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Greg Caputo
08-16-2006, 12:00 PM
Hi, everyone. I want to install some piping for compressed air in the workshop. I have a fairly typical weekend warrior shop in the basement. No one else ever uses the shop. The line will have three drops, one of the drops for spraying. I've read a lot over the years about the need to use black pipe or copper tubing. But a recent woodworking magazine featured a piece on using some sort of flexible rubber or plastic hose. And I've seen photos of shops with PVC for the air. I'm leaning towards PVC due to ease of installation and removal, if we ever move. I can't do black pipe...no experience and no tools. I'd rather not do copper if I don't have to. Any experiences or thoughts from folks who are using or have used PVC? As always, thanks for your advice and guidance.

Greg

Chris Padilla
08-16-2006, 12:05 PM
PVC and copper (maybe the thicker-walled ones can?) aren't typically designed to handle the PSI load that an air compressor supplies so I don't think they are good materials to use.

The flex rubber stuff you saw might have been air compressor rated or something known as Flexsteel. What magazine did you see this in...what issue?

Jim Becker
08-16-2006, 12:10 PM
"Just say no to PVC" for this application. It's not rated for compressed air. Yes, some people have used it successfully, but it's not the right product for the job. Copper is easy and inexpensive.

As to the flexible hose, I use the Flexeel hose that Chris mentions and have a review of it on my web site.

Ed Labadie
08-16-2006, 12:10 PM
I think the only PVC pipe that has a high enough pressure rating for air line use is schedule 80. You will probably have a hard time finding it. It's not available at the Borg. Not all plumbing supply houses carry it.

Ed

Chris Haney
08-16-2006, 12:16 PM
There was an article in September issue of American Woodworker (p. 57) about using rubber air hose with copper fittings for plumbing a shop with compressed air. At the end of the article, they reference MSC Industrial Supply as a materials source (www.mscdirect.com (http://www.mscdirect.com)). It looks like a pretty good alternative to using copper or iron pipes. The MSC part number referenced for the 1/2" rubber hose is 48563720 and can be found on this page of the MSc site: http://www1.mscdirect.com/CGI/NNSRIT?PARTPG=IMLMKD&PMPXNO=1903625. It (currently) costs $.78/foot and is cut to length. They also sell other air handling hoses with increased PSI ratings.

Kyle Kraft
08-16-2006, 12:34 PM
PVC pipe can rupture suddenly under pressure and is not to be used for compressed air piping. Check the OSHA website. Type K copper is perfectly ok. I actually used type M in my shop, but I regulate my air to 100lbs or less. Copper is nice because you don't get the rust and scale flaking off when moisture is present, however, if you have a properly designed compressed air system you can reduce the amount condensate in it.

George Leicht
08-16-2006, 12:34 PM
I would seriously look at black iron. I agree with Jim Becker that copper is easy, but it hasn't been inexpensive for a while. Black iron is not as easy as copper, but it's not that difficult.
George

Kyle Kraft
08-16-2006, 12:38 PM
Thats true George, copper has gone out of sight recently. I figure the value of my house and shop has gone up several thousand dollars just 'cuz of all the precious metals in them!

Go rent a pipe threader and a tri-stand and go to her!

Jeffrey Makiel
08-16-2006, 12:41 PM
Regardless of pipe material and rating, all pipe has the potential of failure (manufacturer defect, improper installation, being struck by an object, etc). The issue is that PVC will shatter should it rupture thus sending air propelled shards of hard plastic all over the place. This is not the case with copper.

My recommendation: avoid the PVC, CPVC and ABS pipe for compressed air use.

cheers, Jeff

Brad Townsend
08-16-2006, 12:45 PM
Although not designed for high pressure air, copper seems to work fine. I suppose theoretically, both it and PVC could burst, but I've never heard of such with copper. The difference as I see it, if copper bursts, it will just split and not send shrapnel flying everywhere. I'm not so sure that would be true of PVC.

Jeffrey Makiel
08-16-2006, 12:49 PM
Threaded black pipe can be difficult to get leak tight at air pressures of 125 to 175 psi. This may not be important, but can be a nuisance because it will bleed down the air compressor's tank between uses unless it's valved off near the tank. Black pipe is best suited for low pressure applications like natural gas and low pressure steam (less than 15 psi).

cheers, Jeff :)

Keith Weber
08-16-2006, 12:53 PM
PVC + High Pressure = Shrapnel (IMHO!)

