Dryer Vent Fires | dryer vent box
Some dryers have indicators designed to alert you when lint has built up and blocked the vent. Our clothes dryer tests have found that LG’s FlowSense and Samsung’s Vent Sensor detect completely blocked vents, but aren’t as good as detecting partially blocked vents. The same is true for the check-vent feature on Whirlpool and Maytag dryers.
A section of flexible metal transition duct is acceptable between the dryer elbow and the rigid duct in the wall, provided the transition duct is UL-listed for this use and is permitted under the…MORE local building code. Do not use unlisted metal transition duct or any foil or vinyl flexible duct.
A clothes dryer that is not working correctly increases the risk of fire. Look for signs that your clothes dryer is not working correctly and any potential increases in the risk of fire. Indicators to keep an eye out for are things like a lack of visible lint on the lint trap, the top of the dryer being hot to the touch while running and clothes take longer than one cycle to dry. Other indications of potential trouble are clothes that come out hotter than usual and the dryer stopping repeatedly during a cycle.
The US CPSC reported in 2000 that the lint trap was the second most common source of clothes dryer fires, and that fires in the lint trap, ducts, and dryer vents were responsible for 1/3 of all 79 dryer fires that the study investigated. Interestingly, fires at other locations such as electric motors, thermostats, and wiring may have also been related to clogged ducts and lint traps that led to overheating of those components as well. 
It doesn’t really matter, in most cases it should be very minimal and take a long time to ever present any problem. If it’s thick and accumulating, then you need to permanently repair the loose connection. Otherwise, just the vent tubes need to be kept clear so the heat can get out and not build to any kind of level that could be a fire risk.
You’ll find a myriad of how-to online videos, such as this one at YouTube that shows the process with a brush system. Some of the DIY cleaning kits do not always properly clean the vent duct. One advantage to hiring an experienced professional is he or she has likely seen just about every make and model of dryer and has the appropriate brush and equipment to effectively do the job.
Rigid seamed exhaust duct ideally should be installed with the seams up to prevent any accumulation of condensation from seeping out. When possible, horizontal runs of dryer ducts should slope slightly downward (1/4 inch per foot) toward the exterior termination to reduce the possibility of condensation accumulating and collecting lint.
If you’ve tried cleaning your vent system and still have the above issues, then it could mean you need to have your vent rebuilt or repaired. Lint should not build up in your dryer if your duct system is properly designed and installed. If you haven’t had your system inspected and cleaned for several years, be proactive and get it done today! Did we miss any other signs that it’s time to clean your dryer vent? Or have you experienced any of the issues described above? Let us know below in the comments!
Unplug the dryer and turn off the gas valve at the dryer (for gas dryers). Disconnect the duct joint closest to the dryer, then gently pull the dryer away from the wall. Disconnect the remaining exposed sections of dryer duct. If the sections are taped, remove and discard the tape.
Another visual red flag that you’re due for a cleaning: You can see lint or debris around the dryer hose or outside vent opening: or the duct hood flap does not open as it is designed to do. An outside vent that doesn’t open when the dryer is running means air flow has been restricted due to lint buildup.
Your own clothes dryer installation has the significant advantage of a very short run from the dryer to the outside of your home. If you select an outside dryer termination and animal/insect screen that does not trap lint (does not include a lint filter screen) and that opens and closes reliably operated by the dryer vent airflow, that device should be not only in compliance with the manufacturer’s recommendations (as it does not include a lint trap screen), it is also (in our OPINION) safer than a vent termination insect or animal screen that becomes clogged with lint.
Experts suggest that the primary cause of clothes dryer fires is failure to clean and maintain them. Check behind the dryer where lint has a tendency to build up. You should clean your dryer annually and perform inspections of the hose and vent for any blockages twice a year.
It is a good idea to consider scheduling a qualified service person to clean the interior of the dryer chassis annually. This will minimize the amount of lint that accumulates as well as give you a professional opinion of the safety status of your unit. A professional can also inspect the venting and exhaust system. To ensure that that this procedure is done correctly, employ only certified dryer exhaust technicians.
Although dryer manufacturers typically recommend the use of rigid aluminum duct venting systems with a minimum of direction changes and not longer than 15′ to the outside, many people have dryer ventilation systems, which utilize flexible vent tubes. This is another area where lint collects. All these areas need to be cleaned on an annual basis.
The opinions and experiences expressed here are those of Kris Fannin unless otherwise noted. This site is not affiliated in any way with Lennar Homes, Lennar Corporation subsidiaries, or any business partner of Lennar. WCI Communities and Lennar Homes (and all variants of those names) are often used interchangeably throughout this website. Lennar finalized the buyout of WCI Communities in February 2017. WCI Communities remains the ‘luxury brand’ subsidiary of Lennar Corporation.
