigned according to the following rationale:

• Low service life of elements – metric score = 0.
• Acceptable service life of elements – metric score = 33.
• Good service life of elements – metric score = 67.
• Excellent service life of elements – metric score = 100.

Table 100. B.6.1 score.

Source: JRC.

Whenever more types of structural materials are present and/or the structural elements face different exposure conditions, the evaluation should be based on the element with shortest service life among those with a share higher than 25% of the total amount of structural materials (either in terms of area or cost). The same applies to internal and external finishes.

For HVAC, water supply and drainage, the assessment focuses on the three pipe system types with the largest total weight of pipes in the building. Each type is characterised by a specific use (i.e. hot, cooling, mixed water, air, oil, etc.), material and jointing method. When pipes are used for water supply and drainage only, with no HVAC system present, the assessment focuses on the two most used pipe system types.

Finally, major equipment and services refer to systems that ensure operationality and liveability in buildings (i.e. generators, boilers, chillers, air conditioners, water tanks, pumps, etc.). The assessment should focus on the devices most extensively used for each main service equipment, based on the number of units and equipment capacity. The final score corresponds to the device with the lowest service life and a cost higher than 25% of the total cost of major equipment and services.

The service life of the main building elements, to be compared against the thresholds of Table 100, shall be determined according to well-established sources and methods such as the factor methodology, defined in ISO 15686-8 (ISO, 2008), accounting for the anticipated building life cycle and the specific operational and environmental conditions of each assessed element that are expected to alter the deterioration rate during its lifespan (IBEC, 2014). Reference service lifespan values are reported by relevant sources such as the Level(s) indicator 1.2 (Dodd et al., 2021b) and the Appendix 1 of the CASBEE manual (IBEC, 2014). The estimation can be supported by specific standards and codes, such as the EN 15459-1 (CEN, 2017) for heating systems, and information provided by manufacturers and suppliers (Dodd et al., 2021b).

Figure 75 shows indicator thresholds adopted to associate the indicator score to an indicator performance class. While these thresholds and performance classes are not directly applied in the evaluation of KPI and dimension scores and performance classes, they are included here to assist users in determining appropriate performance levels for specific project aspects and to offer clear guidance on their improvement.

Figure 75. B.6.1 indicative performance classes and thresholds.

Source: JRC.

4.9.3   Design for adaptability (B.6.2)

The design for adaptability and renovation indicator is evaluated through a dimensionless score based on Level(s) indicator 2.3 (Dodd et al., 2021c). The indicator measures the readiness of a building for adaptation to substantial changes, induced in the medium to long term by demographics, social, economic, technological and physical surrounding conditions (ISO, 2020), such as demand in the property market, existing and future user needs and life changes (Dodd et al., 2021c). The aim is to ensure adequate load capacity and space to accommodate the new functions (IBEC, 2014). The adaptability score varies between 0 and 100 and is the sum of the weighted scores for each adaptability aspect incorporated into the building design (Dodd et al., 2021c). The scores and the aspects that are targeted by B.6.2 are reported in Table 101, where the metric scores are assigned according to the following rationale:

• Changing building use and equipment is extremely difficult – metric score = 0.
• Changing building use and equipment is moderately difficult – metric score = 1.
• Changing building use and equipment is relatively easy – metric score = 2.
• Changing building use and equipment is extremely easy – metric score = 3.

Most of the scores and weights reported in Table 101 were originally proposed for the design of office buildings. In the absence of a standardised alternative method, the values are considered in the NEB self-assessment method as applicable to both residential and non-residential (commercial) buildings. Regarding the ‘higher ceilings for service routes’ aspect, the specific metric score values included in Table 101 for residential buildings are based on values recommended by the building flexibility calculator and the adaptive capacity calculation tool, provided by BREEAM Netherlands (Dutch Green Building Council, 2023). The same sources are used to implement minor amendments to the original Level(s) indicator 2.3 table (Dodd et al., 2021c).

Table 101. B.6.2 score.

¹        Examples of obstacles include bearing interior walls, columns, elevator shafts or installation ducts.

Source: Adapted from Dodd et al. (2021c) and (Dutch Green Building Council (2023).

The adaptability of the building project to accommodate variations in demands and uses is evaluated across three main categories of design concepts: (i) internal space distribution; (ii) building servicing; (iii) building façade and structure.

The organisation of internal space influences the flexibility for reconfiguring interiors as the needs of users change. Vertical load bearing elements and non-structural walls may limit the viable layouts and uses. In particular, greater spacing between vertical load-bearing elements allows for an open-plan design, providing maximum flexibility for reconfiguring spaces. Similarly, walls designed to be demountable or movable, without affecting the structural integrity or interfering with service ducts, can significantly increase the adaptability, as they can easily accommodate new layouts. If more than 20% of the walls (in linear metres) are load bearing, walls should be considered as ‘immovable and multiple functions’. Non-permanent walls are non-load bearing. Walls are movable if they can be placed in another location without material losses and fulfilling the same functions (W/E Adviseurs and Dutch Green Building Council, n.d.). Narrower façade bays contribute by creating smaller, more manageable sections of the façade, which can be more easily modified or replaced independently of the rest of the building, and by supporting the rearrangement of rooms number, sizes and functions. Multiple access points enhance adaptability by allowing different areas to be used independently or in various configurations. This is particularly important for buildings that may be subdivided or repurposed. This aspect is evaluated through the average area of the units, namely portions of the floor area with their own entrance and whose space can be used separately from the others (W/E Adviseurs and Dutch Green Building Council, n.d.).

