Pvc Pipe Or Copper For Air Line?

toolman · Apr 11, 2006

Last year I used pvc for my air compressor lines. After reading many dangers by using pvc I have decided to stop using those lines :eyecrazy:

Now I’m thinking of using copper instead

Is this safe to use. If so is there any special way to install? Is there a certain kind of solder to use?

jerryW · Apr 11, 2006

There is a post under TOOLS showing a copper airline install. Should answer all your question.

I've seen PVC air line explode. Happened in a shop I was working in. Told the boss it was't safe about 20 times before it happened. When it did blow it was a 2'' line that pivotted up thru the ceiling! Only good thin was that it happened at start up when the shop was still empty. Compressor was a 120cfm rotary!

Made one hellova noise!

Just after I quit there they finally started to install black pipe for the air system.

jerry

oldgoat · Apr 11, 2006

I know a couple of guys who used PVC and so far no problems, but I never thought it was the best idea in the world. Where I am now and the place before they all used pipe (1 galv and 1 black).

roger55 · Apr 11, 2006

I have used PVC in a couple of installations with no problems.

However, I won't use it again now that I am educated about it.

Besides safety, it's bad because it doesn't cool the air and allow the water vapor to condense like metal pipe will.

Charles (in GA) · Apr 11, 2006

toolman said:
Last year I used pvc for my air compressor lines. After reading many dangers by using pvc I have decided to stop using those lines Now I’m thinking of using copper instead Is this safe to use. If so is there any special way to install? Is there a certain kind of solder to use?

http://www.copper.org/resources/pub_list/pdf/copper_tube_handbook.pdf

Warning: 6.38 meg download, not for phone modems, for sure.

Charles

Jeepguy · Apr 12, 2006

Dont use pvc, it dries cracks and explodes, youre better off just zip tieing hose on the ceiling than useing pvc. go with copper if you want a rigid line.

AZAV8 · Apr 12, 2006

NEVER, NEVER, NEVER, NEVER, NEVER, NEVER use PVC for compressed gas lines!!! Do you understand? Someone WILL get hurt. Its not a matter of if, its a matter of when.

That said, I would recommend copper. It does not corrode from the condensed water in the compressed air. Black steel or galvanized will corrode and you will end up with rust in your system. It will plug your tools and stain whatever the water gets on. The Copper Handbook listed in another post is the best source around for copper piping. Use the lead-free tin-antimony solder they sell for water pipe. The joint is just as strong and you won't accidentally use lead solder on domestic water pipe. I would recommend you fab up you pipe spools on the bench as much as possible and make as few joints in-place as possible. You will have better access to the joint for heating. You will also have less chance to start something on fire with the torch. Many construction site fires occur immediately after the plumbers have installed the copper water piping. They usually overheat the wood studs with their soldering torches.

Go get yourself a torch that has the torch handle and a hose with a valve to attach to a propane bottle. You will have much better flexibility and can get closer to the joints. It is less ackward to handle. The cheap type where the torch is attached directly to the fuel bottle are ackward and heavy. My Benz-o-matic is a Model JTH-7. I've had it for years and wouldn't have anything else. I use the propane cylinders that are used with the Coleman propane camping equipment, stoves, lanterns, etc. Its a bigger fuel bottle and I only need one type of propane fuel bottle. Also get the Coleman plastic bottle stand that fits on the bottom of the fuel cylinder. It will make the bottle a whole lot more stable and you won't worry about dropping it off the work bench and breaking the valve off the top of the bottle.

Phil

roger55 · Apr 12, 2006

AZAV8 said:
NEVER, NEVER, NEVER, NEVER, NEVER, NEVER use PVC for compressed gas lines!!! Do you understand? Someone WILL get hurt. Its not a matter of if, its a matter of when.
Phil

I'm not saying you should use PVC as you are right, you shouldn't take the risk and I won't again use it.

However, I disagree with your statement about "its a matter of when".
Ther are many, many reports of people using PVC for many years with never a problem.

Bradley Miller · Apr 12, 2006

roger55 said:
I'm not saying you should use PVC as you are right, you shouldn't take the risk and I won't again use it.

However, I disagree with your statement about "its a matter of when".
Ther are many, many reports of people using PVC for many years with never a problem.

Here's a hair-raising PVC story -- didn't burst from brittleness, but instead became contibutor to an inferno:

http://www.project33.com/article.cfm?ID=69

Copper will be my route, especially with that Justforcopper.com stuff . . . no sweating joints. I'm all for that. :beer:

SCOOTER · Apr 12, 2006

Wow I had never heard this before about the PVC...I know of many folks that had no problems using sched. 40 PVC...but seeing how I'm building a new shop I do believe I will be using copper...... :beer:

Bradley Miller · Apr 12, 2006

Only PVC in my garage is for the potato air cannon.

