EN 15804+A2 Explained: What Changed and What You Must Report

Introduction: Why EN 15804 Matters

If you manufacture, specify, or procure construction products in Europe, EN 15804 is the standard that determines how environmental performance is measured and communicated. Formally titled „Sustainability of construction works — Environmental product declarations — Core rules for the product category of construction products,” EN 15804 is published by CEN Technical Committee 350 and provides the methodological backbone for every construction-product EPD issued on the continent.

Understanding what changed and what is now mandatory is essential for any manufacturer preparing an Environmental Product Declaration.

Structure of EN 15804+A2

Scope and Normative References

EN 15804 applies to all construction products and construction services. It establishes core Product Category Rules (core PCR) that every product-specific PCR must follow. The standard references ISO 14025 for the general principles of Type III environmental declarations, ISO 14040 and ISO 14044 for life-cycle assessment methodology, and the CEN/TR 15941 technical report for guidance on generic data selection. It also references the European Commission’s EF 3.0 characterisation factors, which replaced the CML-based impact-assessment methods used in the A1 version.

Declared Unit and Functional Unit

EN 15804 distinguishes between a declared unit and a functional unit. A declared unit is used for cradle-to-gate EPDs where the product’s function in the building is not fully defined. A functional unit is used for cradle-to-grave EPDs and incorporates the product’s performance over a reference service life.

The choice between declared and functional unit has significant implications for comparability, and the standard provides clear rules on when each is appropriate.

Life-Cycle Modules: A1 Through D

EN 15804 organises the life cycle into distinct modules, each representing a specific stage. This modular approach allows EPDs to present data at varying levels of completeness while maintaining a consistent structure.

Product Stage (A1-A3)

Module A1 covers raw-material supply, including the extraction and processing of all input materials and the generation of electricity used in these processes. Module A2 covers the transport of raw materials to the manufacturing plant. Module A3 covers the manufacturing process itself, including energy consumption, direct emissions, packaging, and waste treatment at the factory gate. Modules A1 to A3 are always mandatory in any EPD complying with EN 15804+A2.

Construction Process Stage (A4-A5)

Module A4 covers the transport of the finished product from the factory gate to the building site. Module A5 covers installation, including ancillary materials, energy used during installation, and waste generated on site. These modules are optional in a cradle-to-gate EPD but mandatory in a cradle-to-grave declaration.

Use Stage (B1-B7)

The use stage is the most variable section. Module B1 addresses emissions or impacts during use without any physical intervention. Module B2 covers maintenance activities. Module B3 covers repair. Module B4 covers replacement of the product during the reference study period. Module B5 covers refurbishment. Module B6 covers operational energy use attributable to the product, and Module B7 covers operational water use. Not all modules are relevant for every product. A concrete block, for instance, may have negligible B1-B5 impacts, whereas a window system would have significant B6 contributions due to its influence on heating and cooling loads.

End-of-Life Stage (C1-C4)

Module C1 covers deconstruction and demolition. Module C2 covers transport to waste processing or disposal facilities. Module C3 covers waste processing for reuse, recovery, or recycling. Module C4 covers final disposal, typically landfilling. Under EN 15804+A2, modules C1 through C4 are mandatory for all EPDs, meaning that even a cradle-to-gate EPD must now include end-of-life scenarios.

Module D: Beyond the System Boundary

Module D reports the net environmental benefits or loads resulting from reuse, recovery, or recycling of materials and energy that leave the product system. For example, if steel rebar is recycled at end of life, Module D would credit the avoided production of virgin steel. Module D is reported separately from the A-to-C system boundary and is mandatory to declare under EN 15804+A2, though its results are not aggregated with the other modules.

Mandatory Environmental Impact Indicators Under A2

The most consequential change in the A2 amendment was the overhaul of environmental impact indicators. The following indicators are now mandatory for every EPD complying with EN 15804+A2.

Global Warming Potential (GWP)

GWP is reported not as a single number but as four sub-indicators: GWP-total, GWP-fossil, GWP-biogenic, and GWP-luluc (land use and land-use change). GWP-fossil captures emissions from combustion of fossil fuels and industrial processes. GWP-biogenic captures the uptake and release of biogenic carbon, which is particularly important for wood and timber products. GWP-luluc captures emissions associated with changes in land use. GWP-total is the sum of the three sub-indicators. All four must be reported per life-cycle module. This decomposition was not required under A1, which reported only a single GWP value.

Ozone Depletion Potential (ODP)

ODP quantifies the potential to destroy stratospheric ozone, expressed in kg CFC-11 equivalents. While many ozone-depleting substances have been phased out under the Montreal Protocol, ODP remains relevant for products that use or emit halogenated compounds during manufacturing or at end of life.

Acidification Potential (AP)

AP measures the potential to acidify soil and water bodies, expressed in mol H+ equivalents. Under A2, the characterisation model changed from CML to the Accumulated Exceedance method consistent with EF 3.0, which means A2 values are not directly comparable to A1 values.

Eutrophication Potential (EP)

A2 splits eutrophication into three separate indicators: EP-freshwater (kg P equivalents), EP-marine (kg N equivalents), and EP-terrestrial (mol N equivalents). Under A1, a single EP indicator was reported. The split reflects the fact that eutrophication mechanisms differ fundamentally between freshwater systems (typically phosphorus-limited), marine systems (typically nitrogen-limited), and terrestrial ecosystems.

Photochemical Ozone Creation Potential (POCP)

POCP measures the potential for formation of ground-level ozone (smog), expressed in kg NMVOC equivalents under A2. The characterisation factors changed from the LOTOS-EUROS model used in A1 to the EF 3.0 model, again affecting comparability.

