Whole Life Carbon or Circular Economy Statement
A whole life carbon assessment counts emissions by module. A circular economy statement tracks material flows and diversion. Where they share a bill of materials and where they diverge.
A whole life carbon assessment counts emissions. A circular economy statement tracks materials. The whole life carbon vs circular economy statement question comes up on every referable London scheme and an increasing number outside it, and the practical answer is that the two documents share a bill of materials and then diverge completely in what they do with it.
One reports kilograms of carbon dioxide equivalent by life cycle module. The other reports tonnes of material by stream, with targets for reuse, recycling and diversion from landfill. A developer who commissions them from different consultants at different times ends up with two documents built on different floor areas, which is a bad look in front of a reviewer who reads both.
Carbon accounting against material flows
The whole life carbon assessment follows the life cycle stages in BS EN 15978 and the RICS professional standard on whole life carbon assessment for the built environment. Emissions are reported by module: product and construction, use, end of life, and separately the benefits and loads beyond the system boundary.
The circular economy statement asks different questions of the same building. What is already on the site and can it be kept? What materials are going in, in what quantities, and where do they come from? How will the building be taken apart at the end of its life? What happens to the waste produced during demolition and construction, and what proportion is diverted from landfill?
Carbon is an outcome. Material flow is a mechanism. A scheme can improve its carbon figure by specifying a lower-carbon concrete mix without changing its material flows at all, and it can improve its circularity by designing bolted connections without moving the carbon number much in the short term.
Where the two share a schedule
The bill of materials is the shared artefact, and it should be produced once.
At planning stage it will be coarse: structural frame by material and tonnage, substructure, envelope build-ups, internal partitions, finishes by area, and services by a proxy measure. That level of detail is enough to drive both a module-based carbon calculation and a material stream table.
Two other inputs are shared and worth fixing early. The area schedule, because gross internal area is the denominator for almost every benchmark in both documents. And the demolition and strip-out inventory, which comes from a Pre-redevelopment Audit and feeds both the end of life reporting for the existing building and the waste targets for the new one. That audit is the single most useful early commission on a redevelopment site and it is covered in the pre-redevelopment audit.
Where the two documents diverge, say so explicitly. If the carbon assessment excludes tenant fit-out and the circular economy statement includes it, a reader comparing tonnages will assume one of them is wrong.
Modules, waste targets and how they relate
The relationship between the end of life modules and the waste targets is the part most often handled badly.
The carbon assessment reports deconstruction, transport, waste processing and disposal within the end of life stage, and reports the potential for reuse, recovery and recycling separately as a benefit beyond the system boundary. That separation is deliberate. Netting a future recycling benefit off a present emissions total flatters a scheme, and reviewers pick it up immediately.
The circular economy statement's diversion targets describe the same material movements as percentages of tonnage rather than as emissions. The two should reconcile: if the statement commits to diverting the overwhelming majority of demolition arisings from landfill, the carbon assessment's disposal module should reflect that assumption, and the assumption should be stated in both.
Numeric diversion targets are set by policy rather than by the assessor, and in London by the relevant Greater London Authority guidance. Check the current version rather than reusing a figure from a previous scheme, because the guidance has been reissued.
Which applications need which
Neither document is universally required, and the triggers differ.
| Question | Whole life carbon assessment | Circular economy statement |
|---|---|---|
| Usual trigger | Referable schemes in London and a growing number of local policies | Referable schemes in London, plus authorities with adopted circular economy policy |
| Primary standard | BS EN 15978 and the RICS professional standard | Policy guidance, supported by the bill of materials and audit |
| Core output | Emissions by module against a benchmark | Material tonnage by stream against diversion targets |
| Post-construction duty | Updated assessment where policy requires | Updated reporting on actual waste and materials |
Outside London the picture is uneven. Some authorities have adopted carbon assessment requirements in a recent local plan, some ask for a statement through the validation list, and many ask for neither. Read the validation list and the adopted policies rather than assuming a London template applies. A Whole Life Carbon Assessment prepared to the wrong scope is expensive and unhelpful.
Retention testing in both documents
Both documents should answer the same uncomfortable question: why is the existing building being demolished?
The carbon assessment answers it with numbers. Compare a retention and retrofit option against the proposed new build across the modules, using the same boundary and the same study period, and report both. A comparison that quietly uses a 60 year study period for one option and a different period for the other is not a comparison.
The circular economy statement answers it with a hierarchy: retain, reuse in situ, reclaim for use elsewhere, recycle, recover, dispose. Applications are increasingly expected to show that the higher options were tested and to explain why they were rejected, with evidence rather than assertion. Structural capacity, floor to ceiling heights, contamination and the condition of the frame are all legitimate reasons. A general statement that retention was not viable is not.
Present the retention test once, in a form both documents can cite. Two versions of the same argument invite the reviewer to compare them.
Reporting after construction
Both regimes increasingly extend past the decision, and the obligations are usually secured by condition or by a section 106 agreement.
For carbon, the post-construction assessment updates the planning-stage figure using procured quantities and actual products. For circularity, the reporting covers actual waste tonnages by stream and destination, drawn from waste transfer notes, plus any as-built change to the material schedule.
Two practical points. Name in the planning submission who will produce the post-construction reports and when, because a contractor appointed two years later will not have gathered the data unless it was in the contract. And keep the data structure identical to the planning-stage submission, so the comparison is straightforward. The reporting structure of a circular economy statement sets out how the sections are normally arranged.
Avoiding contradictory numbers
Most reviewer queries on these documents are not about method. They are about inconsistency.
The recurring ones are a gross internal area that differs between reports, a structural tonnage in the carbon model that does not match the bill of materials, a study period stated in one document and not the other, and a demolition arisings figure that changes between the audit and the statement. Each is trivial to prevent and slow to fix.
Set a single data sheet with a version number, list the values every consultant must use, and reissue it when the design changes. Then say in both documents which version they were built on. It is a dull control and it is the difference between a smooth assessment and three rounds of clarification. A Circular Economy Statement and a carbon assessment that agree on their inputs are read as one evidence base rather than two.
Browse the PlanScope report types to see how the carbon, circularity and waste documents fit together for a major scheme.
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Frequently asked questions
Do both documents use the same bill of materials?
They should. Produce one coarse bill of materials at planning stage covering frame, substructure, envelope, partitions, finishes and services, and drive both documents from it. Also fix the gross internal area and the demolition inventory once, because those are the denominators and inputs that most often differ between two separately commissioned reports.
Can future recycling be netted off the carbon total?
No. Benefits and loads beyond the system boundary are reported separately from the modules within the assessment boundary, precisely so that a future recycling benefit cannot be used to reduce a present emissions figure. Reviewers look for this, and a netted total is one of the quicker ways to lose credibility.
Which schemes need a whole life carbon assessment?
Referable schemes in London, and an increasing number of authorities elsewhere through recently adopted local plan policy or a validation list requirement. Outside London the position is uneven, so read the adopted policies and the validation list rather than assuming a London template applies to a scheme in another region.
How should retention of the existing building be tested?
Compare a retention and retrofit option against new build across the same modules, using the same boundary and the same study period, and report both results. In the circular economy statement, work down the hierarchy from retention to reuse, reclaim, recycle, recover and dispose, giving evidenced reasons where higher options were rejected.
What has to be reported after construction?
Where secured by condition or obligation, a post-construction carbon assessment updated with procured quantities and actual products, and circularity reporting on actual waste tonnages by stream and destination taken from waste transfer notes. Name who will produce them and when in the planning submission, or the data will not be collected.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.