Yes, PVC has the pressure rating, in theory, to handle the pressures you are talking about. But, there are a number of things to consider. The pressure rating of PVC drops considerably in warmer temperatures. In colder temperatures, it becomes brittle. If a pressurized PVC pipe is exposed in your shop, you could accidentally bump it with a long piece of wood as you turn it around. If the bump causes it to shatter, the one who bumped it is going to be in the immediated vicinity during the resultant shrapnel attack. PVC will weaken with exposure to UV light. Try whacking that old sun-bleached PVC pipe in your back yard against a tree and see what happens!

I plan on using type L copper when I get around to doing mine. It handles moisture better than the steel varieties, is easy to work with, and will give me a piece of mind that I'm not working around a potential land mine. Type L is a little more expensive than Type M, but its pressure rating is a little higher.

If you need an alternative, that rubber air hose idea someone mentioned sounds safer than PVC. I don't think that the air would flow as well, though, because the fittings would act as bottlenecks in your system.

Keith

Robert Mickley
08-16-2006, 12:54 PM
Nylon tubing, easy to cut, goes together with compression fittings, you can go back later and cut it to add in a drop.

No soldering, no gluing, no special tools.

Rated in a range of about 450 to 550 PSI.
Easy to disassemble and take with you, comes in sizes from 1/8 inch to 3/4

Check out Semi truck parts houses and it can be bought online in price range of .25 to 1.00 a foot For the most part I bet thats cheaper than steel or copper.

Greg Caputo
08-16-2006, 1:10 PM
These are great responses and ideas! So much for my hope to use PVC.

Chris has the citation for the magazine article I mentioned. But this method still requires sweating copper for the drops. The nylon tubing idea from Robert is something I've not seen before. It sounds like it could meet all the requirements I have, especially if it can be accomplished with compression fittings. I'll look at the Grainger catalog, but any other ideas for sources?

Thanks to everyone from your help.

Greg

Rick Lizek
08-16-2006, 1:18 PM
PVC is banned by OSHA with good reason. Type L or K copper is fine for the shop. Faster to use but pricey is abs air line...
http://www.indelco.com/c-345-compressed-180psi-air-piping.aspx
Drops should go up then down, see diagram...
http://www.tptools.com/statictext/airline-piping-diagram.pdf
Info based on fixing improperly insatalled air line sytems.

Gary Hoemann
08-16-2006, 1:32 PM
if you wanted to, why couldn't you just use air hoses. They always seem to be cheap

Robert Mickley
08-16-2006, 2:12 PM
These are great responses and ideas! So much for my hope to use PVC.

Chris has the citation for the magazine article I mentioned. But this method still requires sweating copper for the drops. The nylon tubing idea from Robert is something I've not seen before. It sounds like it could meet all the requirements I have, especially if it can be accomplished with compression fittings. I'll look at the Grainger catalog, but any other ideas for sources?

Thanks to everyone from your help.

Greg

Most likely why you haven't seen it before is, it's most common use every day is on air brake systems for trucks. You will also find it on industrial equipment that use's phnuematics for things like clamping and other repitive operations.

Grainger may carry it but it will be pricey. Just get your yellow pages out and look for truck parts. Any place that sells truck parts and equipment will have it. Try to stay away from the dealers.

I think up ideas like this since I tend to think outside the box a lot. If I had been thinking when we ran the air line from the front shop to the back one it's what I would have done. As it stands I need to run lines around the shop yet and this is how I will do it.

Chris Padilla
08-16-2006, 2:52 PM
Could PEX handle the pressure? This is the new "copper" plumbers are running in new houses.

http://www.sawmillcreek.org/showthread.php?t=40514 is a good thread to read, too. Has a link to a nice diagram in a post from Tod.

Al Willits
08-16-2006, 3:03 PM
I have tried PVC as air lines, with 165psi I blew the end cap off the end of one run, it didn't rupture at the glue joint, but about 2" from it.
fwiw I'd stay away from PVC

Personally I like black pipe, its strong,resists puncturing and with a pipe threader not to bad to work with, and I'd disagree that it leaks easily, I had about 80-100' of it run, and the only leaks I had were the quick connects I use.
On the other hand I used a 18" and a 24" pipe wrench....:)

Teflon impregnated pipe dope seems to work better that the tape, for me anyway.

Al

Dan Oelke
08-16-2006, 3:04 PM
Disclaimer - I haven't yet plumbed my shop for air...

The thing I don't like about using hose (as I saw in that article) is that it is too easy to get a sag someplace where moisture can puddle. With rigid piping you can set it up with a slope and know that all the moisture will come out of one of the drops.

