LIGHTING & LIGHTING CONTROLS


Why TM66 assessment will drive sustainable lighting now and in the future


Alex Hill, managing director at Whitecode Consulting, details TM66’s key objectives and identifies how product manufacturers and specifiers can align with the standard. He then emphasises why this will help enhance trust and transparency in the industry while creating a more sustainable built environment


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efore 2021, measuring a lighting product’s circularity lacked a uniform methodology, complicating sustainability targets for designers, specifiers and building developers. With that in mind, the Lighting Industry Association (LIA) and CIBSE launched Technical Memorandum 66 (TM66) to help verify the circular credentials of lighting products via a standardised approach. There has recently been a significant shift towards


more sustainable building practices, driven by stricter regulatory demands, smart technology advancements, net zero targets, and a sharper focus on human wellbeing in buildings. Part L of the Building Regulations has mandated higher performance bars and required general lighting in non-domestic environments to achieve minimum efficacies – such as 105 lm/W – alongside compulsory, zone-specific controls. The UK’s 2050 net zero target also means specifiers


are under heightened pressure to decarbonise the built environment by utilising smart management systems and high-efficiency LED lighting to reduce carbon footprints and lower energy consumption. However, efficiency only considers operational carbon.


What happens to the luminaire itself, and its materials, went unmeasured until TM66’s launch in 2021.


TM66’s key objectives


Aiming to move the lighting industry toward a circular economy, TM66 encourages more sustainable design. It provides manufacturers with guidance on how to design lighting products for easier disassembly, maintenance, future repair and longer performance. With specifiers needing verifiable evidence of


responsible sourcing, material composition, and recycled content, material traceability is also a central focus for the TM66 initiative. It promotes the use of sustainable, recyclable, and recycled materials rather than raw virgin resources, and minimises the potential for toxic substances to enter lighting products. In addition to promoting repair and reuse to keep


materials and products in active use longer, and enabling component replacement, remanufacturing and upgrades rather than full disposal, TM66 encourages responsible recycling. This allows components to be efficiently separated and incorporated back into the manufacturing stream at end-of-life. By establishing a transparent, concise assessment framework, TM66 enables specifiers and manufacturers to objectively score and evaluate circularity claims and minimise the risk of greenwashing.


How to ensure alignment


While the TM66 framework is currently voluntary, some tenders are now requesting proven TM66 scores to drive sustainable engineering and mitigate greenwashing across the industry. As


a result, manufacturers need to design, and specifiers select, products that score well against TM66’s assessment method.


1.Undertake a CEAM assessment


Ensuring TM66 alignment begins with an internal Circular Economy Assessment Method (CEAM) assessment. This is separated into four key metrics: product design, materials, manufacturing, and ecosystem. Products should be designed for long-life


performance and easy disassembly and repair, so avoid adhesives and prioritise non-destructive mechanical fasteners to allow the quick, easy swapping or updating of internal components, such as drivers and LED boards. High-quality, recyclable materials, such as steel or aluminium, should be favoured over virgin plastics or bonded composites that are hard to separate at end-of-life. During manufacturing, waste must be minimised. Additionally, production should be localised to reduce transportation footprints. What happens to the products and materials after


installation must be considered. For instance, to support commercial remanufacturing, clients must be able to access spare parts and take-back schemes should be offered where possible.


2.Document auditable evidence


While self-assessment is the first part of the process, scores are invalid under TM66 rules unless all results are supported by verifiable and defensible documentation. Maintaining up-to-date, highly traceable


component origins and composition data is essential. So is demonstrating how a technician can non- destructively disassemble the luminaire via a clear step-by-step guide. Formal, documented statements regarding spare part availability periods must also be provided to further ensure a CEAM assessment survives scrutiny.


3.Gain independent TM66 verification


Operated by the LIA Laboratory, the official TM66 Assured Product Verification Scheme will review internal assessments, cross-examine any provided technical evidence, and issue an official TM66 Circular Economy Assured Quality Mark. An average mark above 70% across all four core


CEAM areas is typically the gold-standard target for top-tier certification.


4.Maintain ongoing governance


Aligning with the TM66 standard requires continuous lifecycle control. For example, any changes to a


26 BUILDING SERVICES & ENVIRONMENTAL ENGINEER NOVEMBER 2026


luminaire’s materials, architecture, or supply chain components will require an accurate recalculation of the CEAM score.


Enhancing trust and transparency


While internal self-assessments via the CEAM toolkits are important, having products undergo rigorous independent assessment standardises third-party product verification and provides a trustworthy benchmark. Assessing a product’s design, construction, and supply chain ecosystem enables the identification of luminaires and materials that are sustainably sourced, free of harmful and toxic substances, and manufactured for repair, disassembly, or remanufacturing. Sustainable choices are often removed from


projects during budget reviews. The TM66 framework minimises the opportunity for certified circular ratings to be replicated by cheaper, disposable alternatives or long-lasting products to be replaced by linear equivalents. Crucially, with high ratings only achieved through


transparent evidence, reporting and language, loose interpretations can be prevented. It is also harder for manufacturers to make deceptive claims about environmental benefits of their luminaires.


TM66 alignment and MEP design go hand-in-hand


Integrating TM66 principles into construction projects relies heavily on mechanical and electrical service layouts by MEP design professionals. For example, regardless of a luminaire’s high TM66 rating, if it’s fitted in a hard-to-reach ceiling or integrated with non-standard wiring, it cannot be efficiently extracted or maintained for circular reuse. An electrical designer will ensure that any specified


lighting systems and luminaires are built with smart, open-protocol controls, such as DALI. This will ensure a spare part can be swapped in without needing an entire lighting string replacement. Involving an MEP design consultant early in


the process also enables them to cross-examine manufacturer claims and identify products with high independent ratings. Aside from ensuring verifiable circular compliance, it will protect developers from greenwashing. Energy-efficient lighting has been a core principle


of building design for many years, but it only tells half the story. By shining a light on circularity and making it measurable, TM66 gives manufacturers a clear path to better products, and specifiers the evidence needed to choose with confidence. Ultimately, aligning the lighting industry’s circular economy with early MEP design will help create a more sustainable built environment.


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