Here is a worthwhile video on You Tube. My vent hose on my dryer is plastic and flammable. It looks like metal but it isn't. It is called foilwire bound type. Don't use it.
Don't know how to do links but type this is the Search Box on You Tube.
dryer vent installation bad idea
A 3 minute 3 second video.
http://www.youtube.com/watch?v=vfExQ3mwBH8
Thanks for that Gary. Mine will get changed TODAY!
In roof heating uses the same with an insulation coating around the outside.
Im a general contractor by trade and i totally agree with all of this. they do make a metal version of this pipe but it is hard to find. Using hard metal pipe is by far the best method. The less pipe you use the better. Most dryers are rated to push 30ft of pipe with any elbows counting as 10ft. One decent option is to use 1ft or so of the flexable pipe to attach the dryer to the hard metal pipe. Some may use PVC pipe but as it is not nearly as flamable but it can become charged with static electricity therefore making dryer lint stick to the inside of the pipe... now you dont have to be a rocket scientist to know thats not good.
I want to make a rocket so I'm off to the hardware store to get some PCV pipe for my dryer!
While you are back there flip the breaker OFF for your dryer and pull the cover on the plug and check the connections. They tighten with a screw the pushes a copper plate against the wire(s). They have a tendency to get loose and when that happens it gets hot enough to start a fire. Nearly happened to me last year! I since learned this is a common source of house fires. Check it annually!
You can get the same type piping in metalic form but you must READ the label and be prepared to pay more for it. Hard metal is best/hardest to install and a lint trap close to the drier and easily reached is something most don't think about. Their a must for a long drier hose run because they keep the pipe clean beyond the filter. I have a very short run (2 1/2 to 3 feet) and I'm constantly amazed at how much gets by the standard built-in drier filter and hits the ground.