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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.
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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 ATCO™ Ruber Products, 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 (2013) but both may be found in older homes. Note: not all Owens Corning flex duct products share this defect and disintegration problem.
A Little Owl-Flex Patent History
Owl-Flex gray plastic-covered insulated flex-duct was patented in 1971, US Patent No. 3,606,404, as a "duct to register connection" by John L. McGann and assigned to Intertherm, Inc. in St. Louis MO. Related patents were cited dating back to 1930. Intertherm, Inc. is a company whose roots date to 1919 (http://www.intertherm.net/). The company today specializes in providing HVAC systems for manufatured homes.
Intertherm can be contacted at Intertherm Heating and Cooling Customer Service, 8000 Phoenix Parkway, O'Fallon, MO 63368 but we doubt that the modern company nor its parent company Nordyne accepts responsibility for Owl-Flex duct system failures. Intertherm Inc. (the modern company) is a subsidiary of Nordyne Corp. (http://www.nordyne.com/) who currently holds an extensive range of name brands in HVAC and other equipment and systems.
How to Identify Owl-Flex Gray Flexduct in buildings
Eric Van De Ven shows in the photos below, Owl-Flex is identified by both text and a logo on the duct exterior.
What is the Problem with Owl-Flex and Some Other Flex Duct Insulation Products?
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:
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.
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.
UV Light as a Source of Gray Flex Duct Deterioration
Really? A fluorescent bulb contains low pressure mercury vapor, a gas that produces invisible ultraviolet light (UV radiation) when the gas is excited by electricity. Phosphorescent coating on the inside of the fluorescent light tube absorbs the UV radiation and converts it to visible light.
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 as a Source of Deterioration of Gray Plastic Covered Flex Ductwork
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).
When a flex-duct product has lost its exterior plastic covering the effects are these:
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.
List of plastic-covered flexible HVAC duct products that appear to deteriorate in hot spaces like attics
Readers concerned with deteriorating plastic and fiberglass-covered flex duct in buildings should see the duct failure reports listed below.
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Frequently Asked Questions (FAQs)
The air duct in my house is coming undone,the gray color plastic material has separated form the yellow material . The manufacturer is Owl Flex. I understand that there's a Class action suit against the company and that they should replace at no cost to me. Please,advise. - I.A. 8/13/2013
As you may have seen we discuss the Owl Flex duct disintegration problem in the article above. I have searched periodically without finding any indication of a class action lawsuit, litigation, nor settlement for this product.
Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.
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Technical Reviewers & References