802.7.3 Installation With Appliances Permitted by Section 802.4
TABLE 802.7.3.3 CLEARANCE FOR CONNECTORS*
[NFPA 54: TABLE 22.214.171.124]
|MINIMUM DISTANCE FROM COMBUSTIBLE MATERIAL (inches)|
|APPLIANCE||LISTED TYPE B GAS VENT MATERIAL||LISTED TYPE L VENT MATERIAL||SINGLE-WALL METAL PIPE||FACTORY-BUILT CHIMNEY SECTIONS|
|Listed appliance with draft hoods and appliance listed for use with Type B gas vents||As listed||As listed||6||As listed|
|Residential boilers and furnaces with listed gas conversion burner and with draft hood||6||6||9||As listed|
|Residential appliances listed for use with Type L vents||Not permitted||As listed||9||As listed|
|Listed gas-fired toilets||Not permitted||As listed||As listed||As listed|
|Unlisted residential appliances with draft hood||Not permitted||6||9||As listed|
|Residential and low-heat appliance other than those above||Not permitted||9||18||As listed|
|Medium-heat appliance||Not permitted||Not permitted||36||As listed|
For SI units: 1 inch = 25.4 mm
- For listed appliances with draft hoods and appliances listed for use with Type B gas vents, the thimble shall be a minimum of 4 inches (102 mm) larger in diameter than the metal pipe. Where there is a run of not less than 6 feet (1829 mm) of metal pipe in the opening between the draft hood outlet and the thimble, the thimble shall be a minimum of 2 inches (51 mm) larger in diameter than the metal pipe.
- For unlisted appliances having draft hoods, the thimble shall be a minimum of 6 inches (152 mm) larger in diameter than the metal pipe.
- For residential and low-heat appliances, the thimble shall be a minimum of 12 inches (305 mm) larger in diameter than the metal pipe.
Exception: In lieu of thimble protection, combustible material in the wall shall be removed a sufficient distance from the metal pipe to provide the specified clearance from such metal pipe to combustible material. Any material used to close up such opening shall be noncombustible. [NFPA 54:126.96.36.199]