steel frames making noises is just another one of those myths that gets thrown out there.
I've lived in one now for over 18 months and had temperatures ranging from 0degrees to 45 degrees.. and have not had one noise..
and as far as a fire going through my house.. the last thing I'm going to care about is whether the frame burns or buckles.. I'll just be getting out of there asap! and let the insurance company work out the repairs or rebuild.