A company's annual GHG Protocol report tells you how much carbon the whole facility emitted last year. It won't tell you how much went into making one specific part, cradle to grave. The four phases of LCA, and what an EPD actually is.
A company’s annual GHG Protocol report tells you how
much carbon the whole facility emitted last year. It won’t tell you how
much carbon went into making one specific part, from the raw ore it
started as to the day it gets scrapped. That’s a different question,
answered by a different tool: life cycle assessment.
Life cycle assessment (LCA) quantifies the environmental impact of a
specific product across its full life, rather than a company’s overall
annual emissions. See our related guide on
the GHG
Protocol for how Scope 1, 2, and 3 emissions accounting works at
the organizational level — LCA answers a narrower, product-specific
question the GHG Protocol’s corporate accounting isn’t designed to
answer.
| Phase | What happens |
|---|---|
| Goal and scope definition | Defining the product, functional unit, and system boundary being assessed |
| Life cycle inventory | Collecting data on all inputs (materials, energy) and outputs (emissions, waste) across the boundary |
| Life cycle impact assessment | Translating inventory data into environmental impact categories such as global warming potential |
| Interpretation | Evaluating results and identifying where the biggest impacts and improvement opportunities lie |
An LCA’s system boundary determines how much of a product’s life it
actually covers. Cradle-to-grave assessments trace impact from raw
material extraction all the way through use and disposal. Cradle-to-gate
assessments stop at the factory gate, before the product is used or
disposed of — a narrower and often more practical scope for a
manufacturer who has good visibility into their own process but not
into how a customer ultimately uses or discards the finished product.
An Environmental Product Declaration (EPD) is a standardized,
third-party-verified report of a product’s LCA results, built according
to a Product Category Rule (PCR) that defines how products in that
category should be assessed and compared. EPDs are increasingly
requested in construction materials and automotive supply chains,
giving customers a comparable, verified figure rather than a company’s
own unverified sustainability claims.
Life cycle assessment fits inside the sustainability work covered in
SCMEP’s Sustainability Starter
Workshop. As a NIST Manufacturing Extension
Partnership affiliate serving South Carolina manufacturers since
1989, our focus is helping teams understand what an LCA or EPD
request actually requires before committing to one.
If a customer has requested an EPD or your team is scoping a
product carbon footprint, you can
browse the Supply Chain and
Sustainability training catalog or email the training team.
Life cycle assessment (LCA) quantifies the environmental impact of a specific product across its full life, following the four-phase methodology defined in ISO 14040 and 14044, rather than measuring a company’s overall annual emissions.
The GHG Protocol measures an organization’s overall Scope 1, 2, and 3 emissions at the corporate level. LCA answers a narrower, product-specific question about one product’s total environmental footprint across its life.
Cradle-to-grave assessments trace impact from raw material extraction through use and disposal. Cradle-to-gate assessments stop at the factory gate, before the product is used or disposed of.
An EPD is a standardized, third-party-verified report of a product’s LCA results, built according to a Product Category Rule that defines how products in that category should be assessed and compared.
