1 Introduction

Sustainability and resilience are terms one increasingly hears in discussions about the built environment [1]. While some use the terms interchangeably, they embody different concepts, which sometimes align, but in other cases, can result in competing objectives [2]. The terms sustainable, sustainability, and sustainable development have numerous definitions. It is critical to understand these definitions and juxtapose resilience to sustainability to ensure that one can be met without endangering the other, as clearly both are important. In the context of our world and its inhabitants, the principle of sustainability is based on a simple and long-recognized premise that everything that humans require for their survival and well-being depends, directly or indirectly, on the natural environment [3]. Current conceptualizations of sustainability emerged out of growing concerns in the 1960s and 1970s about whether industrial and economic development was creating long-term impacts on the planet and its flora and fauna, and thereby risk the potential for future generations to meet their needs [3,4,5]. Modern conceptualizations of sustainability typically consider sustainability in terms of three dimensions or drivers: economic, social, and environmental objectives, although other and different numbers of dimensions have at times been included [6].

The concept of sustainable development, which came to the fore in the Brundtland Commission report, Our Common Future [5], was born out of concerns over the depletion of earth’s finite resources and the potential for irreversible damage to the environment as a result of growing industrial activity, energy demands and transportation needs, coupled to the desire to find ways to address both sustainability and development as part of continued expansion of the built environment [6,7,8]. Similarly, the concept of planetary boundaries has also grown out of these concerns [9, 10]. According to the Brundtland Commission, “a sustainable society meets our present needs without compromising the ability of future generations to meet their needs” [5]. The conceptual basis presented here has this definition of a sustainable society as it’s foundation.

Concurrently, sustainability has been coupled with reducing the production of greenhouse gases and subsequent climate impacts, as investigated by the United Nations Framework Convention on Climate Change (UNFCCC) in 1992, the Kyoto Protocol in 1997, the Intergovernmental Panel on Climate Change (IPCC) [11,12,13] in 1998, ultimately culminating in the Paris Agreement in 2015 [14]. Within these efforts there was a clear and global imperative to reduce carbon emissions, and early on it was identified that the built environment was responsible for a significant percentage of carbon emissions, driven largely by energy consumption and embodied carbon [15].

Given the coupling of greenhouse gas emissions and material conservation, the application of sustainability concepts to buildings has often been focused on reductions in fossil fuel energy dependency and minimization of unsustainable material. This, in turn, has given rise to a focus on the development of sustainable materials, technologies and design concepts aimed at reducing energy demands, carbon emissions and material use as part of ‘green’ buildings [16,17,18]; and, of associated assessment methods and rating schemes which recognize such features [19, 20], of regulation (e.g., the Energy Performance of Buildings Directive [21, 22]) and of design guidance for sustainable buildings [23].

As with sustainability, there are many definitions and interpretations of the terms resilient, resilience and resiliency (e.g., [1, 2, 24,25,26,27,28,29,30,31]). With respect to our natural and built environments, and to society as a whole, the terms are broadly accepted as the ability to return to a defined ‘normal’ state after suffering some type of stressor or loss. The meaning of resilience in design has transformed over time with the creation of calculation methods for optimizing safety and use of materials to achieve required stability to static and dynamic forces (e.g., response to earthquake or wind forces). The risk in this change of focus is that layers of fire safety are lost, and redundancy reduced. In the 1970s, the concept of ecological resilience was developed [24] to reflect the ecosystem’s ability to adapt. This idea was then further extended to a more general (system) theory with the hopes of providing a new and useful framework for understanding how individuals, communities, and organizations, as well as ecosystems, are able to respond and adapt in the face of known and not yet known uncertainties, challenges and opportunities [25].

By the early 2000s, resilience took on new meaning relative to performance of buildings and infrastructure under extreme loading from events such as earthquakes, large hurricanes and terrorist attacks [26,27,28], and with consideration of societal and economic impacts, became more broadly discussed in terms of disaster resilience and community resilience [29, 30]. A widely used definition which emerged is the ability to prepare and plan for, absorb, recover from, and more successfully adapt to adverse events [7]. This can be applied to the resilience of infrastructure and complex systems when subject to extreme events [26, 27], including buildings [31,32,33], which are also complex systems.

The need to apply disaster resilience concepts to communities came into focus for many in the early 2000s. In the USA, for example, the terrorist attacks of September 11, 2001, Hurricane Katrina in 2005 (see Fig. 1), devastating tornados in 2011 and Superstorm Sandy in 2012 were watershed events, just to name a few. In more recent times, the harrowing destruction of the town of Paradise by the Camp wildland fire in November 2018 has highlighted the relevance of disaster resilience in communities, particularly those at risk from wildfire.

Figure 1
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Source: US FEMA / Mark Wolfe

Lone home standing in area hit by Hurricane Katrina.

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Increasingly, building fire resilience is being challenged by technologies implemented to meet sustainability objectives. Recent experience from a variety of building fires such as the Grenfell Tower fire in the UK [34], various façade system fires [35], fires in photovoltaic systems [36,37,38] and others, indicates that building choices made to improve building sustainability in some way can have significant implications for building resilience. Similarly, investigation of firefighting chemicals [39], asbestos [40], flame retardants [41] and fire response tactics [42] indicate that there are clear sustainability implications of fire safety and resilience choices. There is, therefore, a need for improved methods to foster the design of the built environment to ensure that it is sustainable AND fire resilient, i.e. to foster a sustainable and fire resilient built environment (SAFR-BE).

