Building LCA Research Articles

Integrating effects of overheating on human health into buildings’ life cycle assessment

PurposeDue to climate change, the severity and length of heat waves are increasing, and this trend is likely to continue while mitigation efforts are insufficient. These climatic events cause overheating inside buildings, which increases mortality. Adaptation measures reduce overheating but induce environmental impacts, including on human health. This study aims to integrate the overheating-related effects on human health in building LCA to provide a design aid combining mitigation and adaptation.MethodsIn a novel approach, an existing building LCA tool is utilised to evaluate life cycle impacts, including damage to human health expressed in DALYs. The overheating risk is then evaluated using an existing dynamic thermal simulation (DTS) tool and prospective climatic data. Overheating is expressed as a degree-hour (DH) indicator, which integrates both the severity (temperature degrees over a comfort threshold) and the duration (hours). By assuming proportionality between DALYs and DH × area in a first step, the 2003 heat wave mortality data, 2003 climatic data, and a simplified model of the national residential building stock were used to identify a characterisation factor, which can then be used to evaluate DALYs corresponding to any building using DH obtained by thermal simulation.ResultsThe proposed overheating model not only allows to derive a characterisation factor for overheating to be used in building LCA but also provides practical insights. The first estimation of the characterisation factor is 1.35E-8DALY. DH-1.m-2. The method was tested in a case study corresponding to a social housing apartment building in France built in 1969 without insulation. The thickness of insulation implemented in the renovation works was varied. For this specific case study, the contribution of overheating is significant, ranging from 1.1E-5DALY.m-2.y-1 to 2.2E-5DALY.m-2.y-1, comparable to the contribution of heating. DTS and LCA results found an optimal thickness, minimising the human health indicator in DALYs. This underscores the potential of active cooling to reduce human health impacts, especially if it consumes electricity produced by a photovoltaic system integrated in the building.ConclusionCombining DTS and LCA makes it possible to evaluate damage indicators on human health, including building life cycles (e.g., material and energy) and overheating-related impacts. An application on a case study shows this method’s feasibility and gives a first order of magnitude of overheating health impacts induced by buildings. A more sophisticated model could replace the assumed proportionality between DALYs and DH.

LCA of net-zero energy residential buildings with different HVAC systems across Canadian climates: A BIM-based fuzzy approach

The urgency of addressing building energy consumption's impact on climate change, particularly from fossil fuels, is of great significance. This study investigates the environmental and economic aspects of different climatic conditions in Canadian regions throughout a building's life cycle. Focusing on HVAC systems, choice between electricity, natural gas and solar sources. Using whole building life cycle assessments and energy simulations, the research examines 36 scenarios, considering three popular HVAC systems with six weather conditions. To reduce uncertainties, the study employs BIM and fuzzy-based methods. The results identified consistent environmental impacts across scenarios, averaging 1.4 tonnes CO2eq/m2 in GHG, 1.74 kg/m2 in PM2.5, and 3.61 kg/m2 in SO2 emissions for a typical net-zero energy building in Canada. Variations primarily result from operational, embodied, and transportation stages, rather than other life cycle stages. Colder climates, like central Canada, exhibit higher energy demands and increased global warming potential. Ground Source Heat Pump (GSHP has lower emissions despite higher upfront costs and is preferred when considering both environmental and economic factors. However, in mild climates like Vancouver, Air Source Heat Pump (ASHP) is optimal. Photovoltaic panels enhance HVAC system feasibility across various options. The study provides insights for building industry stakeholders, including designers, owners, and policymakers.

Dealing with uncertainties in comparative building life cycle assessment

Building LCA aims at guiding designers towards more sustainable projects. Many sources of uncertainties affect environmental modelling. Therefore, the reliability of decisions based on building LCA is questioned. However, information on uncertainties can strengthen decisions, when properly addressed. In this study, seven statistical metrics are compared based on dependent samplings for sensitivity analyses (SA) and uncertainty analyses (UA). It allows to identify a set of indicators on which conclusions are more reliable. For the first time, this methodology is applied to comparative building LCA, considering three construction alternatives: a concrete, a concrete blocks and a wooden-framed house. A new SA method, based on Morris, helps identifying which of 153 uncertain factors are more likely to influence decisions. More precise data is then collected on these uncertain factors. In this case study, the Heijungs significance metric and the distribution of relative differences were the most appropriate metrics to assess UA results. They allow to determine, for each indicator, which is the best alternative and how much better it performs. Consequently, the non-conclusive indicators are discarded. Applying this methodology, decision are enhanced by uncertainties and rely on a smaller set of indicators to select an alternative in terms of environmental performance.

