Building Lifecycle Sustainability Analysis
According to ISO (the International Organization for Standardization), life-cycle analysis (LCA) is a “compilation and evaluation of the inputs, outputs and the potential environmental impacts of a product system throughout its life cycle” (ISO 2006). The life cycle is defined as “consecutive and interlinked stages of a product system, from raw material acquisition or generation from natural resources to final disposal” (ISO 2006).
The usage of LCA began in the United States in the late 1960s with Coca Cola being one of the early adopters by examining the effects the materials, energy, and environmental effects throughout the package manufacturing practice (Hunt et al. 1996). Reducing solid waste was the main point of focus of LCAs until the mid-1970s when energy took the main stage due to the energy crisis. In 1987, the idea of considering the future environmental impacts as a whole on future generations gained attention when the United Nations issued the Brundtland Report. In this report, sustainable development was defined as development that “meets the needs of the present without compromising the ability of future generations to meet their own needs” (United Nations World Commission on Environment and Development 1987, p. 15). This definition is significant for many reasons, but one fundamental significance is that it takes into account the limited resources of the Planet.
In 2015, a historic agenda was adopted by the United Nations titled “Transforming Our World: The 2030 Agenda for Sustainable Development” which includes 17 sustainable development goals (SDGs) (The Sustainable Development Agenda n.d.). While all are a most worthy cause, the SDG most relevant to building lifecycle sustainability analysis is SDG 11: Sustainable Cities and Communities. In today’s age, concerns about climate change and global warming have increased warranting an inclusion of these environmental topics in LCA. With residential and commercial buildings accounting for approximately 39% of the United States’ total energy consumption, implementation of LCA within the built environment context represents a huge opportunity to address and lessen these concerns (U.S. Energy Information Administration 2018).
There are four phases of an LCA consisting of goal and scope definition, inventory analysis, impact assessment, and interpretation (Bayer et al. 2010). The goal and scope definition step includes defining the products and/or services which will be assessed, what impact categories will be used, and what data needs to be collected in order to reach the defined goals and answer the proposed questions. In the inventory analysis phase, the materials and activities of each step of the process are inventoried and quantified based on emissions. The third phase, impact assessment, takes these emissions and converts them into impacts on humans and terrestrial eco-systems. Impacts include global warming potential, acidification potential, eutrophication potential, fossil fuel depletion, smog formation potential, ozone depletion potential, ecological toxicity, and water use. Interpretation, the fourth step, evaluates the impacts based on the proposed questions in the first step and helps make environmentally friendly decisions.
It is important to note that this is an iterative process with the fourth phase potentially prompting design changes which makes the LCA analysis likely to repeat itself. Additionally, LCA environmental modeling software tools have been developed which can help evaluate environmental impacts of a project based on the building products, building assembly, and combined systems and assemblies (Bayer et al. 2010).
This entry begins with a definition and introduction of LCA. Next, LCA is applied to the built environment and the barriers encountered in implementation of LCA initiatives in the built environment are discussed. Several case studies addressing how LCA can be applied to the built environment are reviewed next. This is followed by a summary of LCA variability and limitations as well as how LCA is being incorporated into green building trends. The entry concludes with the argument that the LCA framework encourages an integrated approach in determining environmental impacts throughout the full building lifecycle.
Application of LCA to the Built Environment
LCA incorporation into the built environment landscape is imperative so that environmental sustainability can be addressed. LCA allows evaluation of the building from an environmental impact perspective from womb to tomb. When applying the life cycle definition to the built environment, LCA would include raw material procurement, manufacturing, construction, operation, and decommissioning of a building (Singh 2017). Other terms which are sometimes used in place of LCA are “life-cycle assessment,” “cradle-to-grave analysis”, “womb-to-tomb analysis,” and “eco-balance analysis.”
Implementing LCA into the built environment context can take into account environmental impacts to include toxic emissions, energy use, resource depletion, habitat destruction, and global warming potential (AIA 2018). The American Institute for Architects, with over 90,000 members, published a guide in 2010 to assist architects in applying LCA to their practice during the design process. One goal of utilizing LCA during the design phase is to provide scientific justification for decisions made when designing and constructing a green building (Bayer et al. 2010). Not only is LCA applicable to designers, this type of analysis is also applicable to builders, operators, and corporate real estate users.
