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Low hanging fruit

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Have been reading about the new EN12464-1 - a long-overdue update that comes into force in Spring 2022. There are a number of videos and webinars out there but this one from Fagerhult gives a good clear explanation.

One big change is the much higher light levels. This reflects recent research that suggests that previous levels may have been sufficient for vision, but were simply too low to deliver the non-visual effects of light, setting the sleep-wake cycle or mood for example. This paper gives a good overview - and points out the tension between increased light levels and energy consumption. - 

 

Article: Energy impact of human health and wellness lighting recommendations for office and classroom applications.

Higher light levels brings a greater risk of glare. The standard shifts the balance of reflectance between the walls, the ceiling and the floor from 70/50/20 to 80/50/30 as one way to mitigate this issue - and improve what is called 'cylindrical illuminance' - the amount of light in the space around the occupant's head which is important when you want to see the other persons' facial expression. It's also a valuable measure of the interaction of daylight and artificial light in the space - this paper gives a good explanation. The Fagerhult video points out that this change could help to reduce energy consumption by up to 25%. 

 

Article: Cylindrical illuminance and its importance in integrating daylight with artificial light

** This is a link to the abstract, and article is available for SLL members, or for a fee.

Energy consumption is a real concern with these higher lux levels. But, as this survey from Innovate UK of 50 buildings points out, a great deal of electricity is wasted through inadequate controls or a lack of awareness by the building user of how to use them: 'Comparing the BER against actual energy use from the TM22 worksheets, only College Lake Visitor Centre produced emissions similar to those predicted. The rest produced from 1.8 to 10 times the emissions rate used to show compliance with Building Regulations. The average was carbon emissions 3.8 times higher than the BER design estimate.'

 

Survey Results of Innovative UK's Building Performance Evaluation Programme: Findings from non-domestic projects. Getting the best from buildings, January 2016

Resolving the tension between energy consumption and energy use will demand some creative solutions.  Luckily there are plenty of brilliant lighting people out there ready to take on the challenge.