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Tag: Related study phase: Reporting

G-39 (Buildings) / G-37 (Products) Scenario analysis

Written on 23. October 2012.

*Aspect*		G-39 (Buildings) / G-37 (Products) Scenario analysis
*Description*		Scenario analyses usually refer to future conditions that cannot be fully known by the time the LCA study is conducted. However, the uses of scenarios can meet different goals. Scenarios can look backwards or forwards, and can be linked to different applications. For example, a product is likely to be handed differently in each building. In this context, the use of scenarios may be very helpful in provide complementary results.Within this guidance document, is a scenario analysis necessary? How and when can it be conducted, depending on the study type?
*related study objective*		☒ stand-alone LCA		☒ comparative assertion
*related study phase*		☐	☐	☐	☐	☒
		goal and scope definition	inventory analysis (LCI)	impact assessment (LCIA)	interpretation	reporting
*relevant for*
	new buildings	existing buildings	building products	screening LCA	simplified LCA	complete LCA
*Provisions*	Scenario analyses may be conducted if relevant for the goal and scope of the study. They should be conducted for individual assumptions and choices in order to explain the impacts of such choices. For these cases, a scenario analysis should be conducted against the baseline scenario (see Chapter 2).
*Rules from:*	*EN 15804* 7.3 Scenarios and technical information*ILCD: Provisions: 9.3.3 Sensitivity check (of accuracy and precision)*
*Guidance*	A scenario is addressed for each life cycle stage in EN 15804 and EN 15978. However, in addition to the chosen scenario for each life cycle stage it may be useful to assess alternative scenarios.A scenario analysis is closely related to a sensitivity analysis for key parameters. For example, in a scenario analysis, the practitioner may need to look at different building alternatives or reference study periods. The different aspects to consider for the scenario analysis depend on the goal and scope of the study. For example, the scenario analysis can be predictive (forecast, what-if), explorative (external or strategic) or normative (preserving or transforming) [LoRe-LCA 2011]. 1) Guidance for building LCA studies Different aspects can be considered for a scenario analysis, such as the reference study period of a building, the service life of building products, renovation scenarios, energy demand during the use phase, and user behaviour. For more information about scenario analyses for building LCA, please consult the LoRe-LCA report ‘Report on scenario for LCA in constructions’, available online. 2) Guidance for product LCA studies For product LCA, scenario analysis can be done e.g. for an EPD that is likely to have different impacts in the implementation and use phases. Examples of such products include floor coverings. Having different scenarios enables the building practitioner to select the more appropriate scenarios for the building LCA case study. 3) Specific guidance in EeBGuide reporting templates Scenario analyses are part of the reporting template for products and buildings case studies. In addition to the baseline scenario, the LCA practitioner is invited to conduct scenario analysis on a relevant set of parameters.

G-40 (Buildings) / G-38 (Products) Communication of LCA results

Written on 23. October 2012.

*Aspect*		G-40 (Buildings) / G-38 (Products) Communication of LCA results
*Description*		The external and internal communication of LCA results is still error-prone. How should results be communicated? How should they be presented with regard to different experience levels of the audience?
*related study objective*		☒ stand-alone LCA		☒ comparative assertion
*related study phase*		☐	☐	☐	☐	☒
		goal and scope definition	inventory analysis (LCI)	impact assessment (LCIA)	interpretation	reporting
*relevant for*
	new buildings	existing buildings	building products	screening LCA	simplified LCA	complete LCA
*Provisions*	Especially for complete LCA studies, the documentation should be in line with ISO 14044, EN 15804 and EN 15978. The EeBGuide provides reporting templates for building and product LCA that are generally in line with these standards. These reporting templates should be used.EN 15978 describes possibilities for easier communication of the LCA results.
*Rules from:*	*EN 15978: 12.6 Communication of assessment results* 12 Reporting of the assessment of results*EN 15804:* 8 Project report *EN 15942:* Reporting template for EPDs *ILCD*: 15.4 Misleading reporting and communication
*Guidance*	Requirements concerning reporting are part of the study type definitions. The reporting templates cover these rules.Special requirements for external reports and comparative assertions are given in ISO 14044. In addition, EPD programmes may ask for specific reporting requirements.ISO 14025 (and thus EN 15804) for EPD requires that the independent verifier generate a report documenting the verification process, while adhering to the obligations of the standard regarding data confidentiality. This report should be available to any person upon request.

G-41 (Buildings) / G-39 (Products) Reproducibility

Written on 23. October 2012.

