Could your dryer vent be a fire hazard?

By Tom Phelan - ReminderNews
Featured Article - posted Thu., Sep. 6, 2012
- Contributed Photo

If you read this column regularly, you know by now that I am a little obsessed with developing and attending to home maintenance lists on a periodic basis. Last week's issue should have gotten you thinking about fall chores. One of the things you should do annually is give the vent system of your clothes dryer a thorough cleaning. Why? Because at the very least, your dryer will perform better. But you will also eliminate a fire hazard.

Statistics around this hazard vary. The National Fire Incident Reporting System (NFIRS) cites residential appliance fires annually result in an estimated 9,600 fires, 25 deaths, 525 injuries and $211 million in property loss. The same source reports that, based on data for the years 2008-2010, an estimated 2,900 clothes dryer fires in residential buildings are reported to U.S. fire departments each year and cause an estimated five deaths, 100 injuries and $35 million in property loss.

You may well say that these numbers are not that alarming, and rightly so. But that's valid only until your home becomes part of those statistics. Should you worry a lot about your dryer vent posing a fire hazard? Probably not. But you should at least be motivated to do the vent system cleaning. If you can, you should also pay some heed to the International Residential Code (IRC), and bring your system into compliance with its recommendations.

There are several sections that make up the pathway through which warm, moist air (and the lint it carries) travels in order to vent properly. The one you see and access most easily is the lint screen. But the lint-laden air also bounces around a pathway inside the machine before it makes comes to the back of the dryer. There it starts what is perhaps its longest run through a vent pipe or flexible hose to the external exhaust cover.

Section M1502 of the IRC (Clothes Dryer Exhaust Guidelines) says these exhaust ducts should be constructed of rigid metal, with smooth interior surfaces and joints that run in the same direction as the airflow. They should not be connected with sheet-metal screws that extend into the duct. Tapered pressure joints or external bands make for more preferable connections. The code is explicit in reference to the commonly used flexible vent hose. "This means that the flexible, ribbed vents used in the past should no longer be used. They should be noted as a potential fire hazard if observed during an inspection."

The code then allows for certain exceptions based on manufacturer's recommendations, but their intent is clear. The path should be as straight as possible, as smooth as possible, and made of rigid material wherever practical.

The IRC says the length of the exhaust duct should not exceed 25 feet. And where there are 45- or 90-degree turns, the length should be reduced by 2.5 feet and 5 feet, respectively. Vents should be as straight as possible, making allowance for turns, which restrict airflow.

The first step, as always, is to shut off the gas or electric supply. Because the venting exits at the back of the machine, you have to move it some distance away from the wall. All these appliances are very similar. You will either have to remove the top and front on some machines or just the front panel on others. On top-cover configurations, the lint filter housing is usually held in place with a few screws. Removing them allows you to release the top lid from its fasteners at the corners. Where the front cover can be removed, just remove the two screws near the top, allowing the front to fall free. In both cases the drum is released from its mounting against the front cover.

With this disassembly you can clean the lint from inside the lint filter housing. Use a vacuum to clean lint deposits wherever you see them inside the machine, as well as inside the vent duct. Verify that the exterior vent cover is clean and operates freely.

It's a good idea to take digital photos of the machine as you work through the disassembly process, so you can remember the assembly sequence. While the camera is out, also take photos of the condition of the clothes dryer and its vent pathway before and after your annual maintenance. Having the photos will help you get ready for the next annual cleaning.

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