업무용 건축물 LCA 분석을 통한 녹색건축 인증제도 개선방안 연구

In this study, a study was conducted to identify problems with the "building LCA" evaluation items in a domestic green building certification system(G-SEED), and to prepare improvement plans. To this end, domestic and foreign green building certification systems were compared, and the evaluation items of G-SEED were analyzed and LCA case studies were conducted for Business facilities buildings, and the results were analyzed. As a result of the case analysis, it was analyzed that each environmental load impact category affects the environment in the order of 48.5% global warming, 37.3% resource depletion, 5.8% photochemical oxide production, 4.7% human toxicity, 2.0% acidification, 1.1% eutrophication, 0.4% ecotoxicity, and 0.3% ozone layer destruction. In addition, improvement plans were presented through the results of case analysis.

What is the impact of a basement on a building LCA and what role does the functional unit play?

The goal of reaching nearly zero emissions in the construction sector by 2045 is important and at the same time ambitious. Therefore, emissions from operation and structural design of a building play an important role. Life cycle assessment is an established method for determining the environmental impact of a building throughout its life cycle. The implementation of an LCA follows in general the standards ISO 14040 / 14044, and on building level the standard EN 15978. It requires, among other things, the definition of the goal, the system boundaries and the functional unit. For buildings with basements, there are certain discrepancies in the definitions of goals, system boundaries, and functional units. When the production, construction and maintenance phases of a building are included in the system boundaries of the LCA, the whole building is considered and is for example related to the functional unit gross external area or others as net external area or heated area. The set goal, system boundaries and selection of the functional unit has a direct influence to the LCA results. In this paper, the effects of a basement on the LCA results of the operational and structural design of a building are presented as a function of different functional units. Therefore, a comparative LCA on residential buildings in two different energy standards (level 40, level 55) and additionally for conventional and future-oriented construction were calculated.

Towards indicative baseline and decarbonization pathways for embodied life cycle GHG emissions of buildings across Europe

Buildings’ construction and operation are major contributors to global greenhouse gas (GHG) emissions, and the substantial reduction of GHG emissions across their full life cycle is required to enable meeting international climate targets. For effective climate change mitigation - as recent studies have shown - a special focus has to be put on lowering embodied GHG emissions, i.e., emissions related to construction production manufacturing and construction processes, maintenance and replacement as well as end-of-life processing. As the importance of reducing embodied GHG emissions rises, so does the need for understanding both the baseline and pathways for reduction across the full life cycle of buildings. In this paper, we offer insights into the data-driven analysis of embodied GHG emissions across the whole life cycle of buildings from recent studies. Our investigation builds on the data collection, processing and harmonisation of around 1.000 building LCA case studies. We offer an integrated perspective on GHG emissions across the life cycle of buildings, considering historical trends, current baselines and indicative reduction pathways for embodied GHG emissions in different countries across Europe. This serves to inform our current ‘decade of action’ and the transformation to a regenerative built environment by 2050.

Comparison and analysis of product stage and service life uncertainties in life cycle assessment of building elements

Abstract Life cycle assessment (LCA) has the potential to inform building decisions from the planning process to conceptual design. As such, there is intrinsic uncertainty that needs to be explored further to allow for proper decisions to be made. These uncertainties may be related to parameter definition, such as life cycle inventory or model as service life definition. This paper aims to analyze the influence of two recognized sources of uncertainties in LCA of buildings: product stage uncertainties and uncertainties from SL during the use stage. The Monte Carlo simulation method is applied to conduct uncertainty analysis of the LCA results of four building elements, namely, external cement plaster, external clay brick wall, external painting and internal painting. The functional unit is 1 m2 of each building element. Three different building reference study periods are considered: 50, 120 and 500 years. A global warming potential impact category is chosen since it is one of the most significant indicators for climate change mitigation strategies. Results indicate that SL uncertainties are greater than product stage uncertainties for the four building elements analyzed. Furthermore, based on the findings from this study, distribution choice influences the uncertainty analysis results in Monte Carlo simulation. Standardizing modeling of SL in the LCA of buildings could guide building LCA practitioners and researchers and lead to more comparable results.

