Carbon is one number.
LCA is the whole story.
A product’s footprint isn’t a single statistic — it’s hundreds of resource and emission flows across raw materials, manufacturing, use, and end-of-life. Life Cycle Assessment quantifies all of them under ISO 14040, and grounds every Type III EPD GreenTag publishes.
An LCA gives you
A complete, ISO-compliant inventory of inputs and outputs across the full life cycle.
Characterised impact indicators — climate change, water, eutrophication — ready for an EPD.
A third-party verifiable basis for green-building credits across LEED, BREEAM, and Green Star.
§1 · Definition
What is Life Cycle Assessment?
Life Cycle Assessment (LCA) is the systematic, ISO 14040 method for quantifying a product’s environmental impacts across its full life cycle — from raw-material extraction through manufacturing, distribution, use, and end-of-life.
Rather than reporting on a single impact like carbon, LCA accounts for the full set of physical resource and emission flows associated with a product and translates them into characterised impact indicators.
Three compliance requirements
An LCA report that feeds a GreenTag EPD must:
- 01comply with ISO 14040 & 14044 LCA principles;
- 02follow ISO 14025 data, method, and assumption rules for EPDs;
- 03align with the relevant Product Category Rules (PCR).
§2 · Methodology stack
The standards that govern LCA
LCA sits on a stack of complementary international standards. Each handles a distinct layer of the methodology — together they define what an LCA must do, how it must do it, and how its results may be declared.
ISO 14040
Principles
Defines the four-phase framework and the principles of an LCA study — goal & scope, inventory, impact assessment, interpretation.
ISO 14044
Requirements
Operational requirements that any compliant LCA must satisfy: data quality, allocation rules, sensitivity analysis, and critical review.
ISO 14025
Declaration
The Type III EPD framework — how LCA results become a published, third-party verified, comparable declaration.
EN 15804+A2
Sector PCR · Construction
Construction-products Product Category Rule — defines modules A1–D and the 41 required impact indicators referenced in §3 and §5.
§3 · Life-cycle scope
Life-cycle modules (A1–D)
For construction products under EN 15804+A2, the life cycle is divided into named modules. Every EPD declares which modules it includes — the ribbon below traces a cradle-to-grave-plus-D scope, and the accordion beneath breaks each stage into the individual modules a study can declare.
A1–A3
Product stage
Raw material supply · transport to factory · manufacturing
A4–A5
Construction
Transport to site · on-site installation
B1–B7
Use stage
Use, maintenance, repair, replacement, refurbishment, operational energy and water
C1–C4
End of life
Deconstruction · transport · waste processing · final disposal
D
Beyond
Reuse, recovery, recycling potential
A1–A3Product stageRaw-material supply, inbound transport, and manufacturing. Combined A1–A3 is the most commonly declared scope (cradle-to-gate).4 modules
A4–A5Construction stageGetting the product from factory gate to its installed position on a project site.2 modules
B1–B7Use stageOperational impacts while the product is in service. Most building products declare a subset of B1–B7.7 modules
C1–C4End of lifeWhat happens to the product after the building reaches end of life — deconstruction, transport, processing, and disposal.4 modules
D1–D4Beyond the systemNet benefits and loads beyond the system boundary — credits for materials and energy recovered for reuse outside the product’s own life cycle.4 modules
An EPD must state precisely which modules are included and which are excluded. Cradle-to-gate (A1–A3 only), cradle-to-grave (A–C), and with-module-D scopes are all permitted under EN 15804+A2.
§4 · Modelling alternatives
Scenarios — alternatives within a module
Within each life-cycle module, an LCA can model multiple scenarios — for example, a baseline production run alongside an energy-optimised variant, or a standard transport route alongside a longer regional one. Each module × scenario combination becomes its own column in the results table, letting the EPD show how design choices change a product’s footprint.
Group A
Production
Alternatives for how the product is manufactured.
Typical modules · A1–A3
Baseline Production
Standard manufacturing process with current technology and energy mix.
Optimised Production
Manufacturing with energy-efficiency improvements or low-carbon power.
Group B
Transportation
Alternatives for how the product moves to site (A4) or to end-of-life (C2).
Typical modules · A4, C2
Standard Transport
Average transport distance and mode declared for the typical project.
Long-distance Transport
Sensitivity case for projects further from the manufacturing facility.
Group C
End of life
Alternatives for how the product is processed at end of life.
Typical modules · C3, C4, D
Recycling Pathway
Standard regional recycling and recovery pathway for the material.
Landfill Pathway
Worst-case where the product reaches landfill without recovery.
| Module | Scenario | Resulting column key in the results table |
|---|---|---|
| A1–A3 | Baseline Production | A1–A3 / Baseline Production |
| A1–A3 | Optimised Production | A1–A3 / Optimised Production |
| A4 | Standard Transport | A4 / Standard Transport |
| C3 | Recycling Pathway | C3 / Recycling Pathway |
Each row in the results table reports indicator values across these column keys. Duplicate module/scenario combinations are filtered, and every scenario group must contain a default scenario before alternates can be modelled.
§5 · Impact reporting
Environmental indicators
Each module / scenario column is populated with the 41 environmental indicators required under EN 15804+A2, grouped into 14 categories that span climate, ecosystem effects, energy, water, waste, and end-of-life output flows. The matrix below is what the published EPD reports.
