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Mobile ViewAIR CONDITIONING & HEAT PUMP SYSTEMS A/C - HEAT PUMP CONTROLS & SWITCHES A/C DATA TAGS A/C - HEAT PUMP CRITICAL DEFECTS A/C DIAGNOSTIC FAQs A/C REFRIGERANTS A/C TYPES, ENERGY SOURCES AGE of AIR CONDITIONERS & HEAT PUMPS AGE of HEATERS, BOILERS, FURNACES AGE of WATER HEATERS AIR CONDITIONER BTU CHART AIR CONDITIONER COMPONENT PARTS AIR CONDITIONER TYPES, ENERGY SOURCES AIR CONDITIONER NOT WORKING AIR FILTERS for HVAC SYSTEMS AIR HANDLER / BLOWER UNITS ANIMAL ALLERGENS / PET DANDER ANIMAL ENTRY POINTS in buildings ANIMAL ODORS IN buildings APPLIANCE EFFICIENCY RATINGS ASBESTOS IDENTIFICATION IN buildings BACKUP HEAT for HEAT PUMPS BLOWER DOORS & AIR INFILTRATION BLOWER FAN CONTINUOUS OPERATION BLOWER FAN OPERATION & TESTING BOOKSTORE - Air Conditioning "How To" Books CAPACITORS for HARD STARTING MOTORS CAPILLARY TUBES CHINESE DRYWALL HAZARDS CIRCUIT BREAKER SIZE for A/C or HEAT PUMP CLEANING & Legionella BACTERIA CHINESE DRYWALL HAZARDS COMBUSTION GASES & PARTICLE HAZARDS COMPRESSOR & CONDENSING COIL, A/C CONDENSATE HANDLING, A/C CLEANING & Legionella BACTERIA DEW POINT TABLE - CONDENSATION POINT GUIDE DIAGNOSE & FIX AIR CONDITIONER / HEAT PUMP DIAGNOSE & FIX HEATING PROBLEMS-BOILER DIAGNOSE & FIX HEATING PROBLEMS-FURNACE DUCT SYSTEM & DUCT DEFECTS AIR FILTERS for HVAC SYSTEMS ALLOY SYSTEMS FLEXDUCT ASBESTOS HVAC DUCTS ASBESTOS PAPER on DUCTWORK ASBESTOS TRANSITE DUCTWORK BALANCING AIR DUCT FLOW DUCT & AIR HANDLER ODORS DUCT DAMAGE, MECHANICAL DUCT INSULATION - Asbestos Paper DUCT ROUTING & SUPPORT DUST CONTAMINATION FROM HVAC? FIBERGLASS DUCT, RIGID CONSTRUCTION FIBERGLASS HVAC DUCTS FIRE DAMPERS in DUCTWORK FLOOD DAMAGE in DUCT WORK GOODMAN GRAY FLEXDUCT INCREASING RETURN AIR LEAKY DUCT CONNECTIONS LOCATION OF REGISTERS & DUCTS MOLD in AIR HANDLERS & DUCT WORK NOISES in DUCT SYSTEM ODORS in AIR HANDLERS & DUCT WORK OWENS CORNING FLEXDUCT OWL FLEXDUCT RETURN AIR REGISTERS & DUCTS SOUNDPROOFING for DUCTWORK SUPPLY DUCTS & REGISTERS TRANSITE PIPE AIR DUCTS UNDERSIZED RETURN DUCTS UNSAFE DUCT OPENINGS VIBRATION DAMPENERS WATER & ICE IN DUCT WORK WET CORRODED DUCT WORK ZONE DAMPER CONTROLS DUST CONTAMINATION FROM HVAC? EDUCATION, HVAC SCHOOLS ELECTRIC MOTOR DIAGNOSTIC GUIDE ELECTRIC MOTOR OVERLOAD RESET SWITCH ELECTRICAL POWER SWITCH FOR HEAT ENERGY SAVINGS in buildings EVAPORATIVE COOLING SYSTEMS EVAPORATOR COIL or COOLING COIL EXPANSION VALVES, REFRIGERANT FAN, AIR HANDLER BLOWER UNIT FAN AUTO ON Thermostat Switch FAN, COMPRESSOR/CONDENSER UNIT FAN CONVECTOR HEATERS - HYDRONIC COILS FAN LIMIT SWITCH FAN NOISES FURNACES WARM AIR HEATING SYSTEMS GASES, EXPOSURE, TESTING Carbon Dioxide - CO2 Carbon Monoxide - CO METHANE GAS SOURCES GAS MEASUREMENT TOOLS GAUGE, REFRIGERATION PRESSURE TEST HEAT LOSS (or GAIN) in buildings HEAT LOSS (or GAIN) INDICATORS HEAT LOSS R U & K VALUE CALCULATION HEAT PUMPS HEATING SMALL LOADS HOUSEWRAP AIR & VAPOR BARRIERS HUMIDITY LEVEL TARGET INDOOR AIR QUALITY IMPROVEMENT GUIDE INSPECTION CHECKLIST - OUTDOOR UNIT INSPECTION LIMITATIONS LEED GREEN BUILDING CERTIFICATION LOST COOLING CAPACITY MANUALS & PARTS GUIDES - HVAC MOTOR OVERLOAD RESET SWITCH MOLD in AIR HANDLERS & DUCT WORK ODORS in AIR HANDLERS & DUCT WORK OPERATING COST OPERATING DEFECTS OPERATING TEMPERATURES NOISY AIR CONDITIONER / HEAT PUMP NOISE / SOUND DIAGNOSIS & CURE Air Leak Noises AIR CONDITIONING & HEAT PUMP NOISES PORTABLE ROOM AIR CONDITIONERS PRESSURE READINGS, REFRIGERANT REPAIR GUIDE, AIR CONDITIONERS / HEAT PUMPS REPAIR & DIAGNOSTIC FAQs for A/C REFRIGERANTS GAUGE, REFRIGERATION PRESSURE TEST REFRIGERANT CHARGING PROCEDURE REFRIGERANT DRIERS & FILTERS REFRIGERANT PIPING & DISTANCES REFRIGERANT PRESSURE READINGS RETROFIT SIZING for A/C or HEAT PUMPS SEER RATINGS & OTHER DEFINITIONS SOLAR ENERGY SYSTEMS SPLIT SYSTEM AIR CONDITIONERS & HEAT PUMPS SWAMP COOLERS SYSTEM OPERATION THERMOSTATS, HEATING / COOLING THERMOSTATIC EXPANSION VALVES WATER COOLED AIR CONDITIONERS More Information |
