The chimney must have a fire clay flue liner (or equivalent) with a minimum thickness of 5/8” (16mm) and must be installed with refractory mortar. There must be at least ½” (13mm) air space between the flue liner and the chimney wall (Figure 4). An equivalent liner must be a listed chimney liner system or other approved material.
FIGURE 4
A chimney inside the house must have at least 2” (50mm) of clearance to the combustible structure. A chimney outside the house must have at least 1” (25mm) clearance to the combustible structure. Firestops must be installed in the spaces where the chimney passes through floors and/or ceiling (Figure 5).
FIGURE 5
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