B A R R Y wrote:

The pipes run vertically, as to direct the explosion up and out of
roof stacks. This is the only safe method for PVC dust collection.

When I tell "fibs" to kids I wink while telling them so they'll know
that what I'm saying is probably not "the gospel truth". You
need to add an "emoticon" with statements like that - maybe
; )

If you don't some poor newbie will be cutting holes in his shop
roof and redoing his PVC ducting. If he'd used ABS that wouldn't
have been necessary ; )

charlie b