Underground Fuel Tank for Standby Gensets 3

[arvinolga]

Hi,

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

 

[alehman]

So far as I know FRP is considered permanent for petroleum products. In the U.S. it seems like most new petroleum UST's are double-wall FRP.

 

[edison123]

Thanks alehman.

 

[alehman]

In response to Keith's comment, U.S. federal regs require many UST owners to have the financial means to help pay for the costs of corrective action and third party damages caused by a release from their underground tank. Sometimes this is in the form of a UST insurance policy or participation in state cleanup funding programs. This is getting beyond my area of knowledge. Obviously it's not a total solution.

UST's got a bad reputation when so many single-wall steel tanks installed in the 1940's through the 1970's corroded and leaked. I think FRP has proven to be very reliable. Some states (e.g. Florida) now prohibit single-wall UST's altogether and are requiring their replacement whether or not they leak.

 

[DonPhillips]

I think it was the late 80's when EPA regulations came out regarding UST's and in Ohio, the state fire marshall's office enforces the regulations.

Don Phillips

http://worthingtonengineering.com

 

[alehman]

Enforcement seems to vary a lot. In Michigan, the Dept. of Environment enforces the fire codes. Go figure...

 

[EEJaime]

Arvinolga,

You did not mention the system size, but the choice of tank style will be very dependant on how much fuel you need. If this is an office building as you state, then I imagine the system is quite small. If the genset size you need only needs to feed egress lighting and egress pathway lighting for 90 minutes, then you can probably get away with a packaged system utilizing a skid mounted tank below the genset, or at worst case a concrete, dual walled, fire rated tank such as made my "ConVault". Althought that does introduce pumping and piping, monitoring and spill control. Which will involve Mechanical and Civil/Architecural design.

If the syatem is large, such as one we are currently involved with. Which is the second phase of the construction of a generator plant feeding a large hospital complex in Los Angeles, California. The initial phase included three-2MW gensets, with diesel fired engines generating at 12 kV. We are in the process of adding two more. These are on a closed transition switching scheme with the utility which will be adding a 66 kV-12kV substation.

The site is extremely crowded, there would be no room for above ground storage and having 100,000 gallons of diesel fuel in tanks above ground is not only a physical and safety concern, it is an eyesore the County and the Architect would hang us for. The initial two tanks are underground and have presented no problems whatsoever. We have dozens of installations using Underground tanks. The leakage monitoring of the interstitial spaces, fuel piping, man-wells, etc..., is a well regulated and common installation.

Our Mechanical/Plumbing engineers are well versed in fueling systems, the piping, pumping, monitoring and fuel management systems are part of their daily routine. I suggest Arvinolga, that you contact a local Mechanical consultant and hire him to assist with the design. It is very possible to get a depandable, safe, environmentally friendly design with underground tanks.

 

[ausgen]

To summarise my local (Aus) requirements, you need the following for USTs at least:

-Double walled tank w/ interstitial monitoring.
-Double walled pipework (incl. vent, fill, etc) w/ interstitial monitoring on wet legs.
-Monitored transition pits where joining with single walled pipe.
-All monitoring able to detect 0.76L/hr product loss.
-Pit inspection well.
-Geotextile pit lining.
-Regular statistical inventory reconcilliation.

Like others, I'm frequently faced with needing 30,000L+ of diesel and nowhere to put it so unfortunately have to bury my FRP tanks also. In my experience, vendors will warrant tanks for 25 years and more assuming not greater than E20 biofuel mix.

One final note on FRP - choose your installer carefully as there the risk profile is greatest during install (transporting, handling, alignment, bedding, etc) as opposed to steel tanks whose risk tends to build with time from corrosion. Most FRP vendors should operate an installer accreditation scheme to suit.

 

[arvinolga]

thanks everyone!