We purchased a dryer vent termination product similar to the ones you describe and examined it carefully as we plan to install it on a Minnesota home where frequent checking of the dryer vent termination outside is inconvenient. The model we examined (not one of those you list) does not call itself a lint trap and it does not appear to trap any lint whatsoever. It’s chief advantage is that it blows all dryer exhaust, including lint, into the outdoor air.
According to the National Fire Protection Association, in 2010 an estimated 16,800 fires that involved clothes dryers or washing machines. Clothes dryers accounted for 92% of the fires with the leading cause of dryer fires being a dirty dryer.
Once the ductwork is in good shape, turn on gas valve (for gas dryers) and plug in the dryer. Push the dryer back into its normal position, making sure it’s not kinking or deforming any of the ductwork. Make sure lint screen is in place. Run the dryer and confirm that it is venting completely.
The gas dryer has blown out three times within one year due to the poorly routed dryer vent and possibly electrical issues. As you might recall, there are issues with not only the distance of the gas dryer vent from the exhaust but also the several sharp angles in the dryer exhaust pipes. Although Lennar acknowledges the issue, they would rather keep the fire hazard than cause a potential leak with a roof penetration.
Lint accumulation and reduced airflow feed on each other to provide conditions ripe for a fire. Lint is a highly combustible material, which, interestingly enough, is one of the ingredients in a recipe for home-made fire starters. A number of dryer vent problems contribute to this.
In between professional inspections, clean the outside exhaust vent regularly. It is best to check this when your dryer is running by making sure that the exhaust air is escaping properly. If you cannot feel any air, it is likely that there is a lint accumulation clogging the vent outlet. This might require you to disconnect the exhaust vent from the dryer to remove the clog. Remember to reconnect the ducting to the outside vent and dryer before you use the dryer again. If you are unsure of how to do this, it is always recommended that you contact the manufacturer for help or hire a professional.
TAMPA – According to the U.S. Consumer Product Safety Commission, more than 15,000 fires are sparked every year by clothes dryers. Lint and other debris can build up in your dryer vent, reducing air flow to the dryer, backing up dryer exhaust gases, creating a fire hazard.
“The most common mistake people make is that they don’t clean them,” Lorraine Carli of the National Fire Protection Association told Patch. “The majority of fires happen from buildup of lint. The easiest way to avoid it is to keep your lint filter and dryer exhaust vents clean on a regular basis.”
If you notice that your dryer takes longer to dry laundry than it used to, it’s a clue that there may be a blockage. Another clue: When you’re drying a load, head outside, and take a look at the dryer vent, if you have access to it. Do you see or feel exhaust air? If not, the vent or exhaust duct may be blocked with lint.
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TECHNICAL REFERENCE GUIDE to manufacturer’s model and serial number information for heating and cooling equipment, useful for determining the age of heating boilers, furnaces, water heaters is provided by Carson Dunlop, Associates, Toronto – Carson Dunlop Weldon & Associates
This article series describes good practices for clothes dryer vent installation, lint traps, wall vents, filters, and screens. We include a list of clothes dryer fire safety hazards and other clothes dryer installation or maintenance mistakes that are either unsafe or that interfere with effective, economical dryer operation. We discuss types of dryer vent ducting and dryer vent doors or opening protection devices.
It’s best to use an adjustable, rigid, 90-degree elbow at the exhaust end of the dryer. Semi-rigid flexible duct can kink when the dryer is pushed back into place, causing a major obstruction to exhaust flow.
To check your dryer’s vent – when unit is in use during cold weather: Warm / hot exhaust should result in visible water vapor – localized fog. After starting dryer with wet laundry, wait about five minutes for it to warm, then go out and look for vapor near the vent. This is similar to the vapor emitted from the tailpipes on motor vehicles after the engine is started on a cold day. An absence of vapor may indicate a clogged duct.
I’m also interested in putting in a secondary lint trap, secondary to the one built into the dryer, inside where I can easily open it and clean it out between loads. Several sites say never put a secondary lint trap on a gas clothes dryer because of the danger of combustion fumes escaping inside. Below is a model I found, and when I emailed them they responded that it would be safe.
The U.S. Consumer Product Safety Commission estimates that in 1998, clothes dryers were associated with 15,600 fires, which resulted in 20 deaths and 370 injuries. Fires can occur when lint builds up in the dryer or in the exhaust duct. Lint can block the flow of air, cause excessive heat build-up, and result in a fire in some dryers. 
All too often, dryer exhausts ducts are not given due respect. They receive little to no consideration in the design stage, are often installed haphazardly, and are seldom maintained. Once installed, the ducts are rarely given another thought. Current lax attitudes about dryer exhaust ducts need to change! Home inspectors can help by familiarizing themselves with the current standards and the related issues, by learning to recognize symptoms of potential hazards and, most importantly, by educating others.
Find out more with these resources: https://www.electrical-forensics.com/Dryer/ElectricClothesDryers.html