Life-cycle assessment of a house with alternative exterior walls: Comparison of three impact assessment methods

Monteiro, Helena; Freire, Fausto

doi:10.1016/j.enbuild.2011.12.032

Cited by 208 publications

(122 citation statements)

References 28 publications

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“…Here, the selection of alternatives in each example (PV, eGrid, concrete, and paper pulp) is determined by single impact category. A survey of recent publications from the International Journal of Life Cycle Assessment reporting normalized impacts from CML supports the finding that marine aquatic ecotoxicity is the most influential category in evaluations of water services (Barjoveanu et al 2014), diapers (Mirabella et al 2013), exterior household walls (Monteiro and Freire 2012), packing tape (Navajas et al 2014), thermal insulation (Struhala et al 2014), and an entire inventory data library (White and Carty 2010). These results were also reproduced by Sim et al (2007) in a food sourcing application where authors excluded marine aquatic ecotoxicity from normalized results due to masking of other aspects.…”

Section: Resultssupporting

confidence: 60%

Interpretation of comparative LCAs: external normalization and a method of mutual differences

Prado

Wender

Seager

2017

Int J Life Cycle Assess

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Purpose Identification of environmentally preferable alternatives in a comparative life cycle assessment (LCA) can be challenging in the presence of multiple incommensurate indicators. To make the problem more manageable, some LCA practitioners apply external normalization to find those indicators that contribute the most to their respective environmental impact categories. However, in some cases, these results can be entirely driven by the normalization reference, rather than the comparative performance of the alternatives. This study evaluates the influence of normalization methods on interpretation of comparative LCA to facilitate the use of LCA in decision-driven applications and inform LCA practitioners of latent systematic biases. An alternative method based on significance of mutual differences is proposed instead. Methods This paper performs a systematic evaluation of external normalization and describes an alternative called the overlap area approach for the purpose of identifying relevant issues in a comparative LCA. The overlap area approach utilizes the probability distributions of characterized results to assess significant differences. This study evaluates the effects in three LCIA methods, through application of four comparative studies. For each application, we call attention to the category indicators highlighted by each interpretation approach. Results and discussion External normalization in the three LCIA methods suffers from a systematic bias that emphasizes the same impact categories regardless of the application. Consequently, comparative LCA studies that employ external normalization to guide a selection may result in recommendations dominated entirely by the normalization reference and insensitive to data uncertainty. Conversely, evaluation of mutual differences via the overlap area calls attention to the impact categories with the most significant differences between alternatives. The overlap area approach does not show a systematic bias across LCA applications because it does not depend on external references and it is sensitive to changes in uncertainty. Thus, decisions based on the overlap area approach will draw attention to tradeoffs between alternatives, highlight the role of stakeholder weights, and generate assessments that are responsive to uncertainty. Conclusions The solution to the issues of external normalization in comparative LCAs proposed in this study call for an entirely different algorithm capable of evaluating mutual differences and integrating uncertainty in the results.

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Section: Resultssupporting

confidence: 60%

Interpretation of comparative LCAs: external normalization and a method of mutual differences

Prado

Wender

Seager

2017

Int J Life Cycle Assess

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“…In such cases, the non-operational phase is more significant and green materials exhibit greatest interest. Actually comparisons of concrete-based and wood framework buildings, with similar insulation levels, show that wood-based buildings lead to lower embedded energy and CO 2 emission than concrete ones [11] [16][17] [20]. Similar conclusions are obtained comparing wood products with usual building materials such as brick, glass fibre insulation and extruded polystyrene in [21].…”

Section: Introductionsupporting

confidence: 67%

Life cycle assessment of a hemp concrete wall: Impact of thickness and coating

Prétot¹,

Collet²,

Garnier³

2014

Building and Environment

170

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In a context of sustainable development and energy sparing, a life cycle assessment (LCA) may be useful to make good choices. Thus, this study concerns the LCA of an environmentally friendly material used for building construction, hemp concrete. The functional unit is first defined per square such that the wall may provide the function of bearing wall meter and its thermal performance is described by a thermal resistance of 2.78 m².K/W. The results then showed that the production phase of raw materials is mainly responsible for the environmental impact of the wall, mostly due to the binder production. It was also shown that, compared to traditional construction materials, hemp concrete has a low impact on environment. Moreover, hemp concrete contributes to reduce climate change as photosynthesis-mediated carbon sequestration and carbonation serve to reduce atmospheric carbon dioxide. A sensitivity analysis is performed on three criteria: wall thickness, renewal of coatings and compounds of the indoor coating.Our results show that environmental indicators evolve with wall thickness, except for the climate change indicator. It improves with thickness due to carbon sequestration and carbonation. Moreover the increase in the wall's thermal resistance with wall thickness is not taken into account in such an LCA performed at the material level. The renewal of coating slightly impacts the environmental indicator for small numbers of renewals but it leads to negative effects if they are too numerous. It appears that hemp-lime coating has a greater impact than sand-lime coating as it embeds more binder.

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“…This plan was part of a Research & Demonstration Concerto program called Renaissance, which is focused on reducing CO 2 emissions by decreasing heating and cooling needs in buildings. This case study widens this scope by calculating the impact of a representative building in the ecocity of Valdespartera from an LCA point of view, intending to clarify how important the different life cycle building stages are in terms of CED and GWP [35,36].…”

Section: Presentation Of a Case Study: A Low Energy Building In The Ementioning

confidence: 99%

Use of LCA as a Tool for Building Ecodesign. A Case Study of a Low Energy Building in Spain

et al. 2013

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This paper demonstrates how to achieve energy savings in the construction and operation of buildings by promoting the use of life cycle assessment techniques in the design for new buildings and for refurbishment. The paper aims to draw on the application of a specific methodology for low energy consumption, integrated planning, environmental performance evaluation of buildings, and design for sustainability and LCA techniques applied to buildings. The ENergy Saving through promotion of LIfe Cycle assessment in buildings (ENSLIC) methodology based on LCA for use in an integral planning process has been promoted to stakeholders who require a means to optimize the environmental performance of buildings. Feedback from the stakeholders has facilitated the creation of simplified LCA guidelines, a systematic approach guiding the user through the alternative options regarding software choices, their strengths and weaknesses, the databases available, the usefulness of different indicators, aggregation, definition of limits and options for simplifying the process. As a result, this paper presents the applied results of a case study where this methodology is implemented serving as an energy savings evaluation tool for decision makers, end-users, professionals involved in the different stages of construction, etc. Finally, it is demonstrated how LCA can facilitate comparisons between different buildings, showing the influence of all variables on a building's life cycle environmental impact and showing the potential for energy savings. Removing market barriers to sustainable construction is actually stricter and this is good news for promoting higher energy efficiency in buildings.

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Life-cycle assessment of a house with alternative exterior walls: Comparison of three impact assessment methods

Cited by 208 publications

References 28 publications

Interpretation of comparative LCAs: external normalization and a method of mutual differences

Interpretation of comparative LCAs: external normalization and a method of mutual differences

Life cycle assessment of a hemp concrete wall: Impact of thickness and coating

Use of LCA as a Tool for Building Ecodesign. A Case Study of a Low Energy Building in Spain

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