915.3 Gas-Fired Room Heaters — 2025 California Mechanical Code

Gas-fired room heaters shall comply with Section 915.3.1 through Section 915.3.4. 915.3.1 Prohibited Installations. Unless specifically permitted by the Authority Having Jurisdiction, unvented room heaters shall not be installed as primary heat sources. Unvented room heaters shall not be permitted in spaces that do not have the required volume of indoor air as defined in Section 701.4.

[HCD 1 & HCD 2] Unvented fuel-burning room heaters shall not be installed, used, maintained, or permitted to exist in a Group R Occupancy.

915.3.1.1 Unvented Room Heaters. Unvented

room heaters shall not be installed in bathrooms or

bedrooms.

Exceptions:

(1) Where approved, one listed wall-mounted unvented room heater equipped with an oxygen depletion safety shutoff system shall be permitted to be installed in a bathroom, provided that the input rating does not exceed 6000 Btu/h (1.76 kW) and combustion and ventilation air is provided as specified in Section 902.2.

(2) Where approved, one listed wall-mounted unvented room heater equipped with an oxygen depletion safety shutoff system shall be permitted to be installed in a bedroom, provided that the input rating does not exceed 10 000 Btu/h (3 kW) and combustion and ventilation air is provided as specified in Section 902.2. [NFPA 54:10.21.2]

(3) Portable oil fired unvented heating appliances used as supplemental heating in storage occupancies, utility occupancies, and in accordance with the fire code.

[HCD 1 & HCD 2] Unvented fuel-burning room heaters shall not be installed, used, maintained, or permitted to exist in a Group R Occupancy.

915.3.2 Installations in Institutions. Room heaters shall not be installed in the following occupancies:

(1) Residential board and care

(2) Health care [NFPA 54:10.21.3] 915.3.3 Clearance. A room heater shall be placed so as not to cause a hazard to walls, floors, curtains, furniture, doors where open, and to the free movements of persons within the room. Heaters designed and marked, “For use in noncombustible fireplace only,” shall not be installed elsewhere. Listed room heaters shall be installed in accordance with their listings and the manufacturer’s installation instructions. In no case shall the clearances be

INSTALLATION OF SPECIFIC APPLIANCES

(1) A listed unit heater shall be installed with clearances from combustible material at the back and one side of not less than 6 inches (152 mm). Where the flue gases are vented horizontally, the 6 inch (152 mm) clearance shall be measured from the draft hood or

vent instead of the rear wall of the unit heater. A unit

heater listed for reduced clearances shall be installed in accordance with its listing and the manufacturer’s installation instructions.

(2) Floor-mounted-type unit heaters installed on combustible floors shall be listed for such installation.

(3) Combustible floors under unlisted floor-mounted unit heaters shall be protected in an approved man ner.

(4) Clearances for servicing shall be in accordance with the manufacturer’s instructions.