Good Morning all, I am looking for a bit of help please. Situation is that the business (Low tier COMAH) is investigating processing a very dry, dusty material which will be delivered by lorry and stored in a large shed before processing via a conveyor system. Studies have identified that lighting requires a very high Atex and similar spec due to DSEAR and costs are being challenged (correctly) by procurement – cost per light, fittings and cabling etc is high times number of fittings required for lighting needs. In a discussion with procurement some ideas have come up such as fitting the lights on the outside of the building with “windows” into the building and similar. I also have in mind that I have heard of a large “light box” with light then directed to where a “normal” light fitting would be, but can’t recall where or to be honest cost. This would be a 24 Hr operation so lighting would be important. Has anyone come across an external lighting system for high risk storage facilities? Cheers, Jim

Just take some time before committing to one or the other. Remember that the outside lighting will; have to be able to cope with the weather (so will need IP rating anyway), will have to "shine" through windows (how clean are these going to be after a few weeks, who's now going to go up and clean these windows, replace the bulbs, what happens if there's an incident in the building when the light levels are compromised, etc).

Obviously, a lot will depend on the properties of the particulate in question (Particle size, density, MIT, LIT, MEC, etc.). If it is a large structure, do you really anticipate a MEC of circa 30-40 g/m3 at the level/height/position of the lighting? If so, you will also have considerable OH/IH problems associated with this process. Regardless of settling velocity (stokes law) and considering dust layer accumulation, I would suggest that the likelihood of ignition is greater in connection with the operation of the mechanical equipment (conveyor) and delivery vehicle than that of the lighting. Sorry, cannot be of help in this matter without further details concerning the material in question Regards BLEVE