A SAFR-BE framework will help identify common or conflicting objectives in the built environment as a method to address these in a way that will foster both. This paper will outline a conceptual basis for such a SAFR-BE framework and present examples of its application to different aspects of the built environment. A few key fire incidents involving ‘green’ building attributes will be presented first to contextualize the need for a sustainable and fire resilient built environment (SAFR-BE).

2 Historic Fire Incidents in Buildings with ‘Green’ Attributes

Fire incidents involving green or sustainable building materials, technologies and features (attributes), i.e., buildings where sustainability objectives are guiding design choices, are difficult to isolate in fire statistics for a variety of reasons [15]. However, anecdotal information can be found in scientific studies (e.g., research reports, journal articles) and in the media or general literature. A small number of fire incidents are identified here to illustrate the fire safety implications of designing for sustainability, presented based on the building attribute identified as ‘green’. These lists should be considered exemplary rather than comprehensive. In all cases the evidence indicates that design choices made with sustainability objectives in mind have fire safety or building resilience implications (Fig. 2).

Figure 2
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Source: New Jersey State Fire Marshal, 2013

Aftermath of Delanco, NJ, Warehouse Fire.

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2.1 Exterior Wall Systems

A list of major fires in buildings where the exterior wall system has been identified as key to the fire is summarized in Table 1. In all cases, the exterior wall and cladding system has been identified as the primary ‘green’ element of the building involved in the fire. In some cases, the fire source has been identified, in others not. In most cases, the burning wall system was instrumental in the total failure of the building, often with significant impact on occupants. A variety of fires are presented to emphasize the fact that while the Grenfell fire has been very high profile, it is not unique.

Table 1 Representative Fires Involving Exterior Wall Systems.
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2.2 Energy Storage Systems

A list of major fires in buildings where the energy storage system has been identified as key to the fire is summarized in Table 2. In all cases, the energy storage system has been identified as the primary ‘green’ element of the building involved in the fire although the fire may extend to other elements. In contrast to wall cladding systems, these energy storage system fires seldom result in fatalities. Nonetheless, they represent significant risk to the environment, infrastructure costs and social disruption, all key dimensions of sustainability. Most fires were preventable, e.g. Eckhouse and Chediak [56] reported that “[a]t least 21 fires had already occurred at battery projects in South Korea”, and Colthorpe [57] reported that “in nearly every case the issue appears to have been poor management of batteries”.

Table 2 Representative Fires Involving Energy Storage Systems.
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2.3 Photovoltaic Systems

A list of major fires in buildings where the installation of a photovoltaic system has been identified as key to the fire is summarized in .

Table 3. In all cases, the photovoltaic system has been identified as the primary ‘green’ element of the building involved in the fire although the fire may extend to other elements. Note that while these fires seldom result in fatalities, they represent significant risk to the environment, infrastructure costs and social disruption, all key dimensions of sustainability. Figure 3 shows a photo taken at the scene of the Delanco, New Jersey, USA fire in 2013.

Table 3 Representative Fires Involving Photovoltaic Systems.
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Figure 3
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Source: Captain John Bonadio, Waltham Fire Department

Fire in Timber Frame Apartment Building Under Construction.

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2.4 Timber Framed Buildings

A list of major fires in buildings where the timber frame has been identified as key to the fire is summarized in Table 4. In all cases, the choice of a timber frame has been identified as the primary ‘green’ element of the building involved in the fire although the fire may extend to other elements. These fires represent significant risk to the environment, infrastructure costs and social disruption which are all important aspects of sustainability. Figure 3 shows an on-going fire in a timber frame building under construction in Waltham, Massachusetts, USA in 2017.

Table 4 Representative Fires Involving timber Framed Buildings.
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3 Sustainability and Resilience Interactions

While it can be argued that sustainability and resilience are different concepts, it is clear they are interconnected with respect to protection of humans and the environment. A review of the literature which explored similarities, differences and current management frameworks for increasing sustainability and resilience in an environmental management context, reflects inconsistency in the use of the terms [2]. Marchese et al. [2] found that sustainability was largely defined through the triple bottom line of environmental, social and economic system considerations, and that resilience was largely viewed as the ability of a system to prepare for threats, absorb impacts, recover and adapt following persistent stress or a disruptive event. Overall, the study found that three generalized management frameworks for organizing sustainability and resilience dominate the literature: (1) resilience as a component of sustainability, (2) sustainability as a component of resilience, and (3) resilience and sustainability as separate objectives. Regardless of the approach, however, implementations of these frameworks were found to have common goals of providing benefits to people and the environment under normal and extreme operating conditions, with the best examples building on similarities and minimizing conflicts between resilience and sustainability.

The Resilient Design Institute, for example, defines resilient design as “intentional design of buildings, landscapes, communities, and regions in order to respond to natural and manmade disasters and disturbances—as well as long-term changes resulting from climate change—including sea level rise, increased frequency of heat waves, and regional drought” [74]. There is a growing literature about sustainable and resilient design, largely focused on natural hazard events, in particular events potentially driven by climate change, such as more extreme storms, droughts, and wildland fires [75,76,77,78]; although there are examples of publications considering particularly the sustainability and fire resilience of buildings from more of a technology use perspective, i.e., in terms of fire performance of sustainable building technologies [15, 79, 80]. Given that these concepts are interrelated, we argue that there is a need to deal with them iteratively in building design. It is not sufficient to design for sustainability and assume that building fire safety regulations will take care of resilience requirements, nor is it sufficient to design for fire resilience and assume that environmental and chemical regulations will take care of environmental and/or social concerns while economics take care of themselves. To foster this iterative process, the SAFR-BE framework is proposed, with examples of applications to different contexts.

