generator - fuel tank size

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malachi constant

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Minneapolis
I have a diesel generator set where the only load requirements are elevator and lighting - both considered life safety. The only requirements I can find for sizing the fuel tank are IBC 1006.3 - stating that the emergency lighting must be powered for a duration of 90 minutes.

The fire marshall told me as far as he knows, 90 minutes is the minimum requirement. The elevator code official said he didn't know and deferred to the building code. The Owner's mantra is "code minimum" and has no desire to oversize the fuel tank.

Two questions:
1) Are there other code requirements that dictate duration of emergency power?
2) For the sake of argument, if I were to remove emergency lighting from the genset and provide battery packs everywhere, but still kept the elevators on it, what code would dictate the duration of emergency power (i.e. size of fuel tank)?

Thanks,
Brad
 
Article 700.12(B)(2) calls for 2-hour supply of fuel for an emergency system. 701.11(B)(2) also calls for same 2-hour supply of fuel for a legally required system. If you change the system to an optional stand-by system, then there is no requirement that I am aware of!
 
Brad, You should be looking for gallons per hour @ full load emergency and also gph @ test run.If your planning on sizing the tank for just a two hour use,your going to be constantly refueling the tank just on testing weekly alone.Most diesel generators are sized for a 24 hr run use.This would cover your required testing and any emergency use if checked regulary.
Rick
 
I think you need to find out what code is requiring the generator for the elevator in the first place. You may not need the generator at all, or you may only need it long enough to let people out.

It would be nice to do an elevator recall to a landing before the generator runs out of gas (or even as soon as it switches to the generator). I would hate to be the one that jumps in the elevator 1 hr & 59 minutes after the generator started.

Steve
 
I have one more reason for you:

Many of the newer diesel engines use the diesel to cool the engine in addition to its coolant system. Some that I have seen have the supply fuel flow double that of the return at full load. With a large fuel tank, it shouldn't be an issue because of your "cooling supply". But for smaller tanks, you'll have to install a fuel cooler and power-up its support equipment. . .and that would cost him extra $$.

In all fairness, your engine might be small enough to where it's cooling needs/heat generation are a lot lower than the 1-2 MW units I'm referring to, but they might at least take some consideration.

Good luck.
 
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