Help on PVC pipe pressure ratings

[CraigM]

I'm finally getting around to assembling my boom sprayer. I was pricing some brass fittings at Lowes and ran across some schedule 40, 3/4" PVC pipe that appears to be rated at 400+ psi. Since going plastic in selected places would save a lot compared to brass fititngs , I was pretty interested, but I'm leery of connecting a pump capable of 300 psi to plastic pipe. Just doesn't feel good. A sprayer parts vendor told me that sch40 is only good for 100 psi. Now I'm really confused.

Does anyone know if this pressure rating is real? Is it working pressure or burst pressure? Is there some industry spec that says that sch40 is only good to 100 psi in all cases? Are sch40 fittings rated the same as the pipe? I would hope so, but I don't want to assume anything.



Craig
Hershey, PA

[WVBill]

Craig:

I suspect someone here might know the answer but If you go over to this site http://www.plbg.com and ask, they WILL know. I've gotten much good plumbing advice over there.

[Branch]

One problem with PVC is that with the flexing from being pressurized it will eventually fail. It's not even recommended for airlines where the pressure is closer to 100 psi.

[Bird]

Branch, of course you're right; it ain't recommended for air lines, but that's what I used anyway in my shop and no problems at all now for over 2 years running 120 psi.

Bird

[JerryG]

In my poultry houses, I run 200 psi with water in sch40. The only problem I have ever had is blowing joints loose. The joints that I have put together have worked good, but some of the ones that my construction crew put together blew apart.

[Branch]

Bird,
I too use PVC for airlines, been doing it for years and have never had a problem. I just cringe each time I see something fall against a line. The day I do have a problem I'll walk myself to the wood shed for my come-uppances. Until then I'm congragulating myself on how much money I saved.
Branch

[Chillimau]

Hi,

Check out "ipexinc.com" gobs of piping info.

Sch 40 pressures vary with diameter of pipe. 3/4 pvc max press at 73 degrees Fah. 480 psi working and burst is 3 times that. Fittings should be that or better.

[JATO_RaT]

If you need a higher rating, go with schedule 80 pipe and fittings. If you need to, pipe in copper type L or better for high pressure situations. Rat...

[CraigM]

Thanks for all the input. I knew I would get a few answers here. Looks like I'm going plastic in one area away from the pump. The whole assembly will cost the same as one brass fitting. I'm still going to use brass at the pump as it is more likely to be bumped and banged.

Thanks to all

Craig
Hershey, PA