The one thing driving the adoption of LED lighting on the London Underground?
It’s not carbon emission reductions or savings on energy bills, nor is it the ability to control light. It’s maintenance, maintenance, maintenance.
The high cost of fixing and relamping light fixtures on the Tube is driving a rapid shift toward long-life LED products, speakers at Lux’s Lighting for Rail conference said on Wednesday.
The business case for us is the fact that we don’t have to replace the fittings'
Energy savings in the region of 50-60 per cent can be achieved by replacing traditional lights with LEDs, but these savings are dwarfed by the economies that can be made on maintenance, because LEDs last so much longer than other light sources.
London Underground’s head of stations engineering Bob Benn said: ‘The business case for us is the fact that we don’t have to replace the fittings. So while an LED tube might sound expensive, it can pay for itself in one year of not having to maintain it. And five years [of reduced maintenance] makes a significant difference.’
Changing fluorescent tubes above underground escalators is a particularly difficult procedure, which can cost up to £1,000 for just one lamp. And strict rules on the time in which a failed lamp must be replaced means teams can't always wait for several lamps to fail before intervening.
Leon Smith of Transport for London agreed that the upfront cost of lighting equipment and the ongoing cost of energy ‘pales into insignificance’ next to the labour costs associated with installing and maintaining lighting. ‘There’s no point in us upgrading to another technology if we’re not going to save on this labour cost,’ he said.
Smith also revealed that a major survey of the European lighting market conducted by TfL and a group of other public sector lighting buyers across Europe, found that two thirds of the lighting products on offer carried a warranty of five years or more. ‘So when we ask the market to provide us a product, why would we ask for less than five years,’ Smith said. ‘And why would an organisation be willing to offer less than five years?’
A multimillion-pound Lux Award-winning project to replace the Tube’s many T12 and T8 fluorescent tubes with LED versions is still underway. As well as lasting for five years or more, LED tubes have the advantage that they can be easily cleaned.
Fluorescent tubes, on the other hand, were difficult to clean safely, and so would often simply be thrown away and replaced when they got dirty. Bob Benn said: ‘If we can make the cleaning of the tube a non-skilled operation, that makes a heck of a difference to our maintenance cost.’