4 Sustainable and Fire Resilient Built Environment (SAFR-BE)

As a means to advance the need for the built environment to be both sustainable and resilient with respect to fire as an adverse event, it is useful to think in terms of a Sustainable and Fire Resilient Built Environment (SAFR-BE) as presented in Fig. 4.

Figure 4
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Adapted from Meacham and McNamee [1]

SAFR-BE Concept.

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In this context, the built environment includes buildings, infrastructure, and communities. Sustainable and Fire Resilient buildings (SAFR Buildings) are ones in which sustainable or ‘green’ objectives do not conflict with fire safety objectives, and where the building is resilient to internal and external threats from fire. Similarly, SAFR Infrastructure concerns such infrastructure components as non-fossil fuel (sustainable) energy sources or materials and sustainable technologies that are at the same time resilient to fires resulting from the technologies or that impinge upon the infrastructure from external fire events. SAFR Communities are those in which sustainable urban planning and resilience to wildland and other large open fire events are simultaneously addressed. In this sense, one can see SAFR Buildings and SAFR Infrastructure as important attributes assigned to SAFR Communities. Each of these applications of the SAFR BE concept are described in more detail in the ensuing sections.

4.1 Sustainable and Fire Resilient Buildings (SAFR Buildings)

The SAFR Buildings concept aims to promote buildings which are designed to both be sustainable (in terms of use of resources and greenhouse gas (GHG) emissions) and resilient to fires starting within or external to the building, regardless of the initiators [15, 79]. When a SAFR Building design methodology is adopted, it facilitates holistically designed buildings which seamlessly integrate sustainability and fire resilience objectives and minimize the potential for unintended consequences as illustrated in Fig. 5.

Figure 5
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Adapted from Meacham and McNamee [1]

SAFR Buildings Concept.

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With respect to sustainability and fire resilience, some rather significant fires associated with green building attributes have been observed, some of which relate to a lesser focus on fire safety objectives (see Tables 1, 2, 3, 4). In part, this can be attributed to a building regulatory focus on sustainability as a function of energy performance, and a lack of regulatory focus on resilience [81]. Concerns related to unintended consequences arising from focus on a single attribute of building performance, such as sustainability, without concurrent consideration of other important building performance objectives is not new [15, 80,81,82,83]. Such research has shown that there can exist a potential for:

  • Fire and health hazards due to the flammability and/or fire retarding treatment of thermal insulating materials,

  • Fire and smoke spread potential using double-skinned façades,

  • Ignition and fire spread potential with a coupling of photovoltaic (PV) systems and combustible insulation,

  • Potential contribution of unprotected/inadequately protected lightweight engineered lumber (LEL) or mass timber to fire severity and potential structural failure,

  • Increased potential of high strength lightweight concrete to spall during a fire and present potential for structural failure,

  • Ignition, explosion, and fire hazard potential associated with energy storage systems (ESS),

  • Potential fire hazards and impediments to emergency responders associated with interior and exterior use of vegetation, PV / building-integrated PV systems and other ‘green’ features and elements, and

  • Potential fire hazards of exterior vegetation for shading or other in the wildland-urban interface.

Finding a suitable balance between sustainability and fire safety objectives can be particularly complex due to the multidimensional aspects of each [81]. For example, timber is a sustainable material but is also combustible, so if not addressed appropriately the use of such material can present a significant fire safety hazard [15]. High strength concrete requires less material and is more sustainable than regular strength concrete, but can be particularly susceptible to spalling during a fire [84]. Insulation and alternative energy sources are good for sustainability, but photovoltaic panels which can cause ignition, and together with flammable insulation material, can be a catastrophic combination [15, 84].

The need to consider a SAFR Buildings approach is also a reflection of the evolution of building regulations in some countries where some have suggested that fire resilience of buildings may have inadvertently decreased over time [85,86,87]. Reasons for how potentially competing objectives could be introduced into the regulation and design of buildings, and the uneven levels of building performance that can result, have been explored in other contexts as well. Contributing factors include changes in policy-level focus, a siloed approach to building regulation development and building design, lack of clarity between sustainability and resilience, introduction of new materials and systems without adequate testing and design understanding, and inadequate enforcement mechanisms [81, 88]. In addition to a SAFR Buildings approach to building regulation and design, socio-technical systems (STS) thinking and an STS approach for the whole of the building regulatory system would greatly assist in identifying and managing competing objectives to facilitate delivery on holistic building performance [89]. Further, testing and classification systems are based on known materials and products at the time of development. Additional research is needed to critically review whether such regimes are appropriate for new material and products developed over time.

