Environmental life cycle assessment of a commercial office building in Thailand

Background, aim, and scope  To minimize the environmental impacts of construction and simultaneously move closer to sustainable development in the society, the life cycle assessment of buildings is essential. This article provides an environmental life cycle assessment (LCA) of a typical commercial office building in Thailand. Almost all commercial office buildings in Thailand follow a similar structural, envelope pattern as well as usage patterns. Likewise, almost every office building in Thailand operates on electricity, which is obtained from the national grid which limits variability. Therefore, the results of the single case study building are representative of commercial office buildings in Thailand. Target audiences are architects, building construction managers and environmental policy makers who are interested in the environmental impact of buildings. Materials and methods  In this work, a combination of input–output and process analysis was used in assessing the potential environmental impact associated with the system under study according to the ISO14040 methodology. The study covered the whole life cycle including material production, construction, occupation, maintenance, demolition, and disposal. The inventory data was simulated in an LCA model and the environmental impacts for each stage computed. Three environmental impact categories considered relevant to the Thailand context were evaluated, namely, global warming potential, acidification potential, and photo-oxidant formation potential. A 50-year service time was assumed for the building. Results  The results obtained showed that steel and concrete are the most significant materials both in terms of quantities used, and also for their associated environmental impacts at the manufacturing stage. They accounted for 24% and 47% of the global warming potential, respectively. In addition, of the total photo-oxidant formation potential, they accounted for approximately 41% and 30%; and, of the total acidification potential, 37% and 42%, respectively. Analysis also revealed that the life cycle environmental impacts of commercial buildings are dominated by the operation stage, which accounted for approximately 52% of the total global warming potential, about 66% of the total acidification potential, and about 71% of the total photo-oxidant formation potential, respectively. The results indicate that the principal contributor to the impact categories during the operation phase were emissions related to fossil fuel combustion, particularly for electricity production. Discussion  The life cycle environmental impacts of commercial buildings are dominated by the operation stage, especially electricity consumption. Significant reductions in the environmental impacts of buildings at this stage can be achieved through reducing their operating energy. The results obtained show that increasing the indoor set-point temperature of the building by 2°C, as well as the practice of load shedding, reduces the environmental burdens of buildings at the operation stage. On a national scale, the implementation of these simple no-cost energy conservation measures have the potential to achieve estimated reductions of 10.2% global warming potential, 5.3% acidification potential, and 0.21% photo-oxidant formation potential per year, respectively, in emissions from the power generation sector. Overall, the measures could reduce approximately 4% per year from the projected global warming potential of 211.51 Tg for the economy of Thailand. Conclusions  Operation phase has the highest energy and environmental impacts, followed by the manufacturing phase. At the operation phase, significant reductions in the energy consumption and environmental impacts can be achieved through the implementation of simple no-cost energy conservation as well as energy efficiency strategies. No-cost energy conservation policies, which minimize energy consumption in commercial buildings, should be encouraged in combination with already existing energy efficiency measures of the government. Recommendations and perspectives  In the long run, the environmental impacts of buildings will need to be addressed. Incorporation of environmental life cycle assessment into the current building code is proposed. It is difficult to conduct a full and rigorous life cycle assessment of an office building. A building consists of many materials and components. This study made an effort to access reliable data on all the life cycle stages considered. Nevertheless, there were a number of assumptions made in the study due to the unavailability of adequate data. In order for life cycle modeling to fulfill its potential, there is a need for detailed data on specific building systems and components in Thailand. This will enable designers to construct and customize LCAs during the design phase to enable the evaluation of performance and material tradeoffs across life cycles without the excessive burden of compiling an inventory. Further studies with more detailed, reliable, and Thailand-specific inventories for building materials are recommended.     

Service life of the dwelling stock in Spain

Purpose

Service life of buildings is an essential parameter to evaluate its operational impact in life cycle assessment (LCA). Although most studies assume building service life about 75 to 100 years since no reliable data are available, its accurate quantification is still an unresolved work. To avoid wrong generalizations, the determination of the service life of buildings according to the characteristics of every region is required.

Methods

Life table, a methodology traditionally used in demographic studies, has been used in this paper to estimate the service life of buildings. This methodology has been applied to the dwelling stock of Spain for each of its 19 regions. Data acquisition and sources have been pointed out. The building obsolescence has been considered in the moment that they are in a ruinous state.

