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Underground Fuel Tank for Standby Gensets 3

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arvinolga

Electrical
Apr 17, 2006
41
Hi,

Any additional/special requirement if you want to provide an underground fuel tank for the office building's standy gensets?

 
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Lots & lots of requirements. Check with the local authorities. Probably don't want to go there once you know all the requirements.
 
Double walled tank c/w leak monitoring for a start, the tank vendors can be quite helpful though. As Davidbeach said check with the authorities you will likely change your mind. No doubt driving around you will see lots of old gas station sites where they are trying to suck all the hydrocarbons back out of the ground.
Roy
 
The closest I'd come to doing an underground tank installation is to dig a pit that will allow the installation of an above grade tank with its top below surrounding grade. leave enough room around the tank for inspection and provide a walkable grate over the top to the whole thing.
 
Is it advisable to store diesel in those fibre glass tanks normanlly used for water ? Will the diesel react with the polymers ?
 
Buy a gen set complete with aboveground dike tank. This will save everyone a lot of headaches.
 
Diesel needs to go into double wall tanks designed for use with diesel. Single wall water tanks would be completely unacceptable.
 
but do you still need a double wall tank if it is underground?
 
Double wall would be just the beginning if underground. There's a reason that new underground tanks are very few and very far between.
 
arnolga:

Anything other than a factory built fuel tank in the base of the generator unit, shall be designed by experienced mechanical engineer familiar with fule systems and codes. It is way beyond capability of any electrical engineer. So let the experts handle it, contact your mechanical couterpart or hire some one.

There are several reqquiremetns in NFPA plus the environmental regulations, spill containment and lots of other things.

 
The other problem you have when the diesel fuel tank is below the engine is getting the fuel up from the tank to the engine. The height (when tank fuel level is at its lowest....!) from lower tank level to engine has to be less than the engine pump lift level.

The way round this is to put a day tank in the engine room (bunded) fed by an electric pump from the main tank. Then you are increasing the complexity and reducing the reliability.

itsmoked - natural gas can be used, but the engines are more complex (less reliable [before any one jumps on me, this is because they are usually designed for continuous operation and have more protection than a simple diesel engine]) and the gas gives an additional safety issue..... Beacause the gas is usually piped from the utility and not stored on site, then there is always the risk of a supply interuption.

By the way, avinolga, do you mean underground as in buried in the soil (a real no-no in most places now, as others have said) or do you mean in the basement? Depending on your local codes, you MAY be able to put a bunded tank in the basement. There are so many issues, you really need a local expert to advise you
 
He has posted a plan drawing in another thread. The proposed location for the tank is under the road adjacent he building
 
Hi - Yes, as mentioned by 123MB, I have posted a location plan of the gensets and fuel tank. But am attaching the detail of the fuel tank for reference. Appreciate if anyone can advice as to why underground is not preferred anymore.
 
 http://files.engineering.com/getfile.aspx?folder=be522f4b-8571-412b-81b4-3d775777eafc&file=Underground_Fuel_Tank_Details.PDF
Have you actually read all these responses of which most point out reasons why buried tanks are greatly frowned upon in this century by any modern country?

Tanks leak eventually.

A small leak can pollute a HUGE amount of ground water - damaging entire aquifers! This of course makes the tank owner financially responsible.


Keith Cress
kcress -
 
Thanks

The set-up of the fuel tank can be such that the leak will be isolated to its location only, if possible.
 
I've been the engineer on a few UG tank projects recently. In most areas of the U.S., it's not all that difficult if you use double-wall FRP with appropriate leak detection. They are expensive. By far the easiest configuration is an outdoor genset enclosure with a double-wall base fuel tank. In a few areas (one big city in the southeastern U.S., and another in Texas) the fire departments are up tight about above ground tanks to the point where UST's are easier. Some jurisdictions require AST's to be fire rated. AST's may require a spill prevention control plan (SPCC).

I can't emphasize it enough - carefully determine the applicable codes and READ THEM, carefully. Then consult the local fire dept (may be city, county, state or any combination of those) and state environmental authority.
 
alehman

Will diesel react chemically with FRP tanks over a period of time ?
 
thanks, Alehman. Mentioning the spill prevention control plan is worthwhile. Will require this also.
 
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