4.2 Sustainable and Fire Resilient Infrastructure (SAFR Infrastructure)

A society’s physical infrastructure includes the industries (agricultural and manufacturing) and utility, communication, and transportation systems that keep an economy operating, connected, and moving. In some definitions, buildings are included as well. The draft Good Practice Guidance Framework for Sustainable Infrastructure [90], which is being developed as part of the implementation of United Nations Environment Assembly (UNEA) Resolution 4/5 on sustainable infrastructure (UNEP/EA.4/Res.5), suggests that “[s]ustainable infrastructure systems are those that are planned, designed, constructed, operated, and decommissioned in a manner to ensure economic and financial, social, environmental (including climate resilience), and institutional sustainability over the entire infrastructure lifecycle. Sustainable infrastructure can include built infrastructure, natural infrastructure, or hybrid infrastructure that contains elements of both.” Implicit in the term “sustainability” are the concepts of inclusiveness, health and well-being, quality, service delivery, resilience, and value for money.

In the above definition, ‘natural’ infrastructure is largely ecological systems, and ‘hybrid’ systems contain aspects of built and natural systems, such as ‘green’ roof and wall systems. The rationale behind the Good Practice Guidance document is that existing guidelines, standards, and tools for integrating sustainability into infrastructure and spatial planning are usually only applied at the single-project level and often too late in the process to have an impact, and thus a more integrated, upstream, systems-level approach to sustainable infrastructure planning, preparation, and delivery is needed [90].

This approach is compatible with the Envision framework developed by the Institute for Sustainable Infrastructure [91], which contains a rating scheme, much like ‘green building’ rating schemes, but for application across the realm of physical infrastructure. The Envision framework contains 64 sustainability indicators, called credits, that are organized into five categories and 14 subcategories by subject matter to cover the full dimensions of infrastructure sustainability [91]:

  • Quality of Life: Wellbeing, Mobility, Community

  • Leadership: Collaboration, Planning, Economy

  • Resource Allocation: Materials, Energy, Water

  • Natural World: Siting, Conservation, Ecology

  • Climate and Resilience: Emissions, Resilience

Within the Envision scheme, the above components collectively address areas of human wellbeing, mobility, community development, collaboration, planning, economy, materials, energy, water, siting, conservation, ecology, emissions, and resilience, and collectively become the foundation of what constitutes sustainability in infrastructure [91]. Within the Envision structure, emissions associated with fire in infrastructure systems, as well as emissions associated with materials, construction and use of buildings and systems, are considered.

Critical infrastructures (CI) are those infrastructure systems where their incapacities or destruction could result in debilitating impacts on security, economy, public health, safety, environment, or any combination of these factors [92]. Resilience of CI has been a specific focus globally. In the USA this focus has become more pronounced since the terrorist events of September 11, 2001; and has been further brought into focus from natural hazard events such as Hurricane Katrina in 2005, Superstorm Sandy in 2012 and the wildland fires in 2017–2022. In particular, six critical infrastructure networks (CINs) types have been identified [93]: water distribution networks (WDNs), drainage distribution networks (DDNs), gas distribution networks (GDNs), transportation networks (TNs), electric distribution networks (EDNs), and communication distribution networks (CDNs).

Whereas vulnerability of these CINs to any type of threat is important, only a handful of approaches and methodologies appear to consider fire as a specifically identified hazard [93,94,95,96,97]. Furthermore, it is noted that a lack of system-based thinking exists. While many studies have explored the resilience of individual CINs, they have failed to recognize that complex infrastructure should be recognized as a “system of systems” or as a composite system. The importance of taking a systems-oriented approach, in particular a socio-technical systems (STS) approach, to CINs [98,99,100,101] and to buildings as complex systems of systems has previously been recognized [89, 102]. Failures that can arise when such systems thinking is not undertaken can be significant; however, means to assess gaps and manage risks exist [102,103,104,105].

Certain fire resilience aspects of critical infrastructure have been investigated [106, 107]. The effort by Mostafaei et al. [106] focused on protection and resilience of critical infrastructures against extreme fires, e.g. fuel storage or tanker fires, in light of the collapse of the World Trade Centre buildings in 2001 and the collapse and the MacArthur Maze Bridge in Oakland, CA, in 2007. A significant finding of this work was the need to develop methods and technologies for property protection of critical infrastructures, in addition to the current life safety requirements (as is the focus of building codes), since fast recovery of critical infrastructure after an incident is essential. Gerney et al. [107] expand upon this, while Ouyang et al. [108] describe the need for infrastructure to reflect resistive, absorptive and restorative capacities, meaning it should have means to limit impact from a fire event, limit the loss of function should an event occur, and be able to be readily repaired and returned to normal operation.

A SAFR Infrastructure concept reflects the ideals of the various approaches overviewed above, with a specific focus on dealing with sustainability and fire resilience objectives, see Fig. 6.

Figure 6
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Adapted from Meacham and McNamee [1]

SAFR Infrastructure Concept.

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4.3 Sustainable and Fire Resilient Communities (SAFR Communities)

4.3.1 Sustainable Communities

The somewhat nebulous term “sustainable communities” can encompass many activities or interventions; but, in essence it refers to communities that explicitly incorporate sustainable objectives in their planning and governance. Numerous initiatives focus, however, on the built environment rather than on the community, e.g., those that focus on reduced carbon footprints or life-cycle assessment of buildings and infrastructure. Some initiatives have, however, chosen to focus on the community as a whole, e.g. initiatives by the Institute for Sustainable Communities [109] or the United Nations Sustainable Development Goal 11 Sustainable cities and communities [110]. According to the United Nations, in 2018 approximately 55% of the world’s population lived in cities and just over 800 million of these 4.2 billion city dwellers live in slums. Further, it is expected that the vast majority, some 90%, of urban expansion in the coming decades will be in the developing world. The economic significance of these urban centers is profound with some 80% of the GDP being generated there. Clearly, increasing sustainability in these urban centers is crucial.