Perhaps the most notable program intervention which addresses LCA within the built environment is green building features. Green building features attempt to mitigate climate change and global warming through low-hanging fruit features such as switching to LED light bulbs to costlier features such as adding a photovoltaic array to a building. To assist in implementation of green features, various eco-labels have been established to standardize this process throughout the building lifecycle and among various sectors.
Leadership in Energy and Environmental Design (LEED), arguably the most popular third-party green building certification in the United States, offers eco-labels for buildings based on a number of designated points. Different levels of LEED certification are achieved based on these points with certified requiring the least amount of points and platinum requiring the most amount of points. LEED certification programs are tailored to various building sectors with commercial, neighborhood development, homes, and cities and communities offering a customized checklist to address the nuances of each particular sector. Furthermore, LEED offers certification for the building design and construction phase including demolition and major renovations as well as the operations and maintenance phase of a building including demolition and more minor renovations. The categories of focus for the LEED eco-label include location and transportation, sustainable sites, water efficiency, energy and atmosphere, materials and resources, indoor environmental quality, innovation, and regional priority.
ENERGY STAR is another popular eco-label for buildings in the United States which focuses strictly on the energy component during the operations phase of a building lifecycle. For this certification, the building is benchmarked against similar buildings and given a score between 1 and 100. In order to receive an ENERGY STAR certification, the building must receive a score of 75 or higher which represents that the building performs better than at least 75% of similar buildings. ENERGY STAR certification can also be found on appliances such as refrigerators and dishwashers. The National Green Building Standard (NGBS), the only residential green building certification approved as an American National Standard by the American National Standards Institute, is another eco-label targeted towards single-family, multifamily, and land development (Home Innovation 2018). Categories for this standard include site design, resource efficiency, water efficiency, energy efficiency, indoor environmental quality, and building operation and maintenance. The NGBS can also be found on products such as siding, insulation, windows, and doors.
Internationally, Building Research Establishment Environmental Assessment Method (BREEAM) is an established UK green building certification focusing on energy, health and well-being, innovation, land use, materials, management, pollution, transport, waste, and water (BREEAM 2018). This certification takes into account the building lifecycle from design, construction, operation, and refurbishment phases. Green Star, established by the Green Building Council of Australia, offers four rating tools to achieve certification (Green Building Council Australia 2015). These include Green Star – Communities, Green Star – Design & As Built, Green Star – Interiors, and Green Star – Performance. These various tools address precinct planning and development, building design and construction, fit out design and construction, and building operations and maintenance, respectively. This is not meant to be an all exhaustive list of green building certifications but to illustrate the fact that eco-labels are gaining in popularity around the globe.
Barriers to LCA Implementation in the Built Environment
While these green building certifications take into account and attempt to mitigate environmental impacts, their aim is not to measure environmental impacts throughout the full building lifecycle. This is why an LCA is critical in holistically measuring environmental impacts within the built environment. However, many perceived and actual barriers prevent a fully integrated application of LCA when assessing the built environment. One fundamental barrier encompasses the lack of data both from an environmental impact perspective as well as from a building systems and components perspective (Junnila and Horvath 2003; Scheuer et al. 2003). Without data on important environmental impacts such as ozone depletion and biodiversity as well as building systems material tradeoffs, a comprehensive and accurate LCA is nearly impossible. Information asymmetry continues with the architecture, engineering, and construction community with the majority of stakeholders in this community familiar with sustainability but very few with expertise with LCA (Olinzock et al. 2015).
Not only is lack of data a significant impediment, but the time, effort, and cost to collect the data to run an LCA poses a major obstacle (Cooper and Fava 2006; Olinzock et al. 2015). When factoring the complexity of this type of analysis coupled with the lack of a streamlined LCA approach for the building sector makes LCA a difficult sell in many cases (Olinzock et al. 2015; (Bribián et al. 2009; Cooper and Fava 2006). This implementation is further complicated by the lack of benchmarks which can be used for comparison as well as poor linkages with green building certifications (Bayer et al. 2010; Bribián et al. 2009).
