gas or oil fired water heathers in garages must----so that gasoline vapors are not ignited?
b, insulated, there must be an area between the gas or oil and the tank in which it directly sits in. This I believe is because of pressure of fumes or something.
In CA, elevated (about 20 inches I believe) and the garage must have two vents to the outside.
Oil or gas fired water heaters located inside a garage must be elevated at least 2 feet from the floor. The garage should also be properly ventilated to prevent accumulation of explosive vapors, such as gasoline vapors, to minimize the risk of gas explosion or fire.