The Institute of Sustainable Communities defines sustainability objectives in terms of the three dimensions of sustainability, i.e., in terms of environmental sustainability, economic sustainability and social sustainability. Examples of relevant sustainability objectives are summarized in Fig. 7. As can be seen, there is some clear overlap to resilience concepts in terms of use of renewable resources, investment in the local economy and adaptability to change. Indeed, while sustainability is typically expressed in terms of increasing the quality of life in terms of the environmental, social and economic dimensions of sustainability; resilience is typically expressed in terms of the ability of a system (which might be environmental, social, or economic) to respond to stress [2]. Indeed, Marchese et al. [2] indicated that an increasing number of papers incorporate aspects of both sustainability and resilience considerations into their research.

Figure 7
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Examples of sustainability objectives for the three dimensions of sustainability, from left to right, environmental sustainability, economic sustainability and social sustainability based on definitions from ISC [109]

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4.3.2 Resilient Communities

In parallel with the previous section, the term “resilient communities” is somewhat nebulous, and a common definition is elusive. In some cases resilience is incorporated in the concept of sustainable, in some cases the opposite, in yet others the concepts are dealt with as essentially separate [2]. In the US, the National Institute of Standards and Technology (NIST), has recognized the fact that community resilience needs to be designed with response to numerous hazards in mind. In their Community Resilience program [111], activities across the whole emergency response cycle are developed and disseminated in relation to a variety of hazards.

Further, several international initiatives have incorporated the concept of resilience as the ability of a system to recover to perturbation and have fostered the development of resilient cities or communities through the development of best practices and exchange of ideas, e.g. the Rockefeller Foundation’s initiative focusing on the 100 Resilient Cities [112, 113] which has since 2019 been transformed into the 100 Resilient Cities Network [114]. In most cases, community resilience not only relates to fire resilience, it relates to the ability of a community to minimize the impact of a perturbation due to any major event.

Increasing recognition of the impact of wildland fires on communities in the wildland urban interface, see Fig. 8, has led to the development of numerous programs aimed at increasing community resilience by understanding and reducing community vulnerability to fires. Initiatives such as FireWise (US) [115], FireSmart (Canada) [116] or SaferTogether (Australia) [117] all foster the development of communities with improved resilience specifically to wildland fires, a key aspect of community fire resilience.

Figure 8
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Source: US FEMA, Andrea Booher

Aerial view of homes destroyed in Rancho Bernardo, CA neighborhood.

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FireWise and FireSmart have been developed through close collaboration between authorities having jurisdiction in the US and Canada and have significant similarities. In the case of FireWise, resilient communities are created by following their system comprised of the following parts: organize, plan, do, tell in a cycle, see Fig. 9.

Figure 9
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Steps to becoming a FireWise USA® Community [115]

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The aim of the FireWise USA® vulnerability assessment is to create a community snapshot and identify strengths and vulnerabilities on which the community can direct its focus. Neighbors must work collaboratively to take care of shared risk which is identified. Significant resources have been developed and can be downloaded from the website, including interactive tutorials, fact sheets with clear presentation of key information, renewal information, contacts to other FireWise USA® communities, and much more. The information is under continual development and the interested reader is referred to the website for the latest updates [115].

The need for programs to protect communities against wildland fires is due to the increasing extent of wildland-urban interface (WUI) around the world. Since the 1970’s it has been recognized that the incursion of low-density residential development in the area between urban centers and wildland areas is growing and represents one of the greatest fire challenges faced by the United States [118]. While exact estimates of the extent of WUI areas in various countries is not available, it can be established that the number of evacuations due to wildland fires in recent years has increased [119]. Figure 10 shows just one example of a neighborhood close to wildland areas with an encroaching fire.

Figure 10
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Source: US Federal Emergency Management Agency (FEMA) [120]

Wildland fire encroaching on neighborhood.

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4.3.3 SAFR Communities

SAFR Communities are those in which sustainable urban planning and resilience to wildland and other large open fire events, is addressed. An attribute of SAFR Communities would be SAFR Buildings and SAFR Infrastructure. Using the same basic framework as presented previously, we can infer that SAFR Communities will incorporate buildings, infrastructure, citizens and economy which adhere to both sustainability and fire resilience objectives, see Fig. 11.

Figure 11
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Adapted from Meacham and McNamee [1]

SAFR Communities Concept.

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SAFR Communities need to include an underlying consideration of both sustainability and fire resilience in their policy and planning documents. These documents can be improved by using this framework as it prompts town or community planners to think outside the box. One poignant example is the tendency to think in terms of single natural hazards occurred in 2012, when the tropical hurricane, Sandy, occurred bringing significant flooding with it. This flooding required a particular type of response and was likely to cause damage to infrastructure making the accessibility of first responders to different disaster scenes difficult. While the community planners had considered both fires and flood, they had no provisions on how to deal with fires in floods or the event of a flood while a major fire was taking place, even though fire following flooding has been a longstanding concern. When an area floods, there is often loss of electricity and other infrastructure, roads become impassable, and should a fire occur, it can be impossible for the fire service and other emergency responders to adequately respond.