Major Building Materials in Terms of Environmental Impact Evaluation of School Buildings in South Korea

This study aimed to analyze the major building materials in terms of environmental impact evaluation of school buildings in South Korea. Three existing school buildings were selected as the analysis targets, and building materials were analyzed in terms of cumulative weight and six environmental impact categories (global warming potential, abiotic depletion potential, acidification potential, eutrophication potential, ozone-layer depletion potential, and photochemical oxidation potential). The materials were analyzed from an environmental perspective after integrating the six environmental impact categories into the environmental costs. From the analysis, nine major building materials, including ready-mixed concrete, concrete bricks, aggregate, rebar, cement, stone, glass, insulating materials, and wood, were selected for the school buildings. These analysis results can be used as a streamlined evaluation of the environmental impacts of school buildings. It is thought that the simplified life cycle assessment will help make decisions considering environmental characteristics in the early stage of the construction project. Additionally, it will be possible to make LCA efficient in terms of time and cost, one of the largest constraints of the existing building LCA, and effective reduction in the environmental load.

Natech risk and the impact of high-GWP content release on LCA of industrial components

Industrial facilities can be severely affected by natural hazards (NHs) often resulting in significant social, environmental, and economic consequences. One of the most serious consequences of Natech’s events is the accidental release of hazardous chemicals. While special attention has been paid to leakage prevention of toxic, flammable, or pollutant components to date, the possible effects in terms of green house gas (GHG) emissions have not been thoroughly investigated. NH can trigger, indeed, the release of high global warming potential (GWP) compounds such as fluorinated gases, nitrous oxides and others chemicals from collapsed components and/or structures. Nonetheless, conventional approaches to integrate NHs with LCA of buildings focus mostly on the embodied carbon metric, evaluated as in the Bill of Material procedure. As demonstrated by empirical evidence, these methods do not take into account the possible high-GWP compounds release in the case of extensive damage or collapse, which may lead to a general underestimation of the related carbon footprint. It is worth noticing that current international standards do not explicitly recommend the inclusion of these aspects in LCA procedures for structures. To cope with these issues, we introduce in this paper both the new concept of content release GHG emission potential (CGEP) and, a procedure, capable of integrating these effects with LCA. Finally, we provide some examples of industrial components characterized by a significant CGEP.

Integrating long term temporal changes in the Belgian electricity mix in environmental attributional life cycle assessment of buildings

The operational energy use is responsible for an important share of the life cycle environmental impact of buildings. In the national LCA method for buildings in Belgium, as in most environmental impact assessments, operational energy use and associated impacts are kept unchanged throughout the 60-year service life of the building. The energy mix will however change over the building life cycle and this will influence the impact of the operational energy use. The overall aim of this paper is to analyse how long term temporal changes in the electricity mix in Belgium might influence the life cycle environmental impact of buildings using an attributional approach. This paper focuses on three aspects. First, it analyses future scenarios for the Belgian electricity mix as it is uncertain how it will change over time. Second, the environmental impact of these changes in the mix is evaluated using the Belgian life cycle impact assessment method for buildings considering a broad set of indicators. Finally, it is investigated how these changes in the electricity mix during the building service life can be included in the attributional life cycle assessment and how this influences the overall environmental impact of the operational phase. Within this study, three dynamic scenarios are defined and compared with the static approach, i.e. current electricity mix remains unchanged during the next 60 years. The analysis reveals differences in the building life cycle environmental impact of −29% and +34% compared to the current static approach, while differences in the life cycle carbon footprint range from −59% to +33%. This highlights the importance of considering changes in the electricity mix in LCA of buildings and in considering a broad range of environmental indicators instead of solely focussing on greenhouse gas emissions when making policy decisions. In general, a major challenge for the next decade seems to be phasing out nuclear power, without increasing the environmental impact of the electricity mix.

Comparative study on Life Cycle Assessment of buildings in developed countries and Sri Lanka

PurposeLife cycle assessment (LCA) has considerably contributed to increasing the environmental friendliness of buildings in developed countries. However, it is hard to find evidence on the application of LCA for buildings in developing countries; particularly, Sri Lanka. There is a lack of research to compare the status of LCA of buildings in developed countries vs developing countries. In this context, the purpose of this study aims to examine the status of LCA implementation for buildings between developed countries and Sri Lanka, a developing country.Design/methodology/approachThe exploratory research was adapted, and in-depth interviews were held with LCA professionals from Sri Lanka and developed countries, respectively.FindingsRelatively less attention has been paid to the implementation of LCA for buildings in Sri Lanka compared to the developed countries due to the time and effort required to collect life cycle inventory data and limited stakeholder understanding of the LCA. Hence, this study proposed improvements, including the development of LCA databases containing region-specific data and conducting programmes to raise stakeholders' awareness to address the gaps in Sri Lanka.Research limitations/implicationsThe identified LCA implementation process for buildings could be used as a guide for first-time LCA users, and it equally makes a valued reference for experienced practitioners.Originality/valueA limited number of the studies formulate a comparison between the LCA for building in developed countries and developing countries. This research attempts to address this knowledge gap.