Climate Change
Net contribution to global warming — split across fossil, biogenic, and land-use carbon flows.
4 · GWP
Climate Change
Net contribution to global warming — split across fossil, biogenic, and land-use carbon flows.
Ozone Depletion
Stratospheric ozone-layer depletion from CFC and halocarbon emissions.
1 · ODP
Ozone Depletion
Stratospheric ozone-layer depletion from CFC and halocarbon emissions.
Acidification
Acidification of soil and water from SO₂, NOₓ, and ammonia.
1 · AP
Acidification
Acidification of soil and water from SO₂, NOₓ, and ammonia.
Eutrophication
Nutrient enrichment driving algal blooms and dead zones across freshwater, marine, and terrestrial systems.
3 · EP
Eutrophication
Nutrient enrichment driving algal blooms and dead zones across freshwater, marine, and terrestrial systems.
Photochemical Ozone
Ground-level (tropospheric) ozone formation from NMVOC and NOₓ.
1 · POCP
Photochemical Ozone
Ground-level (tropospheric) ozone formation from NMVOC and NOₓ.
Abiotic Depletion
Depletion of non-renewable mineral and fossil resources.
2 · ADP
Abiotic Depletion
Depletion of non-renewable mineral and fossil resources.
Water Use
Deprivation-weighted water consumption — relative scarcity of the water taken.
1 · WDP
Water Use
Deprivation-weighted water consumption — relative scarcity of the water taken.
Primary Energy — Renewable
Renewable primary energy used as energy, as feedstock, and the total.
3 · PER*
Primary Energy — Renewable
Renewable primary energy used as energy, as feedstock, and the total.
Primary Energy — Non-renewable
Non-renewable primary energy used as energy, as feedstock, and the total.
3 · PENR*
Primary Energy — Non-renewable
Non-renewable primary energy used as energy, as feedstock, and the total.
Secondary Materials & Fuels
Use of recycled materials and secondary fuels in production.
3 · SM / RSF
Secondary Materials & Fuels
Use of recycled materials and secondary fuels in production.
Fresh Water Use
Absolute net fresh-water consumption across the system boundary.
1 · FW
Fresh Water Use
Absolute net fresh-water consumption across the system boundary.
Waste Categories
Mass of waste sent to final disposal — hazardous, non-hazardous, and radioactive.
3 · HWD / RWD
Waste Categories
Mass of waste sent to final disposal — hazardous, non-hazardous, and radioactive.
Output Flows — Recovery
Mass of components and materials leaving the system for reuse, recycling, or energy recovery.
3 · CRU / MFR
Output Flows — Recovery
Mass of components and materials leaving the system for reuse, recycling, or energy recovery.
Exported Energy
Energy exported from the system (e.g. recovered heat from incineration).
2 · EEE / EET
Exported Energy
Energy exported from the system (e.g. recovered heat from incineration).
The full 41 indicators × N module/scenario columns matrix is the numeric heart of every published EPD. ISO 14025 verification confirms that each cell traces back to declared LCI data and the relevant PCR rules.
§6 · From study to publication
How an LCA becomes an EPD
An LCA on its own is a private technical study. An EPD is the published, third-party verified, comparable form of that LCA — assembled per a PCR and registered to a recognised program.
Step 1
PCR selection
Identify or develop the Product Category Rule that governs LCA scope, modules, and indicators.
Step 2
LCA delivery
A vetted LCA consultant conducts the study under ISO 14040 / 14044, aligned to the PCR. GreenTag engages the consultant and facilitates scope on your behalf.
Step 3
Verification
Independent third-party reviewer audits LCA + draft EPD for ISO 14025 conformance.
Step 4
Publication
Registered to the GreenTag Registry; recognised by LEED, BREEAM, Green Star, WELL.
Procedural detail in the General Program Instructions §7.
§7 · Complementary, not redundant
LCA vs. LCBA — impacts vs. benefits
LCA quantifies impacts; LCBA quantifies benefits. They measure different halves of the same product story and are designed to work together. Every GreenTag LCA can be extended with an LCBA Benefit Addendum.
LCA
Burdens
- ISO 14040 / 14044 method
- Carbon, water, eutrophication, acidification
- Outputs the Type III EPD under ISO 14025
- Required for every GreenTag EPD
What both have in common
Full life-cycle scope · ISO 14025 third-party verification · recognised by LEED, BREEAM, Green Star, and WELL
LCBA
Benefits
- GreenTag program methodology
- Sequestration, biodiversity, circularity, social value
- Published as the EPD:BA Benefit Addendum
- Optional extension on any GreenTag LCA
§8 · Clarifying misconceptions
What LCA is not
LCA is often confused with adjacent concepts. For clarity:
Not a carbon footprint.
A carbon footprint reports one impact category (kg CO2e). A full LCA reports a dozen or more.
Not LCBA.
LCA measures impacts (the burdens). LCBA measures benefits (the regenerative contributions). They’re complementary — see §7.
Not a generic sustainability claim.
“Eco-friendly” and “green” are marketing language. LCA produces quantitative, third-party verifiable indicators.
Not ISO 14064.
ISO 14064 is a GHG inventory standard for organisations. ISO 14040 LCA is for products and services.
Ready to start?
From an LCA consultant’s study to a verified, registered EPD.
We engage a vetted LCA consultant on your behalf, align the scope with a recognised PCR, then verify and publish the result on the GreenTag Registry.