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Are water heaters required to be raised off the floor?
Thursday, June 14, 2018
Only older gas water heaters located in a garage are required by the International Residential Code (IRC) and Florida Building Code (FBC M1307.3) to be elevated. It is not necessary for electric water heaters, or 30 to 50-gallon gas water heaters manufactured after mid-2003.
The code states that “appliances having an ignition source shall be elevated not less than 18 inches (457 mm) above the floor in garages,” and the purpose of this stipulation is fire safety. Any gasoline leaking from a car parked in the garage creates flammable fumes that are heavier than air and settle near the floor. An open flame close to the floor, like the pilot light in a water heater, can set off an explosion and subsequent house fire.
FVIR Water Heaters Exempted
But, even with the requirement to elevate any source of ignition up above the floor, numerous house fires continued to be attributed to the gasoline fume ignition in the garage. So the Consumer Products Safety Commission (CPSC) mandated that all 30, 40, and 50 gallon gas-fired water heaters manufactured after July 1, 2003, have Flammable Vapor Ignition Resistant (FVIR) technology.
This makes elevation of the water heater unnecessary, and the code exempts FVIR water heaters from being elevated like the one on the plywood platform in the photo at the top of this page. The code states that “elevation of the ignition source is not required for appliances that are listed as flammable-vapor-ignition-resistant.” There are, however, some jurisdictions that still require even an FVIR water heater to be elevated off the floor, so you should check with your local building department.
The owner’s manual and/or data plate on the side of a newer water heater will state that it is Flammable Vapor Ignition Resistant, so you can verify if yours has this safety feature. If you can remove a cover plate at the base of the water heater and see a pilot light and burner, then you have an older water heater that is not FVIR. See our blog post What is an FVIR water heater? to learn more.
But there are a couple of reasons why you may want to elevate your water heater anyway:
•• An elevated water heater is easier to fully drain by gravity to flush the sediment accumulation out of faucet at the bottom. Several years of sediment buildup is what causes a gurgling or rumbling sound each time the water heater starts a heating cycle. See our article Why is my water heater making strange (rumbling, gurgling, knocking or banging) noises? for more on this.
•• When the water heater sits directly on a concrete floor, the moisture in concrete will lead to earlier corrosion of the base.
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