The fire following the flooding initiated by Superstorm Sandy in 2012 in the US state of New York, occurred in the Breezy Point neighborhood of the borough of Queens [121, 122]. Due to the high flood waters, some volunteer firefighters could not respond, and the fire department was unable to get the fire apparatus near the initial fire location. Further, the cause of the fire was the interaction between high levels of sea water and electrical power lines. Given the high winds of the storm, the fire soon spread, ultimately destroying 127 homes. The disaster mitigation planning that had been in place had not considered fire during or following flooding – just flood control. Figure 12 shows devastation in Breezy Point as a result of the fire. SAFR Communities, not only respond better to incidents, but through preparation for large scale events, they are also better equipped to recover rapidly.

Figure 12
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Source: US FEMA, Andrea Booher

Aerial view of flood and fire damage caused by Hurricane Sandy, Breezy Point Neighborhood, Queens, NY, 2012.

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5 Sustainability and Resilience Integral to the Sociotechnical System

5.1 Sustainability and Resilience – Potentially Competing Regulatory Objectives

As established previously, the way the concepts of sustainability and resilience have been perceived, defined, and incorporated into design of the built environment has varied over time. Resilience was typically associated with the ability withstand an event, e.g., more robust walls, redundant support systems, use of stronger materials etc. Sustainability has evolved to focus more on resource reduction, e.g., use less materials, create fewer environmental impacts, cause less harm. In this manner there is somewhat of an inherent set of ‘competing objectives’, i.e., more (strength) versus less (materials). Therefore, the focus has been different, i.e., resilience has been interpreted as an attribute of structure, and sustainability an attribute of energy usage (both in the sense of material production and building use). These factors have resulted in challenges for building regulations with respect to how best to include and balance the concepts.

A 2012 analysis of building code formulation within and outside the Asia–Pacific region explored the extent to which sustainability and resilience were addressed [75]. In the ESCAP Report, four reference countries were selected: USA (California), Singapore, Australia, and the United Kingdom; along with five target countries in the Asia–Pacific region: Thailand, India, Bangladesh, the Philippines, and Sri Lanka. All building codes were analyzed for six elements of environmental sustainability (material conservation, energy conservation, water conservation, soil/land conservation, solid waste reduction and air pollution control) and six elements of disaster resilience (wind loads, snow loads, seismic effects, rain/flood resistance, wildfire, and landslide resistance).

With regards to environmental sustainability, the ESCAP report found that this is a relatively new element in Asian building codes and is therefore not well integrated. Of the five target countries, India was the only country that addressed all six elements of environmental sustainability. While the approach chosen in India is encouraging, most of the building code there is voluntary, and the parts that are mandatory have low compliance levels, indicating that adoption of sustainability targets is likely low. The main conclusion regarding disaster resilience is that some hazards have been addressed reasonably well (e.g., storms and typhoons) and others not, and that a variety of approaches were employed to encourage better disaster resilience (e.g., fiscal incentives (Japan), financial incentives (India), zoning incentives (Republic of Korea) and a combination of all (Singapore)). In the end, the analysis suggested that it is possible to improve environmental sustainability and disaster resilience of the built environment in all counties. A significant challenge is to find incentives that work in a specific context considering financing, human capacity, enforcement capacity and stakeholder cooperation, in addition to robust regulation.

As a means to further facilitate adoption of resilience into building codes as standards, the U.S. National Institute for Standards and Technology (NIST) identified research needed to facilitate development of guidelines and standards for disaster resilience of the built environment [123]. NIST identified that performance goals and resilience metrics are needed for all building systems. It was suggested that one starting point would be to identify such goals and metrics in current building codes and standards and identify where these need to be improved.

This topic was explored in the USA in a 2014 project by the Fire Protection Research Foundation [124]. The report notes that “applying many of the concepts of resiliency to fire related incidents would introduce some new language but would not radically change the fire safety requirements. It could, however, require more explicit definitions of performance objectives.” This finding is in line with outcomes from a 2010 U.S. DHS workshop report [125] and other research (e.g., [82,83,84, 94]), which found that overall:

  • Mechanisms are needed to define and quantify better levels of tolerable building performance, be they in terms of health, safety, welfare, risk, sustainability, or other measures.

  • Quantified performance metrics must be developed and incorporated into regulations. Recognizing that some metrics may be best addressed prescriptively (e.g., rise and run of a stair), there remains significant scope for performance measures, for which associated verification methods are needed.

  • Tools and methods for helping with the enforcement of performance-based building regulations are still lacking. In part related to the lack of quantified performance measures, those responsible for approval of designs and enforcement of regulations are faced with the challenge of making decisions in the face of significant uncertainty.

Research as recent as 2016 identified that challenges and discrepancies in incorporating sustainability and resilience into building regulations remain [81]. Much like the outcomes from the 2012 ESCAP study and 2010 U.S. DHS workshop, it was found that although the building regulations in the considered countries included some sustainability and resilience objectives, these societal objectives were not being viewed as having the same level of importance as providing for minimum levels of health and safety in buildings. Furthermore, the 2016 research found that holistic or integrated performance (i.e., making sure that adding a new objective does not result in an unanticipated impact somewhere else) has not yet been fully assessed, creating a potential for unintended consequences. Moving forward, concepts of sustainability and fire resilient buildings (i.e., SAFR Buildings) need to be integrated into building regulatory development. This can be facilitated within a holistic, socio-technical systems approach.

