Every fuel-burning appliance shall discharge the products of combustion to a vent, factory-built chimney or masonry chimney, except for appliances vented in accordance with Section 804. The chimney or vent shall be designed for the type of appliance being vented.
Masonry chimney flues shall be provided with a cleanout opening having a minimum height of 6 inches (152 mm). The upper edge of the opening shall be located not less than 6 inches (152 mm) below the lowest chimney inlet opening. The cleanout shall be provided with a tight-fitting, noncombustible cover.
Exception: Masonry chimneys without the required airspace clearances shall be permitted to be used if lined or relined with a chimney lining system listed for use in chimneys with reduced clearances in accordance with UL 1777. The chimney clearance shall be not less than permitted by the terms of the chimney liner listing and the manufacturer's instructions.
The application of vents shall be in accordance with Table 802.2.
|VENT TYPES||APPLIANCE TYPES|
|Type L oil vents||Oil-burning appliances listed and labeled for venting with Type L vents; gas appliances listed and labeled for venting with Type B vents.|
|Pellet vents||Pellet fuel-burning appliances listed and labeled for venting with pellet vents.|
|DIAMETER OF CONNECTOR (inches)||MINIMUM NOMINAL THICKNESS (galvanized) (inches)|
|5 and smaller||0.022 (No. 26 gage)|
|Larger than 5 and up to 10||0.028 (No. 24 gage)|
|Larger than 10 and up to 16||0.034 (No. 22 gage)|
|Larger than 16||0.064 (No. 16 gage)|
For SI: 1 inch = 25.4 mm.
|AREA (square inches)||EQUIVALENT ROUND DIAMETER (inches)||MINIMUM THICKNESS (inches)|
|0—154||0—14||0.0575 (No. 16 gage)|
|155—201||15—16||0.075 (No. 14 gage)|
|202—254||17—18||0.0994 (No. 12 gage)|
|Greater than 254||Greater than 18||0.1292 (No. 10 gage)|
For SI: 1 inch = 25.4 mm, 1 square inch = 645.16 mm2.
|System A |
|A 3.5-inch-thick brick wall shall be framed into the combustible wall. An 0.625-inch-thick fire-clay liner (ASTM C315 or equivalent)e shall be firmly cemented in the center of the brick wall maintaining a 12-inch clearance to combustibles. The clay liner shall run from the outer surface of the bricks to the inner surface of the chimney liner.|
|System B |
|A labeled solid-insulated factory-built chimney section (1-inch insulation) the same inside diameter as the connector shall be utilized. Sheet steel supports cut to maintain a 9-inch clearance to combustibles shall be fastened to the wall surface and to the chimney section. Fasteners shall not penetrate the chimney flue liner. The chimney length shall be flush with the masonry chimney liner and sealed to the masonry with water-insoluble refractory cement. Chimney manufacturers' parts shall be utilized to securely fasten the chimney connector to the chimney section.|
|System C |
|A steel ventilated thimble having a minimum thickness of 0.0236 inch (No. 24 gage) having two 1-inch air channels shall be installed with a steel chimney connector. Steel supports shall be cut to maintain a 6-inch clearance between the thimble and combustibles. The chimney connector and steel supports shall have a minimum thickness of 0.0236 inch (No. 24 gage). One side of the support shall be fastened to the wall on all sides. Glass-fiber insulation shall fill the 6-inch space between the thimble and the supports.|
|System D |
|A labeled solid-insulated factory-built chimney section (1-inch insulation) with a diameter 2 inches larger than the chimney connector shall be installed with a steel chimney connector having a minimum thickness of 0.0236 inch (No. 24 gage). Sheet steel supports shall be positioned to maintain a 2-inch clearance to combustibles and to hold the chimney connector to ensure that a 1-inch airspace surrounds the chimney connector through the chimney section. The steel support shall be fastened to the wall on all sides and the chimney section shall be fastened to the supports. Fasteners shall not penetrate the liner of the chimney section.|
For SI: 1 inch = 25.4 mm, 1.0 Btu • in/ft2• h • °F = 0.144 W/m2• K.
Connectors shall have a minimum clearance to combustibles in accordance with Table 803.10.6. The clearances specified in Table 803.10.6 apply, except where the listing and labeling of an appliance specifies a different clearance, in which case the labeled clearance shall apply. The clearance to combustibles for connectors shall be reduced only in accordance with Section 308.
CONNECTOR CLEARANCES TO COMBUSTIBLES
|TYPE OF APPLIANCE||MINIMUM CLEARANCE (inches)|
|Chimney and vent connectors|
Electric and oil incinerators
|Commercial, industrial-type appliances|
Oil unit heaters
Other low-heat industrial appliances
|High-heat appliances||(As determined by the code official)|
|Masonry or metal connectors|
For SI: 1 inch = 25.4 mm.
Chimneys for use with open combustion chamber appliances installed in buildings other than dwelling units shall comply with the requirements of UL 103 and shall be marked "Building Heating Appliance Chimney" or "Residential Type and Building Heating Appliance Chimney."