Diesel tank storage area

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CCCI

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Location
Orlando, Florida
DIESEL TANK STORAGE AREA ( This is a day tank which feeds two generator - An existing Emergency Generator and a new Backup Generator )
We hired an electrical contractor to add an additional backup generator to our facilities. We added a building to house this generator and its diesel storage tank. The tank has three motors within three feet of the diesel storage tank along with some additional electrical devices. When I first saw this on the prints I thought that this would have to be treated as a Hazardous Location. After I looked deeper into this I found that diesel is not treated as a Hazardous Location and I felt that we would not have a problem. The job is about 95% complete and the electrical inspector has said that everything within three feet of the storage tank is a Hazardous Location and we need to get explosion proof motors and redo everything within the three feet as a Hazardous Location.
I am the Master Electrician here at the facilities and have not worked around a lot of Hazardous Locations. Can anyone tell me where the inspector is getting his three foot rule? Is diesel ever a Hazardous Location?
 

rbalex

Moderator
Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
The inspector is in error. NFPA 497, Table 4.4.2 does not list diesel as a flammable material. Diesel is a Class II, combustible liquid. See NFPA 497, 4.2.7.
 

CCCI

Member
Location
Orlando, Florida
3 Foot Rule?

3 Foot Rule?

I see that this is not a hazardous location, but if the inspector is going to enforce it as a hazardous location where is he getting his 3 foot rule that he wants to enforce around the tank? If it was a hazardous location I could see 501.15 (A) (4) Class 1 Division 1 Boundary which tells us about a 10 foot area. Am I missing something here or is this also something that he is making up? Also if it was looked at as a Class 1 Division 2 Boundary it would also be a 10 foot area. I know that this diesel storage tank area is not a hazardous location, but do you have any idea what he has in mind with his 3 foot rule around the diesel storage tank?
 

rbalex

Moderator
Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
He may be applying a general rule for outdoor pumps; otherwise I no idea. BTW has he made a Division determination?
 
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