The other really nice thing about metal lines is that they will act as a radiator and cool and to some degree dry your air. I know someone here on the creek has posted a thread where they showed in their shop a lot of pipes snaking around just to get that effect. A plastic line, or hose just won't have that cooling effect.

Joe Mayo
08-16-2006, 3:17 PM
Repeat after me ....
I will never, ever, ever use PVC for compressed air.
I will never, ever, ever use PVC for compressed air.
I will never, ever, ever use PVC for compressed air.

If the integrity of the PVC is compromised, it doesn't just break. It explodes, sending lots of shrapnel all over the place.

Now that we got that out of the way … Black pipe or Type "L" copper tubing works well for compressed air. There was an article in FWW's Tool & Shop issue a couple of years ago describing how to run the pipe. They used 3/4 inch for the main line and 1/2 inch for the drops. Put a Tee fitting at each drop with a regulator on one side of the tee and a drip leg with a valve on the other side. When you connect your drops to the main line, go up towards the ceiling and solder 2 elbows together, doing a 180 to come back down. This will, in theory, keep the air drier. Finally pitch your main line back towards the compressor so that any water in the system drains back to the tank. Hook it up like you did the drops by using a tee with a drip leg and a valve. Don't forget to put a shutoff valve at the compressor. Then you won't have to discharge your system to drain the water from the drip legs. To reduce any vibration from the compressor to the lines, use a short piece of rubber hose connecting the shut-off valve on the compressor to the tee fitting at the beginning of the main line.

Good Luck,
-Joe

Lars Thomas
08-16-2006, 3:29 PM
If you used regular hose and it was severed, wouldn't the head-end start whipping around from the pressure releasing?

Rick Lizek
08-16-2006, 3:55 PM
I thought about the Pex as an airline some time ago and put the question to the manufacturer. They would not stand behind Pex for airlines. The only plastic suitable for air lines is the Chem-aire productI linked to before.

Al Killian
08-16-2006, 4:04 PM
go to a local Napa auto store or truck stop and ask about 3/8 air line. It is rated for 175 PSI.

Robert Mickley
08-16-2006, 6:14 PM
I thought about the Pex as an airline some time ago and put the question to the manufacturer. They would not stand behind Pex for airlines. The only plastic suitable for air lines is the Chem-aire productI linked to before.

Pex would be pricey for airline

Nylon tubing is approved for air, If it wasn't they couldn't use it for brake systems on trucks.

I still think it's the most economical way to go, properly anchored your not going to hav an issue with sagging. No reason why it couldn't sloped the same as any ridgid pipe. and its rated up to 550 psi, what more do you want. I doubt you would puncture it, even if you did it would take all of 4 or 5 minutes to fix. Cut it with your pocket knife and install a union, Done!

I can understand not being familar with a product, but don't discount till you have looked it over thoroughly ;)

Robert Mickley
08-16-2006, 6:30 PM
Besides with push to connect fittings you don't even need wrenchs

http://www.imperialinc.com/grp299.shtml

150 working PSI 900 PSI burst
http://www.imperialinc.com/items.asp?item=0908060

Not strong enough?
980 PSI working pressure
http://www.hudsonextrusions.com/nylon_tubing.htm#javascript;

Bruce Wrenn
08-16-2006, 11:40 PM
Saw that article and wasn't the least bit impressed. Many sags in lines equates to a lot of traped moisture. Copper is the way to go. When you turn off a faucet quickly, the resulting shock waves (known as water hammer) are in the multiple hundred pound range. Copper will take this with no problem, so normal (100- 150 psi) should not be a problem. Go to copper institute web site and look for info on running copper air lines. If you don't know how to solder copper, then learn. Go to plumbing supply house and get a jar of Lacco brand flux. It is what all the pros here use. With copper it is easy to cut in a drop. They make special repair couplings that don't have a ridge in the middle just for slipping over copper pipe and then back to area of cut in pipe. Remember that copper is basically a lifetime deal- once and done forever.

Rick Christopherson
08-17-2006, 12:58 AM
The notion of PVC exploding is more fear than reality. Not to say that it can't shatter, just that it is not as prevelent as the fear mongers make it out to be. I installed PVC in my shop 10 years ago because it had a 300 psi rating. In that time, I have had two ruptures. The first was when a plumber was sweating a copper fitting and didn't realize he was heating up the charged air line too. The rupture was a blister in the side of the piping, and did not shatter. The second rupture was when a fitting let loose. This was an explosive separation of the joint, but the pipe did not shatter.

