Why is it that people are so hung up on the improbable happening of pvc causing a fire within their dust collection ? Yet these same people have plastic or cloth bags, or a cardboard container as the final place for their dust to rest. You have a better chance ofa screw going through you metal DC impellar and causing a spark , or getting red hot and starting a fire in your dust.
Not that this is highly probable, but more probable than pvc.
BTW, Oneida which states that they advise not using pvc for pipes because of a fire hazard sells their cyclones with cardboard collectors.
The fire code and OSHAstates that NO part of a DC systen can be flammable in commercial environments.
Juct Wondering. :>)