Routine Dryer Vent Maintenance Can Prevent Fires

  • 01 of 07

    Clothes Dryers Can Pose a Fire Hazard

    Home Laundry Room
    slobo / Getty Images

    In 1999, the U.S. Consumer Product Safety Commission (CPSC) developed a report called the “Report on Electric and Gas Clothes Dryers.” In it, they stated that about 75% of households have a clothes dryer, which means that well over 75 million households in the U.S. have a gas or electric clothes dryer. The report also showed that in 1996 (as a sample year) more than 15,000 fires, 20 deaths, more than 300 injuries and over $80 million in property damage occurred from just dryer fires.

    Of the 15,000 fires, electric dryers were over 2.5 times more likely than gas dryers to be the cause of the fire. This is likely because the higher heat discharge from electric dryers exacerbates the problems of lint buildup. Fires originate most frequently from two places: ​dryer venting and the lint trap.

    Why these two places? Because clothes dryers are often improperly vented, and because those vents may not be properly cleaned on a regular basis. This is why dryer vent safety standards have been developed. There is still a lot of misunderstanding and confusion about types of dryer vent systems and where they can and should be used.

    Here are some basic dryer safety standards and some ways you can increase the safety of your dryer and vent system. 

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  • 02 of 07

    Dryer and Venting Safety Standards

    White plastic flexible venting is deadly as dryer ducting.

    Two voluntary sets of standards exist for dryer venting. For electric dryers, it is Underwriters Laboratories UL 2158. For gas dryers, the voluntary standard is ANSI Z21.5.1 (CGA 7.1). With these standards, rigid and semi-rigid metal vent pipes are the accepted ways to vent the dryer.

    Although we were supposed to use metal pipe, almost all of us remember the flexible white plastic dryer vent hose kit sold in hardware stores. As it turns out, these combustible white plastic hose kits are deadly when improperly used as dryer venting, and are the reason for many dryer vent fires. However, until recently they were still commonly sold as dryer venting.

    It was not until December 2006 that Underwriters Laboratories established UL 2158A “Clothes Dryer Transition Duct,” which is an approved standard for flexible high-temperature exhaust duct rated to 430 degrees F., which can be used on both electric and gas dryers.

    Now be careful. When you go to the hardware store you may see flexible duct that is labeled with a UL listing of UL 181B “Closure Systems for Use with Flexible Air Ducts and Air Connectors.” However, this standard is for flexible plastic and metal heating and cooling ductwork, and for vent fans such as used in your bathroom. These products are not approved for use as a dryer vent.

    Only flexible ductwork meeting UL 2158A can be used as dryer venting.

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  • 03 of 07

    Periodically Clean the Dryer Vent and Exhaust duct

    Dryers require periodic cleaning. © 2009

    The Consumer Product Safety Commission developed CPSC Document #5022, which outlines actions to reduce the risk of dryer fires from overheated clothes dryers. Let's review what you can do:

    1. Check the outside dryer vent while the dryer is operating to make sure exhaust air is escaping. You should feel a strong discharge of moist warm air. If you do not feel a strong discharge of air, the vent or the exhaust duct may be blocked.
    2. It may be necessary to disconnect the exhaust duct from the dryer to remove a blockage in the exhaust path.
    3. Disconnect the ducting and inspect for blockage.
    4. If the duct has lint buildup, clean the duct.
    5. Remember to properly reconnect the ducting to the dryer and outside vent before using the dryer again.
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  • 04 of 07

    Clean the Lint Screen with Each Use

    Removing lint trap filter
    Remove the lint trap filter from dryer and brush it clean to remove lint. © 2009

    What are the warning signs that dangerous lint buildup is occurring in your dryer and venting system? Symptoms may include:

    • Clothes take longer and longer to dry.
    • Clothes don't fully dry.
    • Clothes are hotter than normal at the end of the drying cycle.
    • The outside of dryer gets very hot.
    • The outside exhaust vent flapper does not open very much, indicating low exhaust velocity.
    • Laundry room becomes more humid than it is usually.
    • Burnt smell is evident in the laundry room.

    To clean the lint trap, first, remove the lint trap filter from the dryer and clean it. This must be done before or after each use of the dryer. Then, vacuum the lint trap housing cavity monthly.

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  • 05 of 07

    Clean Behind and Under Dryer

    Clean lint from behind your dryer. © 2009

    You should make a point to clean behind the dryer where lint can build up. Once every couple of years, have a qualified service person clean the interior of the dryer chassis to minimize the amount of lint accumulation. Keep the area around the dryer clean and free of clutter. You can see in the above photo how much lint builds up behind a dryer where it can get very hot.

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  • 06 of 07

    Correct Improper Dryer Ducting

    Do not use flammable plastic accordion ducting. © 2009

    Make sure to replace any plastic or metal foil, accordion-type ducting material, as plastic is not approved for dryer use and some metal foil ducts may not be approved, either.

    You must replace these ducts with rigid duct or corrugated semi-rigid metal duct meeting the UL 2158A standard. You'll find that most dryer manufacturers specify the use of a rigid or corrugated semi-rigid metal duct, which provides maximum airflow. Flexible plastic ducts are flammable, and they, along with foil-type accordion ducts, more easily trap lint and are more susceptible to kinks and crushing, which greatly reduces or obstructs the dryer air discharge.

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  • 07 of 07

    Be Careful Not to Dry Clothes Soiled with VOCs

    Dirty checked shirt
    Michael Wells / Getty Images

    You need to take special care when laundering clothes containing VOCs (volatile organic compound), such as gasoline, cooking oils, cleaning agents, or finishing oils and stains.

    Wash heavily soiled clothing more than once to minimize the volatile chemicals still on the clothes, and, if possible, hang the clothes out to air dry. If using a dryer, use the lowest heat setting and a drying cycle that has a cool-down period at the end of the cycle. To prevent clothes from igniting after drying, do not leave the dried clothes in the dryer or piled in a laundry basket.