Old transformer oil containment

[atrizzy]

Hi all,

I've got a project where a client wants to install a very old transformer (that they got a GREAT deal on I'm sure) and I am in charge of the foundation/oil containment/oil water separation design.

Typically I would design a gravity OWS past the outflow to handle the design flowrate and contain a stop valve at outlet for stoppage of a catastrophic breach.

The client has no appetite for this, however, and has asked why they can't just install a stop valve at the outlflow of the containment pit. My response to this is that for an old transformer, likely to leak as a matter of course, the stop valve may not be sensitive enough to stop minor leaks and we'll likely get some oil escaping.

I also looked into products similar to 'imbiber beads' where even trace amounts of oil should engage the stop valve, but of course with a leaky transformer (and dusty site conditions) the thing would likely always be stopped.

I know I'm asking for a perfect solution here, which may not exist, but I'm curious as to what the group's thoughts are on this issue.

Thanks in advance.

 

[le99]

I suggest talking to your mechanical engineer to explore the feasibility of employing an oily-water separator which is not rare in the powerplant.

 

[dauwerda]

The client has no appetite for this, however, and has asked why they can't just install a stop valve at the outlflow of the containment pit. My response to this is that for an old transformer, likely to leak as a matter of course, the stop valve may not be sensitive enough to stop minor leaks and we'll likely get some oil escaping.

I interpret this as a simple manual valve that is normally off, after a rain event, a maintenance person would go to the site and open the valve to release excess water, then close the valve again. It would be up to the maintenance personnel to refrain from draining contaminated water/oil during this operation. This is a pretty standard design that I have seen implemented all over the US.

 

[atrizzy]

dauwerda, I meant a gravity oil-stop-valve. The type of passive valves that close in the presence of oil. Misspoke, apologize.
Here's what I mean:

http://www.owstech.com/products/oil-stop-valves/

My understanding is that these aren't sensitive enough to stop small leaks.

 

[chicopee]

I do not know in which state you are located, but in our State such exposure would be answered thru an SPCC as long as the the quantity of oil on site requires it. Not knowing the quantity of oil in the transformer, I would approach the problem differently. I would determine the quantity of oil and figure out the possible direction of oil flow should there be a significant loss of oil in the event the casing ruptured. Then identify the closest storm drains and be prepared to stop the oil flow thru damming and plugging nearby storm drains. If the ground slopes is minor you could asphalt the area around the transformer so as to minimize seepage thru the ground. Clean up equipment in containers need to be with the area of the transformer. A berm around the transformer is also a viable method of containment. Responsible personnel need to be available to address an immediate response along with periodic inspections of the site. A standby clean up contractor should also be available. All of these measures along with several others not listed in my reply should be mentioned in the SPCC. I am not sure if the quantity of oil on site requires an SPCC but it would not hurt to have one nonetheless.