That being said, I am planning on replacing the primary lines with copper. Not because I worry about the shattering, but because I have now learned that the joints have age limitations. My primary manifold where I have my dryers, regulators, and several valves is leaking at several joints. I don't regret using the PVC because it was very cost effective for the several hundred feet of piping, except for the feeder that is buried in the wall leading to my garage. If the joints fail on this line, I won't be able to access them for repair. I'm not going to replace the whole system, just the main line between the compressor and the manifold.

Steven Wilson
08-17-2006, 12:41 PM
PSI rating isn't the only rating you need to consider. You must consider if the material you want to use is rated for handling gasses under pressure. PVC pipe is not rated to handle gas under pressure, PVC's pressure rating is for incompressible fluids (i.e. water). Do not confuse these ratings. PVC is a well known hazzard for handling compressed gasses, only fools use PVC for air systems. Copper, black pipe, aluminum (some) and some other plastics can all be used for air and all share the ability to fail plastically (i.e. split open, not break up into shards). Make sure your using a material that works for gasses then take into consideration the PSI ratings.

No PVC ever.

Russ Filtz
08-17-2006, 12:52 PM
Here's a link to an engineering forum discussion on the subject. Not sure if these links are OK. If not, please delete!

http://www.eng-tips.com/viewthread.cfm?qid=122826

Rick Levine
08-17-2006, 5:39 PM
"Just say no to PVC" for this application. It's not rated for compressed air. Yes, some people have used it successfully, but it's not the right product for the job. Copper is easy and inexpensive.

As to the flexible hose, I use the Flexeel hose that Chris mentions and have a review of it on my web site.

I don't know where you live but where I am copper is definitely not inexpensive. My plumbing contractor suggested black pipe. He said he has used it for many customers like gas stations and the like. Just remember to add drains at both ends of the run. I do agree to avoid PVC.

Jim Becker
08-17-2006, 7:32 PM
Rick, in the scope of "how much pipe", most folks shop air systems are not going to use a lot of copper. And unlike black pipe, you don't have to choose between working with fixed lengths or investing in/renting a cutting/threading machine. That, in my mind, can make copper easier to install...and learning how to sweat copper isn't a horrible thing for any homeowner to do since over time, there will be opportunities to repair the stuff in the domestic water supply in a large percentage of homes. (Saves big bucks if you don't need to call the plumber...)

That said, I agree that black pipe is an appropriate material for this application and folks should consider it, comparing both cost and installation aspects for their particular shop. It would have been a pain to use in my shop, for example, but it was really easy to thread 3/4" and 1/2" copper into the places I needed it to go.

Rick Levine
08-17-2006, 8:20 PM
Jim (Becker),

You make a good point about copper. I have plumbed a couple of photographic darkrooms with copper and I find it easy to work with. On the other hand, my Home Depot will thread black pipe for free, even if you don't buy it from them and I assume others will too. I would buy it from them anyway since it is less expensive from them than the other suppliers, again, in my area. My new shop will take 40-60 feet of pipe so the cost would be significant for me.

Brent Dowell
08-17-2006, 11:04 PM
I Plumbed my garage for Black pipe, and the HF threading kit I bought was really quite reasonable.

Kind of a toss up I guess whether you like playing with fire (copper) or Threads.

I liked the threads. No, that's not right, I like both, but from what I had read, the black piped seemed to provide more thermal mass to help cool the air and pull the moisture out. Since I was planning on using mine to paint a car, it seemd to make sense to use the black pipe as a dehumidifer. Just make sure you run the slope so it goes back to the tank.

It's easy to cut black pipe with a pipe cutter and really, the threads aren't that hard to cut either. Just have some cutting fluid, and a pipe vise, and it goes really quickly.

Bruce Wrenn
08-17-2006, 11:19 PM
Repeat after me ....
I will never, ever, ever use PVC for compressed air.
I will never, ever, ever use PVC for compressed air.
I will never, ever, ever use PVC for compressed air.

If the integrity of the PVC is compromised, it doesn't just break. It explodes, sending lots of shrapnel all over the place.

Now that we got that out of the way … Black pipe or Type "L" copper tubing works well for compressed air. There was an article in FWW's Tool & Shop issue a couple of years ago describing how to run the pipe. They used 3/4 inch for the main line and 1/2 inch for the drops. Put a Tee fitting at each drop with a regulator on one side of the tee and a drip leg with a valve on the other side. When you connect your drops to the main line, go up towards the ceiling and solder 2 elbows together, doing a 180 to come back down. This will, in theory, keep the air drier. Finally pitch your main line back towards the compressor so that any water in the system drains back to the tank. Hook it up like you did the drops by using a tee with a drip leg and a valve. Don't forget to put a shutoff valve at the compressor. Then you won't have to discharge your system to drain the water from the drip legs. To reduce any vibration from the compressor to the lines, use a short piece of rubber hose connecting the shut-off valve on the compressor to the tee fitting at the beginning of the main line.