When considering the full building lifecycle, there is a variability of building stakeholders throughout the building lifecycle. These include the architect, engineer, contractor, developer, building owner, occupant, and property manager among others which can create fragmentation when the full building lifecycle is considered. There can be a lack of cooperation between these stakeholders and a deficiency of financial incentives to consider the full building lifecycle versus the here and now (Bayer et al. 2010; Bribián et al. 2009). It has been noted in the research a lack of interest and demand for LCA, but this may be due to the aforementioned barriers, and it is suggested that LCA practitioners marshal the business benefits through client education (Cooper and Fava 2006; Olinzock et al. 2015).
A review of several case studies addressing how LCA can be applied to the built environment can be helpful in assisting entities considering application of LCA in their building decisions or where to focus their environmental reduction efforts. They also shed light on questions of quantification throughout the building lifecycle. For example, Huijbregts et al. (2003) compare two types of insulation throughout the building lifecycle of a single-family dwelling unit and find significant differences among these two types of insulation in regards to global warming, ozone depletion, and eutrophication. This is after quantifying model uncertainty. Asif et al. (2007) perform a LCA on various construction materials for a semidetached house and find that concrete accounts for 65% of the embodied energy and, along with mortar, accounts for 99% of the CO2 from the construction of this home.
Ramesh et al. (2013) analyze a multifamily building and find that the largest source of energy (89%) during the lifecycle of a building is attributable to the operating energy of the building. This is confirmed by Wang et al. (2011) who also find that the majority of lifecycle energy is found in the operating phase within a university building context. Embodied energy, which is the energy used to produce the building, is the second largest contributor of energy throughout the building lifecycle at 11%. To reduce energy consumption throughout the building lifecycle, aerated concrete blocks for the walls and roof were found to decrease building lifecycle energy by approximately 10%. Furthermore, adding photovoltaic (PV) panels reduced energy consumption by 37%. While these results are promising for mitigating environmental impact through reduced energy consumption, the cost to implement these energy-saving measures need to be considered as the financial bottom line guides many decisions by owners in the private real estate sector.
This financial bottom line can be analyzed by reviewing any upfront green premium there is to install more environmentally friendly features with the associated down-the-line savings during the operations phase of the building. This type of analysis discourages use of a strictly upfront costs lens and instead provides a full building lifecycle lens that can help decision makers measure both future and day to day performance (Epstein and Roy 2003). When reviewing the financial upfront green premium to the associated down-the-line energy savings, Hopkins (2015) finds that results are mixed with some buildings making the financial case for these features while other buildings not making the financial cut. Kats et al. (2003) analyzes the upfront green premium along with building operational savings and discovers that the upfront green premium cost is warranted by strictly the energy savings of building operations. Kats (2006) finds further positive financial results of green buildings in another study where an upfront green premium of $3 per square foot is found but a $12 per square foot savings in energy, water, health costs, and improved teacher retention justifies green building features from a financial perspective. Additionally, Kats et al. (2010) discover a $5 per square foot net present value (NPV) in buildings when down-the-line energy and water savings are included along with the upfront cost in the building life-cycle analysis.
LCA Variability and Limitations
As seen from the small sampling of studies reviewed above as well as from the literature review performed by Onat et al. (2014), there is considerable variability among LCA analysis. Even when performing a LCA among the housing sector and not accounting for any building sector variability, LCAs are conducted within different parts of the building lifecycle, focus on different materials, and report on diverse outcomes whether that be energy savings, ozone depletion, financial savings, or some other measure. As seen above, different LCA studies take into account different environmental impacts making comparison across LCAs difficult. Also, LCAs may be predicated on estimated values of items such as energy and materials usage so these estimates may not be accurate (Junnila and Horvath 2003). Questions on quantification throughout the building lifecycle also arise. But, by necessity, the LCA analysis will be limited in scope and certain items may not be included in the system analysis such as furniture and manufacturing of construction equipment (Junnila and Horvath 2003).
