Issue: 52    Date: August 11, 2001

Will Your Dryer Kill You? 

Don't be afraid of a stranger entering your house and doing you harm, you have already invited him in and are living with his potential danger on a daily basis every time you turn on your dryer.   

The Consumer Product Safety Commission reports dryer related home fires are on the increase. CPSC figures show that in 1997 there were 16,800 dryer fires, which caused 30 deaths, 430 injuries and 97.3 million dollars in property damage. CPSC doesn't say much about the other issues related to dryers caused by moisture and carbon monoxide (gas dryers). Jambs and joists rot, windows sweat constantly, water heaters malfunction, metal rusts, mold spore population explodes and gas dryers exhaust potentially lethal combustion gases into the home not to mention pull these gases from furnaces and water heaters. Need a good fire starter for your wood-burning fireplace, try dryer LINT. Storing this lint in any area of your home and one little spark could turn the area into an inferno in seconds.   

Over the years I have observed many methods of venting clothes dryers from no venting at all with the laundry area damp and covered with lent and mold. Venting into a bucket with panty hose covering the end of the pipe to the most recent where an addition had been added with the exterior dryer vent and thru wall pipe removed leaving the dryer venting into the wall cavity which along with the adjacent electrical distribution panel was filled with lint and skin flakes leaving the room smelling like a dead rat. 

I have seen dryers vented into crawl spaces, attic spaces, garages, basements, wall cavities, and chimney flues to mention the ones that come to mind. One of the interesting places I see dryers vented is over or near exterior air conditioning and heat pump units. How do you think the lint and heat affects this equipment? 

Manufacturers recommend, and most building codes require, that dryers be vented to the outdoors using a short, smooth metal vent pipe with minimal bends that can be checked and cleaned periodically. What do we do? We use flexible plastic vent pipe, kink it just behind the dryer and run it to the opposite side of the crawl space or attic like a serpent poorly supported and swaging up and down. The bends are not smooth and uniform; lint builds up on the roughened surface, lint backs up, the lent and pipe is flammable with a heating element on the business end. Do you see a problem here? Its just the beginning. 

Every load of clothes you dry produces about one to two gallons of water, which is changed to vapor. Where does it go?   If it ends up in the wrong place, moisture equals rot, attracts wood destroying insects fungus, mildew and molds. 

If you don't die from the fire or loose your home and belongings maybe the injury from the house falling down around you or sickness from the mold spores will do the job. If you are using a gas dryer, or have your dryer located in a tight room near your furnace or gas water heater, don't worry about the other issues; the carbon monoxide will probably get you before the others have a chance. 

When thinking about dryer venting consider the following: 

Indoor venting introduces excess moisture into the home. This moisture may affect furniture, causing warpage or finish deterioration. Paintings, portraits and other framed objects may be damaged by dampness. Moisture may condense on windows causing casing and frame damage. Interior painted surfaces may suffer mildew or premature deterioration. Ceiling drywall or acoustical tiles may sag. Moisture may be forced thru walls toward the house exterior and cause paint peeling. Metallic objects may oxidize (rust) if moisture remains on the surface. 

The dryer will draw in the moist air and lint dust expelled into the laundry room. The saturated air will prevent the load drying quickly. The contaminated air drawn into the dryer may cause clogging and overheating. 

A spark of fire in the vent piping may be directly introduced into the home. Metal venting to the outside, in case of lint ignition, may save your home. 

Recently Dateline NBC reported on a New Hampshire Deputy Fire Chief who's home was destroyed by a fire, which started in the dryer vent piping. A Manassas Virginia family became ill because their dryer was connected to a heating/air conditioning duct. The family's three children were chronically ill with respiratory problems requiring 200 visits to doctors and emergency rooms during the seven years the family occupied the home. The builder refused to accept responsibility, but agreed to repair the problem. 

Is proper dryer venting and maintenance a concern? If you didn't accept it before maybe you will now. 

So, what should be done to make dryers safe and efficient? 

1. Dryers should be vented, independent of all other systems, to the outside and not terminate near mechanical equipment, decks, porches or areas, which may be occupied for extended periods of time. Concealed ducts must be rigid metal (galvanized or aluminum). Under no condition should a dryer ever be vented into the interior of a home. Vent pipe should be smooth at least 4” diameter metal with minimal length and bends that can be checked and cleaned periodically. Metal screws or rivets should not be used. Use outside straps or tape. Joint connections should not oppose the airflow. The runs should be straight without sags and curves. Flexible plastic or foil pipe should never be used. Underwriters Laboratories standards 560 and 2158 for clothes dryers require that all dryers listed must specify all metal dryer venting unless otherwise tested. 

3. Don't crush the pipe in an attempt to get your dryer close to the wall.

4. Unless otherwise permitted by the dryer manufacturer, developed length of dryer duct shall not exceed 25 feet. A 45-degree elbow counts as 2 ½ feet of pipe and a 90-degree elbow counts as 5 feet of pipe.

5. There must be a hood to prevent water and back draft damper to prevent outside air, birds, varmints and insects from entering the system. Never use a screen, which traps lint.

6. Dryers should not be located in tight closed rooms without provision for make up air and should never be located near combustion fired water heaters or furnaces without proper provision for make up air. Dryers can cause back drafting of water heaters and furnaces leading to flue gases and carbon monoxide entering the home.

7. Clean the lint filter before every use.

8. Check the outside termination periodically to be sure air is escaping normally. 

9. Check and clean the vent piping twice a year.

10. If the clothing is still damp at the end of a normal cycle or requires longer dryer time, this may be a sign that the exhaust or lint screen is blocked.

11. Never leave home with your dryer running. Your home may not be there when you return. 

As if safety is not important enough, be aware that the key to effective dryer performance is optimal airflow. A properly installed all metal dryer vent will help ensure this airflow. When clothes are given the appropriate amount of air, they dry quicker and are subject to less tumbling. This results in less wear on the clothing and use of less electricity or gas.    

Thought for the week