Transformer Foundation - Oil Containment Area Sizing

[dmitriy555]

I am working on a design of a transformer foundation. Transformer contains 1050Gal of oil. That is quite a bit of oil, that would require 146 cu. ft. of containment volume around the transformer pedestal, if I add crushed stone into the pit, it will quadruple the volume.
I have an option of building an underground containment tank with a sump pump. If I do that how shall I size the containment area around the transformer? I could not find any codes with good guidelines.
Any help would be appreciated.

 

[dik]

I've used a product called Sorbweb for containment for the last three transformer yard projects, each transformer having approx 50,000 litres of oil.

They use a specially graded granular material with a high void ratio. The sorbweb 'gels' when exposed to transformer oil and prevents its passage. It also allows water to freely flow and the drainage system is simply to groundwater or if impervious clay, then to a regular storm drain. No containment issues, only catches oil if it leaks (and has to be replaced). It's an excellent product.

The gradation of their stone is:


1-1/2" CLEAN CRUSHED STONE (FOR SORBWEB CONTAINMENT BASIN)
CLEAN, ANGULAR CRUSHER RUN LIMESTONE CONSISTING OF HARD DURABLE PARTICLES FREE FROM SILT, CLAY AND SILT LUMPS, FRIABLE MATERIALS, CEMENTATION, SOLUBLE MATERIALS, FROZEN MATERIALS AND ORGANIC MATTER

FILL SHALL CONFORM TO:
SIEVE SIZE (ASTM) PERCENT PASSING
1-1/2 INCH 100
1.06 INCH 90-100
3/4 INCH 25-35
3/8 INCH 0-5
NO 4 0-2

I have the void ratio for it at the office... will post it tomorrow.

Dik

 

[dik]

Forgot to add that the actual transformers are supported on piles...in excess of 400,000 each... The piles penetrate the Sorbweb basin...

Dik

 

[paddingtongreen]

@dmitriy555, The crushed stone is to limit any fire in the leaked oil, if you had an open pit, you could have a ferocious fire. I don't know if you have contamination limits to runoff, I had to add oil/water separators to the drains.

@dik, that Sorbweb eliminates the oil/water separators, it sounds great.

Michael.
Timing has a lot to do with the outcome of a rain dance.

 

[dik]

Yes it does... and no containment with the exception of the aggregate basin. Transformer oil does not pass through, it causes the sorbweb material to form an impervious gel. On a couple of projects we have put a small perf drain system in a sand bedding; this has gone in one instance to free drain and the most recent is connected to an existing stormwater catchbasin. In impervious material, the containment aggregate has to be drained to keep it from filling with water.

The system was developed by Ontario Hydro and the spin-off is Sorbweb. Do a quick internet search and read all about them.

Dik