The practical use of module D in a building case study: assumptions, limitations and methodological issues

According to the EN 15804 and EN 15978, a material or building life cycle consists of three major life cycle stages or so-called modules: Production and Construction (module A), Use (module B) and End-of-life (module C). Potential benefits and loads occurring beyond the building’s life cycle as a result of recycling, reuse or energy recovery can be declared in an additional module D. As part of the upcoming amendment of the EN 15804 a formula was developed to facilitate the calculation of module D. This paper provides a critical discussion on the practical use of module D. First of all, the development of the formula revealed specific methodological issues, such as the unequal approach to closed and open loop recycling. Secondly, the consideration of module D in a Belgian building LCA case study provided insights in the different methodological choices, interpretations, and assumptions related to the calculation of module D. This concerns for example the calculation of net output flows of secondary materials, modelling of avoided primary production, definition of the point of functional equivalence, efficiency of incineration, etc. Aspects that are not clearly specified in the standard and therefore can be open to interpretation are illustrated with concrete examples from the building case study. Where possible, recommendations for a harmonized approach are made. In any way, the results from the case study analysis reveal that the methodological choices can have a significant effect on the results and that module D results should therefore be considered with care.

Upcycling and Design for Disassembly – LCA of buildings employing circular design strategies

Within the ReSOLVE framework, the concept of ‘Looping’ materials in an efficient way is a crucial theme to ensure environmental sustainability of circular economy. This paper investigates how current calculation practice of building LCA from the EN 15804/15978 standards affects the global warming potential (GWP) of building designs where material loops have been in focus. In this study, we calculate the environmental potentials of circular building design based on two cases; 1) a building constructed from primarily upcycled materials, and 2) a building constructed with principles of design for disassembly (DfD). Results from the two cases point to the significance of the EN standards’ allocation approach in which a system’s use of recycling/reuse is merited, rather than meriting a system providing recyclable/reusable materials. Hence, the upcycling strategy results in lower GWP, especially from the production stage, whereas the DfD strategy does not realize an environmental advantage within the framework of the EN standards. Results further shows that even though concrete elements are notable components of the DfD building, developing DfD-solutions for these exact elements might not be the preferred focus for optimizing the environmental benefits provided by the building. Instead, DfD focus could be on shorter-lived elements of high benefit potentials.

Data Driven Quantification of the Temporal Scope of Building LCAs

In the construction sector, LCAs typically apply an approach based on fixed or partially fixed building lifespans/service lives/reference study period. The temporal scopes applied in building LCAs are hence typically not reflecting that the timeframes buildings can provide the service they are intended to provide, are (highly) dependent on numerous factors e.g.: building location, materials used to construct the building, energy supply and the use of the building. Inaccurate estimation of the temporal scope of a building LCA will lead to incorrect quantification of the environmental impacts of buildings. Incorrect quantification of the environmental performance of buildings may, in the worst case, derange/decelerate the development within the building sector towards more sustainable buildings. In this paper, a data set consisting of 20999 Danish buildings, demolished between 2009 and 2015, is analyzed. A multiple linear regression model is derived and used to quantify the temporal scope (often referred to as the reference study period) of building LCAs in an attempt to improve the accuracy of sustainability assessment of buildings, taking several influencing factors into account. The results obtained from the derived model are subsequently compared with several fixed/partially fixed building lifespan/service life/reference study period quantification approaches The regression model proved to estimate the lifespan with lower errors (compared to observed values) than the prevailing approach relying on a single fixed value for all building locations, uses and building materials. The application of model based site, use, and/or material specific etc. temporal scope quantification in LCA is new and provides a mean to reduce the uncertainty of LCA results; however, the approach needs to be formalized.

LCA of tall buildings: Still a long way to go

Tall buildings are often looked at as unsustainable, energy-voracious buildings. Although this may have been true in the past, modern tall buildings have to meet the same energy-conservation standards of all other buildings. In some cases, outstanding results have been obtained, which are now seen as the exemplary examples of sustainable design. Although the design and usage of buildings is now controlled by norms and codes, minimal studies have examined tall buildings holistically, from a life cycle perspective.The present paper analyzes the state-of-the-art of research on the life cycle assessment of tall buildings, analyzing the evolution of the discipline applied to this specific building type.

Correlations in Life Cycle Impact Assessment methods (LCIA) and indicators for construction materials: What matters?

