NOTE: Where the exhaust duct passes through a wall, ceiling, or roof made of combustible materials, the opening must be
To protect the outside end of the horizontal duct work from the weather, a 90º elbow bent downward should be installed where the exhaust exits the building. If the exhaust duct work travels vertically up through the roof, it should be protected from the weather by using a 180º turn to point the opening downward. In either case, allow at least twice the diameter of the duct between the duct opening and nearest obstruction.
IMPORTANT: DO NOT use screens or caps on the outside opening of exhaust duct work.
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