Hi All!

I am curious if anyone has any knowledge of NESC or other regulations that deal with minimum distance requirements of containment areas between transformers.

FM Global in particular publishes guidelines on this. They like to see 25 feet minimum with flammable fluids, and then they drop to a lower number (10 feet if I recall) for less flammable fluids, unless you have a 2 hour fire barrier between transformers or some sort of fire suppression (deluge) in which case it goes to essentially zero.

The issue or concern for them is really a matter of liability...that if the containment of burning oil on a transformer fails, it overheats another one and causes it in turn to fail as well.

With dry transformers the containment is a nonissue.

Also, containment by itself generally doesn't really do a lot of good from an environmental point of view in the U.S. because it's still a spill and every time you have to drain the containment (rainwater), you have to test it to verify what it is to satisfy the regulators. So we stopped doing containment.

As usual Paul's spot-on. I just thought I'd add there are a couple of companies that I know of who make the less flammable fluids - Cooper's Envirotemp FR3 and ABB's BIOTEMP. Both will require retraining on their use but, since they're plant based, are typically less hazardous to work with.