What Type of Pipe Should be Used to Vent a Clothes Dryer?
According to the U.S. Department of Homeland Security, clothes dryer fires account for approximately 15,600 structure fires, 15 deaths and 400 injuries per year. Eighty percent of clothes dryer fires occur in residential buildings. Residential fires from improper venting number 12,700 annually, causing 15 deaths, 300 injuries and $88 million in property loss. Proper venting of a home's clothes dryer is therefore essential.
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How a Clothes Dryer Works
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Clothes dry in a rotating drum. A clothes dryer works by forcing hot air through a rotating drum. Wet clothes placed in the drum are dried by air moving around and through the clothes. Lint is shed as the water is removed and the clothes dry. Much of the lint is trapped by the dryer's filter, but some is carried by moist air through the dryer vent. It is the accumulation of lint which reduces airflow within the dryer, providing a highly flammable source of fuel for a fire.
Residential Venting Systems
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Laundry rooms are not always in basements anymore. New home construction trends place washers and dryers in areas other than a basement where venting to an outside wall is quick, easy and optimal. Today's laundry area could be situated in an upstairs bedroom or bathroom, in a kitchen or hallway or, as is the case with many apartment or condo rental units, in a closet. The new placement generally requires longer vents to reach an outside wall. Often the vents need to navigate sharp turns or bends, increasing the tendency for lint to be trapped within.
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Dryer Vent Specifications
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Dryer vents in nonbasement applications often have to vent under floors or through interior walls, making access difficult. Flexible ducts should be avoided as they can sag, allowing the buildup of lint and the danger of fire. Rigid aluminum pipe provides less resistance to the flow of air and is therefore recommended. The American Household Appliance Manufacturers Association specifies the use of UL-listed rigid aluminum or steel duct or spiral-wound aluminum flex hose--never white vinyl hose. Dryers should never be vented to an attic, crawl space, chimney or interior wall as this can cause mold buildup and deteriorate indoor air quality.
Installation Tips
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Two layers of metal foil tape should be used on joints to seal cracks in the dryer venting system. Screws or rivets should be avoided as they tend to capture lint. Hanging ducts should be supported with metal strapping at each joint. Minimize 90-degree turns as they decrease air flow. Insulate any part of the duct that passes through an unheated area to avoid condensation resulting in more snaring of lint. Install a 4-by-4 inch vent hood on the outside to keep the exit clean and clear.
Ongoing Maintenance
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Disconnect, clean and inspect the dryer duct and venting every 2 years. Clean the lint trap after every load. Inspect the lint trap for tears at each cleaning. Torn traps should be replaced immediately. Never let a clothes dryer run if it is left unattended. These simple preventative measures will assure safe dryer use.
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References
- Photo Credit laundry dial image by Sirena Designs from Fotolia.com laundromat image by Scott Patterson from Fotolia.com dirty laundry image by jedphoto from Fotolia.com
