i am building a natural gas fired smoke shack out of plywood. i will be using a PID temperature controller to run the gas valve. i will be lining the bottom of the smoker with concrete board to prevent fires.
i would not use one for wood fired or charcoal fired smoking but for propane, gas and electric, they work just fine. you just ahve to have a lot of space around the flame and something like concrete board as a barrier.
Yes they will, if not built correctly! If you build, you need to design that you have at least 10" of free space around your burner. Also you need to flash or line with non flammable material at least 1/2 to 3/4 from bottom up the wood, or flammable surfaces.
Here are some pictures of my smokehouse. May they will give you some Ideas.