The Chartered Institution of Building Services Engineers (CIBSE) and the Society of Light and Lighting have launched a new Technical Memorandum aimed at identifying the extent of current knowledge and providing a framework for action and assessment for all within the lighting industry. 

What is TM66?

TM66 presents a structured approach to both implementation and evaluation, it includes all stakeholders across the sector and is designed to encourage the development of a circular economy within the industry. 

The circular economy TM66 is designed to offer an alternative to the traditional linear consumption model. The new circular economy has the potential to reduce waste and greenhouse gas emissions significantly within the lighting industry, the new economy has all been driven by the development of TM66. With this in mind, TM66 offers a framework which paints a clear picture of the circular economy’s mechanics, drivers and challenges. 

The assessment method provides companies with a simple rating system that offers manufacturers and specifiers a tangible, independent metric to evaluate products.  

Why is TM66 needed?

For a while now there has been an absence of a standardised circularity measurement. Prior to TM66, every company had their own unique approach making it difficult to measure and there being many different methods. TM66 is designed to create a clear approach and provide uniformity within the industry. 

The new standard enables comparability and empowers specifiers to assess circularity across different products with ease. 

How is TM66 beneficial?

In an industry struggling to cover the dual costs of environmental degradation and economic inefficiency, it has become evident that sustainability requires more than just energy efficiency. This is where TM66 comes into place, it is a gateway for manufacturers to declare their circular economy performance. 


The circular economy has been developing for some time, however, with TM66 the approach has now been made a key concept. It requires companies to re-evaluate their circularity endeavours ensuring that final products meet the circular and sustainable principles. 

How is TM66 different to TM65?

Tm66 offers a new metric for all companies to measure circularity which did not exist previously. The new algorithm comes from a cross-industry collaboration and a need to provide practical guidance and tools to develop a joint effort in a circular, sustainable approach to lighting. 

TM65 enables the embodied carbon of building services equipment to be calculated when no environmental product declaration is available. TM65 provides engineers with a consistent approach to the way carbon calculations are embodied for building services products. TM66 is a solution to complement TM65’s embodied carbon work. 

Portland Traffic and TM66

At Portland Lighting we are always aiming to meet the latest standards set out meaning TM66 is no exception. We are thrilled to announce that we achieved a 2.5 TM66 score, which is referred to as “Excellent Circularity”. To view our pedestrian crossing lighting products click here.