TM66: The Circular Economy Explained

Squaring the circle

tm66: circular economy

A transparent guide for those that wish to learn what TM66 is, where it came from and where it's going

CIBSE’s Technical Memorandum 66 (TM66) is an initiative originally published by the Society of Light and Lighting (SLL) in 2021. Over the last few years, it has garnered considerable momentum, and rightfully so. With an increasing number of evaluators meticulously assessing products for their circular attributes, this trend has prompted a greater number of manufacturers to integrate these design principles into their creative and manufacturing processes. In this article, we look at how it all started, the implications and where it is likely to lead us in the future.


What is TM66?

TM66 presents a structured approach for both implementation and evaluation, encompassing all stakeholders across the lighting sector, aimed at fostering the development of a circular economy within the industry.

To comprehend the impact of TM66, we must first grasp the concept it champions: the circular economy. This alternative to the traditional linear consumption model (AKA linear economy) holds the potential to reduce waste and greenhouse gas emissions significantly. Within the realm of lighting, the circular economy has emerged as a beacon of hope, driven by the development of TM66.

Published by the Chartered Institution of Building Services Engineers (CIBSE) and the SLL, TM66 is not just a document. It serves as a dynamic and practical framework which paints a clear picture of the circular economy’s mechanics, drivers, and challenges. But that’s just the tip of the iceberg.

At the heart of TM66 lies its Circular Economy Assessment Methods (CEAM), an innovative tool that quantifies the degree of circularity in lighting products. This assessment method wields the power to transform a complex subject into a simple star rating. This rating system offers manufacturers and specifiers a tangible, independent metric to evaluate products and strive for continuous improvement.


The Origin of TM66

The birth of TM66 in October 2021 marked a significant milestone in the lighting industry. This Technical Memorandum wasn’t crafted by a single individual but instead emerged from the collective effort of volunteers from CIBSE and the SLL. In essence, TM66 stands as a testament to industry collaboration, by the industry, for the industry.

But was there really a need for a new metric like TM66 in the lighting domain? The rationale lies in the absence of a standardized circularity measurement. Prior to TM66’s emergence, every company seemed to have its own approach, resulting in a tangled web of metrics and methods. TM66 sought to untangle this mess, paving the way for uniformity and transparency. Without a uniform system of measurement, lighting manufacturers frequently played by their own rules which left specifiers to decipher fact from fiction.

The significance of this standardized approach cannot be overstated. It facilitates comparability, empowering specifiers to assess circularity across different products with ease. Before TM66, this task was akin to comparing apples and oranges, as each manufacturer had its unique circularity metric. TM66’s arrival heralds a new era of clarity and informed decision-making.

The Industry Ripples: How TM66 Benefits All

With the building industry struggling to cover the dual costs of environmental degradation and economic inefficiency, the spotlight on resource-intensive products is relentless. Leading manufacturers are realizing that sustainability demands more than just energy efficiency; it requires a commitment to longevity, quality, and repairability. 

Enter TM66 – a gateway for manufacturers to transparently declare their circular economy performance. TM66’s rating system offers them a potent tool to carve out a credible, green marketing edge. In addition, it also prevents lighting manufacturers from greenwashing and marketing luminaires with deceptive data.



However, TM66 isn’t just a gift for manufacturers; it’s an empowerment tool for specifiers. Armed with TM66’s insights, they can make informed choices, cherry-picking fittings that boast robust circularity credentials. Specifiers now wield the power to demand a circularity rating for individual products or entire projects. This dual benefit serves both the specifier, armed with irrefutable data, and the manufacturer, armed with a strong, independent rating that withstands scrutiny. Although it remains to be seen, there is a real possibility that these environmental credentials can result in a ‘specification lock’ thereby making value engineering much more difficult for speculative suppliers.

TM66’s Rise to Prominence

Why should we embrace TM66’s approach to achieve circularity, and what makes it so crucial? The circular economy isn’t a newfound concept; it’s been brewing in the shadows for some time. TM66, however, thrusts this concept into the spotlight, compelling companies to reevaluate their supply chain and elevate their circularity endeavours. With end-users increasingly demanding circularity evidence, the pressure mounts on specifiers and manufacturers alike to ensure the final product embodies circular and sustainable principles.

The innovative quality of TM66 lies in its new assessment metric, an uncharted territory in previous circular models. Unlike its predecessors, TM66 doesn’t merely present an abstract theory. It offers a tangible, applicable metric that stems from the collective wisdom of cross-industry collaboration. In other words, it’s not just theoretical jargon; it’s a practical toolkit for realizing circularity in the world of lighting and building services engineering.

