A few weeks back, co-inspector Rick's daughter was minding her own business, doing a little laundry in her apartment, when the dryer door burst open, revealing a rip-roaring fire inside the dryer drum. As bad luck would have it, some of the flaming clothes fell out of the dryer and into the open washer below. Now there were two fires, one high and one low. Luckily, there were people around, and they knew how to work a fire extinguisher. Otherwise, the whole dang apartment complex could've ended up a smoldering heap. Cause of the fire: Dryer lint, stuck in a concealed plastic duct, which was run through the attic of the apartment complex.
Dryer fires aren't so unusual. In 1997, there were about 17,000 of them, according to the Consumer Product Safety Commission (CPSC).
In most cases, it's the lint that's causing the fires. A fist-sized ball of dryer lint makes pretty good kindling. I know, because I've set lint afire just to amuse myself. Bear in mind that my lint came from the Jowers family laundry, so it contained no polyester, or other ready-to-wear, ready-to-burn petroleum-based fabric.
Excluding experiments and mischief, there are basically two ways that dryer lint catches on fire: 1. Negligent dryer users don't clean the lint filter after using the dryer. Lint builds up, blocks the flow of air through the dryer, the dryer heats up, and the lint catches on fire. 2. Lint gets caught inside the duct, and blocks the flow of air through the duct. The duct and dryer heat up, and something in the dryer or duct catches on fire.
Lately, forensic types have discovered one other culprit in dryer fires: Under-wire bras. The wire gets hot, and starts the bra on fire. You women with under-wire bras might want to hang those things over the shower rod, or string up a clothesline.
If you want to avoid the horrors of a dryer fire, here's what you do: First, clean the lint filter every time you use the dryer. Just scoop the lint out, and throw it away with the regular garbage. (I know, I know. Some of you take it outside, so birds can use it in their nests. That's cute, but it's a minor form of littering. Throw the lint away. The birds will find their own nesting materials.)
Second, if your dryer vent is that cheap white plastic accordion stuff, replace it. It's a fire hazard. I don't care if it came with your brand-new house. I don't care if the guy at the hardware store said it was okay. It's not okay. Check with any dryer manufacturer, and they'll tell you to use one of two things: Either flexible metal duct, or rigid metal duct. The rigid duct is the better choice.
Don't confuse real enough rigid metal duct (which is aluminum or galvanized) with that newfangled, paper-thin metallic foil duct. The foil junk might seem like a good compromise between plastic and rigid metal, but it's not. It's a useless or near-useless product. It might be suitable for arms on a Halloween robot costume, but that's about it.
Even if you're not afraid of the fire hazard that comes with that god-awful plastic dryer duct, you still need to get rid of it. It's contributing to the destruction of the planet. All you people who get mad when I say bad things about those "water-saving" 1.5-gallon toilets, go check your dryer vents, right now. Are they white plastic? Well, feel guilty. Your duct is so prone to catching lint, so bad at letting air go through, that you're wasting a whole bunch of energy every time you dry your clothes. Get yourself some real metal dryer duct, and help us conserve our finite energy resources.
Dryer manufacturer's specifications, and building codes, go into great detail about the right way to install dryer vent. Even so, I see improperly-installed dryer vents just about every day. Apparently, a whole lot of installers just ignore the specs and the codes, and do whatever is easiest and cheapest.
You can outsmart the errant installers, though, because I'm going to tell you the right way to install dryer duct:
1. The dryer duct has to be at least four inches in diameter, and it can't be smaller than the outlet on the dryer. Concealed ducts must be rigid metal. (No running plastic or foil duct through walls, or into concealed spaces, like Rick's daughter's attic.)
2. Duct joints must be secured with metal tape, not rivets or screws that will penetrate the duct and catch lint.
3. The duct can't be longer than 25 feet. (A 45-degree elbow counts as 2 1/2 feet of duct; a 90-degree elbow counts as 5 feet.)
4. The dryer vent has to be independent of other vents. (No running the dryer vent into a chimney, or a vent that serves another appliance.)
5. The outside termination has to have a backdraft damper.
Of course, dryer and/or duct manufacturer's specifications supersede the above, and supersede the building code.