Mechanical Considerations

HVAC Appliances
The installation of all HVAC appliances shall conform to the conditions of their label and the manufacturer’s installation instructions. The manufacturer’s installation and operating instructions shall remain attached to the appliances.

Equipment Located In Garages
  • Appliances that generate a glow, spark or flame capable of igniting flammable vapors and located in a garage shall be installed with the burners, burner ignition devices or heating elements and switches at least 18 inches above the floor level.
  • These appliances shall have combustion air taken from and the products of combustion discharged to, the exterior of the garage.
  • Doors from garage to living area shall be solid core wood minimum 1-3/8-inch or steel door with a minimum 20-minute fire rating with a self-closing device.
  • Doors on furnace rooms that open into the garage shall have a threshold or a sweep.
Equipment Located In Attic or Crawl Spaces
Attics containing appliances requiring access shall be provided with an opening and a clear and unobstructed passageway large enough to allow removal of the largest appliance, but not less than 30 inches high and 22 inches wide, and not more than 20 feet in length when measured along the center-line of the passageway from the opening to the appliance. The passageway shall have continuous solid flooring in accordance with Chapter 5 not less than 24 inches wide. A level service space at least 30 inches deep and 30 inches wide shall be present along all sides of the appliance where access is required. The clear access opening dimensions shall be a minimum of 20 inches by 30 inches, where such dimensions are large enough to allow removal of the largest appliance.

The exception to these requirements is when the passageway and level service space are not required where the appliance is capable of being serviced and removed through the required opening. A permanent electric outlet and lighting fixture shall be provided near the equipment that shall be controlled by a switch located at the passageway opening.

Appliance and Gas Connection
  • Gas appliances and equipment shall be connected by rigid pipe, tubing or flexible connectors. A union shall be installed between the appliance and the appliance shut-off valve.
  • Appliance connection every gas outlet shall have an individual shut off valve.
  • Gas outlets located in fireplaces shall be controlled by labeled valves located in the same room outside the hearth and not more than 4 feet from the outlets.
  • The hearth and the hearth extension shall extend a minimum of 36 inches from the back of the firebox to the end of the hearth extension.
  • The hearth extension shall extend at least 16 inches in front of and at least 8 inches beyond each side of the fireplace opening.
Chimneys and Vents
  • Termination chimneys shall extend at least 2 feet higher than any portion of the building within 10 feet, but shall not be less than 3 feet.
  • The horizontal run of an un-insulated connector to a natural draft chimney shall not exceed 75% of the height of the vertical portion of the chimney above the connector. The horizontal run shall not be less than 45 degrees. Insulated connectors are not to exceed 100% of the vertical portion.
Combustion Air
  • Volume of space where furnace is located must be greater than 50 cubic feet per 1,000 BTU/h.
  • If space does not meet requirements, two openings (one within 12 inches of the floor) are required. Each will have an area equal to 1 square inch for each 1,000 BTU/h.