Results and discussion

Life table of buildings showed that the average service life of a residential building constructed in 2001 in Spain was expected to be 80 years. Significant different results of service life among regions were found, from 54 years for a building in Ceuta to 95 years in La Rioja. It also showed that 50 % of total Spanish dwellings are younger than 30 years, and they are expected to reach the ruinous state in 2063 to 2081.

Conclusions

Life table applied to buildings allows determining their service life. Its quantification is based on the buildings census, given by official institutions. Building census has to consider the year of construction and the state of conservation of the building to be applied in buildings' life table. Building service life can be used in LCA, renovation and deconstruction of the building stock, and future construction and demolition debris management.     

Assessment of ecological sustainability of a building subjected to potential seismic events during its lifetime

Purpose

Sustainable development aims to enhance the quality of life by improving the social, economic and environmental conditions for present and future generations. A sustainable engineering decision-making strategy for design and assessment of construction works (i.e., civil engineering and buildings) should take into account considerations regarding the society, the economy and the environment. This study presents a novel approach for the life cycle assessment (LCA) of a case-study building subjected to seismic actions during its service life, accounting for structural reliability.

Methods

A methodology is presented that evaluates the time-dependent probability of exceeding a limit state considering the uncertainty in the representation of seismic action. By employing this methodology, the earthquake-induced damages are related to the environmental and social losses caused by the occurrence of the earthquake. A LCA of a case-study building accounting for the time-dependent seismic reliability is conducted using a damage-oriented LCA approach.

Results and discussion

The contributions of the different life cycle phases to the total environmental impact related to the building lifetime are in agreement with previous results in this field of study. However, the LCA results revealed significant risk-based contributions for the rehabilitation phase due to the induced damage resulting in seismic events. Particularly, the rehabilitation phase is expected to contribute to the total environmental impact with around the 25 % of the initial environmental impact load (related to the pre-use phase) as a consequence of seismic damage.

Conclusions and recommendations

The probability of occurrence of seismic events affects the LCA results for various life cycle phases of a building in terms of all the indicators adopted in the analysis. The time-dependent probability of collapse in a year can represent a benchmark indicator for human safety in the context of social sustainability for the building sector. The proposed approach can be implemented in a sustainable decision-making tool for design and assessment.     

Sustainability of port activities within the framework of the fisheries sector: Port of Vigo (NW Spain)

Sustainability of the fisheries sector is nowadays a key issue due to the significant impact that this activity may have on the environment. Besides fishing activity itself, other indirect impacts, like those originated from related activities and services also need to be addressed. For assessing the environmental burden of this sector, the Ecological Footprint (EF) indicator can be used. The application of EF to the fisheries sector is still uncommon and studies of associated activities (such as ports) even more. In this work, classical EF methodology was applied in order to evaluate the environmental impact of the fisheries sector, taking as a representative sample the global activity (fishing and transportation) of the Port of Vigo (Spain), one of the biggest fishing ports in the world. A high value of total EF for both port and fishing activities was obtained. However, relative EF is much higher in the case of fishing, due to the low natural productivity associated to fish resources. Energy-land and sea area were the most affected land-components within the footprint, while among the different categories, resources consumption was the main contributor to the EF value in all the assessed scenarios.     

An accumulative model for the comparative life cycle assessment case study: iron and steel process

Life cycle assessment is a powerful tool in the evaluation of the environmental performance. However, there is no generally accepted methodology. To develop a practical method, an accumulative model for the comparative life cycle assessment is established and applied in the two typical iron and steel processes, the DRI/EF process and the BF/BOF process. The results indicate that the method could quantitatively compare the alternatives. When the DRI/EF process is compared with the BF/BOF process, it is shown that the IREI (integrated relative environmental index) is 60.22% for the production of iron and 52.4% for the production of steel, respectively. The environmental performance of the DRI/EF process is superior to that of the BF/BOF process.     

Discounting and the environment should current impacts be weighted differently than impacts harming future generations?

