26 August 2026

How to Create an EN 15804 EPD From a Manufacturing BOM

A manufacturing bill of materials gives an EN 15804 study a practical starting point: parts, materials, subassemblies, quantities, packaging and supplier references. It is not the finished declaration. Facility energy, transport, allocation, waste, use-stage scenarios and end-of-life assumptions may still sit outside the BOM and must be added to the product model.

Manufacturing BOM feeding an EN 15804 product model, EPD documentation, independent verification and publication

TL;DR

Use the BOM to establish the product composition, then freeze the relevant version and fill its environmental-data gaps. Select the applicable product category rules, model the required life-cycle stages and indicators, prepare the declaration documentation, and send it through independent verification and programme-operator publication. Keep later product changes separate from the declared version.

What the BOM provides—and what it does not

A manufacturing BOM can identify components, materials, subassemblies, quantities, packaging items and supplier references. However, the manufacturing BOM description from Arena also shows why a production-oriented structure is not automatically a complete environmental inventory.

Start by extracting:

Part and material identities
Component quantities and units
Reused subassemblies
Product and packaging items
Supplier or manufacturer references
Variant-specific components
The BOM version and effective date

Then identify missing information. Common gaps include factory electricity and fuel, production scrap, water or utility use, inbound and outbound transport, allocation between co-products, installation losses, maintenance or replacement scenarios, demolition, waste processing, recycling and disposal.

These additions need evidence. Record whether each value comes from a supplier document, site measurement, calculation, environmental dataset or scenario assumption. That distinction matters during review because an apparently complete model may still rely heavily on generic data.

Choose the PCR before fixing the model boundary

An EPD communicates independently verified environmental information based on an LCA and applicable product-category rules. The International EPD System describes the overall sequence as PCR selection, LCA execution, EPD compilation, independent verification, registration and publication—not simply exporting a carbon result from a BOM model (International EPD System EPD process).

For that programme, the current construction-products document is PCR 2019:14 version 2.0.1. It was published on June 5, 2025 and is listed as valid until April 7, 2030. A relevant product category may also require a complementary PCR, so confirm both the main rules and any category-specific requirements before modelling.

PCR 2019:14 version 2.0.1, published June 5, 2025 and valid until April 7, 2030

PCR selection determines more than report wording. It affects the declared unit, system boundary, required modules, allocation choices, scenarios and documentation. Changing those foundations late in the project can force substantial rework.

An eight-step BOM-to-EPD workflow

A controlled workflow separates product-data preparation from LCA calculation and separates report preparation from external verification. The eight steps below end with the independent review and publication process rather than treating a software-generated table as a published EPD.

Eight-step EN 15804 workflow from freezing the manufacturing BOM through external verification and programme publication

1. Freeze the declaration BOM

Create a dated, immutable version of the assembly used for the study. Record its component revisions, quantities, packaging and production location. Product development can continue, but later changes should create another version rather than silently altering the declared model. Versioned assembly BOMs provide a way to retain this relationship over time.

2. Confirm the PCR and declared unit

Identify the programme operator, main PCR and any complementary PCR. Define the declared or functional unit and document which product variants the result covers. Do not assume that one result automatically represents every size, supplier configuration or manufacturing route.

3. Complete the non-BOM inventory

Add manufacturing utilities, losses, transport, facility data and relevant downstream scenarios. Map supplier evidence to the affected parts instead of storing it as an unconnected folder of files. Where primary evidence is unavailable, document the selected secondary dataset and the reason for using it.

4. Map parts and processes to datasets

Connect each material, transport activity, utility and waste flow to appropriate environmental data. Check geography, technology, age and system-model compatibility. SimaPro, for example, offers an ecoinvent Allocation, cut-off, EN15804 system model and an EN 15804+A2 method, while its documentation notes that some non-LCIA parameters can require custom handling (SimaPro EN 15804 documentation).

5. Model the required life-cycle stages

Build the applicable modules rather than reporting only cradle-to-gate carbon. openLCA supports separate life-cycle-stage models that can be combined into a product system, with an EN 15804 add-on covering relevant data and indicators (openLCA EPD modelling). The exact modules included still depend on the PCR and declaration scope.

