How to read an EPD

Most people who use EPDs never write one. They receive them: in a tender, from a supplier, in a product library. The skill that matters is reading one quickly and knowing whether you can rely on it, and whether you can compare it with another.

This lesson gives you a ten-point checklist and works through it on one EPD. It is the kind of check the epd-reader skill in the Skills class runs for you, so once you have done it by hand you will be able to check the skill’s work.

In one line

Same LCA method, fixed format, third-party verified, valid for a limited time.

Fictional example

Everything about the EPDs in this lesson is invented for teaching: the programme operator, the manufacturers, the products, the registration numbers, the verifier and every number. They are laid out the way real EN 15804+A2 EPDs usually are, but they describe no real product and cannot be found in any library.

The ten-point checklist

#	Check	Where to look	What you’re looking for
1	Programme and registration	Cover page	Programme operator name and registration number. Look the number up in the programme’s library.
2	Standard and PCR	Programme information	Core PCR (EN 15804+A2 for European construction products) and any complementary PCR, with versions
3	Declared or functional unit	Product or LCA section	Exactly what the numbers are “per”, with conversion factors (mass, thickness, area)
4	Product and plant	Product description	The product you buy, from the plant you buy from. Single product, or an average across products or plants?
5	Modules declared	System boundary table	Which of A1 to D are declared, and which are ND
6	Validity	Cover page	Date of issue and “valid until” date
7	Verification	Programme information	Independent third-party verification, and by whom
8	Data sources	LCA rules section	Reference year, share of specific data, background database and version, how electricity was modelled
9	GWP split	Results table	GWP-total and its fossil, biogenic and land-use parts; any biogenic carbon that is taken up and later released
10	Comparability notes	Anywhere, often small print	Warnings about comparing, variation between products, and indicators to use with care

You can do all ten in about ten minutes once you know where to look.

Worked example: a fictional insulation board

Here is the key information from a fictional EPD, the way it would appear across its first few pages.

Environmental Product Declaration in accordance with ISO 14025 and EN 15804:2012+A2:2019/AC:2021

• Product: LB-100 mineral wool insulation board, 100 mm
• Manufacturer: Exampleboard Ltd (fictional), plant in Exampletown
• Programme operator: The Chalkboard EPD Programme (fictional)
• Registration number: EPD-EXAMPLE-0001
• Issued: 2024-03-01 · Valid until: 2029-02-28

Declared unit: 1 m² of board, 100 mm thick, mass 4.0 kg/m², thermal resistance R = 2.70 m²K/W. Results for other thicknesses of the same product may be obtained by multiplying by thickness ÷ 100 mm.

Verification: independent external verification of the declaration and data, according to ISO 14025, by A. Verifier (fictional), approved by the programme.

Data: specific data from the Exampletown plant, reference year 2023. Background data from ExampleDB v1.0 (fictional). Electricity modelled with the national residual grid mix.

System boundary:

A1–A3	A4	A5	B1–B7	C1	C2	C3	C4	D
X	X	X	ND	X	X	X	X	X

Results, climate change, per declared unit (kg CO₂-eq):

Indicator	A1–A3	A4	A5	C1	C2	C3	C4	D
GWP-total	5.20	0.30	0.15	0.00	0.05	0.00	0.20	−0.10
GWP-fossil	5.10	0.30	0.15	0.00	0.05	0.00	0.20	−0.10
GWP-biogenic	0.05	0.00	0.00	0.00	0.00	0.00	0.00	0.00
GWP-luluc	0.05	0.00	0.00	0.00	0.00	0.00	0.00	0.00

