the fire would not dry the water or the water put out the fire.
There wouldn't be any reason to put gold under stainless steel. Especially in pipes. THe old pipes from the 1940's and 1950's are usually galvanized iron. They screw together so you see the threads if you get behind the walls or in a basement. You can't judge the plumbing by what sticks out of the walls. This portion is often added later as a connector. Old pipes would have pipe dope which sealed them from leaks. Copper would have sweated-on solder that stops leaks. Lead was a common solder until recently. That's why we were told to run the water for 60 seconds before drinking from the faucet. Seemed like a waste of water so few people ever did it. You talk about replacing a fitting in the bathroom. What about the pipes you can't see. that is where the problems lurk. Good luck.
Depends on where you live and the fire code for that locale. Where are you located?
