LED lighting in hazardous environments
LED Lighting has been around for a while now, and in the Industrial and Commercial space the change has been dramatic. The desire for longer life lamps fuelled the original drive to LEDs, but there have been many more advantages that came as part of the package.
In hazardous environments (flammable areas) the move to LEDs has been slower and more measured. There are so many boxes to be ticked before a technology can be used in a potentially flammable environment that manufacturers cannot make a change like this lightly. The cost of the approval process alone would bring tears to the average accountant’s eye.
The main challenge for manufacturers has been dealing with the heat generated by the electronics driving the lamps. Some manufacturers rushed in and then discovered the lifespan was no better than before. This was mainly due to electronic failures, often attributed to the enclosed fittings not being able to dissipate a suitable amount of the heat. Their challenge was that a Hazardous Area fitting must have a designed in, maximum surface temperature. The more LEDs the more power required to drive them and the more heat generated.
As each gas, vapour or dust has a temperature that it will automatically ignite, it is important to keep that heat below those temperatures, and therefore keep the environment safe. High power LED technology is still a work in progress and multiple LEDs are needed to create enough light. This has meant some LED fittings are larger than the previous light source models, as surface area is the only cost effective method to dissipate the heat.
Some manufacturers that have recently entered this challenging field have opted for later technologies, with smarter electronics, to maximise the light output in a smaller and more efficient fitting. If the plant has existing fluorescent fittings, replacing these directly with LEDs has advantages. A replacement can be made within the same mounting footprint and use the same brackets if the right model is chosen. If this LED fitting also meets all of the explosion protection characteristics of the fluorescent it can be used in the same flammable atmosphere without any degradation in safety.
LEDs also allow for innovation from the lighting manufacturer. Tubular fittings of different lengths for applications where traditional fittings have not previously fitted are making the Hazardous area less of a challenge to light than ever before. LED work lights for confined spaces are a huge asset. No more bumping the lamp and having the light go out just as you got to the work space. Additional voltages for a larger range of applications are now available.
The other advantage of LEDs is energy saving. The lumens or lux (some have preferences) output per watt of energy is significantly reduced. In one case to achieve the typical light output of a 2 x 58W fluorescent fitting only requires a fitting the length of a traditional 2 x 36W, and uses less energy. This will see significantly less space required for lighting over time and definite reductions in energy bills. The one down side can be the intense light from the fitting. Choosing a fitting with an optically correct diffuser with LEDs is important to reduce glare.
There is no doubt that LEDs are the flavour of the month in flammable environments. Be careful to check the “T” rating. That’s the maximum surface temperature that the fitting will attain under a normal ambient temperature. Check for diffusers; are they available? LEDs without diffusers could be a hazard in themselves. Each LED is very bright. Check for energy saving and lux output. They should be significantly better than a standard fitting.
The bonus: Extremely long lamp life and peace of mind. Supplied by Mike Barker, Market Manager Control & Defence, Electropar PLP