According to the National Fire Protection Association, nearly 17,000 home clothes dryer fires are reported each year. These clothes dryer fires cause around 51 deaths, 380 injuries, and $236 million in property loss.
Of these 15,000 fires, electric dryers were shown to be more than 2.5 times more likely than gas dryers to cause fires. 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. Although dry vent safety standards have been developed over the years, there is still considerable confusion about the types of dryer vent systems and how they should be maintained. Clothes dryer fires are by no means a thing of the past.
Here are some basic dryer safety standards and some ways you can increase the safety of your dryer and vent system.
Dryer and Venting Safety Standards
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 metal pipe was always the preferred method of venting, almost everyone remembers 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 used as dryer venting, and many homes still vent their dryers using this dangerous product.
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. (see image example below)
You need to exercise care when choosing this type of flexible metal dryer vent. 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 vent fans such as those used in bathrooms. These products are not approved for use as dryer vents.
Only flexible ductwork meeting UL 2158A can be used as dryer venting.