Background  In Life-Cycle Assessment (LCA), decision makers are often faced with tradeoffs between current and future impacts. One typical example is waste incineration, where immediate emissions to the air from the incineration process have to be weighted against future emissions of slag landfills. Long-term impacts are either completely taken into account or they are entirely disregarded in case of a temporal cut-off. Temporal cutoffs are a special case of discounting. Objective  In this paper, discounting is defined as valuing damages differently at different points of time using a positive or negative discount rate. Apart from temporal cut-offs, discounting has rarely been applied in LCA so far. It is the goal of this paper to discuss the concept of discounting and its applicability in the context of LCA. Methods  For this purpose, we first review the arguments for discounting and its principles in economic sciences. Discounting in economics can be motivated by pure time preference, productivity of capital, diminishing marginal utility of consumption, and uncertainties. The nominal discount rate additionally includes changes in the price level. These arguments and their justification are discussed in the context of environmental impacts harming future generations. Results and Discussion  It is concluded that discounting across generations because of pure time preference contradicts fundamental ethical values and should therefore not be applied in LCA. However, it has to be acknowledged that in practice decision makers often use positive discount rates because of pure time preference — either because they might profit from imposing environmental damage on others instead of themselves or because people in the far future are not of immediate concern to them. Discounting because of the productivity of capital assumes a relationship between monetary values and environmental impact. If such a relationship is accepted, discounting could be applied. However, future generations should be compensated for the environmental damage. It is likely that they would demand a higher compensation if the real per capita income increases. As both the compensation and the discount rate are related to economic growth, the overall discount rate might be close to zero. It is shown that the overall discount rate might even be negative considering that the required compensation could increase (even to infinite) if natural assets remain scarce, whereas the utility of consumption diminishes with increasing income. Uncertainties could justify both positive and negative discount rates. Since the relationship between uncertainties and the magnitude of damage is generally not exponential, we recommend to model changes in the magnitude of damage in scenario analysis instead of considering it in discounting (which requires an exponential function of time in the case of a constant discount rate). We investigated the influence of discounting in a case study of heavy metal emissions from slag landfills. It could be shown that even small discount rates of less than 1 % lead to a significant reduction of the impact score, whereas negative discount rates inflate the results. Conclusions and Recommendations  Discounting is only applicable when temporally differentiated data is available. In some cases, such a temporal differentiation is necessary to take sound decisions, especially when long emission periods are involved. An example is the disposal of nuclear or heavy metal-containing waste. In these cases, the results might completely depend on the discount rate. This paper helps to structure arguments and thus to support the decision about whether or not discounting should be applied in an LCA.     

LCA and LCC of the world’s longest pier: a case study on nickel-containing stainless steel rebar

Purpose

Built in 1941, the Progreso Pier was the first concrete structure in the world built with nickel-containing stainless steel reinforcement. The Pier has been in service for over 70 years without any significant repair or maintenance activities. The aim of this study was to understand the environmental and economic implications of selecting nickel-containing stainless steel reinforcement using the Progreso Pier as the case study.

Methods

A combined environmental life cycle assessment (LCA) and life cycle costing (LCC) study was conducted. The analysis considered the potential environmental impacts and the net present cost of the stainless steel reinforced structure from cradle to grave and compared it to the same structure using conventional carbon steel.

Results and discussion

The results indicated that while using stainless steel reinforcement resulted in a marginally higher environmental impact after initial construction, this is offset by the increased service life and, hence, less frequent maintenance and reconstruction activities. Relative to the as-built stainless steel reinforcement design, the environmental impacts of the carbon steel reinforced design are between 69 and 79 % higher over the analysis period. Similar observations were made for the other investigated impact categories. The cost implications of using stainless steel reinforcement show economic benefits that are complementary to the environmental benefits. Similar to the LCA, the service life benefits outweigh the higher unit costs for stainless steel, assuming a discount rate of 0.01 % as the baseline scenario. The carbon steel reinforced design has a net present cost that is 44 % higher than the as-built stainless steel reinforcement design. The crossover point for the two designs occurs at year 50, which corresponds to the reconstruction activity. A sensitivity analysis shows that the results and conclusions are sensitive to the choice in discount rate: Rates 3 % and lower produce net present costs that are lower for the as-built design; rates 4 % and higher produce net present costs that are lower for the alternative design.

