The fast pace of modern life often causes us to take our home appliances for granted. We assume that refrigerators, stoves, washers and dryers will be there when we need them. One appliance that should not be taken for granted, however, is your clothes dryer. The U.S. Consumer Products Safety Commission estimates that in 1998 alone, 15,600 fires, 20 deaths and 370 injuries resulted from the buildup of lint in dryers or their exhaust pipes.

Why is this a problem?

Bosch (ENLARGE)
Lint buildup in the dryer exhaust pipe can cause the appliance to work harder, at higher temperatures, resulting in fire.
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A dryer's lint filter catches only a small amount of the lint produced in drying clothes. The remaining lint goes out the exhaust pipe. When lint builds up in the dryer exhaust pipe, it reduces airflow, causing the dryer to work harder, at elevated temperatures. The higher temperatures can cause the dryer or the lint to catch fire. Some modern house designs can make this problem worse. Often dryers are not located close to exterior walls, requiring long exhaust pipes with sharp turns. This increases the chances for lint buildup.

How do I know if my dryer vent pipe

is blocked?

Here are some warning signs that there may be a blockage in your dryer vent:

• Your clothes are taking longer to dry than they used to.

• There is not much airflow at the exhaust hood on the exterior of your house.

• Your laundry room feels hot and humid when the dryer is running.

• Your clothes are excessively hot when they finish drying.

• Water drips out of the front of the dryer when it is operating.

• The case of the dryer is excessively hot to the touch.

• There are burning smells in the laundry room when the dryer is operating.

• There are unexplained water stains on ceilings or walls where dryer vent pipes are located.

What do I do

if my dryer vent pipe

is blocked?

The simplest remedy is to disassemble the vent pipe and clean it out. This should be done periodically to avoid the buildup of lint. If the pipe runs through walls and ceilings and is inaccessible, this may need to be done by a professional with special equipment such as vacuum cleaners with long extension hoses.

What should I look for to avoid this problem?

Contemporary building codes contain specific requirements for the installation of dryer vent pipes. Even if your house is older and was not constructed to current codes, observation of these requirements can help ensure safe operation of the dryer. When examining your dryer vent pipe, look for these conditions:

• The vent should terminate outside (not into attics, crawl spaces or basements).

• The end of the vent pipe should have a cover with a back-draft damper to keep pests from entering and blocking the pipe.

• No screens can be installed on the end of the pipe. Screens will catch lint and result in a blockage.

• Sheet metal screws that extend into the pipe cannot be used. They can catch lint.

• The pipe should have a smooth interior finish and must be at least 4 inches in diameter.

• The piping must be well-supported and secured throughout its entire length.

• The piping cannot be longer than 25 feet from the outside vent to the dryer connection. This total length must be reduced by 2 feet for every 45-degree bend and by 5 feet for every 90-degree bend.

• The transition duct (pipe from the dryer to the permanently installed pipe) cannot be longer than 8 feet.

In addition to examining your dryer vent pipe for proper materials and installation, observe the following safety procedures:

• Clean the lint filter after every load of clothes.

• Periodically clean behind the dryer to avoid lint buildup.

• Replace plastic or foil pipes with flexible metal pipes.

• Take special care if you are drying clothes that have been soiled with volatile substances like gasoline, paints, stains or cooking oils.

Send home repair questions to Ask the Inspector at H&G@ajc.com. Because of the volume of mail, not all questions can be answered. Our expert, Bill Garwood, spent 15 years as a building contractor before becoming a home inspector in 1990. He is part owner of a residential inspection firm and a company providing training in building inspection and codes.