Good Luck,
-Joe You said pitch lines towards compressor- This means every air use will bring back moisture that is draining towards compressor. Have lowest point and drain at fartherest point from compressor

Guy Fuson
08-17-2006, 11:59 PM
Greg,

I installed schedule 40 PVC in my shop 10 years ago with 15 different drop downs, my compressor stays at 125 lbs all day 7 days a week, no problems. Just make sure you clean, primer & glue good and most of all let it dry completely before applying pressure.

Good Luck
Guy

Rick Lizek
08-18-2006, 8:02 AM
http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=INTERPRETATIONS&p_id=20202
"Since PVC material does not possess shatter resistant property, and since it is very clear from the industry's recognized practice that PVC pipes are prohibited for above ground transportation of compressed air and gases (unless the pipelines are encased in shatter resistant material), any such use by the employers, where employees may be exposed to hazards, will be in violation of Section 5(a)(1) of the OSH Act. Therefore, employers who are found to violate the above described conditions or manufacturer's recommendations, during an OSHA inspection, shall be issued a 5(a)(1) citation." quote from OSHA

It's been my experience that many home shops eventually become real businesses so it's best to really know what's legal and best for insurance purposes. I've spent many years going in places and undoing usafe and just bad set-ups. You'd be amaized how many shops just run airlines any old way with no regard to standard procedures which minimize moisture issues. All good compressor companies have guidelines on how best to run airlines but I have seen few that read such info until they ran miles of airlines and experienced al kinds of water issues which could have been prevented early on.

tod evans
08-18-2006, 8:32 AM
All good compressor companies have guidelines on how best to run airlines but I have seen few that read such info until they ran miles of airlines and experienced al kinds of water issues which could have been prevented early on.

this fits me to a "t" ! after a few ruined paint jobs and having to replace some cleco motors i started listening to what the folks whos business is compressed air had to say. it really doesn`t cost to do things right the first time, in fact it`ll probably save you a chunk of change in the long run..02 tod

Al Willits
08-18-2006, 8:42 AM
Be nice if all would put the Town/state in where the Join date is on the posted page, I have both pipe threading equipt and soldering/braizing/welding tools and would be happy to help thoose who needed either the equiptment or tech help to install pipe/copper.

Unfornately I sold my power vise years ago, but threading pipe manually just takes a bit more time and isn't all that hard.

Whether PVC is rated for it or not, I know of three people who had it come apart on the, me being one, and when it does there's the chance of pieces flying off and striking someone...
You always wear protective eyewear in the shop? How about that daughter/son/wife that comes out to say hi?

If I was going to go back to painting bikes/cars, I'd be more concerned with the water/particle filters I used than if copper or black pipe controled moisture better, drip tee's/traps at the end of each run will probably do more than the material you use.
I think I used 2 water traps and 2 filters on the line I used for painting, and those I got at a commercial supply house.

Nothing is worse than to be in the last stages of painting and have the gun spit out a chunk of water, especially when doing metalflake...:)

I like black pipe also as I can hang stuff off it...:)

Al ......light stuff btw...:)

Chris Padilla
08-18-2006, 11:25 AM
...my Home Depot will thread black pipe for free, even if you don't buy it from them and I assume others will too.

Seems that my two local HDs have a permanently broken pipe threader....:mad:

Teri Lu
08-18-2006, 2:12 PM
Mention PVC for air lines and it WILL get a rise out of every partisan :-)

On some other forum, I remember this discussion and a point that was made was the possible problem in case of a fire. Obviously the PVC and other plastic piping would soften, burst and blow compressed air possibly on the fire! Someone pointed ot that the soldered joints in copper would do that too although at somewhat higher temperature. That being said, I suppose threaded black iron (steel) pipe is safer from that catastophic scenario.

Now where did I put that pipe threader ...

-- Teri

Be nice if all would put the Town/state in where the Join date is on the posted page, I have both pipe threading equipt and soldering/braizing/welding tools and would be happy to help thoose who needed either the equiptment or tech help to install pipe/copper.

Unfornately I sold my power vise years ago, but threading pipe manually just takes a bit more time and isn't all that hard.

Whether PVC is rated for it or not, I know of three people who had it come apart on the, me being one, and when it does there's the chance of pieces flying off and striking someone...
You always wear protective eyewear in the shop? How about that daughter/son/wife that comes out to say hi?