It is important to note that most previous standards were too focused on operational carbon and neglected the holistic, embodied carbon approach. CIBSE’s TM65, the predecessor, laid the groundwork by addressing embodied carbon. TM65’s role is pivotal; when Environmental Product Declarations (EPDs) are missing, it steps in to calculate the embodied carbon of building services equipment. This supplementary tool, coupled with TM65’s overarching goal, paves the way for TM66 to emerge as the natural complement to TM65’s embodied carbon focus.

Navigating the TM66 Landscape: Specifiers’ Role

Curious about specifiers’ role in this circularity revolution? It’s pivotal. If specifiers raise the bar by demanding circularity ratings, manufacturers will undoubtedly rally around TM66’s metrics. As a collective industry force, they possess the power to catalyse change by promoting smarter, more sustainable lighting and lighting control solutions. Specifiers, armed with TM66’s insights, play a key role in reshaping the industry’s trajectory.

But what does this mean for the future of the lighting industry? Are we headed toward a circular renaissance? The answer lies in TM66’s expansion plans. TM66 CEAM-Make is just the beginning. A concise version, CEAM Design, is already in the mix, providing specifiers with a condensed yet impactful set of questions. Looking ahead, CEAM-Manage is set to guide Facilities Managers in nurturing sustainability in the long term. It’s all part of a grander vision – extending TM66’s influence on other building services, mainly thanks to its roots in CIBSE.

TM66 CEAM Manage offers guidance to individuals tasked with maintaining sustainable lighting systems within buildings. This metric supplements TM66’s two additional methodologies: CEAM Make, which serves as a specialized tool for manufacturers to quantify the design and specifications of circular economy lighting products, and CEAM Design, which provides a curated set of crucial inquiries for specifiers.

circular economy

TM66’s Role in New Product Creation

It’s important to clarify that TM66 isn’t a dictatorial regime; it’s a voluntary model. So why should manufacturers and specifiers willingly embrace it? Simple – TM66 presents an accessible and cost-effective measurement framework. It offers assurance to both parties, embodying the industry’s aspiration for transparency while doing things the right way. It’s a bridge that spans the gap between industry ambitions and tangible results.

But, of course, no solution is without its limitations. TM66 may not be the silver bullet for all sustainability conundrums. Sustainability, by nature, is a labyrinth of complexities. The more you delve into a product, its materials, and the manufacturing process, the more sustainability impacts you uncover. The ‘rabbit holes’ are endless. TM66, while powerful, simplifies the complex to ensure usability. It strikes a balance between complexity and effectiveness, relying on the intelligence of its users to navigate the right way forward.


Beyond TM66: BS 8887 Update

Since the initial release of the first instalment of the design for manufacture + series in 2006 (titled “Design for Manufacture, Assembly, Disassembly and End-of-life Processing MADE – Part 1: General Concepts, Process, and Requirements”), the BSI committee responsible for this domain has concentrated on formulating standards that align with the sustainable design objectives. These standards address the imperative for designers to account for the complete lifecycle of products.

The predominant portion of a product’s ecological influence over its lifecycle is shaped during its design phase. The BS 8887 series of standards serves as a guide for designers to make well-informed decisions concerning a product’s intended function, utility, materials composition, manufacturing techniques, and potential for recycling or repurposing at the conclusion of its useful life. BS 8887-1 establishes stipulations for the formulation, content, and structure of design output and correlated technical product documentation pertaining to MADE (Manufacturing, Assembly, Disassembly, and End-of-life Processing) products. It delineates fitting methodologies and norms for creating documentation that facilitates the transition of a design concept into a manufacturable entity.

In 2012, BS 8887-1 was proposed to the ISO (International Organization for Standardization), and it has gained approval to be integrated into the ISO committee’s work agenda, which handles technical product documentation. A novel task group, led by the UK, is in the process of being formed to transform BS 8887-1 into an international standard. Other segments of the BS 8887 series are pertinent to processes earmarked for product reuse. In 2012, BS 8887-211 was published, marking the series’ maiden sector-specific standard. It zeroes in on the information and communication technology domain, specifically delving into computer hardware. The objective was to furnish the wording and protocols for ‘remarketed products’—in other words, products that cannot be sold as entirely new.


So, where do we stand in the grand tapestry of the circular economy? The future of the lighting industry lies in embracing durability, upgradability, and repair. As manufacturers, policymakers, consumers, and other stakeholders unite to prioritize sustainability and responsible resource management, a future characterized by extended product lifespans, reduced waste, and enhanced environmental stewardship gradually becomes a reality. The wheels of progress may grind slowly but the strides already being made towards circular design, advanced recycling techniques, and novel business models signify a growing commitment to forging a more sustainable and resilient industry. By continuing to foster innovation, collaboration, and education, the lighting industry can navigate this transformative path, creating a brighter and greener future for generations to come.



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