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Section 804 Direct-Vent, Integral Vent and Mechanical Draft Systems

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804.1 Direct-Vent Terminations
Vent terminals for direct-vent appliances shall be installed in accordance with the manufacturer's instructions.
804.2 Appliances With Integral Vents
Appliances incorporating integral venting means shall be installed in accordance with their listings and the manufacturer's installation instructions.
804.2.1 Terminal Clearances
Appliances designed for natural draft venting and incorporating integral venting means shall be located so that a minimum clearance of 9 inches (229 mm) is maintained between vent terminals and from any openings through which combustion products enter the building. Appliances using forced draft venting shall be located so that a minimum clearance of 12 inches (305 mm) is maintained between vent terminals and from any openings through which combustion products enter the building.
804.3 Mechanical Draft Systems
Mechanical draft systems of either forced or induced draft design shall be listed and labeled in accordance with UL 378 and shall comply with Sections 804.3.1 through 804.3.8.
804.3.1 Forced Draft Systems
Forced draft systems and all portions of induced draft systems under positive pressure during operation shall be designed and installed so as to be gas tight to prevent leakage of combustion products into a building.
804.3.2 Automatic Shutoff
Power exhausters serving automatically fired appliances shall be electrically connected to each appliance to prevent operation of the appliance when the power exhauster is not in operation.
804.3.3 Termination
The termination of chimneys or vents equipped with power exhausters shall be located not less than 10 feet (3048 mm) from the lot line or from adjacent buildings. The exhaust shall be directed away from the building.
804.3.4 Horizontal Terminations
Horizontal terminations shall comply with the following requirements:
  1. Where located adjacent to walkways, the termination of mechanical draft systems shall be not less than 7 feet (2134 mm) above the level of the walkway.
  2. Vents shall terminate not less than 3 feet (914 mm) above any forced air inlet located within 10 feet (3048 mm).
  3. The vent system shall terminate not less than 4 feet (1219 mm) below, 4 feet (1219 mm) horizontally from or 1 foot (305 mm) above any door, window or gravity air inlet into the building.
  4. The vent termination point shall not be located closer than 3 feet (914 mm) to an interior corner formed by two walls perpendicular to each other.
  5. The vent termination shall not be mounted directly above or within 3 feet (914 mm) horizontally from an oil tank vent or gas meter.
  6. The bottom of the vent termination shall be located not less than 12 inches (305 mm) above finished grade.
804.3.5 Vertical Terminations
Vertical terminations shall comply with the following requirements:
  1. Where located adjacent to walkways, the termination of mechanical draft systems shall be not less than 7 feet (2134 mm) above the level of the walkway.
  2. Vents shall terminate not less than 3 feet (914 mm) above any forced air inlet located within 10 feet (3048 mm) horizontally.
  3. Where the vent termination is located below an adjacent roof structure, the termination point shall be located not less than 3 feet (914 mm) from such structure.
  4. The vent shall terminate not less than 4 feet (1219 mm) below, 4 feet (1219 mm) horizontally from or 1 foot (305 mm) above any door, window or gravity air inlet for the building.
  5. A vent cap shall be installed to prevent rain from entering the vent system.
  6. The vent termination shall be located not less than 3 feet (914 mm) horizontally from any portion of the roof structure.
804.3.6 Exhauster Connections
An appliance vented by natural draft shall not be connected into a vent, chimney or vent connector on the discharge side of a mechanical flue exhauster.
804.3.7 Exhauster Sizing
Mechanical flue exhausters and the vent system served shall be sized and installed in accordance with the manufacturer's installation instructions.
804.3.8 Mechanical Draft Systems for Manually Fired Appliances and Fireplaces
A mechanical draft system shall be permitted to be used with manually fired appliances and fireplaces where such system complies with all of the following requirements:
  1. The mechanical draft device shall be listed and labeled in accordance with UL 378, and shall be installed in accordance with the manufacturer's instructions.
  2. A device shall be installed that produces visible and audible warning upon failure of the mechanical draft device or loss of electrical power, at any time that the mechanical draft device is turned on. This device shall be equipped with a battery backup if it receives power from the building wiring.
  3. A smoke detector shall be installed in the room with the appliance or fireplace. This device shall be equipped with a battery backup if it receives power from the building wiring.

Related Code Sections

804.3 Chimneys and Vents, Mechanical Draft Systems
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804.3 Chimneys and Vents, Mechanical Draft Systems
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804.3 Chimneys and Vents, Mechanical Draft Systems
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Section 804 Chimneys and Vents, Direct-Vent, Integral Vent and Mechanical Draft Systems
Appliances designed for natural draft venting and incorporating integral venting means shall be located so that a minimum clearance of 9 ...