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Chimney connectors shall not pass through any floor or ceiling, nor through a fire-resistance-rated wall assembly. Chimney connectors for domestic-type appliances shall not pass through walls or partitions constructed of combustible material to reach a masonry chimney unless:
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 identified in Table 18-28-803.10.4. Concealed metal parts of the pass-through system in contact with flue gases shall be made of stainless steel or equivalent material that resists corrosion, softening or cracking up to 1,800°F (980°C).
System A (12-inch clearance) | A 3 1/2-inch-thick brick wall shall be framed into the combustible wall. A 5/8-inch-thick fire-clay liner (ASTM C 315 or equivalent)
c 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 metal 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 manufacturer's parts shall be utilized to fasten securely the chimney connector to the chimney section. |
System C (6-inch clearance) | A sheet metal (minimum No. 24 Gauge) ventilated thimble having two 2-inch air channels shall be installed with a sheet steel chimney connector (minimum No. 24 Gauge). Sheet steel supports (minimum No 24 Gauge) shall be cut to maintain a 6-inch clearance between the thimble and combustibles. 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 sheet steel chimney connector (minimum No. 24 Gauge). Sheet metal supports shall be positioned to maintained 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 shall not penetrate the liner of the chimney section. |
For SI: 1 inch = 25.4 mm.
a Insulation material that is part of the wall pass-through system shall be non-combustible and have a thermal conductivity of 1.0 Btu x in/ft
2
x h x °F or less.
b All clearances and thicknesses are minimums.
c Materials utilized to seat 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.
ASTM C 315.