DRYER FIRES PEAK IN WINTER
Article Provided by: John Watkins, Nashville Home Inspection
Fall and winter are seasons of cooler temperatures, holiday parties – and dryer fires. Reports of clothes dryer fires is highest in the fall and winter months and peaks in January – the month in which ten percent of all dryer fires occurs. An estimated 2,900 clothes dryer fires are reported to U.S. fire departments each year with a resultant $35 million in property damage.
According to fire department studies, failure to clean the vents (34 percent) was the leading factor contributing to the ignition of clothes dryer fires in residential buildings. Dust, fiber, and lint (28 percent) and clothing (27 percent) were determined to be the items first ignited in the dryer fires.
While much of the lint is trapped by the dryer’s filter, lint is also carried through the vent system along with moist air. Lint is highly combustible and can accumulate in the dryer and dryer vent. Accumulated lint leads to reduced airflow and poses a potential fire hazard. Other blockages in dryer exhaust vents can occur if the vent is damaged, or if small birds or other animals build nests in the vent.
In order to limit potential fire hazards, building codes require that clothes dryers be exhausted directly to the outdoors. Venting a dryer into attics, soffits, ridge vents, or crawl spaces is expressly prohibited. Building codes also require dryer vents be made of metal with smooth interior finishes, that sections of vent duct are securely supported and firmly sealed together, and the total length of the vent duct does not exceed 35 feet (shorter if there are turns or bends).
Flexible transition ducts used to connect the dryer to the exhaust duct system are required to be no longer that eight fee, not concealed within construction, and listed and labeled in accordance with Underwriters Laboratories (UL) requirements.
However, many of these requirements are often overlooked. New construction trends often situate washers and dryers in nontraditional areas of the house, such as an upstairs bedroom, hallways, bathrooms, kitchens, and closets.
These new sites may require longer dryer vent ducts in order to reach an outside wall. Unfortunately, if a dryer vent is too long, moisture in the warm air passing through it condenses on the vent surfaces, attracting lint. Eventually, the lint accumulates and creates a fire hazard.
Serious hazards occur when dryer vents do not exhaust directly to the outside. Because of the numbers of new homes built in the last decade and the speed at which construction occurred, inspections have uncovered dryer vents expelling exhaust into attics, crawl spaces, chimneys, or interior walls. In these cases, indoor air quality is greatly diminished, mold build-up occurs and the likelihood of a home fire increases.
In addition, all manufacturers now state in their manuals that using plastic, flexible dryer ducts between the vent and the clothes dryer is prohibited, Yet many homes continue to use them. The plastic itself can provide additional fuel for a fire. Even flexible foil vents are not a good choice for venting clothes dryers. Only flexible transition ducts listed by Underwriters Laboratory (UL) or another approved safety testing agency should be used.
What can homeowners do to prevent these occurrences? First, consider using metal ducts (flexible or solid) as a way to vent a dryer. Metal ducts are far safer because they don’t sag; reducing lint build-up and metal ducts may contain a fire if one starts.
No matter what type of duct is used, it should be cleaned regularly, and the dryer lint screen should be removed and cleaned after each load. This will not only reduce the risk of a fire, but save energy and time. Cleaning inside, behind, and underneath the dryer will also reduce the amount of lint build-up and possibility of fire hazard.
What are some signs that dryer vents may be blocked and needs attention? Clothes that are taking too long to dry, clothes that smell moldy after a dry cycle, and clothes (or dryer top) are very hot to the touch. If any of these signs are present, dryer venting needs to be examined and cleaned immediately.
Source: John Watkins, Nashville Home Inspection, November 2012 Monthly Tip | Blog distribution provided by Kenneth Bargers and Bargers Solutions, member of Pilkerton Realtors, residential real estate services located in Nashville, Tennessee