SPONSORED ROUNDTABLE | LOW ENERGY LIGHTING Its good to push things forward, but there must be education behind why its being done. It should be about good design Andrew Bissell Task lighting gives people control of their own environment and they feel happier, and productivity will increase, but theres a reluctance to add that second tier of lighting purely due to cost, and this needs to change, said Rahim. Waskett argued that we cant achieve lower energy use by light luminaire efficacy alone. Things must be done differently if we are to achieve change. She recommended that fewer fittings should be specified, and lighting consultants need to be more closely involved in the commissioning of controls. She said the problem is that lighting experts dont have the privilege of continuing their appointment post-occupancy. Therefore, they have no idea why some lighting doesnt work properly or in the most efficient way. Bissell also cautioned that it is important not to become obsessed with figures to achieve a net zero carbon building, as it becomes a barrier to good lighting design. He cited a Cat A fit-out in Birmingham that achieved a blanket lighting scheme with 120 lumens per watt that used 4.5 watts per metre square. Bissells suggestions of first considering different scenarios of where desks might go near windows, for example before installing the lighting were largely ignored. Everyone raved about this office because of the lumens per watt that was achieved, but the result was a five-year step back. Its good to push things forward, but there must be education behind why its being done. It should be about good design, said Bissell. Youre not going to achieve anything with a single number; you might achieve slightly less energy being used, but its still wrong. Desai added that, with the targets of the regulations changing, clients will have to increasingly implement more energy saving CIBSE Journal editor Alex Smith (centre) listens intently to the roundtable discussion Traditionally, weve designed the lighting so that it delivers the same illuminance level everywhere. We must stop doing this now Ruth Kelly Waskett measures in terms of the operational energy use of buildings. Theres a lot of greenwashing, he said. A building may have been designed to be net zero, but five years down the line is it being operated as it was intended? Thats why things like Energy Performance Certificates and Part L are important, because theyve been designed for operational compliance. The discussion then turned to whether the circular economy is important when specifying lighting. Waskett said it is hugely important. As a specifier, she can distinguish between products based on their embodied carbon and the provenance of all the materials, and how the fitting has been put together. She is also concerned about disassembly and ease of use. Bissell agreed, and said that he knows of a manufacturer who will replace a light if the driver fails and ask for the broken one to be sent back. The manufacturer will then fix it and return it to the stock. Bissell believed that environmental, social, and governance (ESG) is behind this approach. This manufacturers clients are looking for every possible way 40 November 2022 www.cibsejournal.com CIBSE Nov 22 pp38-41 Roundtable.indd 40 21/10/2022 16:21