> At lunch today a friend of mine reported setting up an air line using
> Schedule 40 PVC and seeing just as he finished that it was not
> recommended for air lines. Why is that?
>
> I assume it is because the PVC can shatter and shrapnel around. But he
> thought that the 480 PSI rating of the tube was well over rated for the
> 100 PSI he was planning to run. Any comments or experiences?
I've heard the theory forwarded that the tiny amounts of compressor oil
carried along with the air will eventually weaken the pipe and make it
brittle. Or possibly it's the heat when the system is used heavily (Sch 40
is not rated for even 180F water, and the pressure rating of 3/4" Sch 40
drops from 480 psi @ 73F to only 106 psi @ 140F).
Or, it may be just that the potential for human injury is so much higher
with compressed air than with liquids at the same pressure, and there is
some small random failure rate.
http://www.osha-slc.gov/dts/hib/hib_data/hib19880520.html
has several 'official' comments, including several that imply PVC may be
used for compressed gases if an appropriate shatter-proof shield is used.
Randall
///
/// shop-talk@autox.team.net mailing list
/// To unsubscribe send a plain text message to majordomo@autox.team.net
/// with nothing in it but
///
/// unsubscribe shop-talk
///
///
|