We call 'em closets, electrical rooms, vaults, etc. (Storage rooms )
Building codes have a distinct difference between electrical closets and vaults, but try to find a hard definition of vault and you can run into a stone wall.
Does anyone have a definition, from an authority, of the difference between a vault and an electrical room? I've always held oil filled equipment as the difference, but there is truly no proof of that from NFPA, IEEE, or ANSI that I can find.
Fire resistance 3hr or greater, direct ventilation etc? 110.31(A) and 450 chapter III That seems to be the best NEC reference for the definition of a vault I can find. There are also references like 450.2x that say where a vault is necessary.
I consider a vault to be any space that meets NSA/GSA requirements, but I don't think that's what NEC is referring too...
In the 2004 NEC comments, someone made a (rejected) suggestion regarding a definition of "vault". In the commentary, the panel states that the 110.31(A)/450.42 requirements are needed only when containing equipment having a degree of hazard that warrants a vault. Oil filled equipment certainly seems to fit that, but other medium and high voltage equipment might as well.
Re: Vault Definition#100080 10/13/0605:36 AM10/13/0605:36 AM
Thanks guys for the replies. It is one of those thorny points in the code and the first time I had no other issues to influence the outcome.
Sometimes, as we all know, the code is ambiguous in their definitions, not necessarily a bad thing, often what plays in Peoria will make NO sense in DC, New York, or Chicago. A uniform code will not always work.
This situation came down to me calling a meeting between 2 Fire Protection engineers, a Fire Marshal, and myself to come to a conclusion.
FYI, the bone of contention in this particular matter was a 60+ year old cinderblock wall (some solid, some MAYBE not) and a medium voltage vault. We had removed all the oil filled equipment a few months ago. The room was not near any egress path so that was not an issue, and in fact it was really set off by itself, just well hidden.