If I was going to go back to painting bikes/cars, I'd be more concerned with the water/particle filters I used than if copper or black pipe controled moisture better, drip tee's/traps at the end of each run will probably do more than the material you use.
I think I used 2 water traps and 2 filters on the line I used for painting, and those I got at a commercial supply house.

Nothing is worse than to be in the last stages of painting and have the gun spit out a chunk of water, especially when doing metalflake...:)

I like black pipe also as I can hang stuff off it...:)

Al ......light stuff btw...:)

Rick Levine
08-18-2006, 3:07 PM
Seems that my two local HDs have a permanently broken pipe threader....:mad:

That's odd, my HD also has a broken pipe threader. The automatic oiler has quit. I hope this isn't a trend. I did find another hardware store that will cut and thread for a small fee. I only have a few to make so it isn't an issue. I won't be ready to install the pipe for a month or so so it all may be moot.

Rick Levine
08-18-2006, 3:09 PM
Threaded black pipe can be difficult to get leak tight at air pressures of 125 to 175 psi. This may not be important, but can be a nuisance because it will bleed down the air compressor's tank between uses unless it's valved off near the tank. Black pipe is best suited for low pressure applications like natural gas and low pressure steam (less than 15 psi).

cheers, Jeff :)

According to my plumbing contractor, as I have said in an earlier post, he has used black pipe for many compressor installations. He does use both teflon tape and teflon based pipe dope to insure a tight seal though.

Matt Warfield
08-18-2006, 11:12 PM
Could PEX handle the pressure? This is the new "copper" plumbers are running in new houses.

Chris, I looked into this and yes, PEX can handle the pressure. However, PEX rapidly deteriorates in sunlight and becomes brittle. So, unless your shop is in a cave, probably not the best solution.

Matt

Rick Levine
08-19-2006, 10:35 AM
After reading the section on choosing pipe for a compressed air system in Sandor Nagyszalanczy's book "Setting Up Shop" (he's a former editor of Fine Woodworking and American Woodworker) I have decided to use galvanized pipe instead. The cost is irrelevant compared to the time it would take, at least for me, to replace any sections if there was corrosion due to moisture. My compressor will be located in the utility room which is separated by a wall from the shop. The pipe will run through the wall into the shop and feed various locations in the shop. Check out his book, he makes some pretty good points.

Edward Norton
04-15-2009, 2:09 PM
"Just say no to PVC" for this application. It's not rated for compressed air. Yes, some people have used it successfully, but it's not the right product for the job. Copper is easy and inexpensive.

As to the flexible hose, I use the Flexeel hose that Chris mentions and have a review of it on my web site.

Just as most have mentioned copper is expensive. I see everyone here talking about PVC but nobody talking about CPVC. HUGE difference in the wall thickness as well as pressure ratings.

CPVC is rated at 100 PSI @ 180 degrees and 400 PSI @ 73 degrees. I have several friends that have had CPVC pipe for air lines in their garages and shops for years with no bursts or problems.

I am getting ready to do my garage using CPVC. I think one of the major things to consider here is to not run your air settings through the roof. I use all sorts of air tools in my garage from a simple brad nailer through a 1" impact wrench for truck tires and none of them require more than 90 PSI.

If I were worried about bursting then I would run the pipes through the stugs and them run a 1x2 along them as a shield.

Copper, galvinized & black iron are all good choices as well but you'll spend upwards of 200% more using these. Also unlike the other piping options CPVC does rust.

Just my thoughts...

Pete Shermet
04-15-2009, 2:16 PM
I used type "L" copper for the higher burst pressure, black pipe is what they install in the auto shops but I don't have a threader but I do have a torch and know how to sweat a copper joint together!
Best Regards
Pete

Chris Padilla
04-15-2009, 2:21 PM
FYI, Ed dug up a post that is 2.5 years old! Still good stuff...just letting folks know.

Raymond Gerdes
04-15-2009, 2:46 PM
Our Lowes Denton,TX has grey sch 80 pvc.

I used shd 40 white pvc (not 200) and was careful to twist each joint and was quite pleased. I like it that it permits modification so easily.