5.2 A Sociotechnical Systems Approach to Building Regulatory Systems

There are no easy solutions for developing building regulatory systems that are holistic and balance multiple objectives, such as sustainability and resilience, since while the problems are easy to recognize, the solutions are difficult to agree and implement [81, 89, 102, 126, 127]. Often there is not a single policy area which has responsibility. For sustainability, energy, resource management, and environmental regulation have impacts, not just building regulation. For resilience, planning, zoning, environmental and resource legislation all have a significant effect on the susceptibility of buildings to natural hazard events. If policy makers wish to avoid moving people or restricting expansion into hazard-prone areas (e.g., flood, earthquake or wildland fire prone), this places limits on regulating against such development. Decision-making in such environments is complex. The challenges become even more amplified when addressing existing buildings, as there can be less regulatory oversight, significant extra-regulatory tools in use (e.g., LEED, BREAM), and often less economic capacity to manage change from the ownership side (i.e., older buildings, particularly residential, house a higher percentage of lower income families).

These challenges exist in part because ‘newer’ objectives such as sustainability are not viewed holistically with existing objectives, such as health and safety, and are layered on rather than integrated into existing regulations. One step that can be taken towards resolving these challenges is better engagement of stakeholders, better characterization of use of risk and hazard data, and better clarification of roles, responsibilities and accountabilities of system actors through implementation of a socio-technical systems approach to building regulation and design of complex systems [81, 89, 102, 126,127,128].

Socio-technical systems (STS) theory developed from studies of organizations that identified linkages between social and technological components, whether at an individual organizational level or as a collection of organizations and institutions operating at the overall level of society [89]. Building regulatory systems reflect well the STS concepts at the societal level when considering the interaction of actors (stakeholders), institutions and innovation in defining and achieving acceptable building performance in both regulatory and market environments [88, 89, 102].

The Socio-Technical Building Regulatory System (STBRS) model developed by Meacham and van Straalen [89] was adopted from the system model outlined by Petak as applied to environmental management [127] and earthquake resilience [126]. This foundation is a suitable framework for describing building regulatory systems as STS, and for illustrating how that structuring could facilitate incorporation of risk as the basis for performance requirements in next-generation performance-based building regulation. In the original form [89], the STBRS model focused on fire as a hazard of concern, noting that other hazards could be considered in a similar manner (as Petak did for earthquake hazards). The concepts have been expanded upon in subsequent research [88, 102, 129].

In brief, while regulatory objectives are nominally focused on diverse areas, such as health, safety and sustainability, they must be considered together, so as not to create ‘competing’ objectives, such as inadvertently permitting combustible thermal insulation for energy efficiency, resulting in an unintended increase in fire hazard, or permitting the use fire retardant chemicals in foam insulation, which might create unintended human health hazards. In order to minimize the potential for such competing objectives and unintended consequences, the regulatory objectives, performance requirements and criteria need to be developed in an integrative and comparative manner. There will be need for iteration between objectives, considering risks and risk perceptions, through the process. The same holds true for sociotechnical system design [102].

6 Opportunities and Challenges for a SAFR-BE

The fundamental societal objective in the context of ‘green’ buildings has focused on sustainability. It has been argued in this paper that there is a need to broaden our basic understanding of societal objectives as being many, which must work together, and to include resilience with sustainability into the context of a Sustainable and Fire Resilient Built Environment (SAFR-BE). An underlying principle is the need to include risk and performance considerations into the overall assessment of whether particular structures meet design criteria across all societal dimensions.

With energy performance regulations, energy conservation codes, and ‘green’ construction codes, as well as energy conservation standards and ‘green’ certification schemes, there are myriad regulatory and market-based incentives to make buildings more sustainable. Some of the market focus on certification schemes, however, is still largely reserved for larger and costlier buildings, where developers, owners and managers are willing to invest in their ‘green’ status for triple bottom line benefits. Such buildings are likely to be able to also invest in fire safety as part of their overall functionality. At present, we lack the type of market-based incentives that ‘green’ certification provides in the fire safety performance realm. While some corporations have their own guidelines, most building construction is governed by regulations and insurance requirements, neither of which explicitly provide benefits for achieving fire performance that is higher than minimum requirements.

The SAFR-BE concept represents a framework to develop incentives for fire resilience along with environmental sustainability. Indeed, it is important to see the SAFR-BE concept as reinforcing sustainability objectives by increasing the status and value of fire safety objectives. However, for the concept of SAFR-BE is to become mainstream, it will be necessary to ensure that our understanding of the risks and performance of ‘green’ building attributes is sufficiently well developed to ensure sound construction practices and facility operations and maintenance within the ‘green’ market. This is a particularly important point given that the vast majority of buildings are not new, but are already existing, and often outside of strict regulatory compliance for some types of rehabilitation and renovation. The fire resilience of buildings needs to migrate into the realm of building renovation for sustainability, and to do so, it is critical to understand the implications of material, technology and design choices when the majority of the structure is already standing. New models and best practices to migrate existing buildings stock safely into the modern ‘green’ building paradigm is necessary.

While some fire incident data regarding fire performance of ‘green’ building attributes are available, there remains significant gaps in reporting on fire ignitions and contributions of ‘green’ attributes of buildings, and how sustainable planning and building features may have impacted the severity of a fire or the response of the fire service. There is a need therefore to broaden the input data fields on fire incident reporting systems to better capture green attributes that are suspected of contributing to fires [15, 82, 83].

