CNG dispensing station lighting

[texie]

In a CNG open air dispensing facility with a canopy, what would be the requirement for the light fixtures on the underside of the canopy? It would seem that 514.3(2) would apply here. But what if there is about a 4" skirt around the perimeter of the canopy? Would that be enough to require rated fixtures?

 

[petersonra]

In a CNG open air dispensing facility with a canopy, what would be the requirement for the light fixtures on the underside of the canopy? It would seem that 514.3(2) would apply here. But what if there is about a 4" skirt around the perimeter of the canopy? Would that be enough to require rated fixtures?

I don't see how it makes any difference. How would the skirt change it any?

 

[eHunter]

I don't see how it makes any difference. How would the skirt change it any?

As an engineered solution it could and should matter if the hazardous material was lighter than air and able to accumulate against the ceiling trapped by the skirt and a possible source of ignition was within the confines of said skirt.

 

[petersonra]

As an engineered solution it could and should matter if the hazardous material was lighter than air and able to accumulate against the ceiling trapped by the skirt and a possible source of ignition was within the confines of said skirt.

I am not real familiar with the codes regarding this kind of thing but I seem to recall that the canopy on such an installation is required to be designed so it does not trap anything. So, unless someone added this skirt after the fact, I just don't see that it makes any difference.

 

[renosteinke]

IMO, there's no avoiding the use of explosion-proof lighting.

Forget this "denser than air" stuff. A CNG dispensing station will often have sections of piping with high pressures in it - as high as 3000 PSI. Get a leak anywhere, and that gas will shoot out in a directed stream for a considerable distance before dispensing as a cloud of vapor.