Working through the checklist

1. Programme and registration. Named programme, registration number given. In real life, you would now search the programme’s library for EPD-EXAMPLE-0001 and confirm it is listed and current.
2. Standard and PCR. EN 15804+A2 with the 2021 corrigendum. Good: the current core rules for European construction products.
3. Declared unit. 1 m² at 100 mm, with mass and R-value given. The EPD also tells you how to scale to other thicknesses. For 150 mm: 5.20 × 150 ÷ 100 = 7.80 kg CO₂-eq for A1–A3.
4. Product and plant. One named product from one named plant. If you buy from a different plant, this EPD may not represent your product.
5. Modules. A1–A3, A4, A5, C1–C4 and D declared; use stage not declared. That is a “cradle-to-gate with options, modules C1–C4 and D” EPD.
6. Validity. Issued March 2024, valid until February 2029. Valid at the time of reading.
7. Verification. Independent and external, to ISO 14025. Good.
8. Data. Plant-specific data for one recent year, a named background database with a version, electricity modelled with a residual grid mix (the national mix after certified renewable electricity sold to others is taken out). All clearly stated.
9. GWP split. Almost all fossil. Check the sum: 5.10 + 0.05 + 0.05 = 5.20, which matches GWP-total. If the parts don’t add up, ask why.
10. Comparability. A single product, not an average, so no variation note is needed.

Verdict: a clear, current, verified EPD for one product from one plant. You can use it, for this product from this plant.

Tip

When someone quotes “the carbon footprint” from an EPD, ask which modules they mean. Here, A1–A3 alone is 5.20 kg CO₂-eq per m². A1–A3 plus A4, A5 and C1–C4 is 5.90. Module D (−0.10) is reported separately and should not be netted off silently.

Exercise: can you compare these two?

A contractor sends you a second fictional EPD for a competing board and says “Board B is lower carbon”. Here are its key facts:

• Product: Board B, 120 mm (fictional)
• Programme: Another Example Programme (fictional)
• Standard: EN 15804:2012+A1:2013
• Valid until: 2025-06-30
• Declared unit: 1 kg of board. Density 30 kg/m³. Thermal conductivity 0.044 W/mK.
• Modules declared: A1–A3 only
• GWP (A1–A3): 1.1 kg CO₂-eq per kg

Exampleboard’s LB-100 has a thermal conductivity of 0.037 W/mK. Assume today is 29 September 2026.

1. Convert Board B’s result to 1 m² at 120 mm.
2. Why 120 mm and not 100 mm?
3. Is the contractor right? List every reason the two EPDs can or cannot be compared.

Answer

1. Mass per m² = 30 kg/m³ × 0.12 m = 3.6 kg. GWP = 3.6 × 1.1 = 3.96 kg CO₂-eq per m² (A1–A3).

2. To deliver the same insulation. Thermal resistance is thickness ÷ conductivity: LB-100 gives 0.100 ÷ 0.037 = 2.70 m²K/W; Board B at 120 mm gives 0.120 ÷ 0.044 = 2.73 m²K/W. Comparing 1 m² at the same thickness would compare boards that do different jobs.

3. On the face of it, 3.96 is lower than 5.20. But the comparison doesn’t hold:

   • Expired. Board B’s EPD ran out on 30 June 2025.
   • Different standard. EN 15804+A1 uses different impact methods from +A2. The GWP figures are not calculated the same way.
   • Different modules. Board B declares only A1–A3, so you can compare A1–A3 at most. You know nothing about its end of life.
   • Different programmes and PCRs. Check that the complementary rules are compatible.
   • Conversion needed. Board B is per kg; you had to use its density to get to m². Check that the density in the EPD is the one for the product you’d buy.

   The honest answer: “Board B might be lower carbon, but this EPD can’t show it. Ask the manufacturer for a current EPD to EN 15804+A2.” And for a real decision, compare at the level of the building element over its life, not just the board.

Check yourself

Supplier A declares A1–A3. Supplier B declares A1–A3, C and D. Can you compare their GWP-total directly?

Show answerHide answer

Only module by module. Compare A1–A3 with A1–A3; B’s extra modules are outside A’s boundary.

What you should now be able to do

• Run a ten-point check on any EPD and say whether you can rely on it.
• Find the declared unit and convert results to the quantity you actually need.
• Tell which modules are included, and quote a figure with the modules named.
• Explain why two EPDs to different versions of EN 15804 are not directly comparable.
• Set up a fair comparison based on the same function, such as the same thermal resistance.

Sources

• ISO 14025:2006, Type III environmental declarations, iso.org.
• ECO Platform, Verification Guidelines V8.0, December 2024 (content expected on an EPD cover page, EPD types, data age).
• EPD International, PCR for construction products (EN 15804+A2).
• The example EPDs in this lesson are fictional and all their data are hypothetical.

Checked: 2026-09-29