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PVC for air lines

41K views 61 replies 17 participants last post by  S10xGN 
#1 · (Edited)
With the recent discussions about using PVC for air lines I contacted an engineer acquittance and asked for his input and he E mailed me this link. Looks like it actually may be illegal to use even in a private installation in some states and soon to be in others. Whether it is or not this is something that should be considered by someone thinking about or already using this very dangerous system. I think the problem here is that most people have no idea just how violent a PVC pipe rupture can be and how much damage it can do nor do most realize how easily it can happen.

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

Just an added note to think about, he also pointed out that if you are involved in a PVC accident small deeply embedded and potentially life threatening shards will not show up on an x-ray!

Here are a couple of DOCUMENTED incidents.

PVC piping buried 3 feet underground at a Yakima manufacturing plant exploded, opening up a crater approximately 4 feet deep by 3 feet across.

Last year, a section of PVC pipe being used for compressed air exploded 27 feet above a warehouse floor. A fragment of the pipe flew 60 feet and embedded itself in a roll of paper. Fortunately, nobody was in the area at the time.
 
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#27 ·
I put 3 drops in my shop and frankly i use em all, one by each bench and one for the sandblast cabinet. one is in the center of the shop with a 50 foot reel, the last is by a workbench by the garage door - easier than uncoiling 40ft of hose (usually over or around a car ) to air up tires outside the garage door. Everyone's situation is different. For me this seems to work well, actualy i wish I would have put a couple more drops in, but thats just me.. to each his own - it's all good
 
#28 · (Edited)
ddrumguy said:
...
For me this seems to work well, actualy i wish I would have put a couple more drops in, but thats just me.. to each his own - it's all good
Well, that's another plus for that Airmax stuff. Shut off the ball valve at the tank, bleed the line pressure off, and reconfigure at will.

It's all slip-fit and only takes seconds to release, install a tee, and extend the line.

Want to move that FRL or drier?
Same thing.

I know that I sound like I'm trying to sell this stuff, but honest ... the place I work at now doesn't even sell it. :D

They have JUST released a PDF file that shows more of their product displays.
 
#29 ·
66, I guess I am still stuck on what I have used for so long and would probably spring for Copper or use black iron if I were to build a new shop today but as I said earlier one should at least look at new ideas and products. That stuff does look interesting and looks as if it would make for a neat clean installation but most of all it is designed for the purpose and should be safe. I have been thinking of adding a pressure washer pad (an area beside my shop to clean parts), this would be plumbed for water and air and since I have harped so much on air systems here I think maybe I will try the AirMax line for the air part of this and find out for myself how well it works. I can't believe I am actually considering using a plastic air line :rolleyes: but after screaming so loudly against it for so long I have to admit this is different and as I said it is interesting so I would just like to know. :)
 
#31 ·
I am one who agrees with Oldred on this airline deal..I have run a short piece of hose down to a bench or something when I needed to do a quick fix..

This Airmax stuff sounds like it may be good for that sort of thing to me..Any way when I put in a new system I put in some tees and plug them so I can put in an extra drop or two if I find I need to..saves having to cut into a line and using a union to get another tee..

I also find 1/2" black iron to be sufficient for most apps..3/4" is way overkill in an automotive shop as far as I am concerned..

Sam
 
#32 ·
One more time

A company I worked for had a plastic system of the type you describe. While it was easy to fix and add to, It was also high maintenance. Every time a hot spark hit it , it got a leak. It was finally replaced with iron pipe. Before I went off the deep end and installed a system, I would pressurize a short section and see how it responded to welding and grinding sparks.
The reasoning behind 3/4 is that slows the velocity of the air through the line thus is less apt to carry contaminants with it and cools better.. If capacity was the only consideration, 3/8ths would do the job for just about any shop. :)
 
#33 ·
61, My first impression from looking at the AIRMAX is just what you are pointing out but I thought I would try some of it anyway and find out first hand. My biggest concern would be water because of the poor cooling that I assume would result from the plastic and of course durability would be a concern also. Where I intend to add this line it will be after the seperator and will never have hot air reach it so I might tap into the tank and run a section to use for a while to see how well it works and then move it to the addition. As soon as the weather warms up I am going to be undertaking this pad addition project so as soon as I get this stuff up and running I will get back on it.

I could not agree more with what you said about the 3/4" especially when using iron pipe.
 
