EN 15941:2024 is the current European standard for assessing, selecting and reporting the data used in construction environmental product declarations (EPDs). Relevant data must be assessed for how well they represent the period, location and technology of production. Specific data are the first choice, and data quality and gaps are reported in both the project report and the EPD.
Scope and key terms
BSI lists BS EN 15941:2024 as current. It supersedes the 2010 technical report CEN/TR 15941 and applies to data used in EPDs under EN 15804 and in building assessments under EN 15978.
An EPD reports the results of a life cycle assessment (LCA): a product’s potential environmental impacts, calculated from its inputs and outputs across defined life cycle stages. EN 15804 serves as the core product category rules (PCR) for construction products, and each EPD programme verifies and publishes EPDs under its general programme instructions (GPI).
The requirements focus on relevant data: data that together contribute at least 80 % of the absolute impact of any core environmental indicator in the EPD, across the life cycle modules assessed (excluding module D where the full life cycle is covered). Their quality is assessed with one of the schemes in Annex E of EN 15804+A2, applied consistently, covering time, geography and technology together with precision, completeness, consistency and data sources.
Time, geography and technology
| Dimension | Assessed in terms of | Typical evidence (practical) |
|---|---|---|
| Time | Age of data, reference year, validity, data collection period | Production and energy records with start and end dates |
| Geography | Production sites, delivery regions, end-of-life regions | Site list, sales markets, electricity supply per site |
| Technology | Process technology, scaling factors, mix of technologies | Process description, product variants covered, output share per line |
Raw data should normally cover one year; other periods must be justified. Where regions or technologies in one EPD have significantly different impacts, data must be collected for each, and production-weighted averages are recommended. Raw data are checked for plausibility, for example with a mass, energy or carbon balance.
Specific and generic data: fit for purpose
Following EN 15804, specific data, or averages of specific data, are the first choice, and an EPD for a specific product must use them at least for processes the producer can influence. Supplier-specific data are usually the most representative upstream but still need checking. If an EPD relies on one supplier and that supplier changes, recalculation and reverification may be needed; where suppliers change often, generic or average data may fit better.
Generic datasets differ in quality. Each candidate is assessed against the same criteria, checked for plausibility and ranked so that the most representative one is used.
Reporting quality and documenting gaps
The project report, which supports verification, must include:
- sources of raw data, and sampling and averaging methods;
- the data quality scheme applied;
- the time, geography, technology and source of every dataset;
- an explanation for any relevant data rated poor or very poor;
- missing data and deviations from EN 15804;
- mass balance checks and evidence that electricity is not double counted.
The EPD itself must summarise data quality qualitatively in a prominent section, using the Annex E terminology of EN 15804+A2, naming the scheme and noting any poor data. It also states the data collection period, production and modelled locations and the technology, and must not exaggerate data quality.
Checklist for manufacturers and suppliers
These are practical recommendations, not requirements of the standard.
- Fix the data collection period, normally one year, with start and end dates for each source.
- List the sites, lines and product variants covered, with their output shares.
- Ask your LCA practitioner for a contribution analysis identifying relevant data, and collect those first.
- Request specific data or current EPDs from key suppliers, recording validity, location and technology.
- For each generic dataset, record the database, version, reference year and reason for selection.
- Keep contractual evidence of electricity supply to rule out double counting.
- Keep a gap log of missing data, proxies and assumptions.
- Agree the Annex E scheme with your verifier early.
For sector-specific data, see our steel producer data checklist; on comparing EPDs, see PCR selection and EPD comparability. EPDportal.org hosts EPD Poland (EPD Polska), an EPD programme operated by Multicert. Browse the EPD Polska register or contact us about a project.
Frequently asked questions
- Does EN 15941 rule out generic or secondary data?
- No. Generic data may be used for upstream commodities and for processes the producer cannot influence, but they must be assessed, checked for plausibility and documented.
- Is there a single quality score an EPD must reach?
- EN 15941 sets no overall pass score. It requires consistent assessment and transparent reporting, including poor data; your PCR or programme may add requirements.
- Does EN 15941 replace EN 15804?
- No. It complements EN 15804+A2 with more detailed rules on selecting data and assessing and reporting their quality.