Apparently the whole area gets flooded with halon
(sp?) to quickly absorb
any oxygen from the air, so if you hang about ......
"Absorb any oxygen" is a bit harsh. Halon is pretty good at stopping
things from burning but it doesn't make it impossible to breathe. It's
not the most healthy thing to breathe but in the 80's and earlier a
very common demo of halon extinguishers had the salesman in a halon filled
booth, demonstrating how all fires go out, while happily breathing the
stuff.
Now, CO2 oxygen-displacement extinguishers, that's a different story.
Tim.