This article explains Owl brand gray flex duct disintegration as an example of defective heating or cooling ductwork materials. Photo of deteriorated Owl brand gray flex duct and the suggestion of possible UV degradation of flex duct (in addition to heat) are courtesy of Florida home inspector Eric Van De Ven who has reported on several homes with badly-deteriorated flexduct. We include references to product failures by manufacturers of similar flexible duct work products. Readers concerned with deteriorating plastic and fiberglass-covered flex duct in buildings should see these duct failure reports: ALLOY SYSTEMS FLEXDUCT, and GOODMAN GRAY FLEXDUCT, and OWENS CORNING FLEXDUCT and OWL FLEXDUCT. Also see our more broad category: DUCT SYSTEM DEFECTS. © 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. OWL FLEX DUCT - Deterioration - Caused by UV Light Exposure?Air conditioning duct system defects include a remarkably wide range of errors, from failure to supply cool air or failure to even circulate air in the building, to health hazards such as use of asbestos material in or on duct work, to very dangerous conditions such as drawing heating equipment combustion gases into the building cooling (or heating) air. This article explains Owl brand gray plastic-covered flex duct failures that appear as loss of the gray plastic duct covering due to brittleness that appears to be caused by exposure to heat (such as in a hot attic), with references to product failures by several manufacturers of flexible duct work, including Alloy Systems™, Goodman™ flex duct, Owens Corning™ flex duct, Owl™ flex duct. We believe that none of these defective flex duct products is currently sold (2010) but both may be found in older homes. Note: not all Owens Corning flex duct products share this defect and disintegration problem. How to Identify Owl-Flex Gray Flexduct in buildings
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The loss of the protective plastic covering on flex duct poses several concerns including loss of the duct insulation, increased air conditioning system operating costs, and possibly air leaks out (if supply ducts are damaged) or un-wanted attic debris leaks in (if return ducts are damaged), and in-duct condensation in the HVAC system leading to mold and indoor air quality concerns.
Discussing the page top photograph of badly-deteriorated Owl-Flex duct, Mr. Van De Ven had an interesting observation:
I did an inspection yesterday and found some of the Owl-Flex duct work. The interesting thing that the most damaged portions were located near a window, that someone thoughtfully installed in the attic.
Because we argue that if we completely understood any building failure, there would be no coincidences, we speculate that in addition to the role of of high attic temperatures in some gray flex-duct deterioration, the window cited by Mr. Van De Ven may have provided added light and possibly some UV (depending on glass type) and certainly some additional sunlight-generated heat that helped explain why the flex duct was most-deteriorated where light from the window was shining on it.