*Aspect*		*G-41 (Buildings) / G-39 (Products) Reproducibility*
*Description*		Reproducibility is an important aspect of the reporting step in life cycle assessment. According to ISO 14044 and the ILCD Handbook, it is characterized by providing comprehensive documentation on data, assumptions, calculation rules etc. that would allow an independent reviewer to adequately reproduce the results and the corresponding interpretation of any LCI and LCA study. Because of different data sources and confidential datasets, reproducibility may sometimes be difficult to achieve. In addition, the use of LCA in the building sector leads to the development of LCA software that may use different data, assumptions and calculation rules for a national context. How can reproducibility of LCA studies in the building sector be ensured without excessively increasing the time needed to complete a study?
*related study objective*		☒ stand-alone LCA		☒ comparative assertion
*related study phase*		☐	☐	☐	☐	☒
		goal and scope definition	inventory analysis (LCI)	impact assessment (LCIA)	interpretation	reporting
*relevant for*
	new buildings	existing buildings	building products	screening LCA	simplified LCA	complete LCA
*Provisions*	The description of all aspects related to the LCA study should be as transparent as possible.For confidential data, the assumptions should be made available to the independent critical reviewer (if relevant for the review process).For building LCA studies, the documentation may not be required at the same level of detail as for other LCA studies, owing to the use of predefined data or models (e.g. aggregated generic or EPD datasets with only impact indicators).
*Rules from:*	*EN 15978: 13 Verification of results EN 15804:* 9 Verification and validity of an EPD *ILCD: Provisions: 6.2.2 Reproducibility* I) SHALL – Documentation for reproducibility II) MAY – Accompanying documentation process III) SHALL – Confidential information Provisions: 10.2 Reporting principles I) SHALL – Reproducibility and target audience to guide reporting
*Guidance*	1) General guidance for ensuring reproducibility of product and building LCA studies The ILCD Handbook provides detailed guidance on reporting. To ensure the best reproducibility of results, detailed reporting should be provided. This is especially true for aspirations concerning the quality of complete LCA studies. So, for instance, the author(s) of a complete LCA study should review whether the documentation using the EeBGuide reporting templates provided is sufficient to allow third parties to reproduce their study. If not, the practitioner should extend the documentation by considering the ILCD LCA report template and LCI reference dataset format. 2) Specific guidance for confidential product or building LCA studies It is not always possible to make all the assumptions available to the public, e.g. for a comparative LCA study of two structural systems, owing to confidential industry data. According to the ILCD Handbook, there is a need to balance reproducibility and confidentiality. In general, an independent external reviewer (e.g. for an LCA study) or verifier (e.g. for EPD) is a sound option to ensure that the results of comparative LCA studies (disclosed to the public) are reproducible. In this special case, the confidential data are made available only to the reviewer for e.g. raw data or unit process data in the case of a product LCA. 3) Specific guidance for building LCA studies The LCA methodology cannot be applied with the same level of detail for building LCA studies. Various simplifications are applied, e.g. by using only LCIA indicators instead of full LCI or unit processes. In this context, reproducibility remains as important as for product LCA. It is very important in a national context, when e.g. several LCA software tools exist on the market. Possible ways of achieving reproducibility for building LCA studies include: – harmonization of physical building description data (see the corresponding aspect); – choice of a common national set of generic LCA data (that can be used for early design stages). In addition, some specific requirements are needed for each LCA software: – Provide dedicated user manuals. – Document, in a transparent way, the assumptions of the LCA software (data, calculation rules, expression of results). – Facilitate data selection with e.g. a predefined building description. Reproducibility can be assessed in various ways. For example, training tests can assess the reproducibility among different LCA practitioners using the same LCA software and case study. Here, the influence of the practitioner is being assessed. Conversely, the same LCA practitioner can model the same case study using two different building LCA software tools. Here, the databases and methodological assumptions of the software are being assessed. One important aspect of reproducibility is the use of common datasets. Unfortunately, in some national contexts, different databases (e.g. generic and EPD data) can be used, answering different goals. In this specific case, data analysis tools may need to be developed to assess the differences in LCA data on building products and processes, in addition to the reproducibility tests explained above. Some guidelines on this topic, and on implementation in the French context, can be found in [Lasvaux 2011].

G-42 (Buildings) / G-40 (Products) Life cycle inventory documentation

Written on 23. October 2012.

