Comparing environmental product declarations without false equivalence
Admin · 22 October 2026
Illustrative image. Photo by Tolu Olubode on Unsplash. Unsplash License.
An environmental product declaration can provide useful evidence for a material decision, but two published figures are not automatically comparable. The products may serve different functions, use different reference quantities or describe different assessment boundaries. A procurement team that ranks the headline numbers without examining those details can reach a confident conclusion unsupported by the information.
For construction buyers, the practical task is to organise the evidence so the relevant environmental and technical specialists can assess it. The comparison should connect the product’s required function to the declaration’s scope and assumptions. It should also distinguish an environmental assessment from technical suitability. A lower reported impact does not by itself establish that a product meets the project’s other requirements.
Define the decision and required function
Start with the material or assembly the project needs and the performance it must provide. Identify the relevant specification and quantity basis with the design team. A comparison per unit of mass may not represent the quantity needed to perform the same function. Ask the appropriate specialists how to establish a meaningful basis for the actual decision.
Record whether the assessment concerns a product, an installed assembly or a wider building option. These scopes can require different information. A declaration for one component may not include associated materials needed for installation. Keep those interfaces visible so the buyer does not mistake a component comparison for an assessment of the complete solution.
Check the declaration’s identity
Identify the product, manufacturer, publication reference and version. Record the declaration’s date and status through the appropriate programme or publication source. Confirm that the document applies to the proposed supply rather than a similar product or a broad range with different characteristics. Where applicability is unclear, request clarification and retain the response.
Keep the declaration linked to the supplier proposal and specification. A later substitution can make an earlier comparison irrelevant. The buyer should know which product selection the assessment describes and when it must be reviewed again. Avoid storing declarations in a generic sustainability folder without a clear connection to the item actually being procured.
Examine reference quantities
Record the unit and any stated conditions, including dimensions or other characteristics relevant to the declared quantity. Appropriate specialists should determine whether conversion or another assessment is required. Do not compare numbers simply because both documents contain the same impact indicator. Their reference quantities need to support the intended comparison.
A hypothetical flooring procurement may involve declarations using different product descriptions and reference thicknesses. The team should establish how each option meets the required application and what quantity is needed before interpreting the figures. A direct ranking of the printed values could obscure a consequential difference in the installed arrangement.
Review boundaries and assumptions
Identify which life-cycle stages and assumptions the declaration reports, using qualified environmental expertise. Record consequential differences rather than hiding them in a footnote after a ranking has already been presented. The assessment may need additional project information to examine transport, installation or other relevant stages. The declaration is an input, not an automatic answer to every project-level question.
Do not assume that information omitted from a document represents zero impact. Ask the specialist to explain the appropriate treatment and limits of the available evidence. Where the options cannot be compared fairly on the proposed basis, state that conclusion and identify what further information would be useful.
Keep methodology differences visible
Record the relevant rules, standards and assessment basis stated in the documents. Appropriate specialists should assess whether the declarations can support the intended comparison. Buyers should avoid inventing a universal compatibility rule from document titles alone. A familiar format can still contain differences that matter to interpretation.
Building Transparency’s EC3 documentation provides an example of a material comparison workflow and the information presented from declarations, including units and publication details. A tool can assist the process, but its output still needs to be understood within the project’s requirements and the evidence it uses.
Separate data from claims
Supplier descriptions such as greener or low carbon should be examined against the actual evidence and comparison basis. Ask what baseline the claim uses and whether it applies to the proposed product and supply. Avoid turning a relative statement into an absolute guarantee. Keep the source wording and the project’s assessment distinguishable.
Where the project reports a benefit, identify the options, quantity, scope and assumptions behind it. Use the appropriate professional review and avoid unsupported precision. The management summary should preserve consequential limitations rather than present a simple percentage detached from the calculation. This makes the claim easier to evaluate and less likely to mislead later users.
Bring technical reviewers into the choice
Confirm that environmental options remain consistent with the project’s technical and operational requirements. The relevant designers should review performance, interfaces and installation implications. An alternative may need a different arrangement that affects both the material quantity and the wider assessment. The comparison should reflect the solution the project could actually adopt.
Keep approval responsibilities clear. An environmental specialist’s assessment does not necessarily authorise a product substitution, and a buyer’s preferred option may still need design or client approval. Follow the project’s actual procedures so the selected product and its supporting evidence move into procurement through a coherent decision.
Use a reviewable comparison register
For each option, record the declaration reference, applicability, quantity basis, assessment scope and outstanding questions. Link to the controlled source rather than copying isolated figures without context. Name the reviewer and date. A concise register helps the team identify which comparisons are ready for a decision and which still require specialist work.
Retain rejected options with a short explanation where useful. Future team members may otherwise repeat a comparison without knowing why the product was not suitable. If circumstances change, the record helps them identify which assumption needs review rather than starting from an unsupported recollection.
Verify the procured position
Before reporting the final outcome, confirm that the actual selection remains the one assessed and that the relevant supply information is available. Changes in product, quantity or arrangement may require reassessment. Assign responsibility for that check rather than assume the early comparison remains valid throughout delivery.
A useful EPD comparison gives decision makers an honest account of evidence, applicability and uncertainty. It supports a material choice when connected to function, quantity and the complete proposed arrangement. Its credibility depends on qualified interpretation and traceable records, with environmental claims kept proportionate to what the declarations and project information can actually establish.
Make the review reproducible
Keep the calculations and interpretation accessible to an authorised second reviewer. They should be able to identify the original figures, any conversions and the reason for excluding or including information. A comparison assembled from screenshots or copied values can be difficult to check if document versions are missing. Record the references and preserve the issued basis. Where the assessment tool applies its own treatment of uncertainty or data, understand and explain that treatment with appropriate expertise rather than presenting the output as a direct transcription of the declarations.
Ask the decision maker to confirm which conclusion the evidence supports. A product-level result may justify further investigation without establishing a final design preference. That distinction is useful when other performance questions remain unresolved. Record the next step and the person responsible for obtaining the missing evidence. A transparent comparison can add value even when it concludes that the current information is insufficient for a fair ranking, because it prevents a weak claim from becoming embedded in procurement or external reporting.
