Verified Embodied Carbon for Lighting
TM65.2 is widely used to estimate the embodied carbon of lighting products.
But TM65.2 is a self-assessment tool.
The LIA TM65.2 Assured Certification Schemes independently verify those self-assessments, transforming declared carbon values into evidence-backed, confidence-led data.
No assumptions. No interpretation drift. No spreadsheet shortcuts.
Just verified embodied carbon.
Why TM65.2 Assured?
Without Independent Verification
Without independent review, TM65 calculations can vary significantly, creating inconsistency and risk across sustainability-led projects.
- The same product can generate different DT65 outcomes
- Interpretation can vary
- Specifiers may struggle to compare like-for-like
- Responsible manufacturers risk being undercut by weaker claims
TM65.2 Assured
Independent verification providing clarity, credibility and confidence in embodied carbon reporting.
- Drives consistency
- Reduces greenwash risk
- Increases specifier confidence
- Protects credibility in sustainability-led projects
- Levels the playing field
Two Routes to Assurance
Independent verification of a specific product or product family.
- Mid-Level DT65 required
- Full evidence pack submitted
- Physical product disassembled by LIA
- Independent DT65 recalculated
- ±5% alignment required
Result: A 3-year TM65.2 Assured Product Certificate.
Verification of a manufacturer’s internal TM65.2 capability.
- Laboratory audit
- Process and QMS review
- Witness assessment
- Annual surveillance
Result: Recognition of internal competence and streamlined certification pathway.
What This Means
- Independent validation of carbon claims
- Stronger position in public procurement
- Clear differentiation in competitive tenders
- Increased trust from specifiers, consultants and councils
- Protection against greenwash accusations
Raising the Standard
In sustainability reporting, independent verification represents the highest credibility tier.
Self-declared → Independently verified
Assumed → Evidence-based
Variable → Consistent
This is not about who has the lowest number.
It’s about who can prove it.
TSD-015 (Company assured)
The sole purpose of the TM65.2 Assured Company Verification Scheme is that under a formal agreement, a manufacturer may be given permission to make assessment of TM65.2 values in accordance with CIBSE TM65.2:2023 and CIBSE document DT65 Embodied Carbon Calculator and TSD-016. Such assessment data will then form a submission for generation of a TM65.2 Assured Product certificate by the LIA Laboratory Ltd for addition to the LIA Certification website in accordance with the requirements set out in TSD-016 - TM65.2 Assured Product Verification Scheme.
TSD-016 (Product assured)
TM65.2 Assured Product Verification Scheme addresses the substantial industry interest in the need to deliver sustainable lighting, building on the methodology in CIBSE TM65.2 “Embodied Carbon in Building Services: Lighting”, specifically its Embodied Carbon Calculator (DT65). It provides robust third-party assessment of claims made using the TM65.2 methodology and tools, increasing confidence that products are truly compliant to the principles of embodied carbon assessment through DT65.
TM65.2’s Embodied Carbon Calculator (DT65) is a self-certification metric that allows a manufacturer or interested party to evaluate and quantify the embodied carbon of a luminaire or associated accessories, applicable under the TM65 methodology, to enable comparison between products fulfilling the same function.
Embodied carbon metrics can have a problem of interpretation, different evaluators using different interpretations of the same question, or the answer to a question will yield different results making comparisons between products difficult. TM65.2 Assured Product Verification Scheme is a programme of trained, independent, 3rd party assessments that reviews both the embodied carbon claims and the evidence given to support those claims and the methods used to record and report the claims. The result is a greater level of confidence in any one DT65 embodied carbon value and therefore comparisons between those values.
FAQs
Frequently Asked Questions
The LIA independently reviews and recalculates the manufacturer’s Mid-Level DT65 assessment. For product verification, the physical luminaire is disassembled and weighed. The embodied carbon result must align within ±5% of the manufacturer’s claim.
No. Only Mid-Level DT65 assessments are eligible for TM65.2 Assured.
TM65.2 is a structured methodology, but certain inputs such as BOM granularity, manufacturing energy data, replacement assumptions and assembly location can materially influence outcomes. Independent review reduces interpretation variability and increases market confidence.
No. TM65.2 Assured verifies that the claimed carbon value is technically justified and evidence-based. It does not rank products or certify low carbon status.
Certification is valid for 3 years, subject to no material changes. If materials, factory location, manufacturing energy or core product design changes, reassessment may be required.
If within ±5%, certification is granted.
If outside tolerance but within defined thresholds, a revised certified value may be issued.
If materially outside tolerance, certification will not be granted.
Yes, provided they share:
- The same material breakdown
- The same final assembly location
- The same manufacturing energy inputs
Significant variations may require separate certification.
Product Verification:
Certifies an individual product or product family.
Company Verification:
Audits and certifies the manufacturer’s internal capability to produce reliable
DT65 assessments, with ongoing surveillance.
No. TM65.2 Assured complements LCA and EPD reporting. It strengthens confidence in embodied carbon estimates where full EPDs may not yet be available.
- Manufacturers supplying sustainability-led projects
- Organisations bidding into public procurement
- Companies producing Mid-Level DT65 assessments
- Businesses seeking to reduce greenwash risk
- Brands wanting stronger technical credibility