I can't resist another "PVC for air" comment since I did some research on it for my garage before I asked my chemical engineering friend and found that even the white papers elude to the danger.
PVC doesn't do well with heat when it comes to pressure ratings as stated in every white paper I came across: "480psi maxiumum water pressure at 73f. Derate 50% at 110f and 78% at 140f" Typical temp of air exiting a compressor is ~175f. 3/4" Schedule 40 PVC is rated at 480psi @ 73f. But as the temp goes up the rating comes down- 110f=240psi 140f=105psi. This is the typical white pipe you see at HomeDepot. There is schedule 80 pvc from plumbing supply shops, but it's about 4x the cost of the Sched40 at homedepot. It's rated at 690psi at 73f. Derating for pressure is the same for this pipe- 110f=345psi and 140f=152psi. So I can see where the "fear" lies in using this stuff. Using it is a fine line since the temps are getting near the pressure limit of even the thick Sched 80. The variables in each system, the environment/exposure and frequency probably plays a big role in the failures, or successes. What none of this takes into account, and what the engineer revealed, is the degradation of the material over time with exposure to heat, air and pressure. He said it's not designed for air, it's designed for water, and that's why it is explicitly stated in the white papers. Just sayin' ;-) On Oct 13, 2011, at 3:36 PM, bill z wrote: > PVC is fine as long as you use tube with sufficient wall thickness, and so > easy to work with > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Rob Ebersol > Sent: Thursday, October 13, 2011 2:54 PM > To: [email protected] > Cc: [email protected] > Subject: Re: EXTERNAL: Re: Wally's future Garage-Mahal > > Friend of mine, who happens to be a chemical engineer, likened PVC failing > under pressure to shrapnel. > > > On Oct 13, 2011, at 1:47 PM, Ian McCloghrie wrote: > >> On 10/13/11 10:38 AM, Helsel, Walt wrote: >>> >>> Air plumbing, agreed. I have a hose reel in the center of the 24x24 now, > plus a loose hose to drag around as needed. What piping would you use, PVC, > black pipe or copper? I've heard pros and cons for each.. >>> >> >> I've never heard anyone say that PVC is safe to use for this. :) >> >> steel vs copper comes down to price of materials vs time to put it > together, no? >> >> --Ian >> >> _______________________________________________ >> Miatapower mailing list >> [email protected] >> http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower > > _______________________________________________ > Miatapower mailing list > [email protected] > http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower > _______________________________________________ Miatapower mailing list [email protected] http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower
