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 Mobile ViewCHIMNEY INSPECTION DIAGNOSIS REPAIR Abandoned Chimneys - Indoor Inspection Abandoned Chimneys: Outdoors Angled Chimney Flues Attic Chimney Inspection BACKDRAFTING HEATING EQUIPMENT BAROMETRIC DAMPERS Blocked Chimney Flues Bracket Chimney Collapse & Fire Risks B-Vent Chimneys B-Vent Clearances Table CARBON DIOXIDE - CO2 CARBON MONOXIDE - CO CHIMNEY INSPECTION & REPAIR GUIDE Chimney Cap & Crown Inspection CHIMNEY CHASE Construction & Defects Chimney Cleaning Advice, Procedures Chimney Cleaning Fraud Warning Chimney Cleanout Doors Chimney Components Definitions Chimney Crack & Collapse Risks, Repairs Chimney Crack Detection & Diagnosis Chimney Draft & Performance CHIMNEY FIRE ACTION / PREVENTION Chimney Flashing Mistakes & Leaks CHIMNEY HEIGHT & CLEARANCE CODE Chimney Height Extensions Chimney Inspection Checklist Chimney Inspection: Flue Interiors ChimScan: Inspecting Flues by Cameras Chimney Inspection Indoor Procedures Chimney Inspection Outdoors From Ground Chimney Inspection Outdoors at Rooftop Chimney Leaning, Separation, Movement Chimney Repair Fraud Warning Chimney Repair Methods Chimney Safety - CPSC Alert Chimney Shoulder Leaks Chimney Spalling, Exterior Chimney Sweeps Chimney Types & Materials Device Categories vs. Chimney Requirements Double-Wall Metal, Type B & Type L Chimneys Draft Hood Appliances Factory Built Chimneys High Efficiency Heating Appliances High Temperature Plastic Chimneys & Vents Masonry & Clay Tile Chimneys Mid-Efficiency Heating Appliances New Vent Requirements Single-Wall Metal Pipe Chimneys Vents Three-Sided Chimneys: Problems Transite Pipe Chimneys & Flues CO2 TOXICITY COALSTOVE SAFETY COMBUSTION AIR DEFECTS COMBUSTION AIR for TIGHT buildings COMBUSTION GASES & PARTICLE HAZARDS COMBUSTION PRODUCTS & IAQ COMPLETE COMBUSTION, Stoichiometric CREOSOTE FIRE HAZARDS Dead End Chimney Flue Hazards Definitions of Chimney Types & Parts DIRECT VENTS / SIDE WALL VENTS DRAFT HOODS - gas fired DRAFT MEASUREMENT, CHIMNEYS & FLUES DRAFT REGULATORS, DAMPERS, BOOSTERS EFFLORESCENCE, Salts & White / Brown Deposits EMERGENCY RESPONSE, IAQ, GAS, MOLD FIRE CLEARANCES INDOORS Fire Clearances for Masonry Chimneys Fire Clearances for Metal Chimneys FIRE CLEARANCES, Single-Wall Metal Flues Fire Clearance Wood & Coal Stove Flues CHIMNEY HEIGHT & CLEARANCE CODE Reduction in Fire Clearance - Heat Shields Single Wall Metal Flues - Oil fired heaters Single Wall Metal Pipe Flues - Gas heaters Wood & Coal Stove Flues Fire Clearance Safety Hazards, other FIREPLACES & HEARTHS Fire stopping at Chimney Passage Through Floors FLAME COLOR, BLUE vs YELLOW COMBUSTION FLUE SIZE SPECIFICATIONS Flue Separation Requirements Flue Tile Damage in Chimneys Flue Vent Connectors - Boilers, Furnaces Blocked Chimney at the Flue Vent Connector Dead End Chimney Flue Hazards Extended Too Far into Chimney Joint Connections - Single Wall Metal Flues Length Limits for a Flue Vent Connector Loose, Leaky, Not Sealed, Flue Vent Connector Plastic Heater Vents Plastic Vents Goodman HTPV Recall Rusted Metal Flue Vent Connectors Slope, Proper Flue Vent Connector Fuel Changes for Heating ApplianceS HEATING COST FUEL & BTU Cost Table HEATING INSPECTIONS HOME HEATING SAFETY HEATING SYSTEMS INDOOR AIR EMERGENCY RESPONSE Lennox SAFETY WARNING Metal Chimneys & Flues Bracing for Metal Chimneys Class A Chimneys, MetalBestos™ Connecting Metal Chimney Sections Continuous metal chimneys Definitions of Chimney Types & Parts Fire Clearances for Metal Chimneys Height required for L Vents & B Vents Indoor Hazards, Metal Chimney & Vent Manufactured Chimneys Offset from Vertical in Chimneys, excessive Replacement Components for Metal Chimneys Single-Wall Metal Vents & Chimneys Super Chimneys, 629 Chimneys Triple-Wall Metal Fireplace Chimneys Type B-Vents Type L Vents Wet time & Corrosion in Chimneys, Vents Wood Framed Chimney Chases Moisture / Frost Damaged Chimney Nanomaterials Hazards NOISE / SOUND DIAGNOSIS & CURE ODORS & SMELLS DIAGNOSIS & CURE ODORS FROM HEATING SYSTEMS OIL HEAT SAFETY INSPECTIONS PLASTIC HEATER VENTS Safety Recalls, Chimneys, Vents, Heaters Shared Chimney & Shared Flue Hazards STAIN DIAGNOSIS on BUILDING EXTERIORS STAINS on/near CHIMNEYS Three-Sided Chimneys: Problems Transite Pipe Chimneys & FlueS UNLINED FLUE INSPECTIONS WOOD, COAL STOVES & FIREPLACES WOOD STOVE SAFETY More Information |
This article describes how to select, install, and inspect Class-A insulated metal chimneys such as the Insulated Double Wall MetalBestos™ manufactured metal chimney, also called a zero clearance chimney. These articles on chimneys 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. InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers nor with topics or services discussed at this website.© Copyright 2012 InspectAPedia.com, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use page top links to major topics or use links at the left of each page to navigate within topics and documents at this website. Green links show where you are in a document series or at this website. Class A Chimneys - Insulated Double Wall MetalBestos™ type
Improper metal chimney installation: As you can see from our photo ( above left), even this superb product can be reduced to shambles when installed by an idiot. The chimney in this photo was not supported, is falling and is unsafe. See Chimney Collapse Hazards & Chimney Support & Bracing Requirements. This unfortunate collapsing Class-A type metal chimney was the replacement for the abandoned masonry chimney under the corrugated metal roof we show at Chimneys Abandoned Outdoors and that whose remains we showed at Chimneys Abandoned Indoors. It looks as if more than one generation of inexpert chimney installers worked in Dover, NY. Our photo at above right shows an end view of a section of Metalbestos SS All Fuel Chimney™. The fiberglass insulation is not part of the product and was just left stuffed in that opening.
Class A Chimney Height RequirementsMore complete details about chimney height requirements on buildings including Class A Chimneys is at CHIMNEY HEIGHT & CLEARANCE CODE Class A Chimney Fire Clearance DetailsMore complete details about Class-A chimney fire clearances indoors can be read at Fire Clearances for Metal Chimneys Should an Insulated or "Air Cooled" Metal Chimney Be Replaced After a Chimney Fire has Occurred?Question: What Kind of Inspection Is Required After a Metal Chimney Fire?I was looking for information on chimney fires, specifically, on how to inspect double wall pipe after such an event. The outside of the outer pipe had paper stickers on it that were not burnt or discolored, so I am assuming the pipe did its job. However the top of the chimney run did catch on fire, presumably from the heat generated from the chimney fire. Anyway, I was looking for a category on how to inspect double wall pipe after a fire. - K.M. Reply: Inspect for visible flue damage, color changes, movement, cracks; but to be safe: in our opinion you should replace the chimneyAfter a chimney fire (such as from igniting creosote in a metal flue), a competent onsite chimney inspection by an expert usually finds additional clues that help accurately diagnose a problem. That said, we add the following opinion: In sum: in our opinion after a chimney fire in an insulated metal chimney or an air-insulated metal chimney the chimney should be replaced entirely in order to be safe and to assure that maximum fire protection for the building is maintained. In addition you should inspect for heat or fire damage to surrounding building components. Details follow. Some chimney repair companies and building codes cite that "metal chimneys must be inspected after a fire for possible need for replacement". We speculate that the chimney inspector will look for deformed, cracked, metal components, movement, color changes in the stainless steel, or signs of overheating or damage to surrounding building components. If the metal chimney liner and metal exterior of a multi-wall insulated metal chimney are undamaged, one might think that the internal chimney insulation of a multi-wall insulated metal chimney or flue was intact. But that may not be true. In addition there may be subtle damage to surrounding building components such as pyrolysis (discussed at Fire stopping at Chimney Passage Through Floors) that could lower the combustion point and increase the risk of a future fire in nearby wood materials. Some sources point out that
We have observed steel flues that turned blue and also black after a fire. A "be safe" approach requires that insulated chimneys are replaced after a fire. We believe that this makes sense because because during a chimney fire the internal temperatures can be extremely high and thus can damage the flue in both obvious and less obvious ways that may not be visible and no one wants to take a chance. Furthermore, the "after 900 degrees" rule is impractical: - who is actually measuring chimney temperature during a fire? The 900 degF number in our OPINION is not helpful. Most chimney sources point out that it's common for a chimney fire to reach 2000 degF! Who wants to risk an unsafe flue after a fire when a new fire could still occur and could meet less protection. A similar example is with earthquake-resistant construction: the construction is designed to keep the building from collapsing and killing the occupants, but it is not expected to prevent any damage whatsoever to the building. So after a quake repairs are going to be needed. CONTACT us with suggestions for this topic. Chimney Safety References:
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