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CHIMNEY INSPECTION DIAGNOSIS REPAIR
BACKDRAFTING HEATING EQUIPMENT
CARBON MONOXIDE - CO
CHIMNEY COMPONENT DEFINITIONS
CHIMNEY FIRE ACTION / PREVENTION
COMBUSTION GASES & PARTICLE HAZARDS
COMBUSTION PRODUCTS & IAQ
FLAME COLOR, BLUE vs YELLOW COMBUSTION
HEATING SYSTEM INSPECTION
HOME HEATING SAFETY
ODORS & SMELLS DIAGNOSIS & CURE
SAFETY RECALLS CHIMNEYS VENTS HEATERS
STAIN DIAGNOSIS on BUILDING EXTERIORS
WOOD, COAL STOVES & FIREPLACES
WOOD STOVE SAFETY
Chimney construction: fire stopping. This article describes the basic requirement for fire stopping needed where building chimneys or flues pass through building floors. Fire stopping is a measure taken to slow the spread of fire between building floors - an event that could occur at openings cut to permit a chimney to pass through from one floor to another.
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Sketches courtesy of Carson Dunlop. Readers of this article should also see FIRE CLEARANCES for MASONRY CHIMNEYS and FIRE CLEARANCES, METAL CHIMNEYS as well as FIRE CLEARANCES, SINGLE-WALL METAL FLUES. This article series on chimneys, chimney construction, and chimney safety provide detailed suggestions describing how to perform a thorough visual inspection of chimneys for safety and other defects. Chimney inspection methods and chimney repair methods are also discussed.
Chimneys that pass through several floor levels of a home may be required to be fire stopped at each penetration. Typical fire stops are sheet metal or fire code sheetrock.Carson Dunlop's sketch shows fire stopping at the fire-clearance gap provided between the chimney and wood floor framing (above left) and fire stopping around a metal chimney as it passes through building floors (above right).
The reason that building codes specify a healthy distance between wood materials (or other combustibles) and flue vent connectors is not just that the heat from the flue will immediately set the wood on fire. Rather it is also that wood that has been heated over time, even to the relatively low temperature of 200 to 300F, will be chemically affected to become more readily combustible.
Details are at PYROLYSIS EXPLAINED - separate article
Frequently Asked Questions (FAQs) about fire stopping requirements in building walls, stairways, chimney chases etc.
Questions & answers or comments about fire stopping in buildings where chimneys pass through floors.
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