CSLB C-36 Plumbing ContractorFixture and Appliance InstallationHard
A plumber is installing a new residential gas-fired tank water heater in a garage. The local plumbing code requires the ignition source to be elevated a minimum of 18 inches above the garage floor. The water heater being installed has a standard bottom-fired burner. To comply with this code, which of the following is the most appropriate method?
- ABonding the water heater to the main electrical service ground.
- BConstruct a concrete or masonry platform for the water heater.
- CEncasing the water heater's burner in a fire-rated insulation.
- DInstall a sediment trap on the gas supply line to the water heater.
Show answer & explanationAnswer & explanation
Correct answer: B. Construct a concrete or masonry platform for the water heater.
The 18-inch elevation requirement for gas water heaters in garages is to prevent the ignition of flammable vapors, which tend to settle near the floor. Constructing a compliant, non-combustible platform is the standard and most appropriate method to elevate the entire water heater and its ignition source.
Why the other options are wrong
- A. Bonding is for electrical safety and grounding, unrelated to the elevation of the gas ignition source.
- C. Encasing the burner would not meet the elevation requirement; it might address fire spread but not vapor ignition.
- D. A sediment trap is for gas piping integrity, not elevation of the ignition source.
Water Heater Garage Elevation
Gas water heaters installed in garages must have their ignition source (burner) elevated a minimum of 18 inches above the garage floor to prevent the ignition of flammable vapors (e.g., gasoline fumes) that may accumulate at floor level.
- Required for gas water heaters in garages.
- Prevents ignition of flammable vapors.
- Typically achieved with a non-combustible platform.
Memory trick: Gas in a garage, 18 inches to save us from a fiery barrage.