Ray Gerdes in beautiful Texas

phil harold
04-15-2009, 3:18 PM
copper can be easier to work with than threaded pipe

3/4" m pipe seems to hold enough pressure for me 611psi at 250 degrees
http://www.ccbda.org/publications/pub28E/28e-publicationptb6.html

joints are 200psi lbs with 95-5 solder
http://www.ccbda.org/publications/pub28E/28e-publicationptb11.html

Walt Nicholson
04-15-2009, 4:57 PM
Chris, I noticed the date on this one as well and since the original post, Pex has introduced a new product called AL-Pex. http://www.pexsupply.com/Mr-PEX-PEX-AL-PEX-Tubing-389000

It has good pressure ratings, is easy to work with and the fittings use special ferrels and ends that can be installed with two crescent wrenches (or the right size end wrenches for the purists) instead of some of the special (spendy) tools the other Pex products require.. (No affiliation with the company) I just bought some for the new shop and it works great. So far I just did a little short run as a test but hope to have the whole shop done soon. The fittings are a little spendy ( I used black iron for elbows instead of theirs) but I bought a 300 foot roll for $139 bucks. The last time I worked with copper was not a pretty sight and I was always worried about my lack of expertise with the sweating/soldering process. Like a lot of other folks, have heard some real horror stories about pvc.:eek:

Edward Norton
04-15-2009, 11:19 PM
FYI, Ed dug up a post that is 2.5 years old! Still good stuff...just letting folks know.

Sorry about that. I was doing a search when I came across this site and post so I joined just to put in my 2 cents! :D

BTW I put together a test pipe using 3/4" CPVC and cranked up the air pressure. The pipe did burst but not before it reached a bit over 300 PSI! I don't know any shop running that much pressure.

The pipe did not shatter & throw shards of razor sharp plastic everywhere as some indicated it would. The pipe did came apart at a connector with an interesting kinda noise followed by the sound of a mad rush of air. The only thing harmed was my undies!

Ok I am done with the 2 1/2 year old post.

Larry Prince
04-16-2009, 6:03 AM
FWIW; I've been using PVC in my shop for about ten years now with no problems. I don't know what schedule it is, but I got it from Home Depot and its marked at 480PSI.

A friend of mine who happened to work for an automobile company which shall remain nameless used their testing facilities to find out what happens when PVC is over-pressured. A 2" piece was capped off and placed in an enclosure with a glass view. Air was pumped in at increasing pressures until at about 600PSI the side of the PVC started to balloon. A few more pounds and the balloon split. That was it, no shrapnel, no explosion, just a split. (Chuck if you're watching feel free to correct my number. It might not have been quite that high).

YMMV. Something I think about is that all plastics seem to get brittle with age, which could seriously hamper their strength and result in that shrapnel we hear so much about. I've considered a simple shield over the pipe that would deflect any shards.

Brian Backner
04-16-2009, 7:48 AM
Just a few comments.

The concern about PVC pipe shattering into shrapnel is only partly due to overpressurization. The real concern is what happens when a pressurized length of PVC is hit hard enough, by a board or whatever, to cause the pipe to crack. If Larry's buddy were to go back and repressurize a piece and set up an impact test at the same time, I wouldn't be surprised if the results weren't a little more "spectacular."

One of the concerns mentioned about the use of black pipe regarding leaking threaded joints can be easily solved by a product used by gas fitters (they obviously cannot allow ANY leakage!!!). Use a pipe dope called X-Pando - you mix it with water before using. Stuff expands to seal every little space in the made joint and sets like a rock. Stuff is rated to handle to 5,000 psi! It is almost impossible to break a fully cured joint unless you happen to be King Kong.

http://www.xpando.com/pjc.html

Brian

Rick Christopherson
04-16-2009, 1:28 PM
Since the time I made my previous posting in this very old thread, I have replaced all of my original lines with copper. Well actually, I can't afford to put as many lines in as I originally had, because I went with extreme overkill the first time around. I had dual pressure lines running all the way around an 1800 sqft shop. I think I originally had 14 drops, but over time I realized that I only needed a couple standard drops and a dedicated drop for my sander (plus a new line going upstairs into the garage).

I have no regrets with putting in the original PVC (I think it was CPVC) because it was cost effective and lasted 10-12 years before I started getting a lot of joint failures. It fit my budget and needs at the time.

As I already said, the risk of shattering a line is more fear mongering than reality. I replaced the lines because I was getting joint failures (leaks) with the aging lines, not because they were exploding and killing small animals. :D Yes, the PVC will shatter, but you have to take a full-swing with a hammer to do it, and even then, it frequently takes two hits to actually break the line....yes, this was my chosen method for quickly removing the old lines.

If I had to do it over, I would do the same thing. I would put the PVC lines in again under a tight budget, and replace them later when the shop could afford the more expensive copper. Regardless of cost, I wouldn't even consider black pipe unless I was a plumber with all of the cutting and threading tools at my disposal. The only regret is that I didn't install copper up to the garage before I closed the walls with sheetrock.

