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, unless otherwise approved by the commissioner. The exhaust shall be directed vertically away from the building.

804.3.4 Horizontal terminations.

Horizontal terminations and discharges, including any horizontal direct vent terminations subject to Section 804.1 and horizontal integral vent terminals subject to Section 804.2, shall not be permitted, unless otherwise authorized by the commissioner.

804.3.5 Vertical terminations.

Vertical terminations and discharges shall comply with Section 801.21.

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 or power exhauster.