LED and lighting levels
Perth 7th March 2012
We went out tonight to do some spot measurements in a brick factory that is considering doing a full lighting audit to check if they are still complying to the Australian lighting codes. These lighting standards are becoming more and more of a legal issue, certainly when accidents happen on site during night shifts. I believe I once blogged about about us being called out to investigate the lighting at a 24 hour mining plant after a worker died during night shift as a result of an accident. Though the exact cause of death was not conclusive, we did have to report that the lighting was definitely not to standard at that location and could have contributed to the unfortunate accident.
This factory produces tons of bricks and runs 24/7. The site manager knows that his lighting is probably lacking which is pretty obvious when you visually check the place already. Different colour temperatures kind of indicate that some lights are reaching end of life and even without doing any measurements you will know that this means at least 30% down on initial output. The factory is generally lit with 400W Metal Halide high bay lights. It is also visible from just observation that some of them need some serious maintenance.
One of the reasons we did get out to do some measurements is that they had mounted an LED high bay light, supposedly compatible with the MH light as a possible replacement and wanted to know how well it was doing its job. Interestingly from direct visual observation it was easy to spot the LED high bay light, it had a much more pronounced brightness and colour then the metal halide. The LED high bay was listed as being a 150W with about 80 usable lumens per watt whereas the existing 400W MH generally has about 60 usable lumens per watt. I say usable as the rest is mostly “lost” in the optics and fitting. Our one on one measurement predictably showed the MH outperforming the LED by nearly 2 to 1, but then that is if we would replace the MH one to one. The issue here is that the lighting performance of the LED is different and that it would require a new lighting layout (with more LED lighting points) to recreate the same lighting results. With its higher performance we would however be looking at a much lesser energy consumption, a much better uniformity due to the higher quantity of fittings required. But a ROI calculation would be required to get a handle on the higher capital costs of replacement.
Light Watch 3-32: Some pictures of the site. Spot the LED in the first and second picture as well as Stan showing of with his lux meter 🙂