Dave Lessley
04-16-2009, 3:45 PM
Rubber air hose decomposes over time and will provide you with little bits of rubber in your air stream. As someone else mentioned it will sag and create pockets to collect water.

The reason to use metal pipe is it encourages the process of condensing the water out of the air. That process happens more quickly with Black or Galvanized pipe than Copper or PVC.

There are a couple of schools of thought and you can probably make a case for a bunch more. You want to get the water out of the air. It is usually recommended to run 50 feet of metal pipe before your outlet to let the condensation process take place. You want to have a drain to let the water out.

Usually it's recommended to slant the pipes that feed your outlets back to a water filter which is at the end of that 50 feet of pipe and then slopethe 50 feet of pipe back to the compressor or towards the water filter. Water being heavier than air it will go to the bottom of your tank little will remix with your air the water comes from the compressed air being hot and condensing in the pipes. Thats also why the manufacturer however tells you to drain your tank daily. This also helps keep your tank from rusting out. You want to keep your water filter as close to your outlets as possible. You want to use as short of hose as possible the more hose you have running accross a concrete floor especially if your not using a water filter and your hose is coming directly out of your compressor it will condensate in your hose. Not good for air tools or finishes.

Sorry this is a little convoluted I'm at work and need to go get some lunch so I'm kind of in a hurry.

DaveL

John Fricke
04-16-2009, 9:22 PM
PVC for airlines "USED" to be used extensively in farm shops in my area. (farms are not subject to osha inspections" PVC airlines are a ticking time bomb with shrapnel included. I have not heard of any major injuries but I have heard of several instances of lines exploding. For the few hours and dollars you save to plumb a small workshop it is not worth it in my opinion. Steel would be my first choice. Like others said rent the equipment for a weekend and have a teachable moment.

David Hostetler
04-16-2009, 10:59 PM
I haven't been able to keep up with the posts, so I don't know if anyone has mentioned this, but...

PVC pipe is NOT rated for compressed air, under the high pressure load of air systems, PVC can rupture suddenly and explosively producing small bits of shrapnel that would be more than happy to embed itself in whatever body parts were within range.

DO NOT USE PVC PIPE FOR COMPRESSED AIR!

My fist career was as an auto mechanic, and I have seen the end results on the job of this poor plumbing decision. You DO NOT want those results. I was lucky, I wasn't near the rupture, a coworker of mine required fairly invasive surgery and suffered facial scars and required several surgeries over it. The shop we worked at was shut down over this...

David Freed
04-19-2009, 2:25 PM
If you used regular hose and it was severed, wouldn't the head-end start whipping around from the pressure releasing?

Over the years, I have repaired many rubber air lines by cutting the damaged area and using hose clamps to fasten the new end or splice. I have had the ends pop off a few times (sometimes months after the repair), and the hose does fly all over the place. It probably could cause an eye injury, but I have been slapped a few times by a runaway hose and it doesn't hurt. I just turn the air off at the shutoff valve and fix it again.

When a 1/2" hose with 175 psi pops, I'm not sure which jumps farther, me or the hose.

Curt Harms
04-19-2009, 3:57 PM
and I hope no one here gets to experience it. In the event of a fire with pressurized air lines, if the sweated joint melts and fails the fire is now being fanned by high pressure air. That doesn't seem like a healthy situation. Of course if you shut the air off at or near the compressor this wouldn't be an issue. I guess if you were really a tinkerer, you could install a solenoid at the compressor outlet and wire it somehow that when you turn the lights out or whatever the solenoid closes and the lines downsteam would no longer be pressurized.

Curt

Greg Bender
04-19-2009, 4:48 PM
I'm late getting in on this but PVC is something that you can get away with but it's not recommended.I work for Ingersoll Rand and they absolutely consider it a safety issue,If you must do it on a budget and you want to keep it easy then use Synflex.It's available in several sizes and uses push in connectors.We use it on the interior of all recip and rotary compressors up to 200 psi and never have any problems as long as it is seated well during assembly.And as far as moisture,always run your drops through a T fitting and stub down 6 or so inches to a small ball valve so as to drain your drops.We use modular aluminum so you can drill and tap a drop anywhere in the system but it is pricey.BTW It is installed level and plumb for appearance and never sloped back to the tank.You don't want moisture in your tank either.Ball valve the output of the compressor so its not loaded all the time and for maintenance also.Install a blow down valve to dump the system at power off and a timer based automatic drain valve on your tank to control moisture build up in the tank.If I can help anybody out with questions PM me.
Greg