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

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

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 […]”

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 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. 

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