Conclusions

The study demonstrates how LCA and LCC are complementary tools that can be used in decision-making for sustainable construction. The Progreso Pier exemplifies the importance of considering the entire life cycle with service life and recycling as well as long-term life cycle impacts of infrastructure projects from an environmental and economic perspective.

     

Environmental and economic optimisation of the floor on grade in residential buildings

Purpose

The goal of the study was to determine the preferred composition of the floor on grade in residential buildings in the Belgian context from a life cycle environmental and financial perspective. In addition to the life cycle costs, the required investments were evaluated to take into account budget restrictions. The analysis of current available materials and techniques allows both the designer and building owner to extend their decision criteria from mainly investment cost to life cycle aspects as well.

Methods

In this study, the potential environmental impact was assessed by considering the environmental external cost of the floors. Several existing methods were combined to enable a full assessment, taking the ExternE methodology (willingness to pay) as the main base. The ecoinvent database was used to gather the inventory data but was adapted to increase the representativeness for Belgium. The financial evaluation included both the investment and life cycle aspects. The latter was analysed through the sum of the present values of all costs occurring during the life span of the floor.

Results and discussion

The necessary assumptions (e.g. transport, end-of-life treatment, cleaning, life span, economic parameters) and the adaptations to the ecoinvent data are transparently reported. The methodological steps (e.g. monetary valuation, transmission losses, equivalent degree days, Pareto optimisation) are elaborated in detail. This allows the results, which are graphically presented, to be correctly interpreted. The contribution of the life cycle stages and the optimisation potential of the considered impacts are discussed.

Conclusions

The environmental external cost based on the willingness to pay to reduce environmental impacts proved to be relatively low, representing about 9?% of the financial cost. The cost reduction of current common practice was estimated to be about 20 and 60?% from a financial and environmental perspective, respectively. The insulation level and the floor covering were identified as the most important optimisation parameters.

Recommendations

Internalisation of environmental external costs might be an important step to achieve more sustainable solutions. However, it is recommended to consider financial and environmental external costs separately too because both contain important information for the decision maker. Because it is hard (if not impossible) to increase the insulation level of the floor on grade later on in the life cycle of the building, a high insulation value should be a priority during construction. The floor covering can more easily be adapted and is thus considered a secondary priority.     

基于LCA的传统农田与苜蓿草地生态效应分析

为评估传统农田与苜蓿草地两种生态系统在资源投入和环境效应方面的差异,基于2019-2022年中国北方山东省、陕西省、山西省、宁夏回族自治区、新疆维吾尔自治区、内蒙古自治区、黑龙江省、河北省共14个县区的农牧户调研数据,应用生命周期评价（Life cycle assessment,LCA）方法,对中国北方传统农田和苜蓿草地生态系统全生命周期的能源消耗、土地利用、水资源消耗、全球变暖、环境酸化、富营养化这六类资源消耗和环境影响进行核算。将LCA方法应用于两类作物生产的环境影响分析,探究该方法在农业环境研究领域的有效性以及传统农田和苜蓿草地生态系统资源投入和环境效应的差异特征。结果表明：（1）传统农田和苜蓿草地生态系统环境综合影响指数分别为0.1569和0.1269,苜蓿草地生态系统的综合环境效应比传统农田生态系统低19.09%,对环境友好程度相对较高。（2）在整个区域范围内,传统农田的环境影响高于苜蓿草地的环境影响,且传统农田的环境影响效益差异显著,而苜蓿草地的环境影响整体波动较小。其中,在资源消耗方面,与传统农田生态系统相比,苜蓿草地生态系统的能源消耗减少了31.21%,所需土地面积减少了43.61%,水资源消耗减少了63.43%;在环境影响方面,与传统农田生态系统相比,苜蓿草地生态系统的气候变暖潜值降低了43.09%,环境酸化潜值降低了50.27%,富营养化潜值降低了46.78%。（3）中国北方地区传统农田和苜蓿草地生态系统在资源利用和环境代价在空间尺度上差异较明显,呈现出西部高于东部的特征。（4）影响两种生态系统的主要环境影响类型均为环境酸化和富营养化,与大量的化肥生产、施用和灌溉电力消耗密不可分,因而实施配方施肥、合理灌溉、秸秆还田是降低我国北方地区传统农田和苜蓿草地生态系统生命周期内生态环境负面影响的关键。     