LCA may not be appropriate in all situations. For example, if the building has been acquired during the operations and maintenance phase, LCA may not be the most appropriate analysis as the building has already been designed and constructed. An environmental audit or environmental impact assessment may be more beneficial in this case. Additionally, LCA requires complete data when performing the analysis. This data availability is limited when attempting to complete the life-cycle inventory although a database continues to be created by NREL, a national laboratory of the U.S. Department of Energy.
LCA is an evaluation tool for decision-making based on environmental impacts. While LCA is an extremely valuable tool to account for environmental impacts throughout the building lifecycle, it typically does not address the economic or social aspects (ISO 2006). Therefore, LCA should be incorporated when completing a cost-benefit analysis where benefits including both direct and indirect positive outcomes are compared to the costs including the direct and indirect inputs required to produce the program intervention (Rossi et al. 2003). A cost-benefit analysis is “an analytical procedure for determining the economic efficiency of a program, expressed as the relationship between costs and outcomes, usually measured in monetary terms” (Rossi et al. 2003, p. 424).
Green Building Trends and LCA
While many organizations in the built environment claim sustainability as a goal, the Triple Bottom Line (TBL) accounting framework is gaining in popularity to allow these organizations to measure their sustainability performance towards these goals. TBL looks at performance from the three perspectives of people, profit, and planet. This trend is away from the traditional sole focus of profit and instead incorporates harder to quantify measures of people and planet as well (Slaper and Hall 2011). TBL also assists decision makers who need to consider sustainability holistically versus strictly from an environmental impact perspective which a LCA does (Onat et al. 2014).
Regarding profit, this is typically measured in a monetary measure such as dollars while social capital and environmental health can be difficult to quantify using the same monetary measurement since many object to putting a monetary value or find it difficult to arrive at an accurate price for something such as lost wetlands (Slaper and Hall 2011). A benchmark framework is one way to address these issues but another issue arises of how to weight the three dimensions of people, profit, and planet based on various viewpoints of stakeholders (Slaper and Hall 2011). Therefore, the TBL framework remains flexible allowing various entities to develop this framework based on their needs (Slaper and Hall 2011). Examples of environmental components in this TBL framework include target goals such as number of green certified buildings, reduction in energy, water, and waste, number of individuals who ride public transportation, and increase in air quality.
This TBL framework can be incorporated throughout the various building lifecycle phases and complements the LCA quite nicely. However, Kloepffer (2008) acknowledges that the definition of sustainability includes not only environmental but also economic and social spheres. Because of this, it is suggested that a life-cycle costing (LCC) and social life cycle assessment (SLCA) also be utilized in concert with the LCA to address all three spheres of sustainability. The integration of all of these analyses is a newer concept coined life cycle sustainability assessment (LCSA).
Onat et al. (2014) actually integrate the TBL analysis into the LCSA framework when analyzing buildings in the United States at a national level. The economic sphere of sustainability is represented by indicators such as GDP, the social sphere indicators represented by measurements such as government tax, and the environmental pillar indicators represented by a measurement such as greenhouse gas emissions. When analyzing electricity from these spheres, it represents the most positive component for economic indicators during the use phase in the residential sector while also representing the leader of environmental impacts throughout all building lifecycle phases. Regarding the social sphere, electricity is a positive factor to government taxes which the authors state would help to support national health and education programs. Additionally, the use phase of the building lifecycle is the main driver of sustainability categories.
Supply chain factors, which take into account the raw materials and work in process to achieve the final good, are also stressed for inclusion in an LCSA by Onat et al. (2014) when evaluating policies to reduce environmental impacts as the use of raw materials such as fossil fuels can cause negative environmental impacts. This includes the indirect and direct impacts of a TBL approach. This helps in accurately estimating the social, economic, and environmental impacts of buildings versus underestimation when not including the full supply chain and indirect impacts. Kucukvar and Tatari (2013) utilize a TBL framework to assess the sustainability of the United States construction industry and also stress inclusion of supply chain components so that sustainability indicators are not underestimated. This is because the results of this study reveal that the construction suppliers have a larger sustainable impact in comparison to the on-site activity.