While some progress has been made on better understanding fire performance of sustainable building materials, systems and technologies, some of the current standardized testing may not capture well enough the fire safety hazards and risks of the materials, systems and technologies in use (i.e., real life scenarios). Furthermore, the outcomes of the tests are not always conducive to engineering analysis through computational methods. Given the cost of mid- and full-scale testing, relevant data for the extrapolation or interpolation of results using engineering methods, are not developed. If there are inadequate data to inform regulation and support engineering tools, gaps may exist in resulting regulations, standards and guidance. Fire performance of complex façade systems is but one example. Data for engineering analysis is needed for all components, and the means to assess real-scale system performance is required. Development of standardized fire tests that deliver data that can be used in engineering analyses and computational analyses, and development of ‘appropriate-scale’ fire test methods to deliver more robust data on expected performance in real-scale applications, is needed [15, 88, 89, 102].

The use of sustainable materials, reducing energy consumption, and reducing the overall carbon contribution to the environment, are all key components to ‘green’ or sustainable design. Likewise, use of fire safe materials and systems provides a good starting point for the design of fire safe buildings. SAFR Buildings need to holistically include both considerations. While ‘simple’ in concept, materials, systems and features are often complex composites of individual components, just as the buildings themselves represent complex combinations of materials and systems. The way the current regulatory systems are working, testing and assessment of materials, systems and features occurs within the silo of the regulated performance, such as ‘energy performance’ or ‘fire performance’, and the holistic ‘energy and fire performance’ objective might be missed [1, 15, 88, 89, 102].

Finally, control mechanisms that require and reward a SAFR-BE are also needed. Control mechanisms can be defined as the methods by which democratic societies impose safety provisions on materials, products and systems designed to meet specified societal objectives. In the case of products and services, there is a long tradition of establishing performance requirements through standards or guidelines to define acceptable levels of performance for market accessibility. There are a variety of approaches to the development of control mechanisms from component testing to end use testing. In the case of many complex products, component testing may be adopted due to the prohibitive cost associated with testing all possible combinations of components in the potential end use. Typical for many control mechanisms is that they include aspects of testing, inspection and compliance over a period of time to ensure that established levels of safety are maintained over time. Unfortunately, such systems are often reactive, with standards being developed as a reaction to incidents or based on the development of innovations which have met the market but where there are indications that risks might exist but remain to be manifest. Also, if the test and analytical methods are lacking, there may be gaps in the regulations and resulting building designs. There is a clear need for such control mechanisms to become more proactive and reflect a socio-technical systems (STS) approach for ensuring fire safety ahead of the curve of development of the product, building or service [1, 15, 88, 89, 102].

As emerging technologies such as carbon capture systems, new structural materials, BIPV and more are developed, fire safety needs to be at the front end of the design process, and not an afterthought. Consider what happens as building integrated photovoltaics system (BIPV) technology becomes fulling integrated into façade systems, providing a potential source of ignition that is continuously available. One could argue that, by definition, emerging technologies will have many unknowns, and therefore risk. While testing, such as component level fire testing, can provide insight into part of the scenario, it may be insufficient to understand the overall fire performance. Risk-informed performance-based methods are needed to provide insight into the range of possible realizations of complex systems designs, and to inform mitigation strategies to control the risks to tolerable levels. Without all of the physical or statistical data needed to make judgements with very small bands of uncertainty, expert judgment, broad stakeholder deliberations, and use of available data will be needed. Methodologies that appropriately integrate these components will be essential [1, 102].

Fire safety design is not, and should not, be an isolated practice. Rather, it is part of a holistic design of a building. Better analysis and design tools for support of multi-dimensional performance assessment will be needed, and more use of technologies such as BIM, which are already widely used in the design practice, will be needed. As the industry moves to modular, or prefabricated prefinished volumetric construction, analysis and design decisions will be made ‘in the shop’ prior to manufacturing of components for shipment to the site and assembled into a finished building. Not only will the design technologies be essential, but also the means to assure the assembled building has addressed key issues, such as fire protection of connections, fire protection of void spaces, and the like [1, 102, 130].

7 Summary

The comparatively recent introduction of sustainability objectives to building regulations, facilitated by environmental impact concerns and fossil fuel energy shortages in the 1970s, and more recently by climate change impacts associated with buildings, has created the potential for competing objectives and unintended consequences as related to building performance. One area in which impact has been observed is an increase in fire hazard protection, which is a decrease in fire safety resilience. However, buildings need to be sustainable and fire resilient, which means a change in thinking and approach is needed. This need for a new approach extends beyond buildings to infrastructure and communities as well, encompassing an approach to a SAFR Built Environment.

This paper has discussed the concepts of sustainability and resilience as used within the built environment – buildings, infrastructure and communities – and has presented a discussion of how a SAFR Built Environment approach to planning, design and regulation can result in a built environment that more holistically meets the fire safety and sustainability needs and expectations of society. Opportunities and challenges were presented with traditional approach to building design. To create a SAFR Built Environment it is necessary to improve our understanding of the risks through improved data collection on building fires due to ‘green’ attributes, improve input data for sustainable AND fire resilient design and methods for multi-performance assessment. Digitization and future development in areas such as BIM may provide some opportunities for solutions. Perhaps most importantly, we need to bring the sustainability and safety communities together to better understand the challenges each faces and find solutions together.