Multi-attribute life cycle assessment of preventive maintenance treatments on road pavements for achieving environmental sustainability

Purpose  

Although a significant number of environmental protection measures concerning industrial products and processes have emerged over the past few years, similar measures have only started to appear in road construction and related practices. There is a need for understanding what a “sustainable pavement” would entail in terms of greenhouse gas emissions and energy consumption. Since environmental impact assessment of major projects is becoming mandatory in many countries, various research projects attempt to evaluate the environmental impact of different pavement materials, technologies, or processes over the road life cycle. To support these efforts, there is a need to measure and describe different aspects of sustainability related to road pavements. In particular, keeping road pavements at high service levels through a preventive maintenance approach during the pavement service life has been proven to provide significant improvement of their performance and reduce their deterioration rate.     

Material and Energy Flows and Environmental Impacts of the Internet in Switzerland

The Internet leads to material and energy consumption as well as various environmental impacts on both the regional and global scale. Yet, assessments of the Internet's energy consumption and resulting greenhouse gas emissions are still rare, and assessments of material flows and further environmental impacts are virtually non‐existent. This article investigates material flows, the direct energy consumption during the use phase, as well as environmental impacts linked to the service, “Internet in Switzerland.” In our model, the service, Internet in Switzerland, is divided into various Internet participant categories. All devices used to access or provide Internet services are merged in a limited number of equipment families and, as such, included in an inventory of the existing infrastructure (stock). Based on this inventory, a material flow analysis (MFA) is performed, which includes the current stock as well as flows resulting from growth and disposal. The direct energy consumption for the operation of the infrastructure is quantified. Environmental impacts are calculated with a life cycle assessment approach, using the ecoinvent database and the software, SimaPro, applying four different methods. The MFA results in a 2009 stock of 98,100 tonnes. Approximately 4,130 gigawatt hours per year, or 7% of the total Swiss electricity consumption, were used in 2009 to operate the Swiss infrastructure. The environmental impacts caused during the production and use phases vary significantly depending on the assessment method chosen. The disposal phase had mainly positive impacts as a result of material recovery.     

Ecological footprint study on tourism itinerary products in Shangri-La, Yunnan Province, China

The eco-footprint analysis of tourism is one of the most up-to-date and effective methods used to analyze the environmental effects of tourism. This study constructs a model to calculate the ecological footprint (EF) of tourism itinerary products by using a component approach, rudimentarily exploring the calculation methods for EF which target necklace-like tourism itinerary products and base tourist trips. By applying the model to calculate and analyze an “8-day tour of Shangri-La”, a typical tourism itinerary product, results of this study suggest that: (a) Tourism is a kind of life style with tremendous ecological consumption, that is, per capita EF that tourists produce in the course of travel is more than the one that local people produce in their daily life in tourist source areas, and it also exceeds the per capita EF that local people produce in their daily life in tourist destination; (b) According to the component approach, EF of tourism itinerary products is broken down into 7 components, among which “Transport”, “Food”, “Waste” and “Accommodation” play important roles; (c) There exist significant differences in ecological efficiency between different departments of tourism; the travel and entertainment sectors maintain a relatively high ecological efficiency, while the food and lodging departments have relatively low ecological efficiency.     

Energy simulation and LCA for macro-scale analysis of eco-innovations in the housing stock

Purpose

Energy consumption of buildings is one of the major drivers of environmental impacts. Life cycle assessment (LCA) may support the assessment of burdens and benefits associated to eco-innovations aiming at reducing these environmental impacts. Energy efficiency policies however typically focus on the meso- or macro-scale, while interventions are typically taken at the micro-scale. This paper presents an approach that bridges this gap by using the results of energy simulations and LCA studies at the building level to estimate the effect of micro-scale eco-innovations on the macro-scale, i.e. the housing stock in Europe.