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The photo at above-right, also taken in the same building by Eric Van De Ven shows the brand name on ductwork installed in the building. The photo at above-left identifies the deteriorated duct shown in our page top photo. Owl-flex flexible ductwork has been the subject of litigation, as shown in this flex duct lawsuit document filed in 2009. As with the Goodman flex-duct problem described at GOODMAN GRAY FLEXDUCT, and also at in hot attic spaces or where exposed to UV light, the Owl-Flex flexible air conditioning duct material disintegrates leaving its fiberglass insulation exposed to also disintegrate, leak, or possibly blow into the building living space. Does Exposure to a Nearby UV Light Also Cause Gray Flex Duct Damage?Two common sources of deterioration in plastics are heat and UV light. |
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According to General Electric, a manufacturer of fluorescent light bulbs,
But bringing up the sun does not address the impact of UV on thin plastic covering flexible ductwork. UV absorption and polymer degradation occurs when polymers such as polypropylene and polyethylene absorb UV light causing weakening of molecular bonds at weak points in the polymer chain. So since many polymers are degraded by exposure to UV light, and therefore many plastics are damaged and made brittle by UV light, the close proximity to the bulb is a very strong suggestion. |
Heat is also a factor in plastic degradation, which may explain why more of the Goodman, Owens Corning, Or Owl type gray flex duct deterioration was in (hot) attics. Wikipedia: "Polymers are susceptible to attack by atmospheric oxygen, especially at elevated temperatures encountered during processing to shape." Presumably also in a hot attic heat is a well understood factor in plastic deterioration such as plastic covering flexduct.
A UV light also gives off some heat, though usually less than a typical incandescent bulb. So heat from a UV light very close to the plastic duct cover may also be a factor in deterioration.
The hypothesis that gray flex duct deterioration close to a fluorescent bulb is strengthened if the damage was less or absent on the same material where it was more distant from or not exposed at all to the UV light from the bulb, but where otherwise it was of the same age in the same general building conditions (such as exposure to temperatures).
Replacement of the heating or air conditioning flexible sections of duct work is required - a significant expense which will be greater if flex-duct needs to be replaced where it passes through inaccessible areas such as finished walls or ceilings.
Notice that not all flex-duct products will fail in this manner and unless you specifically find evidence of this deterioration, replacement of the flex-duct in a building may not be warranted. Where this duct is found in a building it should be replaced.
Below at Technical Reviewers & References we include Flexible Air Duct Installation Manuals, standards, guidelines, and contact information for several flexible air duct manufacturers as well as access to Flexible Duct Performance & Installation Standards provided by the Air Diffusion Council.
Readers concerned with deteriorating plastic and fiberglass-covered flex duct in buildings should see these duct failure reports: ALLOY SYSTEMS FLEXDUCT, and GOODMAN GRAY FLEXDUCT, and OWENS CORNING FLEXDUCT and OWL FLEXDUCT. Also see our more broad category: DUCT SYSTEM DEFECTS.
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AIR CONDITIONING & HEAT PUMP SYSTEMS
AIR CONDITIONER COMPONENT PARTS
A/C - HEAT PUMP CONTROLS & SWITCHES
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CLEANING & Legionella BACTERIA
CHINESE DRYWALL HAZARDS
COMBUSTION GASES & PARTICLE HAZARDS
COMPRESSOR & CONDENSING COIL, A/C
CONDENSATE HANDLING, A/C
BACKUP HEAT for HEAT PUMPS
BLOWER DOORS & AIR INFILTRATION
BLOWER FAN CONTINUOUS OPERATION
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BOOKSTORE - Air Conditioning "How To" Books
CAPACITORS for HARD STARTING MOTORS
CAPILLARY TUBES
CHINESE DRYWALL HAZARDS
CIRCUIT BREAKER SIZE for A/C or HEAT PUMP
CLEANING & Legionella BACTERIA
DEW POINT TABLE - CONDENSATION POINT GUIDE
DIAGNOSE & FIX AIR CONDITIONER / HEAT PUMP
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DIAGNOSE & FIX HEATING PROBLEMS-FURNACE
DUCT SYSTEM & DUCT DEFECTS
AIR FILTERS for HVAC SYSTEMS
ALLOY SYSTEMS FLEXDUCT
ASBESTOS HVAC DUCTS
ASBESTOS PAPER on DUCTWORK
ASBESTOS TRANSITE DUCTWORK
BALANCING AIR DUCT FLOW
DUCT & AIR HANDLER ODORS
DUCT DAMAGE, MECHANICAL
DUCT INSULATION - Asbestos Paper
DUCT ROUTING & SUPPORT
DUST CONTAMINATION FROM HVAC?
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FIBERGLASS HVAC DUCTS
FIRE DAMPERS in DUCTWORK
FLOOD DAMAGE in DUCT WORK
GOODMAN GRAY FLEXDUCT
INCREASING RETURN AIR
LEAKY DUCT CONNECTIONS
LOCATION OF REGISTERS & DUCTS
MOLD in AIR HANDLERS & DUCT WORK
NOISES in DUCT SYSTEM
ODORS in AIR HANDLERS & DUCT WORK
OWENS CORNING FLEXDUCT
OWL FLEXDUCT
RETURN AIR REGISTERS & DUCTS
SOUNDPROOFING for DUCTWORK
SUPPLY DUCTS & REGISTERS
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UNDERSIZED RETURN DUCTS
UNSAFE DUCT OPENINGS
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ENERGY SAVINGS in buildings
EVAPORATOR COIL or COOLING COIL
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