PVC Dryer Vent

[Rob Will]

At first glance it may appear that this thread does not have a connection to woodworking. However, much discussion has taken place here regarding the use of PVC pipe for dust collector piping and how static electricity might build up in the PVC.

I had something interesting happen today regarding a clothes dryer vent I was working on (not my house). In fact, this is the third time I have seen this.

4" PVC had been used for the clothes dryer vent. The PVC was connected to a flexible metal foil hose at the dryer itself. Both appeared clean and normal from the OUTSIDE.

Upon further inspection, the metal was totally clean on the inside but just as soon as it switched to PVC, here is what it looked like. The lint was attracted to the PVC and totally blocked the pipe. Read: FIRE HAZARD! (not to mention the wasted energy).

I'm not trying to say that PVC dust collector systems behave like PVC on a clothes dryer vent, but it is interesting to see the effect of static at work.

If you have PVC anywhere on your clothes dryer vent - look inside.

Hopefully this will help someone save some $$ and avoid a tragedy. If you have seen this problem occur or if this post helps you find a hidden fire hazard, please post a reply.

Rob

[Jeffrey Schronce]

Question: It looks like the beginning of the elbow is clean on the first photo. Did the metal come out the dryer, go down through the floor, go the the PVC elbow, then run parallel through PVC?

[Rob Will]

Question: It looks like the beginning of the elbow is clean on the first photo. Did the metal come out the dryer, go down through the floor, go the the PVC elbow, then run parallel through PVC?

No, that is where the elbow went up through the floor. Prior to tearing it all out and taking this picture, I stuck my hand down in the pipe and cleaned out a thick layer of lint. That is the clean spot you see. Very observant!

Rob

[Richard Blaine]

I'm not saying that static doesn't play a part in the blockage, but I've always heard another reason not to use pvc. Because PVC does not conduct heat as good as metal, it takes longer for the vent to heat up. Until the vent heats up, condensation happens inside the vent, and causes the lint to clump.

Whatever the reason, it is against UBC to use PVC as a dryer vent.

[Rob Will]

I'm not saying that static doesn't play a part in the blockage, but I've always heard another reason not to use pvc. Because PVC does not conduct heat as good as metal, it takes longer for the vent to heat up. Until the vent heats up, condensation happens inside the vent, and causes the lint to clump.

Whatever the reason, it is against UBC to use PVC as a dryer vent.

That is interesting. The lint does indeed seem to be damp inside the PVC. In fact, this one was choked down so bad that condensate had accumulated in the PVC pipe.

Rob

[Russ Filtz]

PVC also loses a LOT of its structural strength as it heats up. Could get floppy and cause low spots that could clog even easier.

[Jeffrey Schronce]

My dryer vent vertically down about 2 feet then elbows to a 10-12 ft run to the outside of the house, all PVC. Never had a problem. I do disconnect the elbow and push a rag through the run with a stick to make sure it stays clear. I have done that 3 times over 6 years with no problems. The age/efficiency of the dryer may contribute to the problem of the line getting clogged. I don't see where static would really change much in a DC system.