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PVC pipe for compressed air

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Forum topic by MrRon posted 08-18-2013 10:54 PM 2169 views 0 times favorited 70 replies Add to Favorites Watch
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MrRon

2933 posts in 1967 days


08-18-2013 10:54 PM

I know this topic has been brought up many times in the past on this and other forums. The bottom line has always been; CAUTION, PVC pipe should never be used for compressed air. There are some who have ignored this and use it with no problems.

I have two ideas about this. 1. There are high pressure air systems(>135PSI) and medium pressure (m in the hospital.


70 replies so far

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b2rtch

4351 posts in 1772 days


#1 posted 08-18-2013 11:30 PM

I have used PVC for year with no problem

-- Bert

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MrRon

2933 posts in 1967 days


#2 posted 08-18-2013 11:35 PM

I went back and reposted this thread. Somehow, it didn’t appear in it’s entirety.

I know this topic has been brought up many times in the past on this and other forums. The bottom line has always been; CAUTION, PVC pipe should never be used for compressed air. There are some who have ignored this and use it with no problems.

I have two ideas about this. 1. There are high pressure air systems(>135PSI) and medium pressure (m in the hospital.

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patron

13146 posts in 2065 days


#3 posted 08-18-2013 11:47 PM

schedule 40 seems to work OK
for most shop compressors
as most don’t go past 120lb’s

just have a pressure gauge at the start
(water traps need to be further down the line
as the air needs to cool some first
to turn from condensation to water)
to keep the incoming air from fluctuating
when the compressor goes thru its start-up cycle

any pressure changes can be done at the end of a run
with a water trap there too if needed

a simple T before the regulator dropping down
(6”-10”_with a valve to drain works good too)

-- david - only thru kindness can this world be whole . If we don't succeed we run the risk of failure. Dan Quayle

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BArnold

174 posts in 556 days


#4 posted 08-18-2013 11:48 PM

I considered PVC for about 150’ of air piping in my shop, but decided to bite the bullet and use Type M copper throughout. I know some people use PVC successfully, but I didn’t want to take a chance.

-- Bill, Thomasville, GA

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MrRon

2933 posts in 1967 days


#5 posted 08-18-2013 11:55 PM

.

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MrRon

2933 posts in 1967 days


#6 posted 08-18-2013 11:57 PM

I have two ideas about this. 1. There are high pressure air systems(>135PSI) and medium pressure ( wide filament tape. The objection to PVC pipe has been if you bang into it, the pipe will shatter and project sharp shards of plastic. I think the filament tape would prevent this from happening. What do you think? I like the idea of PVC as it is so easy to work with and inexpensive.

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MrRon

2933 posts in 1967 days


#7 posted 08-18-2013 11:59 PM

Something is amiss here. Part of my thread doesn’t appear. The part missing is about spirall wrapping PVC pipe and fittings with firerglass reinforced filament tape.

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REO

653 posts in 798 days


#8 posted 08-19-2013 01:18 AM

the best solution I have seen for air supply piping is PEX. fast, cheap, it doesent shatter and takes impact very well.

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jmartel

2589 posts in 874 days


#9 posted 08-19-2013 01:24 AM

Absolutely not. The problem with PVC is that when it fails, it splinters. Very dangerous to use in a pressurized situation like that. You guys can do what you want, but I never will use PVC.

-- End grain is like a belly button. Yes, I know you have one. No, I don't want to see it.

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JAAune

939 posts in 1040 days


#10 posted 08-19-2013 02:03 AM

I’m not positive about this but I think that PVC piping for compressed air will fail to meet code for fire inspection in a commercial building. PVC melts and in the event of a fire there’s a good chance that it will become an excellent source of oxygen to feed the blaze.

-- See my work at http://remmertstudios.com and http://altaredesign.com

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Biff

126 posts in 738 days


#11 posted 08-19-2013 02:10 AM

I’ve used PVC in my shops, current system has been in place over 10 years. I wouldn’t use it if it was ever subjected to freezing temps consistently because it seems to make it brittle.

Yes, I understand the splinter possibility. No, I don’t worry about it feeding a fire. You could apply that same theory to sweated copper lines, the heat could raise to a temp that would melt the solder and the joint could separate. Of course, the pressure relief probably would have gone off or the tank ruptured by then. Oh yeah, those cans of aerosol solvent already would have BLEVE’d as well.

-- Interested in Oregon property? Visit me at http://www.willamettepropertiesgroup.com

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ajshobby

14 posts in 1032 days


#12 posted 08-19-2013 02:15 AM

Mainly the reason you should not use PVC piping for compressed air systems is mainly due to the fact that PVC becomes very brittle over time. If the PVC pipe is exposed to direct sunlight it will deterioate faster as most PVC pipe does not have any type of UV protection. Schedule 40 or even schedule 80 cpvc will just delay the eventual breakdown. That is why even the national plumbing code does not approve PVC for air systems

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Grandpa

3193 posts in 1399 days


#13 posted 08-19-2013 02:27 AM

I believe this has been discussed thoroughly in the past so you might also look for that post. I also think there is information about this on the internet. I remember that PVC becomes brittle because of the oil in the air from the compressor. In the other post there were a couple of guys that had been involved in this stuff exploding. One of them was in a drafting room and a large line ran near the feet of some of the workers. I will say that I have a friend that has used PVC for air for about 30 years now. As far as I know, he has never had a leak of any kind. He uses 180 PSI in his machine shop. He has a small metal building that probably freezes on most winter nights. He heats with wood in the daytime. I think he always warmed the air before he started his compressor. He turned the air off every night with a valve at the air tank. In the mornings he warmed the air and then started things. With all that said I decided I didn’t want it in my shop. I do think I will use PEX. I have another friend with a machine shop that has had PEX for about 4 years now and it seems to be good. I have read of no reason I shouldn’t use PEX. Look for that other discussion and see what you can learn from it before you plumb up with PVC. I would also encourage you to look for a study on the internet about this.
I found this right away. http://www.lni.wa.gov/Safety/Basics/HazAlerts/902.asp

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Shawn Masterson

1262 posts in 672 days


#14 posted 08-19-2013 02:41 AM

I used 3/4” pex main with 1/2” pex drops. I says right on the pipe that its good for 145 psi. Pvc/Cpvc makes me nervous as it ages. Try to cut an old pvc water line the stuff gets brittle and shatters.

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jmartel

2589 posts in 874 days


#15 posted 08-19-2013 03:08 AM

Considering a PVC pipe fitting manufacturer specifically states not to use it, I’ll take it from them.

http://www.lascofittings.com/supportcenter/compressedair.asp

-- End grain is like a belly button. Yes, I know you have one. No, I don't want to see it.

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