Regarding adaptability aspects relevant to service ducts, the assessment should focus on system parts which support and provide the main functions required for each building use, namely the main parts of air conditioning pipes, the main sections of the building plumbing and wiring system, and the main sections of the building communication cables. 

The ease of replacing and reorganising service and equipment is a critical aspect of adaptability in building design. It is essential to position key service ducts in locations that are accessible without causing damage to surrounding building components. Placing them above or below elements such as false ceilings or raised floors or in exposed areas facilitates maintenance, upgrade, or replacement operations with respect to embedded solutions. However, false ceilings and raised floors that are closed and non-accessible for inspections require intrusive operations to allow replacement and reorganisation of the service, including demolition and reconstruction, potentially damaging the surrounding elements. In this case the ducts are considered as located between two building layers and a limited improvement to adaptability is obtained. Ducts in exposed areas or covered by easily removable floors and ceilings (e.g., suspended tiles and metal framework, or lamellar ceilings) allow higher adaptability. Additionally, having greater internal height in a building to accommodate service routes further enhance adaptability. In the assessment this is calculated as the clear height from the top of the finished floor surface to the bottom of the lowest structural section. The maximum value representative of at least 95% of the floor area should be considered (W/E Adviseurs and Dutch Green Building Council, n.d.). Similarly, the location and accessibility of plantrooms are crucial for streamlining alterations to mechanical and electrical equipment. Longitudinal ducts for service routes, facilitating the distribution from central sources to different building areas, offer more flexibility in the placement of service points compared to connection grids in which connections are at fixed locations. This longitudinal ducts or connection grid can be distributed along a single direction, i.e. within a wall. However, the flexibility further benefits from distributions occurring in two directions. Regarding sanitary facilities, accommodating future subdivisions is facilitated by having a larger number of individual servicing points. This aspect is evaluated by considering the average portion of floor area served by each sanitary facility.

Ultimately, adaptability is significantly impacted by the structural capacity of load-bearing elements. On one hand, any proposed new use or alteration to the horizontal or vertical layout is constrained by the structure ability to support increased loads. In particular, structural floor systems must present an adequate load bearing capacity, at least for 75% of the total floor area, for anticipated changes in live loads, due to repurposing. Whereas actual load-bearing elements must support future additions of storeys. On the other hand, the presence of load-bearing elements within or interacting with the façade restricts the permissible alterations and reorganisations of both internal room subdivisions and external façade patterns.

Figure 76 shows indicator thresholds adopted to associate the indicator score to an indicator performance class. While these thresholds and performance classes are not directly applied in the evaluation of KPI and dimension scores and performance classes, they are included here to assist users in determining appropriate performance levels for specific project aspects and to offer clear guidance on their improvement.

Figure 76. B.6.2 indicative performance classes and thresholds.

Source: JRC.

4.9.4   Design for deconstruction (B.6.3)

The Design for deconstruction indicator is quantitatively evaluated through a dimensionless score originally developed as Level(s) indicator 2.4 (Dodd et al., 2021d). The indicator varies between 0 and 100, for increasing ease of disassembly and extent of reuse, and may be weighted by mass, by volume or by value of the applicable elements (components, parts and materials). Mass is considered as a convenient common unit to compare distinct building elements, as it is expected to be easily estimated even when these products are supplied in units other than mass. To prevent an excessive influence of heavier products on the final score, the overall score may be weighted by volume or by economic value. In this case, cost should be specific to the building elements (components, parts and materials), excluding any labour or installation (Dodd et al., 2021d).

The spreadsheet calculator of the Level(s) indicator 2.4 may be used to identify the relevant building elements (Table 102). Subsequently, for each element the respective mass, volume or economic value should be estimated.

Table 102. Taxonomy of building elements.

Source: Dodd et al. (2021d).

For each building element (components, parts and materials), the best practical outcome at the end-of-life (i.e. disposal, recovery, recycle, reuse) must be identified. B.6.3 score is calculated as the ratio of the actual quantity of deconstructed elements (Q_dec) to their total quantity (Q_total), measured by mass (kg), volume (m³) or by economic value (Euro).

(141)

(142)

(143)

Q_i and c_i are the quantity and the circularity coefficient of the i-th product, respectively, out of the n forming the whole building. The circularity coefficient varies from 0 to 1, depending on the outcomes defined in the hierarchy of the Directive on waste (Directive, 2008; Dodd et al., 2021d), presented in Figure 77. The circularity coefficients associated with the outcomes are provided in Table 103.

B.6.3 score can be further broken down to scores corresponding to specific elements, as a means to identify weak building elements in terms of deconstruction.

Figure 77. Logic process for the assignment of circularity coefficient and waste hierarchy.

Source: Dodd et al. (2021d).

Table 103. Circularity coefficient.

Source: Dodd et al. (2021d).

Recommended performance thresholds for B.6.3 indicator and the minimum percentage of materials that should be directed to a specific end-of-life outcome are found in international and national standards and well-established certification schemes. Although a B.6.3 score equal to 100 is potentially achievable especially for buildings with limited service life, requiring full reusability is often impractical as some components may be obsolete by the time of the deconstruction (ISO, 2020). According to the European Directive on waste (Directive, 2008), at least 70% (by weight) of the non-hazardous construction and demolition waste (excluding naturally occurring material) generated on the construction site shall be prepared for reuse, recycling and other material recovery.