500 Gallon Double Wall Diesel Storage Tank

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I'm a Civil Engineer working on this small project to replace a gravity fed single walled diesel storage tank with a new double walled tank where we'll be replacing the entire foundation etc...

I've been working my way through EPA, SPCC, API, NFPA and seem to be going back and forth between all rather than getting a definitive answer on whether a secondary containment is met by the double wall tank itself.

I've come up with the requirements

-Must be shop fabricated
-Inner tank must be an Underwriter Laboratories listed steel tank
-Outer tank must be constructed in accordance with industry standards.
-Overflow prevention
-Overfill alarm
-All product transfers must be constantly monitored

Other than this am I on the right path?

Any guidance is appreciated.

Thanks,

 

[BJI]

I am not necessarily familiar with all the standards you mention but seems like you are on the right track. We used to build these with a 'spill box' on the top, if you have any process connections. They would also typically have a bunded cowling on the end for pumps and connection points to contain any spills. As well as overflow prevention on the inlet, an anti-siphon valve (basically a check valve) was also included on the suction line. Allow for interstitial space monitoring to check for loss of primary containment.

 

[LittleInch]

The only thing you missed out was monitoring of the interstitial space as noted above.

But is this tank buried?

Normally above ground tanks are just bunded.

Also study a few vendor specs.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[fel3]

Have you looked at ConVault (

http://convault.com/)?

They manufacture integral secondary containment tanks in a variety of sizes.

At a minimum, I suggest looking at their brochure (

http://convault.com/Content/pdfs/Convault-Brochure-v91913.pdf)

and specifications (

http://convault.com/Specifications)

for information.

Over the years, I have specified at least a half dozen ConVault tanks for ground-level fuel storage. If your gravity feed system requires the tank to be elevated, this might not be your best bet due to the weight of the concrete shell around the steel out tank. On the other hand, if you want "hell for stout," ConVault is a good choice.

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