#35 ·
In the interests of the science of hotrodding and garages, I am willing to sacrifice for the good of home shop users everywhere. If everyone pitches in a small donation, I'll give up space and time to install 12" diameter galvanized steel pipe in a U-shaped loop around my garage just above the floor, leaving out only the entranceway. I solemnly pledge to tirelessly collect the data and make the reports about whether it significantly increases the air storage capacity, decreases the delivered air temperature, and makes for comfortable seating for spectators. Some miniscule part of donations will be used for a trip to some small tropical island to determine if the females there find such piping to be aesthetically more appealing than plastic piping. After all, I'm certain my air tool using brethren are deeply concerned about this aspect of airlines, so I must shoulder this burden for the good of hotrodding!
 
#37 · (Edited)
Not sure what he was saying either but that sure would eliminate water problems, just as a case of dynamite would rid your yard of ants! :D I checked out that link and unless someone is concerned with precise air control on say some kind of robotic gizmos I think that it is way overkill. On a shop system of 20-30 CFM 3/4" pipe is going to be all anyone is likely to need and 1/2" would supply the air but 3/4" will help for moisture control. The extra capacity of the 3/4" vs 1/2" is negligible (as if it would make any difference anyway) but the velocity will be slower which can make a difference. It can be argued that using the 1/2" pipe for the "drops" can be beneficial because the law of physics dictates that the higher velocity of the contaminates (water and oil droplets or whatever) will cause them to want to continue in a straight line making it more difficult to make the turn in order to enter the tee going to the air hose, thus they will continue past the tee and into the collection part of the "drop". How well does that work in the real world? Well 1/2" pipe is not going to be an issue at this point in the system and it's a bit cheaper so why not? :) For the primary part of the system suppling the air from the tank to the "drops" I really do think using 3/4" is worth the minuscule (compared to most everything else) extra cost but while in theory 1" would be even better I don't think it would help much vs the 3/4" In any case you would have to be using a heck of a lot of air for it to matter anyway but with a sandblaster or running multiple tools this could very well happen.
 
#38 ·
grouch said:
In the interests of the science of hotrodding and garages, I am willing to sacrifice for the good of home shop users everywhere. If everyone pitches in a small donation, I'll give up space and time to install 12" diameter galvanized steel pipe in a U-shaped loop around my garage just above the floor, leaving out only the entranceway. I solemnly pledge to tirelessly collect the data and make the reports about whether it significantly increases the air storage capacity, decreases the delivered air temperature, and makes for comfortable seating for spectators. Some miniscule part of donations will be used for a trip to some small tropical island to determine if the females there find such piping to be aesthetically more appealing than plastic piping. After all, I'm certain my air tool using brethren are deeply concerned about this aspect of airlines, so I must shoulder this burden for the good of hotrodding!
as a plumber for the past 30 years having worked on up to 6" i would gladly donate a small amount to watch you thread and hang 12" galv steel pipe
 
#39 ·
russlaferrera said:
I will be placing money collection jars in all the auto parts stores to collect donations for this worthwhile evaluation...russ
It will be a big job, so we might need a whole committee to go poll the inhabitants of various tropical islands regarding their airline preferences. ;)

oldred said:
Not sure what he was saying either but that sure would eliminate water problems, just as a case of dynamite would rid your yard of ants! :D
You gotta admit, it makes more sense than using PVC for airlines, at least!

oldred said:
The extra capacity of the 3/4" vs 1/2" is negligible (as if it would make any difference anyway) but the velocity will be slower which can make a difference. It can be argued that using the 1/2" pipe for the "drops" can be beneficial because the law of physics dictates that the higher velocity of the contaminates (water and oil droplets or whatever) will cause them to want to continue in a straight line making it more difficult to make the turn in order to enter the tee going to the air hose, thus they will continue past the tee and into the collection part of the "drop".
Hey, that sounds reasonable! I remember using something similar in a chemistry lab class. I think that's also the way certain vacuum cleaners work.

So, 3/4" running at a slight pitch near the ceiling, maybe 1/4" per foot, with a tee that sends the 3/4" up a little ways to then begin another run and the other side of the tee sending a 1/2" down to another tee. The 1/2" goes straight through its tee, at some convenient height above the floor, down to a collector or valve near the floor, and the branch is where you connect the air hose.

