Two events caused me to check the clothes dryer vents to find that there was too much lint:
- I noticed that there was humidity in the laundry when drying clothes. Normally there is no increase in humidity
- A recent fire incident at Upper Hutt College [Link added] was caused by a pile of linseed oil soaked rags that were left in a pile rather than being placed in water. I was told that there was no fire just smoke damage from the smouldering rags which were five minutes from catching fire. News reports all said fire but the cleanup mainly involved removing the residue deposited around the building deposited by the smoke.
About 2,900 clothes dryer fires cause an estimated 5 deaths, 100 injuries, and USD35 million in property loss.
Failure to clean (34 percent) was the leading factor contributing to the ignition of clothes dryer fires.
Dust, fiber, and lint (28 percent) and clothing not on a person (27 percent) were, by far, the leading items first ignited.
Fifty-four percent of clothes dryer fires were confined to the object of origin
Organic oils remaining on laundry items after they have been washed and left in a pile or in an enclosed space
I am aware of the dangers of organic oils but I had not realised how common fires are that involve washed laundry. The NZ Fire Service Fire Research & Investigation Unit have a 2 page PDF that provides some good advice and information: "Heads Up, Issue 13 - Spontaneous Combustion with Organic Oils"
Oil contaminated fabrics that have been sent for laundering have also been known to ignite while being dried. Enzyme-based laundry powders and cold washes do not remove all oils and fats and these can remain in the fabrics.
Lint from your clothes dryer in places the you don't see
I've always been aware of lint as a highly combustible material. That is why Bear Gryll uses pocket lint to more easily start fires when he's in the wild. Lint, like the oils, is more dangerous the more surface area that is exposed and the greater the simultaneous oxidation on those surfaces, e.g. on warmer days. That's why I clean the lint filter - here's what can happen if you don't - every time I open the dryer door, even if the dryer is empty.
What I did not realise is how much lint can build up in hidden places in and around a clothes dryer. Lint also builds up when a dryer is vented through ducting or even into the ceiling cavity (a definite no-no anyway because it keeps the damp inside the building envelope). In the presence of oils, humidity/dampness is not protection against spontaneous combustion through oxidation. For similar reasons the following is common advice:
Do not leave damp items in a warm or hot dryer --- start the drying cycle immediately.
That quote is from advice for commercial cleaners but the same applies to home laundries. So here's some Clothes Dryer Safety Tips. There's heaps more on the Web.
I also read a lot of articles about the increased danger of contemporary laundries placed in cupboards or small rooms in the middle of houses or where there is no access to an exterior wall. Enclosed spaces, a lack of ventilation, and longer runs of ducting all contribute to greater risk.
Anyway, I took my wall-mounted dryer off the wall, vacuumed and cleaned out the vents, the dryer interior and exterior, the walls and the external ducting, everything I could think of. I found a lot more lint than I expected and I'm happy that I cleaned it.
[Edit: Link added]
Trusted
