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803.8 Vent connector construction.
A vent connector for a nonresidential, low-heat appliance shall be a factory-built chimney section or steel pipe having resistance to heat and corrosion equivalent to that for the appropriate galvanized pipe as specified in Table 803.8. Factory-built chimney sections shall be joined together in accordance with the chimney manufacturers' instructions.
Diameter of Connector (inches) | Minimum Thickness (inches) |
Less than 6 | 0.019 (No. 28 gage) |
6 to less than 10 | 0.023 (No. 26 gage) |
10 to 12 inclusive | 0.029 (No. 24 gage) |
14 to 16 inclusive | 0.034 (No. 22 gage) |
Over 16 | 0.056 (No. 16 gage) |
For SI: 1 inch = 25.4 mm.
803.9 Chimney connector construction.
Chimney connectors for low-heat appliances shall be of sheet steel pipe having resistance to corrosion and heat not less than that of galvanized steel specified in Table 803.9(1). Connectors for medium-heat appliances and high-heat appliances shall be of sheet steel not less than the thickness specified in Table 803.9(2).
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 mm
2
.
803.10 Installation.
Connectors shall be installed in accordance with Sections 803.10.1 through 803.10.6.
803.10.1 Supports and joints.
Connectors shall be supported in an approved manner, and overlapping joints shall be tight-fitting and fastened with sheet metal screws, rivets, welds or other approved means.
803.10.2 Length.
The maximum horizontal length of a single- wall connector shall not affect the capability of the system to produce adequate draft.
803.10.3 Connection.
The connector shall extend to the inner face of the chimney or vent liner, but not beyond. A connector entering a masonry chimney shall be cemented to masonry in an approved manner. Where thimbles are installed to facilitate removal of the connector from the masonry chimney, the thimble shall be permanently cemented in place with high-temperature cement.
803.10.4 Connector pass-through.
Chimney connectors shall not pass through any floor or ceiling, nor through a fire-resistance-rated wall assembly. Chimney connectors shall not pass through walls or partitions constructed of combustible material to reach a chimney or vent, except where such chimney connector complies with Section 803.10.4.1 or 803.10.4.2.
System A (12-inch clearance) | A 3.5-inch-thick brick wall shall be framed into the combustible wall. A 0.625-inch-thick fire-clay liner (ASTM C 315 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 (9-inch clearance) | 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 (6-inch clearance) | A sheet metal (minimum No. 24 gage) ventilated thimble having a minimum thickness of 0.0236 inch (No. 24 gage) having two 1-inch air channels shall be installed. Steel supports shall be cut to maintain a 6-inch clearance with a sheet steel chimney connector 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 (2-inch clearance) | 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/ft
2
• h • °F = 0.144 W/m
2
• °K.
a. Insulation material that is part of the wall pass-through system shall be noncombustible and shall have a thermal conductivity of 1.0 Btu - in/ft
2
• h • °F or less.
b. All clearances and thicknesses are minimums.
c. Materials utilized to seal penetrations for the connector shall be noncombustible.
d. Connectors for all systems except System B shall extend through the wall pass-through system to the inner face of the flue liner.
e. ASTM C 315.
(Am. L.L. 2023/077, 6/11/2023, eff. 6/11/2023)
Editor's note: For related unconsolidated provisions, see Appendix A at L.L. 2023/077.
803.10.4.1 Manufactured insulated chimney connectors.
Manufactured insulated chimney connectors that pass through walls or partitions of combustible construction must comply with the following:
1. The connector is labeled for wall pass-through and is installed in accordance with the manufacturer's instructions; or
2. The connector is put through a device labeled for wall pass-through; or
3. The connector has a diameter not larger than 10 inches (254 mm) and is installed in accordance with one of the methods in Table 803.10.4. Concealed metal parts of the pass-through system in contact with flue gases shall be of stainless steel or equivalent material that resists corrosion, softening or cracking up to 1,800°F (982°C).
(Am. L.L. 2023/077, 6/11/2023, eff. 6/11/2023)
Editor's note: For related unconsolidated provisions, see Appendix A at L.L. 2023/077.
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