integral fuel tank in skid?

[MikeHalloran]

People who claim long experience in "the oil patch" tell me that it's acceptable/ customary to construct a Diesel fuel tank within a steel skid simply by welding 1/4" plate between the channels that comprise the skid structure.

I.e., no leak detection, no alarm, no secondary containment.

Please direct me to any US or global standards that address the issue.

Thanks.


Mike Halloran
Pembroke Pines, FL, USA

 

[gr2vessels]

Mike,
I have a bit of experience with Caterpillar gensets fitted with the skid doubling for the fuel tank. Never been any problems. I'm unable to guide you to a specific standard, but they have presented all the standards on the Earth for those gensets. There was some MIL standard compliance, I wouldn't be surpised with the White House stamp also. By the way, I suppose that you have a very complex fuel leak alarm in your car's tank, don't you?
cheers,
gr2vessels

 

[BigInch]

Never heard of or had any problem with them.

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"We can't solve problems by using the same kind of thinking we used when we created them." -Albert Einstein

 

[MikeHalloran]

I have had car tanks develop leaks. The smell of gasoline is plenty alarming, people are almost guaranteed to be nearby most of the time, and most car tanks are much smaller than typical skid tanks.

I submit that the chance of a leak going undetected is greater for an unattended Diesel genset, the extant case.

I asked because yacht and workboat builders are starting to require double wall tanks with leak alarms, as are now customary (and I think required in the US) for terrestrial stationary Diesels.





Mike Halloran
Pembroke Pines, FL, USA

 

[BigInch]

Car gas tanks arn't 1/4 inch thick either. Put a drip pan underneath if you're worried. Since you said oil patch, I perhaps wrongly assumed you were not talking about an inside enclosed space. Anyway diesel isn't near as bad as gasoline as far as explosive limits and alarms go.

I think the yacht and workboat builders have to comply with zero discharge into navigable water regs. Which makes me think that if the diesel tank is going to an offshore platform, the platform guys will have built a drip pan underneath the space they are planning to put it in already.

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[MikeHalloran]

It's going to another continent, so it's "not our problem", I'm told. It's still our planet.

I think it's going onto a platform. Is it customary for platforms to have drip pans under everything that could leak? Or is it required by some set of rules?



Mike Halloran
Pembroke Pines, FL, USA

 

[gr2vessels]

Mike,
It will take years to corrode through 1/4" plate of a diesel fuel tank, skid enclosed underneath the engine. With some care, it might never corrode, despite the water content of the beast quality of diesel oil. Using a good coalescer on the fill line will help a lot;- you could have a handhole for inspection and test the thickness regularly, once a year, to identify the potential trouble spots. Once in a while, you might even clean the tank to remove any water accumulated in the botoom of the tank, painting inside is not impossible...Also, many good diesel tanks lasted longer than the ship itself...

 

[MikeHalloran]

I was more concerned about engine vibration cracking the welds than corrosion.



Mike Halloran
Pembroke Pines, FL, USA

 

[BigInch]

Last I knew in GOM, drip pans were placed under any piece of equipment that might drip or leak with outlet run to a drain. Sorry I can't remember if it was simply our practice or required by the Coast Guard regs. I suspect it might have been required by CG and/or MMS.

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"We can't solve problems by using the same kind of thinking we used when we created them." -Albert Einstein

 

[gunnarhole]

While not directly applicable to the original post you may want to consider the following from API RP14J Recommended Practice for Design and Hazards Analysis for Offshore Production Facilities

3.3.11 Drain Systems: Planning and construction of offshore production facilities should include methods to collect and direct escaped liquid hydrocarbons to a safe location in an “open drain”(deck or drip-pan drainage) system. All components subject to leaks or overflow should be protected by curbs, gutters or drip pans that drain to a sump.

This is similar to the guidance provided in NFPA 37 Standard for the Installation and Use of Stationary Combustion Engines and Gas Turbines

Protection is generally limited to an overflow line, a high level alarm and an automatic pump shutoff. Secondary containment is an alternative to the curbs, gutters & dikes mentioned above.

For a full blown discussion of the design of fuel tanks see NFPA 30 Flammable and Combustible Liquids Code.

 

[BigInch]

RP14J, That's precisely the one I was thinking about. Thanks Gunnar.

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