The slower moving air in the 3/4" pipe hits the tee intersection, causing particulates to slow down even more and some condensation. The air splits both ways, up the 3/4" riser and down the 1/2" drop. The air speeds up as its taken from the 1/2" and helps move the particulates and condensation on their way down the pipe to be taken out at the bottom.

59 wagon man said:
as a plumber for the past 30 years having worked on up to 6" i would gladly donate a small amount to watch you thread and hang 12" galv steel pipe
Hmm, might need to use some donations to make a study of the potential problems. Think they teach plumbing in Tahiti?
:evil:
 
#41 · (Edited)
Steve, That sounds like the specs I have seen on some compressors :)

I know it seems like splitting hairs and making a big to-do out of nothing BUT, seriously, the size of the pipe is important. The 3/4" pipe has more mass to radiate heat and more surface for water to condense on plus the air will dwell longer inside due to the slower velocity so it does have an advantage, ever so slight that it may seem. Even though we are talking about only a few drops of water and a relatively huge volume of air the problem is that due to condensation this water rarely is evenly dispersed within this volume of air, if it were then it would be of no significance. Those few drops of water become significant indeed when your sandblaster becomes clogged due to wet sand or far worse those few drops of water end up in that last coat of $300 per gallon paint :pain: .

I think the message trying to come across here is that this air line subject has been beaten to death and recently we have been abusing the corpse :spank:
 
#42 ·
ok boys and girls this should hopefully give everyone an ideal product to use . go to www,transairaluminumpipe.com and check this product out. aluminum tubing and fittings especially designed for air and vacuum systems . lightweight easy to join approved for high pressure and the koolest shade of blue you will find on copper or steel
 
#43 ·
I took a look at that at that transair site (need to change the comma to a dot). Man, that is a nifty setup. Their catalog, btw, has some great illustrations if anyone wants to knockoff their design. I didn't see any pricing information anywhere on the site though but I'm guessing a bit expensive. Oldred is right in that we have beat up this topic pretty bad but this site is one of very few that I have found that has good information on plumbing a home air system. I ended up using 1/2" black pipe. I thought about using 3/4" but figured the 1/2" would be easier to handle and, of course, it was cheaper. If I did it all over again, I would use copper (damn the expense!). The reason I say this is that it took me forever to chase down all my leaks and, not being a plumber, I neglected to put in unions where I should have so I ended up disassembling a lot of pipe to get to each leak. Anyhow, it's all tight now but I'm thinking just re-sweating some joints would have been a lot easier. Finally, I used the TPTools suggested configuration and I gotta say, I get NO WATER in my media blaster. Anyhow, here's a couple of photos of the way I did it.
jor
 

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#44 ·
Think I got lucky!

Bought my copper today, 1/2" type M rigid for $1.05/ft (and that was at a plumbing supply house). Snagged 100 ft of pipe, 20 ell's, 10 tee's, 10 sweat-to-pipe bushings, 5 couplings, 20 strap mounts, solder and flux for $160 bux! I'm gonna start tomorrow on my cooler/drier coil to practice my soldering "skills"... :sweat:

Russ
 
#45 ·
Main thing on sweating copper is to get the fittings and ends of the pipe or tube clean..thay make a brush for this which should be a tthe local hardware store..it has one end wiht the bristles in a hole for doing the pipe and the other end looks like a bottle brush...

Clean the mating areas real well and not touching as the oil on your fingers will cause soldering issues..appy flux put then together and sweat away..when it is right the solder should just wick around the fitting..

Sam
 
#46 ·
Found 2 more good tips (don't remember where though):

1). Heat the joint until you see a greenish flame and it's ready for solder.

2). Do as many parts of a fitting as possible at the same time, i.e. all legs of a tee simultaneously.

Sounds hard but it's really easier! Got my cooling/drying rack done today with no leaks.

Thanks for the tips!

Russ
 

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#48 ·
hey cliff double check that abs deal like i said previously abs is generally used for waste lines. therefore i believe it is only good for low pressure the grey stuff your referring to is schedule 80 pvc .while the fittings might take more pressure this would also require schedule 80 pipe.this is not so easy to find and with the rising prices on pvc might actually prove to be more expensive then copper or steel .
 
#49 ·
Cliff, Since this thread is intended to cover all of the pros/cons of using PVC/plastic I am curious what is your is reasoning for wanting to use plastic of any type? I am completely convinced that PVC should NEVER be used for air line and there are no good reasons to do so however if ABS or some other type is safe then perhaps there may be a place for it, maybe?
 
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