Onat et al. (2014) mention that the trade-offs between these spheres should be optimized based on the priorities of decision makers. However, the argument remains that environmental priorities may justify a greater weight over economic and social priorities due to the very definition of sustainability. According to the Brundtland Report, the definition of sustainable development is “development that meets the needs of the present without compromising the ability of future generations to meet their own needs” (International Institute for Sustainable Development n.d.). Future generations may not exist to even collect government taxes or make a profit is the Planet is not protected.
Eco-labels such as LEED, which are growing in popularity as a signal of commitment to environmental sustainability, support the LCA framework. For example, Kucukvar and Tatari (2013) find that truck transportation ranks among the top three contributors within the supply sector regarding total energy footprint. LEED supports a decrease in this energy footprint by offering a credit for using regional materials which decreases truck transportation distance and hence lowers the energy footprint. Furthermore, it is also important to note that LEED version 4 Building Design and Construction, the most current version of this certification, is the first version to include a credit for building life-cycle impact reduction with three points offered for whole building life-cycle assessment (Singh 2017).
As the phases of the building lifecycle progress, there is typically a disconnect between the building design phase, the construction phase, and the operations phase (Bonandrini et al. 2005). One fundamental reason for this is a difference in team members during these phases. One intervention to prevent this disconnect and loss of knowledge between building phases is creation of a building information system from building inception (Bonandrini et al. 2005). Building information modeling (BIM), a 3D design and modeling software growing in popularity, is a tool to bridge this gap (Green 2016). By creating models of the building structure from project inception to building demolition, it allows for full building lifecycle consideration as well a platform that various stakeholders can access worldwide (Green 2016). Furthermore, BIM is designed to be flexible and workable so that various questions and problems can be addressed during the design phase (Green 2016). This includes sustainable design issues and questions. For example, Azhar et al. (2009) discover that BIM can handle sustainable design components such as energy usage, daylighting, and carbon emissions.
The theme of the high environmental impacts of electricity consumption throughout this entry is evident. When taking into account all three spheres of sustainability, energy efficiency throughout the building lifecycle can increase sustainability holistically by reducing environmental impacts, saving money from an economic perspective, and providing better health and safety for society by decreasing pollution. Another common theme is that the operations phase is the most impactful for sustainability. Therefore, the operations phase needs to be emphasized since it has the most impact. However, the majority of green building certifications attained to date focus on the building design and construction phase. While a sustainably minded building design can help the building operate more efficiently and BIM is a promising tool to consider the full building lifecycle, there are also operational measures such as purchasing, waste management, and green cleaning policies that are important to consider during the operations phase. LEED offers a certification focused on operations and maintenance, but it is not as popular as the building design and construction certification at this point. The Institute of Real Estate Management (IREM) recently developed a Certified Sustainable Property (CSP) for existing buildings which focuses on sustainably managing the building which is gaining traction.
LCA is an important tool that takes into account the environmental impacts of the built environment throughout the full building lifecycle. As the population needs the built environment to live, work, and play, green building can provide a way to build in a more environmentally responsible manner. With the world population continuing to grow on Earth, fostering and creating a more environmentally sustainable built environment becomes ever more important. While LCA has been adapted in some cases to a LCSA to incorporate all three spheres of sustainability, it is argued that the environmental sphere must be a priority as the Earth must be protected in order to focus on the other two spheres. However, it may be difficult to change priorities of various decision makers from a strictly profit-based perspective. This is where education of the business benefits of LCA are paramount.
LCA barriers such as complexity and lack of a streamlined process for the building sector prevent an increase in industry adoption. By addressing the aforementioned barriers regarding LCA, the building sector can increase utilization of LCA to more comprehensively address environmental impacts and in turn further mitigate environmental impacts of the built environment. LEED and ENERGY STAR certifications for greener buildings may be more attractive for industry to embrace as there is a checklist which is used to attain this certification. While these types of certifications do help in mitigating environmental effects of the built environment, it is imperative to persuade organizations to consider the full building lifecycle versus strictly the portion of the lifecycle which may they may directly be a participant. This requires an integrated approach which must orchestrated among all stakeholders. LCA encourages this integration by providing a framework to account for a building’s environmental impacts from cradle to grave.
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