CSLB C-36 Plumbing ContractorFixture and Appliance InstallationMedium
A plumber is installing a gas-fired tank water heater in a garage. The local code requires the water heater to be elevated to prevent ignition of flammable vapors. What is the minimum height above the garage floor that the ignition source of the water heater must be located?
- A18 inches
- B24 inches
- C12 inches
- D6 inches
Show answer & explanationAnswer & explanation
Correct answer: A. 18 inches
According to most plumbing and mechanical codes, including the Uniform Plumbing Code (UPC), the ignition source of a water heater or other appliance in a garage must be elevated a minimum of 18 inches above the garage floor level to prevent accidental ignition of flammable vapors, which tend to settle low.
Why the other options are wrong
- B. 24 inches would also be compliant but is not the minimum specified by code.
- C. 12 inches is also insufficient for the required safety clearance.
- D. 6 inches is too low and does not meet code requirements for garages.
Water Heater Elevation in Garage
The code requirement to elevate the ignition source of a gas or propane-fired appliance in a garage to prevent ignition of flammable vapors.
- Minimum 18 inches above the garage floor.
- Applies to gas water heaters, furnaces, and other appliances with ignition sources.
- Flammable vapors (e.g., gasoline) are heavier than air and settle low.
Memory trick: Eighteen inches is the 'Ignition Elevation' for 'Increased Safety'.