Transformer Blast Pressures

[dik]

We have a project that has several high voltage mineral oil filled Transformers (138 kV, 16MVA typical size) that are located outdoors and are not enclosed. They are, however, separated by walls between the transformers.

I've done a search on the various threads in this forum and have not been able to determine/estimate design blast pressures for designing walls separating these transformers?

Does anyone have a good source for the magnitude of the pressures? I've checked IEEE and FM Global without success.

thanking you in advance,

Dik

 

[waross]

When a transformer fails, it can range from a quiet burp to catastrophic. I understand that the walls are to contain fires, not the actual blast and should at a minimum be fire rated.
A more conservative approach would be to use walls that are earthquake rated as well as fire rated.
I realize that this doesn't answer your question, but I hope it helps.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[dik]

waross:

That's what I've done with two previous projects... light steel frame, metal siding and rockwool insulation.

This client wants them designed for blast. Existing ones cantilever about 20' up and are 16"-18" reinforced concrete. He wants them to protect against 'blast'.

I've found reference to it in many locations including FM Global and IEEE, but cannot find any reference to exposions except one (sorta unrelated) article lists 20 psi and another lists 27 psi...

Dik

 

[whycliffrussell]

I did one a while back - the purpose of the wall was not rated for hte blast but to be "fire rated" and therfore be able to contain the oil from the transformer from splashin on the protected area. We used a cinder block construction - I have not found any reference to any standard which makes reference to the "tonnage" of the explosion of the transformer.

 

[caporter]

You could plan for worst case by using the short circuit current energy plus the heat of combustion at about 19,660 Btu/lb 45.7 MJ/kg assuming mineral oil coolant. Converting energy into blast pressure is beyond my understanding though.