Methods

LCA and dynamic energy simulations are integrated to accurately assess the life cycle environmental burdens and benefits of eco-innovation measures at the building level. This allows quantitatively assessing the effectiveness of these measures to lower the energy use and environmental impact of buildings. The analysis at this micro-scale focuses on 24 representative residential buildings within the EU. For the upscaling to the EU housing stock, a hybrid approach is used. The results of the micro-scale analysis are upscaled to the EU housing stock scale by adopting the eco-innovation measures to (part of) the EU building stock (bottom–up approach) and extrapolating the relative impact reduction obtained for the reference buildings to the baseline stock model. The reference buildings in the baseline stock model have been developed by European Commission-Joint Research Centre based on a statistical analysis (top–down approach) of the European housing stock. The method is used to evaluate five scenarios covering various aspects: building components (building envelope insulation), technical installations (renewable energy), user behaviour (night setback of the setpoint temperature), and a combined scenario.

Results and discussion

Results show that the proposed combination of bottom–up and top–down approaches allow accurately assessing the impact of eco-innovation measures at the macro-scale. The results indicate that a combination of policy measures is necessary to lower the environmental impacts of the building stock to a significative extent.

Conclusions

Interventions addressing energy efficiency at building level may lead to the need of a trade-off between resource efficiency and environmental impacts. LCA integrated with dynamic energy simulation may help unveiling the potential improvements and burdens associated to eco-innovations.

     

Comparison of reusable and disposable laparatomy pads

Laparotomy pads made of cotton are used in operative medicine as a tamponade, and as a means of preventing organ injury. In our study, the environmental impact and hygienic aspects of reusable and disposable laparotomy pads (also made of cotton) were investigated. The study is no complete LCA, but rather a life cycle inventory (LCI). Reusable laparotomy pads are superior as far as energy consumption, water and production of waste are concerned. Disposable laparotomy pads have a larger impact on the environment, causing a greater consumption of resources. The environmental impact caused by their production is much greater than the environmental impact of cleansing the reusable laparotomy pads. On the one hand, growing cotton and producing laparotomy pads requires much more water than the cleansing procedure for reusable pads. On the other hand, washing reusable laparotomy pads and bleaching with sodium hypochlorite results in the formation of adsorbable organic halogen compounds (AOX). Reprocessing laparotomy pads made of cotton meets the hygienic standards when the requirements for the special cleaning procedures are fulfilled.     

Valuation, appraisal, discounting, obsolescence and depreciation

Previous editions of this Journal have drawn attention to the critical role valuation plays in life cycle analysis and environmental impact assessment (see for exampleVolkwkin andKlöpffer |1|). In particular, the critical role of valuation has heen highlighed in a number of discussions on ‘valuation step’ within life cycle costing, ‘hedonic and contingency’ assessments of environmental impact and both the utility and welfare of ‘pathway’ analysis/assessment (Krkwitt, Mayerhofer, Trukenmüller andFriedrich, 1998;Powell, Pearce andCraighill, 1997;Volkwein, On in andKlöpffer, 1996 |2-4|). Focusing on the utility of market valuation, this paper examines the critique of discounting environmentalists have made in relation to property valuation, investment appraisal and the application of the principle in the income based net annual return model of land use time-horizons and the spatial configuration of building programmes-a criticism implict in ‘valuation step’, ‘hedonic, contingency’ and ‘pathway’ analysis/assessments. It examines the argument put forward regarding the link between the selection of a discount rate, the valuation of property, appraisal of investment and inter-generational downloading of costs associated with the use of land, repair, maintenance and refurbishment of buildings: the downloading of costs, seen by some, to have an adverse impact and work against the introduction of experimental designs aimed at energy saving, clean air environments.     

Alternative Scenarios for Managing the Environmental Performance of a Service Sector Company

This article presents a scenario analysis for a life-cycle model of service sector companies. The model is based on six case companies and it is applied to test the influence of 32 management scenarios. The scenarios simulate feasible options for environmental management measures in companies, and the life-cycle assessment method is used to model their relevance in terms of the total environmental impact of the company. The study found that the bulk of tested scenarios had only a minor influence on the total environmental impact of the company. Some individual management scenarios, though, turned out to have a major influence on the organization's environmental performance. The scenarios with greatest influence were those related to the procurement of electricity, building energy consumption, commuting vehicle mix, space usage efficiency, and refurbishment periods of the building. All of these management scenarios had an influence of more than 10% on the environmental impact of the model organization.     

