Navigating the circular maze: tools to create more sustainable lighting design

How are the new CIBSE/SLL circular tools measuring up? Nulty’s Gary Thornton discusses plotting a path to sustainability from a lighting designer’s perspective

The path to sustainability is a well-used phrase, but navigating this ever-evolving issue feels more like a maze. Facing up to this has led to a realisation that we can’t wander along aimlessly or take shortcuts.

Fortunately, the lighting industry has been working tirelessly to put tools in place to help designers find their way.

We’re now starting to see the influence of TM66: Creating a circular economy in the lighting industry, which establishes an accessible methodology for assessing the circularity of luminaires.

It’s still early days for TM65.2, the lighting addendum to the TM65 Embodied carbon in building services calculation tool, but it’s a toolkit we must embrace as we’re at the cusp of understanding the embodied carbon emissions associated with a light fitting.

Pre-TM66, the lighting industry was pulling away from a linear model of take, make, use and dispose, but recycling had become our safety net, and the circular economy was an aspirational concept. 

At Nulty, we were trying to include environmental and life-cycle analysis research on our specifications. It was progress of sorts, but with everyone starting to create their own metrics, there was no easy way to compare results and make like-for-like comparisons between specifications.

TM66 changed this by giving us CEAM-Make and CEAM-Specify, two metric-driven tools that created a base line from which to compare and appraise luminaires. It enabled us to hold ourselves accountable as a practice.

In April 2023, we embedded the TM66 methodology into our design process and set ourselves a target of achieving a two or above score for 50% of specified luminaires across all projects over six months. Our goal was to establish a minimum threshold and make circularity a non-negotiable attribute in our design specifications.

With everyone starting to create their own metrics, there was no easy way to compare results and make like-for-like comparisons between specifications

It’s has been a big learning curve. Projects come with a challenging mix of constraints, so adding circular principles into the mix is not easy, especially as we operate in a time-sensitive industry with demanding project programmes. It takes time to pull in the data. Manufacturers need a few days to respond to TM66 requests and we have to plan ahead to populate our specifications. There’s also work to be done to achieve the depth of detail required. The majority of TM66 scores that we received over the past six months came via the CEAM-Specify triage tool; in some instances, we had to give products a 0 score when manufacturers couldn’t provide the information we asked for. 

All of this shows us that the circular economy is a proposition in its infancy. We need widespread adoption of TM66. Lighting designers can help by advocating the need for data to back up decision-making. It should be our responsibility to encourage manufacturers to adopt TM66, and clients to invest in sustainably viable luminaires by using the data from TM66 to safeguard our specifications. 

Like the rest of the built environment industry, we have a lot to learn about calculating the embodied carbon emissions associated with a light fitting. TM65.2 is relatively uncharted territory for us all, so it’s important that we use this tool to accelerate learning. It establishes a framework for assessing the embodied carbon values in the short term, to give manufacturers the time they need to dig into the seemingly infinite layers of detail around materials, processes and supply chains.

In its current iteration, TM65.2 can give us indicative estimates of embodied carbon emissions, which will help to improve our knowledge on a holistic level and create a context in which more informed decisions can be made. It’s a work in progress, and we’re a long way off the tipping point where we can affect the design process, but TM65.2 can be an educational tool to move things along.

The lighting design industry should also improve its definition of the term net zero. We need to move away from separating embodied and operational carbon when we assess project carbon footprints. We need to widen the scope to consider how that building performs over time, how it’s dismantled, and how it’s repurposed after use.

Whole life carbon calculation is the direction in which we should be pointed – we need to make this term an instinctive way of thinking, as it will make sustainability easier to navigate in the long run. It’s one thing to design a carbon-neutral lighting scheme, but another thing entirely to deliver a carbon-neutral project.

About the author
Gary Thornton
is an associate lighting designer at Nulty