Different Life Cycle Impact Assessment (LCIA) methods have been developed over the past twenty years. While the use of a single score indicator may, on the one hand, ease the decision making it may also induce a loss of information. On the other hand, the use of a large set of environmental indicators may increase the difficulty of decision making due to the high number of parameters. In this paper, a statistical methodology is used to identify a simplified set of environmental indicators. This methodology applies Principal Component Analysis (PCA) to five LCIA methods (CML’01, Eco-indicator99, IMPACT 2002+, ecological scarcity, EPD) using a building products database. For each method, the results show that only 4–6 dimensions are sufficient to explain at least 90–95% of the variance for each set of indicators. They refer to the following environmental themes: fossil-fuel consumption, ecotoxicity, ionising radiation, land use and mineral resources. The use of a selected set of five LCI flows is found to be as relevant as current LCIA methods from a statistical point of view. Furthermore, PCA applied to a building LCA case study shows similar trends as for the database results. Further studies are now needed to confirm these findings for going towards simplified structural relationships among LCIA indicators for building materials.

LCA of timber and steel buildings with fuzzy variables uncertainty quantification

Steel and timber structures constitute a construction technology which holds significant potential in terms of sustainability and are therefore selected as sustainable solutions for the construction of housing, commercial or other types of building projects. This paper consists of two parts. Firstly, to quantify the sustainability potential of timber and steel construction by calculating the environmental impact caused throughout the life cycle of a steel-framed residential building and a timber building. The calculation has been extended with the usage of fuzzy variables that represent uncertainty of the various parameters involved.

Productivity metrics in dynamic LCA for whole buildings: Using a post-occupancy evaluation of energy and indoor environmental quality tradeoffs

The IEQ + DLCA framework, which integrates indoor environmental quality (IEQ) and dynamic life cycle assessment (DLCA) at the whole-building level, was revised and expanded to consider non-chemical health impacts and productivity/performance impacts. The complete framework was evaluated for a case study of a LEED gold rated university building, supplemented with a post-occupancy evaluation (POE) designed to elicit qualitative feedback on IEQ and productivity impacts specific to the building. Most non-chemical health impacts (e.g. sick building syndrome (SBS), asthma) were not able to be included in the framework, due to potential overlaps with chemical-specific impacts already included in LCA. However, productivity impacts were able to be included in the framework for the purpose of comparing different design and operational choices for a given building. Occupants were also asked to evaluate the anticipated effects on their individual productivity due to IEQ changes associated with hypothetical energy-saving strategies. Results of the POE showed occupants were generally satisfied with IEQ, and considered that increasing summer cooling temperature set points would enhance productivity. Energy savings were calculated using an empirical energy and IEQ model calibrated with sensed data from the building. Evaluation of the full IEQ + DLCA framework suggested potentially significant energy savings potential and possible productivity enhancement, but indicated tradeoffs between internal chemical impact categories related to building ventilation, indoor pollutant generation and outdoor pollutant intake. The tradeoffs and overlaps between internal chemical impact categories themselves, as well as between chemical and non-chemical impact categories such as (SBS) are a challenge for LCA of whole buildings.

Life-cycle assessment of residential buildings in three different European locations, basic tool

The paper deals with the development of a tool used for the life cycle assessment of residential buildings located in three different European towns: Brussels (Belgium), Coimbra (Portugal) and Lulea (Sweden). The basic tool focuses on the structure and the materials of the buildings and permits the evaluation of the Embodied energy, Embodied carbon and yearly energy consumption. For that purpose, a different set of original data is taken into account for each location, in which the monthly temperatures, energy mix, heating and cooling systems are defined. The energy consumption, being for heating space or water, for cooling or for lighting is transformed into CO2 emissions to deduce the Operational carbon as well. The influence of the energy mix can therefore be assessed in the basic tool. As a matter of fact, the heating and cooling systems habitually used in the three countries are also of great importance. The District Heating system, is, for instance, incorporated in the basic tool. The presence of solar water heater or photovoltaic panels is also strongly influencing the operational carbon. After a short literature review on building LCA and the description of the basic tool, the software Pleiades + Comfie combined with Equer is used to achieve the complete LCA for one building using two different load bearing frames. The results of the calculations for Brussels climate are verified against these software results. The dependence of the results to parameters such as climate, energy mix and habits is then discussed in the companion paper.

Current Situation of Combined LCA and LCC Method of Buildings Used by National/ Local Governments and Private Companies

Current Situation of Combined LCA and LCC Method of Buildings Used by National/ Local Governments and Private Companies