Abiotic Depletion Potential (ADP)

ADP is reported in two sub-indicators: ADP-minerals and metals (kg Sb equivalents) and ADP-fossil resources (MJ, net calorific value). ADP-mm assesses the depletion of non-renewable mineral and metal resources, while ADP-ff assesses the depletion of fossil energy carriers. These indicators remained conceptually similar between A1 and A2 but received updated characterisation factors.

Water Deprivation Potential (WDP)

WDP is a new mandatory indicator introduced in A2, expressed in m3 world equivalent. It quantifies the potential impact of water consumption considering regional water scarcity. WDP was not required under A1, making it one of the most visible additions in the amended standard.

Additional Environmental Impact Indicators

Beyond the core indicators above, EN 15804+A2 also mandates six additional environmental impact indicators, drawn from the EF 3.0/3.1 framework. These cover human-health pathways, ecosystem toxicity, and soil quality.

These indicators were introduced to align with the EU Environmental Footprint methodology. They address human health (particulate matter, ionising radiation, carcinogenic and non-carcinogenic toxicity), ecosystem health (freshwater ecotoxicity), and land-related impacts (soil quality). While they receive less attention in market discussions than GWP, they are equally mandatory in a compliant EPD and must be reported for each declared life-cycle module.

Resource Use Indicators

In addition to environmental impact indicators, EN 15804+A2 requires reporting of resource use indicators that quantify the energy and material flows entering the product system.

Waste and Output Flow Indicators

EN 15804+A2 also requires two further categories of reporting that complete the material balance of the product system: waste indicators and output flow indicators.

Waste Indicators

Output Flow Indicators

The waste indicators (HWD, NHWD, RWD) quantify the mass of waste leaving the product system for final disposal. The output flow indicators (CRU, MFR, MER, EEE, EET) quantify materials and energy that exit the product system as usable outputs rather than waste. Together with the impact indicators and resource use indicators, these categories form the complete set of mandatory data that every EN 15804+A2-compliant EPD must report per declared life-cycle module.

Key Changes from A1 to A2

Alignment with EF 3.0/3.1 Characterisation Factors

The single most impactful technical change was the adoption of Environmental Footprint characterisation factors. Under A1, impact-assessment methods were drawn from CML (developed at Leiden University) and other established sources. Under A2, the standard references EF 3.0 (and subsequently EF 3.1) characterisation factors published by the European Commission’s Joint Research Centre. This alignment ensures consistency between EPDs and the broader Product Environmental Footprint (PEF) framework, but it also means that indicator values from A1-era EPDs cannot be directly compared with A2-era EPDs, even for the same product.

Expanded Indicator Set

As described above, A2 introduced GWP sub-indicators, split eutrophication into three compartments, added WDP, and introduced six additional indicators covering particulate matter (PM), ionising radiation (IRP), freshwater ecotoxicity (ETP-fw), human toxicity for cancer and non-cancer effects (HTP-c, HTP-nc), and soil quality (SQP). The total number of mandatory impact indicators increased significantly, providing a more nuanced environmental profile but also requiring more comprehensive LCA modelling.

Mandatory End-of-Life and Module D

Under A1, it was possible to publish a strictly cradle-to-gate EPD covering only modules A1 to A3. Under A2, modules C1 to C4 and Module D must always be declared, even in a cradle-to-gate EPD. This ensures that end-of-life impacts and recycling benefits are always visible, preventing cherry-picking of favourable life-cycle stages.

Biogenic Carbon Accounting

A2 introduced detailed rules for biogenic carbon, requiring separate tracking of carbon uptake during biomass growth (reported in A1) and carbon release at end of life (reported in C3 or C4). The split GWP-biogenic indicator makes the carbon balance of bio-based products transparent. This is particularly consequential for wood, timber, and other biomass-derived construction products.

The Role of PCRs

EN 15804 functions as a core PCR. Product-specific PCRs, also called complementary PCRs or sub-PCRs, add detail for specific product categories. For instance, a PCR for cement and concrete will define the appropriate declared unit, specify which use-stage modules are relevant, set data-quality requirements for clinker production, and prescribe end-of-life scenarios for demolition concrete. PCRs are maintained by programme operators and must be consistent with EN 15804+A2. When commissioning an LCA, the first step is always to identify the applicable PCR from the programme operator’s library.

EPD Comparability Rules

EN 15804+A2 sets strict conditions under which EPDs may be used for product comparison. Two EPDs can only be meaningfully compared if they meet all of the following criteria:

• Both EPDs comply with the same version of EN 15804 (both A2, or both A1 — never mixed).
• Both EPDs are based on the same Product Category Rules (PCR).
• Both EPDs use the same declared or functional unit.
• Both EPDs cover the same set of life-cycle modules.
• The underlying LCA datasets use equivalent system boundaries and allocation rules.

In practice, comparison is most reliable at the building-element level, where a structural engineer or LCA practitioner defines a functional equivalent — for example, one square metre of load-bearing wall delivering a specified thermal resistance over a 50-year reference study period — and then calculates the total environmental impact of each design option using EPD data for all constituent materials.

Implications for Manufacturers

The transition from A1 to A2 has several practical consequences. First, any LCA study initiated today must use A2 methodology and EF 3.0/3.1 characterisation factors. EPDs based on A1 methodology will progressively lose acceptance as markets and regulations converge on A2. Second, the expanded indicator set means that LCA practitioners need more detailed inventory data, particularly for water use, biogenic carbon, and land-use change. Manufacturers should ensure that their production data covers these dimensions. Third, the mandatory inclusion of end-of-life modules requires defensible assumptions about deconstruction, transport distances, waste-processing routes, and recycling rates. These scenarios should be documented transparently in the EPD.

Manufacturers should focus their efforts on A2 compliance. The revised Construction Products Regulation references EN 15804 as the methodological basis for GWP declaration, reinforcing the standard’s central importance.

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