You must distinguish methodology classes—an LCA following ISO 14040/14044 is not necessarily an EPD, and an EPD demands additional constraints. You need to define from the outset the target framework in order to ensure compliance.
Key Standards & Their Roles
Standard
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Purpose / Scope
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Relation with LCA / EPD
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ISO 14040
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Principles and general framework for Life Cycle Assessment
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Defines four phases (goal & scope, inventory, impact assessment, interpretation) and general rules
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ISO 14044
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Requirements and guidelines for LCA (data quality, allocation, critical review, etc.)
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Must be followed for an LCA to be ISO-compliant
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ISO 14067
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Carbon footprint of products (greenhouse gas) – additional requirements for quantifying and reporting CF
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A carbon-footprint study is a specific subtype of LCA, and ISO 14067 outlines a set of specific rules
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ISO 14025
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Type III environmental declarations (EPDs)
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EPDs are “Type III” declarations under ISO 14025, and must be based on LCA conformant with ISO 14040/14044
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EN 15804 (or ISO 21930)
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PCR (Product Category Rules) for construction sector EPDs in Europe
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Sets rules, modules, and reporting formats for construction EPDs built on ISO LCA standards
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Thus: an LCA built per ISO 14040/14044 is necessary for an EPD, but not sufficient. The EPD framework (PCRs) adds constraints, required modules, verification, and fixed disclosure formats.
What Makes an LCA ISO-Compliant?
To claim compliance with ISO 14040/14044, the following conditions (among others) must hold:
All four phases must be present, documented, and coherent (goal & scope, inventory, impact assessment, interpretation).
Transparency of assumptions, data sources, allocation choices, uncertainties.
Data quality rules (temporal, geographical, technological representativeness; completeness; consistency; reproducibility).
Handles multi-functionality via acceptable allocation or system expansion approaches, with justification.
Clearly stated system boundaries, unit functional, exclusions and cut-offs.
A sensitivity analysis aiming at identifying how variations in key assumptions, data, or methodological choices affect the robustness and reliability of the LCA results
If you adhere to those, your LCA can be “ISO-compliant” in principle.
Will It Be ISO-Compliant Automatically?
No. If you do a simplified, coarse LCA with many estimations or exclusions, you may not meet some ISO requirements (e.g. completeness, consistency, transparency). So even if you follow the four phases, you might not satisfy all ISO demands. For example, non-disclosure of assumptions or missing critical data may disqualify it in a formal or peer review context.
EPDs and Their Additional Requirements
For an EPD, beyond having an ISO-compliant LCA, you must meet further requirements:
Use the PCR (Product Category Rules) that define how the LCA must be done for that product category (allocation rules, module structure, cut-offs, impact indicators)
Submit to third-party verification by an independent verifier to check conformity with the PCR and ISO 14025
The EPD is typically valid for 5 years, unless there is a major change in product, process, or supply chain
The published EPD document must include references to standards (ISO 14040, 14044, 14025), the PCR used, assumptions, verification statement, and modules results
For construction EPDs under EN 15804, certain modules (A1–A3, A4–A5, etc.) and mandatory indicators are prescribed by the standard
Hence, producing an EPD is doing a specialized LCA under stricter rules.
ISO 14067 (Carbon Footprint) in Relation
ISO 14067 focuses on greenhouse gas emissions (carbon footprint) of a product, which is a narrower scope than a multi criteria analysis
It requires that the carbon-footprint calculation is based on LCA data and respects additional requirements (e.g. reporting, allocation of biogenic carbon) consistent with ISO 14040/14044
If your LCA is carbon-oriented (only GWP), aligning with ISO 14067 helps with consistency and external recognition
Summary
You must decide, from the start, the framework (ISO LCA only, ISO + EPD, carbon footprint) and design your methodology accordingly
An LCA that follows ISO 14040/14044 is a prerequisite, but not automatically sufficient to become an EPD
EPDs impose extra constraints (PCR, verification, fixed disclosure, 5-year validity) above standard LCA requirements
If your goal is public declaration (EPD) or regulatory compliance, you must ensure alignment with PCRs, verification, and disclosure rules, not just ISO LCA procedure