SpudFiles

while i was ordering my parts for my first air cannon[from mcmaster]it sais word for word !Do not use sch40 pvc fittings with compressed air they are not pressure ratted! The pipe is rated but not the fittings.How do u know this is safe.

go to your local hard ware they will most likely have pressure rated fittings.

pressure rated fittings should have a NSF-PW label. not a NSF-DWV label.
This applies to fittings only because Pipe has both.

If mcmaster dosent have it my local hardware store dosent have it.

cork9 wrote:If mcmaster dosent have it my local hardware store dosent have it.

Ugh, ya they do.
MCMASTER HAS PRESSURE RATED FITTINGS
DON'T SAY THEY DON'T THEY DO

I think we're confusing pressure ratings for water and air.

No PVC pipe is rated for air. PVC tends to shatter, so all pressure ratings are for water only. Water is ok, because it's incompressible, so a break does not cause shards of PVC to fly everywhere. Air is compressible, so energy is stored in the pipe.

PVC manufactures, OSHA, and most everyone avoids using PVC for compressible gases.

http://www.osha.gov/dts/hib/hib_data/hib19880520.html

ok so its saying no more than 100 psi witch was gona be my max anyway.

they all say not for compressed air, every nsf-pw fitting i buy says that. its fine to use.