*Aspect*		G-42 (Buildings) / G-40 (Products) Life cycle inventory documentation
*Description*		In order to fulfil the reproducibility requirement of a project, documentation of life cycle inventory datasets is very important. What level of detail makes sense?
*related study objective*		☒ stand-alone LCA		☒ comparative assertion
*related study phase*		☐	☐	☐	☐	☒
		goal and scope definition	inventory analysis (LCI)	impact assessment (LCIA)	interpretation	reporting
*relevant for*
	new buildings	existing buildings	building products	screening LCA	simplified LCA	complete LCA
*Provisions*	If no inventory documentation is asked for, it is sufficient just to name the methodology applied. If documentation is mandatory, use of the format mentioned in the ILCD Handbook is recommended as a minimum, including compliance with the nomenclature of the ILCD reference elementary flow list.
*Rules from:*	*ILCD: Compliance rules and entry-level requirements* Provisions: 7.4.5 Naming and other conventions“I) SHALL – Elementary flows I.a) Use ILCD reference elementary flows […] I.c) Use ILCD elementary flow categories […]”
*Guidance*	This point is subject to ongoing discussion, and will need to be revised in future.In the construction sector, building-level LCA studies are frequently conducted solely on the basis of impact indicator datasets for products, for example from EPDs or LCIA databases. In such cases, the life cycle inventory cannot be documented by the practitioner, and hence this aspect does not apply.For some selected data, simplified rules for the inventory analysis (e.g. a minimal list of substances) may be defined. However, a high level of accuracy should be ensured by checking a complete LCI against a reduced LCI for the same building material. This recommendation was part of a previous European project (LoRe-LCA) report ‘Building LCA good practice report’, available online. Examples of studies assessing the relevance of a complete list of elementary flows according to the chosen impact category can be found e.g. in [Lasvaux 2012]. It may be appropriate, for example, to list all inventory flows that are responsible for more than 1% of impact in any category. ISO 14044 4.4.2.5 suggests it may also be appropriate to list separately all inventory flows that do not contribute to any impact category: this can highlight errors in the classification and characterisation processes of LCIA.

G-43 Documentation of LCA results

Written on 23. October 2012.

*Aspect*		G-43 Documentation of LCA results
*Description*		Each LCA study has to be documented by means of an LCA report to demonstrate compliance with existing LCA standards (e.g. [ISO 14040], [ISO 14044] or [EN 15804], [EN 15978]). The hypotheses, methodological choices and LCA results are reported. However, how can be such a report be structured/documented for any LCA study for buildings? What is the important information to give in the report?
*related study objective*		☒ stand-alone LCA		☒ comparative assertion
*related study phase*		☐	☐	☐	☐	☒
		goal and scope definition	inventory analysis (LCI)	impact assessment (LCIA)	interpretation	reporting
*relevant for*
	new buildings	existing buildings	building products	screening LCA	simplified LCA	complete LCA
*Provisions*	The documentation of LCA results should be in line with ISO 14044; different templates should be used according to the level of complexity of the analysis (screening, simplified or complete).
*Rules from:*	*EN 15978: 12. Reporting of the assessment of results* 12.1 General information on the assessment 12.2 General information on the object of assessment 12.3 Statement of boundaries and scenarios used in the assessment 12.4 Data sources 12.5 List of indicators used for assessment and expression of results 12.6 Communication of assessment results” *ISO 14044:* 5 Reporting *ILCD*: 10 Reporting (General Guide for Life Cycle Assessment)
*Guidance*	The ISO 14044, ILCD and EN 15978 provisions should always be respected. The template defined for each study type (screening, simplified and complete) within the EeBGuide project should be used according to the goal and scope of the study. The template for case studies can be filled in by reporting information from the building project, and by identifying any deviation from the EeBGuide recommendations (e.g. for LCA data and methodology).

G-44 (Buildings) / G-41 (Products) Critical review

Written on 23. October 2012.

*Aspect*		G-44 (Buildings) / G-41 (Products) Critical review
*Description*		A critical review may be needed, especially if comparative results are intended to be disclosed to the public.How should this aspect be considered for building and product LCA?
*related study objective*		☒ stand-alone LCA		☒ comparative assertion
*related study phase*		☐	☐	☐	☐	☒
		goal and scope definition	inventory analysis (LCI)	impact assessment (LCIA)	interpretation	reporting
*relevant for*
	new buildings	existing buildings	building products	screening LCA	simplified LCA	complete LCA
*Provisions*	The critical review (or verification if it concerns an EPD) should be in line with the ILCD Handbook, and with ISO 14040/14044, as well as with ISO 14025 (for verification of EPD).The EeBGuide provides a review template that can be used to review an LCA study conducted according to the EeBGuide provisions. In this case, the review provisions supersede the ILCD and ISO 1404 ones.
*Rules from:*	*EN 15978: 12. Reporting of the assessment of results* *ISO 14044:* 5 Reporting *ILCD: Provisions: 11 Critical review* I) SHALL – See Chapter 6.11 for key decisions made on the critical review II) SHALL – Review scope, methods, and documentation
*Guidance*	The needs of a critical review depend on the goal of the study (stand-alone LCA vs. comparative assertions).Please note that within the context of EPD, the word to use is ‘verification’. In that context, it is likely that national EPD programmes will provide checklists of aspects to check for EPD conformity.In other cases, a critical review may be needed. The time and efforts required depend on the goal of the study.The EeBGuide provide a simplified review checklist that can support compliance with the EeBGuide provisions for building and product LCA studies.