6. Review indicators, assumptions and hotspots

Check mass balance, allocation, transport, production waste and scenario assumptions. EN 15804 reporting extends beyond one climate number. The International EPD System’s climate indicators alone include GWP-fossil, GWP-biogenic, GWP-land use and land-use change, GWP-total and GWP-GHG (environmental performance indicators).

7. Prepare the EPD report and verification material

Compile the required tables, product description, system boundary, data-quality explanation, assumptions and supporting evidence. The International EPD System provides a mandatory verification-report template for construction-product EPDs (EPD templates). Internal review should resolve inconsistencies before files reach the verifier.

8. Complete external verification and publication

Independent verification remains outside the modelling application. Under the International EPD System, a declaration must be independently verified before registration and publication (EPD creation requirements). The verifier and programme operator, not the BOM or LCA software, control those final stages.

PCF versus a complete EN 15804 EPD

A product carbon footprint may reuse the same inventory, but it is not automatically a complete EPD. An EN 15804 declaration reports multiple environmental indicators plus resource-use, waste and output-flow information (Emidat’s EN 15804 overview). ISO 14067 PCF work and EN 15804 EPD work can therefore share data without becoming the same study by default. See this practical comparison of LCA versus carbon footprint.

Comparing BOM-to-EPD approaches

The main choice is between specialist modelling control, guided EPD workflows and connected product-data systems. Desktop tools focus on detailed study modelling; manufacturing platforms connect BOM information and environmental datasets; living product models help preserve assemblies, suppliers, variants and versions after the first calculation.

Comparison of Dawn, One Click LCA, Ecochain, Makersite, SimaPro and openLCA for BOM-based EN 15804 work, including EF 3.1 in Dawn workflows

| Tool | Sourced capability relevant to BOM-to-EPD work | Workflow emphasis | | --- | --- | --- | | Dawn | Excel/CSV part import; assemblies, variants, versions, suppliers and living product-plus-LCA data management | Maintains connected BOM and LCA records for carbon numbers, EPD-style tables and supporting evidence; verification remains external | | One Click LCA | Product-data collection, LCA modelling, impact analysis and EPD report preparation | Guided workflow followed by third-party verification and publishing | | Ecochain | Connects BOM information to ecoinvent, PEF and World Steel data | Central reuse of environmental information across construction-product portfolios | | Makersite | Maps BOM components to supply-chain data and incorporates supplier primary data | Product-level modelling across complex BOM portfolios | | SimaPro | ecoinvent EN 15804 system model and EN 15804+A2 impact-assessment method | Expert study modelling and methodological control | | openLCA | Separate life-cycle-stage modelling and an EN 15804 add-on | Flexible product-system construction and EPD data import |

No approach removes the need for PCR interpretation, evidence review or verifier dialogue. One Click LCA explicitly places final documents with third-party verifiers and publishers after internal review (One Click LCA manufacturing workflow). Ecochain describes BOM-to-dataset mapping and portfolio reuse (Ecochain EPD software), while Makersite focuses on BOM mapping, supply-chain data and supplier inputs (Makersite EPD workflow).

Dawn fits the connected-model approach. Its product and environmental data management keeps parts, assemblies, BOM versions, LCA studies, suppliers and files in one system. It runs Ecoinvent-based studies using EN 15804, EF 3.1 and cutoff methods, then presents hotspots, life-cycle stages and kg CO2e through its product carbon footprint workflow. EPD-style tables can support documentation, but human methodological decisions, independent verification and programme publication remain outside the app.

Keep the declared version reproducible

The first EPD is not the end of the data problem. Materials, suppliers, packaging, factories, electricity mixes and product variants change. Preserve the exact BOM, datasets, assumptions and evidence used for the declaration while allowing a new version to inherit unchanged components.

This avoids rebuilding every study from scratch without obscuring product-specific differences. Shared subassemblies can retain common data, while changed parts trigger review in the affected variants. The result is a traceable path from the published declaration back to its product configuration—and a controlled starting point for updating an LCA when the BOM changes.