Exploring the Use of Ecological Footprint in Life Cycle Impact Assessment

Ecological footprint (EF) is a metric that estimates human consumption of biological resources and products, along with generation of waste greenhouse gas (GHG) emissions in terms of appropriated productive land. There is an opportunity to better characterize land occupation and effects on the carbon cycle in life cycle assessment (LCA) models using EF concepts. Both LCA and EF may benefit from the merging of approaches commonly used separately by practitioners of these two methods. However, few studies have compared or integrated EF with LCA. The focus of this research was to explore methods for improving the characterization of land occupation within LCA by considering the EF method, either as a complementary tool or impact assessment method. Biofuels provide an interesting subject for application of EF in the LCA context because two of the most important issues surrounding biofuels are land occupation (changes, availability, and so on) and GHG balances, two of the impacts that EF is able to capture. We apply EF to existing fuel LCA land occupation and emissions data and project EF for future scenarios for U.S. transportation fuels. We find that LCA studies can benefit from lessons learned in EF about appropriately modeling productive land occupation and facilitating clear communication of meaningful results, but find limitations to the EF in the LCA context that demand refinement and recommend that EF always be used along with other indicators and metrics in product‐level assessments.     

Assessment of the environmental performance of buildings: A critical evaluation of the influence of technical building equipment on residential buildings

Purpose

Sustainability assessments of buildings using the life cycle approach have become more and more common. This includes the assessment of the environmental performance of buildings. However, the influence of the construction products used for the fabric, the finishing, and the technical building equipment of buildings has hardly been described in literature. For this reason, we evaluated the influence of the technical building equipment and its impact on the environment for different residential buildings.

Materials and methods

Five residential buildings were evaluated by applying the methodology of life cycle assessment (LCA) (ISO14040) expressed using quantitative assessment categories according to prEN15978.

Results and discussion

Results show that the optimization of energy performance has already reached a high level in Austria, so that the overall potential for possible improvements is quite low. Especially in low-energy and passive?Chouse-standard residential buildings, the limits for energy optimization in the use phase have mostly been achieved. In contrast to this, the integrated LCA (iLCA) findings attribute a high optimization potential to the construction products used for the technical building equipment as well as to the building fabric and finishing. Additionally, the passive house shows the lowest contribution of the technical building equipment on the overall LCA results.

Conclusions

The iLCA findings suggest that it is recommended to include the technical building equipment for future assessments of the environmental performance of buildings. It is also suggested to use a broad number of environmental indicators for building LCA.     

Proposal of a method for allocation in building-related environmental LCA based on economic parameters

Application and development of the LCA methodology to the context of the building sector makes several building specific considerations necessary, as some key characteristics of products in the building sector differ considerably from those of other industrial sectors. The largest difference is that the service life of a building can stretch over centuries, rather than decades or years as seen for consumer products. The result of the long service life is that it is difficult to obtain accurate data and to make relevant assumptions about future conditions regarding, for example, recycling. These problems have implications on the issue of allocation in the building sector, in the way that several allocation procedures ascribe environmental loads to users of recycled or reused products and materials in the future which are unknown today. The long service life for buildings, building materials and building components, is associated with the introduced concept of a virtual parallel time perspective proposed here, which basically substitutes historical and future processes and values with current data. Further, the production and refining of raw material as a parallel to upgrading of recycled material, normally contains several intermediate products. A suggestion is given for how to determine the comparability of intermediate materials. The suggested method for allocation presented is based on three basic assumptions: (1) If environmental loads are to be allocated to a succeeding product life cycle, the studied actual life cycle has to take responsibility for upgrading of the residual material into secondary resources. (2) Material characteristics and design of products are important factors to estimate the recyclable amount of the material. Therefore, a design factor is suggested using information for inherent material properties combined with information of the product context at the building level. (3) The quality reduction between the materials in two following product life cycles is indicated as the ratio between the market value for the material in the products. The presented method can be a good alternative for handling the problem of open-loop recycling allocation in the context of the building sector if a consensus for the use of the fictive parallel time perspective and the use of the design factor can be established. This as the use of the time perspective and design factor is crucial to be able to deal with the problem of long service lives for buildings and building materials and the specific characteristics of the same building materials and components built into different building contexts.