G-25 Choice of LCI/LCIA-datasets for complete LCA

Aspect G-25 Choice of LCI/LCIA-datasets for complete LCA
Description
Different LCI/LCIA data are needed to assess the environmental impacts of buildings. They make it possible to quantify the different impacts related to the building products and equipment, the construction site, the operational energy and water uses, and the deconstruction of the building. Depending on the study type (screening, simplified or complete), different LCI/LCIA data can be used in practice, depending on their availabilities at the European level, but also in a national context (average, generic or specific LCI/LCIA data for building materials, products and processes). How can this be addressed for complete 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 construction products screening LCA simplified LCA complete LCA
Provisions The LCA practitioner or the user of dedicated building LCA tools should use adapted data for description of the building components in complete LCA. In contrast with simplified LCA, the data should reflect the building element, product or material more closely. They can represent a full building component (e.g. 1 m2 concrete block wall insulated with wood wool), or a building product (e.g. 1 m2 of rockwool) or a building material (1 m3of ready-mixed concrete), depending on the need of the practitioner and the stage of the building project. Provisions for the choice of data to use for complete LCA for the construction site, the operational energy and water uses, and the deconstruction activities are described in the corresponding aspects.LCA data for the building products cited above should correspond to specific industry data (e.g. EPD data) provided by the building manufacturers at the European level, or also in the national context; generic or average LCA data (refer to the provisions for simplified LCA) should be used if specific data (e.g. EPD) are currently missing for some building products or technical equipment.Cut-off rules and impact categories may be considered according to the ILCD Handbook if the goal of the study is to assess indicators and data beyond the EN 15804 cut-off and impact category. The practitioner is likely deviate from the above provision and use instead generic or average datasets providing a high level of detail in terms of the cut-off and impact categories to be calculated.
Rules from:

EN 15978

9.4 Type of data for the assessment
The type of LCA data for the assessment referred in EN 15978 to the CEN/TR 15941. The choice of the data will depend on several aspects including stage of the building project, intended use/scope etc. According to EN 15978 the data (either bill of quantities, building description of components or the LCA data) may be given in different types: aggregated, specific, generic, average. They describe different levels of specificity concerning the description of the building components as well as the representativeness of the LCA data.

ILCD

7.5 Developing generic LCI data
7.6. Selecting secondary LCI datasets
7.7 Averaging LCI data

According to the ILCD Handbook, a dataset is a generic dataset if “it has been developed using at least partly other information then those measured for the specific process. This other information can be stoichiometric or other calculation models, patents and other plans for processes or products, expert judgements etc. Generic process can aim at representing a specific process or system or an average situation.”

According to ILCD, the supply mix for an average data is the production mix plus the import mix i.e. the mix of what is available in the country for consumption. This applies to a specific data like an EPD for a product sold by a company.

Figure 14 representing the trade relations between countries, as a basis for calculating the production, consumption and supply mixes of products [ILCD 2011a]

Guidance
In practice, the LCA data for a complete LCA should closely represent the building components, products or materials, or the part of the building. The building LCA practitioner may use an existing national EPD database to collect specific EPD data on building products, depending on the requirements. Three different practical recommendations can be given for the use of data on building elements, the associated LCA data, and the currently available specific (e.g. EPD) databases.1) Practical guidance for the use of data describing the building elements

The data describing the building components should correspond to the components implemented in the building. Please refer to the description of the complete LCA study type for more information.

Other data include building products and materials LCA data. These ‘raw’ data usually serve when deriving data for building components or parts of the building. Consistency should be ensured between the different levels of data for complete LCA (part of the building, components, products and materials).

2) Practical guidance for the use of specific LCA data for a European or national context

ILCD provisions can be consulted concerning the consumption mix of the building product. Specific data such as EPD reflects the production volume of a building product sold on a national market.

3) Practical availability of specific (e.g. EPD) databases in Europe that can be used by the practitioner

Specific EPDs may be found in available national EPD databases or European EPD databases (e.g. ECO-EPD). Examples of such databases can be found several European countries:

France: INIES

Germany: Institut Bauen und Umwelt

UK: BRE Profiles

Spain: DAPc system

The Netherlands: MRPI

Finland: RTS

The International EPD (R) ‘The Green Yardstick’ also provides EPD data for some European countries, such as Sweden and Italy.

If specific EPD are not available, the practitioner may use generic data or average industry data. Consultation of the LCA Resources directory of the European Commission – Joint Research Centre, section ‘Databases’ may be then needed. Generic databases include, for example, the ELCD, GaBi and ecoinvent databases. Other generic databases developed in European countries include, for example, the German Ökobau.dat and the Swiss Catalogue Construction/KBOB databases.

Care has to be taken when using EPDs for complete LCA, as they may not include a full LCI (depending on the PCR, only environmental indicators may be required). Thus they may not allow the use of LCIA indicators outside the scope of the Product Category Rules. For example, the EN 15978 standard does not yet include land use, toxicity or ecotoxicity indicators. The same remarks apply to cut-off rules and infrastructures issue.

The LCA practitioner should be aware here that the choice of LCI/LCIA datasets for complete LCA is intended primarily to be as accurate as possible for the current impact of the manufacture of a building product. However, the cut-off rules and LCI documentation may not be as comprehensive as needed by the practitioner.

For alternative goal definition beyond the scope of EN 15804, the practitioner may need a complete LCI in order to consider a full suite of impact categories. The same applies for the cut-off criteria. In this special case, the practitioner is likely to rely on generic datasets that may be the only possible way to provide such a level of detail (LCI, cut-off rules).

At this point, there is a trade-off between using specific data for a commercial reference of a product, and maintaining a high level of detail in terms of LCI, cut-off rules etc.


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