I'm assuming....
I'm assuming that you question the wisdom of such an act,
thereby asking for a reference to an authoritative document
prescribing the use of water on a brake fire. I cannot help you,
as I've always been taught to NEVER use water on a brake
fire. Instead, dry chemical is what we should use.
Actually, I'm thinking dry chemical is the only approved fire
retardant that is approved for this....but, not being a trained
fire fighter, I could quite likely be wrong.
Fly safe,
PantLoad