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angel;

The max. pressure rating for "40" is on the low side for compressed air (or anything) applications when heat is present.
Threaded fittings for ends are rated at 1/2 the pressure rating for glued fittings.
Schedule 80 is not much more expensive and will work for these applications.

John

ps: Remember to "prime & glue" your joints.
 

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There have been stories that I have heard about PVC pipe blowing up. Too high a pressure, hit while under pressure..ect.,ect. Please use steel pipe for safety.I know its not as easy, but what if you lost your sight?



"you'll put your eye out kid"
 

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Doug G is right... it's just not worth risking getting hurt.
 

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On a related subject, I know a guy (who knows a guy) who had a potato gun made of sched 40. I don't know what he used for propellant, but it blew up in his arms. He had chunks of PVC shrapnel in his side and arm. Completly trashed his tricep. Nasty nasty stuff. If you have ever seen a PVC pipe that has failed you can just imagine the damage it did to this guy.
 

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Angel, at work we have an extensive air system that controls all of our HVAC in the building...The mains and larger branch lines before the regulators are all Type L copper...If I were you, go with the copper, you will never have to worry about it again...Mike
 

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Angel:

Sorry - wasn't trying to scare you :eek:

Schedule 80 PVC in 3/4" or 1" are both nominally rated at over 6oo PSI @73*F (1/2" is over 800 PSI). Their Stress/Time-to-failure rating is about 10 Million Hours at 200 PSI and 73*F. So in San Francisco, where it doesn't get to hot very often, that would be somewhere over 1000 years at 200 PSI before a line would fail - you planning on living real long...

I use PFE and PVC piping routinely in pressure applications at major US Semi-Conductor plants - it passes all codes and inspections for this use.
Here is a link from my "Favorites" to the George-Fisher Company Engineering info for PVC - http://www.piping.georgfischer.com/index.cfm?424D3C4A152F4697ABE3201FA7EC26D1.
I know it's a lot of boring reading - but, it may answer some questions about this application.

If you can 'sweat pipe' and want metal pipes I would go with Copper over Cast any day. But, read up on it's installation and use before you start - you may be supprised at it's nominal pressure ratings v.s. PVC.

Hope this helps - feel free to contact me with questions if you need to;

John

BTW - Sch 40 PVC does make a lousy Patato Cannon - if he was using 3" the burst strength for "Hammer" (or instant pressure application) could be around 150 PSI at 73*F and as low as about 70 PSI, if the cannon had been "Fired" a couple times and the "Barrel" heated.
This would be using Compressed Air as the propellant - If the "rube" was using A flammable as his propellant... well then all bets are off with the ratings


[ 04-20-2004, 09:00 PM: Message edited by: Vintage 68 ]
 

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Originally posted by zuma1211:
Angel, at work we have an extensive air system that controls all of our HVAC in the building...The mains and larger branch lines before the regulators are all Type L copper...If I were you, go with the copper, you will never have to worry about it again...Mike
That's what I used - 1/2" type L copper. I wonder how strong the fittings are. Oh well, 3 years and no troubles. My compressor maxes at 120 psi.

If you're plumbing a long distance, say over 100', consider using bigger diameter pipe. Compressed air is similar to water in that you get "friction loss" when the air is flowing, and bigger pipe minimizes that.
 

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I used 1.5" sched 40 thru my intire shop and ran an IR T30H at 175psi all day long for years....and never had a problem. Just make sure nothing scratches or impacts the pipe.
 

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Here's a page of info: http://www.fpweb.com/archive/June_99_piping.html
I also found an OSHA page that recomends only ABS pipe approved for air systems.
California has the toughest regulations and testing for plastic air pipe. If you use California approved pipe, it will be one of the safest.

I do have to say I have experience with sched 40 1" pipe in four shops. Two have been in use for over 20 years, the other two 10 years. All operate at 175 psi and no failures (so far). None of the pipes are in areas where they would be hit by anything large enough to damage them. The total length of pipe I'm talking about for these shops is over 900 feet. Plus, I've had it in my garage since the late 70's but only 125 psi. Mine is rated at 450 psi.

I have read in Hot Rod that the glue joints are the weak points, not rated as high as the pipe and when they get hot can fail. None of the info on the net says that though. The OSHA page says it's a danger if broken by impact, it shatters and sharp pieces fly! The ABS pipe ruptures if struck but does not explode into pieces.

If it is underground, PVC you have has no problems, as it's not likely to get hot or get hit. I would look for an approved ABS pipe and plumb all the above ground sections in that.

I'm not going to recomend PVC pipe for air, but I've seen it done a LOT!
I live in a coastal area and it dosen't get too hot here which helps.

Here's an OSHA page talking about it for industrial use: http://www.osha.gov/dts/hib/hib_data/hib19880520.html
David

[ 04-21-2004, 11:12 PM: Message edited by: davidpozzi ]
 

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I am using schedual 40 with a IR T30 also at about 175 psi. The pipe is rated at about 320 but I have been warned by friends that the fittings are the weak link. The really scary part is the plastic shrapnel will not show up on a Xray. They suggested that I wrap the joints with duct tape to contain any shrapnel.
 

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clill,
I'd suggest somthing better than tape, I don't think it would help much.
You could cut the end off and slip some steel conduit over the sections near floor level. Mine come down from the rafters and drop straight down near each column support. I could probably slip a conduit over them and glue the end back on.

I guess if I'd ever seen a failure, I'd be more motivated to change it out.

Maybe I could replace the drops with the ABS.
David
 
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