Traditional Ex luminaire manufacturers often only quote lumens at source, i.e. lumens at the bulb before it’s travelled through any lensing. But traditional Ex light fittings are typically only around 60% efficient in transmitting useable light out of the luminaire, meaning that the delivered lumens can often be up to 40% less than quoted. In addition, consumption is usually quoted without considering gear losses, so you’ll often find the ‘true’ consumption of your traditional Ex luminaire to be up to 15% more.
In contrast, Raytec Ex LED White-Light luminaires (Raytec Range) are >90% efficient, delivering more lumens per watt and achieving significant power savings over traditional Ex fittings. They also have a much higher CRI (or true colour representation) than traditional luminaires, and deliver a highly directional beam of light with minimum wastage. This gives the appearance or perception that the illuminated area is in fact much brighter.
The two sets of images below show just how much of a difference this one aspect makes.
25K Lumens at Source:
25K Delivered Lumens:
Further energy and CAPEX savings can be made by using a lower lumen LED fitting due to the perceived brightness of LEDs to the human eye. This concerns mesopic vision and the mesopic effectiveness of an LED lighting solution but is a case study by itself.