Standby Generator Fuel Tankage

[doehl1]

I am installing a standby generator for a local business and the local governing body is requiring compliance with NFPA 37 "Standard for the Installation and Use of Stationary Combustion Engines and Gas Turbines". Unfortunately, I am not familiar with the standard. The generator is 40kW, 208V 3ph and has an integral fuel tank (80 gal) that is built into the bottom of the skid. The tank is currently single-walled. My question is, do I need a double-wall tank, or need containment basin to meet the standard? The installation is outside, and the generator will sit on a concrete foundation. Fuel is diesel.

 

[dpc]

I think double-wall tank or dike tank has been basically the law of the land almost everywhere in the US for several years.

If you are replacing an existing tank, I'd imagine it would have to be double wall or something equivalent.

 

[itsmoked]

Any reason the foundation can't be made to have a leakless raised curb around it? Hence, secondary containment. It must be high enough to hold the fuel and engine oil. Be generous.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[doehl1]

I think double wall is what we'll have to go for. I may be in luck if the bottom of the generator is an enclosed skid, out and around the principal fuel tank. This is in essence a secondary containment as required by the standard.

As for a leakless raised curb, this is another option, but not optimal, as standing rainwater becomes a real issue. Location is FL and this containment would constantly be full of water.

Thanks for your suggestions.

 

[itsmoked]

Water!!! This thing isn't roofed or enclosed? Tisk tisk..

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[doehl1]

Yes, it is an enclosed package. However, not necessarily sealed on the bottom skid. Foundation extends several inches beyond the generator canopy. My concern was that having a foundation as the containment basin would retain water.

 

[catserveng]

You might want to check with the local Fire Marshall, as he is the AHJ for fuel tanks in most areas of the US.

We used to run into this quite a bit, depending on how the local authority interpets the regs, and applies their own regulations, you can find that unless the tank is UL approved and originally a double wall listed containment system, you may not fly. I have found it's easier these days to go ask the Fire Marshall before sticking mt feet in our collective mouths.

Florida Department of Environmental Protection Approval is required for tanks over a certain size, but not certain anymore what that size is, so you may need to check with them as well.

Hope that helps.

 

[alehman]

We do engineering for a lot of fuel tank installations. Typically single vs. double wall is an environmental requirement rather than a fire code issue. NFPA 37 is a fire code for engines. NFPA 30 is a fire code for flammable and combustible liquids.

You will need to consult the Florida Department of Environmental Protection (Chapter 62), the state fire marshal, the county and the city. Most of the codes are available on-line if you look hard enough. It is important to find them all to avoid surprises later.

If your facility isn't required to have an SPCC plan, you may not have to use double-wall for a small tank. To be safe and simplify your life, use a double-wall UL 142 listed tank although it may not be strictly required. They are fairly standard equipment.

 

[EEJaime]

We've run into this many times. As suggested by other posters, the local Fire Marshall and AHJ need to be consulted. Some locations are ok with a single wall tank with secondary containment. Most want double wall tanks. And some want secondary containment even with a dual wall tank, (the FM's logic in this case was that he wanted accidental spills during re-fueling contained).

What we have done on exterior installations is to install the secondary containment curb, but slope the surfact to drain through a 2" round opening in the curb fitted with a manual drain valve. That way rainwater can be drained so as to not have a mosquito breeding pond.

 

[jghrist]

I suggest that you spring for the $33.50 and buy the standard at

http://www.nfpa.org/catalog/.

Citing responses to an internet forum might not go real far in a dispute.