AZAV8 · Apr 12, 2006

roger55 said:
I'm not saying you should use PVC as you are right, you shouldn't take the risk and I won't again use it.

However, I disagree with your statement about "its a matter of when".
Ther are many, many reports of people using PVC for many years with never a problem.

There may be many reports of PVC use with "never" a problem. My professional experience says otherwise. This is what the Plastic Pipe Institute says:

RECOMMENDATION B 1997
THERMOPLASTIC PIPING
FOR THE TRANSPORT OF COMPRESSED AIR
OR OTHER COMPRESSED GASES
Originally Adopted January, 1972
Revised December 30, 2005
The evaluation of thermoplastic piping for compressed gas service should
consider all pertinent design and safety factors. Chemical effects oxidation and temperature should be taken into account. The Plastics Pipe Institute
recommends that thermoplastics piping intended for the transport of compressed air or other compressed gases should be installed by burial, encasement in shatter resistant material, or other appropriate means, to prevent or minimize the possibility of mechanical damage.

Thermoplastic piping that fails from mechanical impact by shattering or whipping can be hazardous to personnel. The potential safety hazard posed by failure must take into consideration the nature of the material, internal pressure, pipe size, and the nature of the gas.

Aboveground installations of thermoplastic piping should be installed per the
manufacturer’s recommendations using only products that are recommended by the manufacturer for the particular intended service. Some thermoplastic pipe materials have limited resistance to shatter-type failures from mechanical impact. Suddenly released compressed gas can propel pipe shards or fragments. Materials that can fail by shattering pose a hazard to employees if they are installed above ground without encasement or other protection.

Other thermoplastic materials that resist shattering, may be sufficiently flexible that if there is a failure or separation of the piping the piping can whip about uncontrollably as the pipe is propelled by the energy of the suddenly
decompressing gas. Flexible aboveground piping should be properly restrained
to prevent or limit whipping of the piping material.

When they refer to "thermoplastic pipe" they mean PVC pipe. They say bury it, or encase it in some other shatter-resistant material. In other words take your plastic pipe and put it inside some other material pipe so you protect it from mechanical damage. Impact blows to the PVC will cause a failure. Why install PVC when you have to protect it with something like copper or steel!!! You are paying double for piping material.

They do not address one specific failure mode, shock waves, commonly called "water hammer" in water systems. A water hammer is a wave initiated by closing a valve too quickly that travels along the pipe to the end of the system and then reflects back. You can get the same thing in a compressed air system. I have seen and had to fix the results of the damage caused by these waves. You WILL break a PVC pipe system with one with the possibility of injuring someone. That is why I say it is a matter of when.

Copper is a much better choice without the potential of catastrophic failure that goes with PVC. There are TOO many other risks in the shop/garage to knowingly add another one by using PVC pipe.

That's my nickle's worth. Remember: KISS = Keep It Simple & Safe

Phil

AndrewM · Apr 12, 2006

Bradley Miller said:
Copper will be my route, especially with that Justforcopper.com stuff . . . no sweating joints. I'm all for that.

I just tried that stuff. My local mom and pop hardware store gave me a tube for free, because they had just got it in and wanted some feedback on it (and I am in the process of plumbing my shop in copper).

I used it on 3 parts (2 elbows and 1 pipe to NPT fitting). 2 of them failed while I was working with it.

The first to fail was 1 elbow. I had a pipe coming straight out of the wall. Put a 90 degree elbow to aim the pipe up. I used JFC on that elbow. Shake the JFC like crazy for a couple minutes to make sure it's well mixed. Clean the parts shiny, put JFC on the outside of the pipe and inside of the elbow, push 'em together and give 'em a slight twist. Hold for a few seconds... and then I went and got distracted on something else. Come back about 30 minutes later add another 90 degree elbow on top of that run.

As I'm adding the new elbow, I wiggle the tube slightly (not hard at all). I hear a metallic "tink"... and the JFC elbow twists at the jont. The JFC weld failed. So I pull the elbow off. The JFC scrapes off with my fingernail. I re-clean and sweat the joint with silver solder.

The second joint was a fitting where an NPT to 1/2" copper tube was. The other end of the tube was a compression fitting. It wasn't tight, but it was "on there" finger tight. I was snugging down the NPT fitting (getting ready to fully snug the compression), and I see that the tubing is turning at a slower rate than the NPT fitting. Uggh. I get the compression fitting barrel off, and redo the pipe with solder.

I took the JFC back to the store today, maybe they can give it to someone else to try. They said "that's disappointing".

Just my $.02.

I did not use any of it in my setup. It does fine under fore-aft pressure, it seemed, but give it a bit of a twist, and it failed.

Bradley Miller · Apr 12, 2006

Great info -- I read they didn't recommend putting rotational toque on the fittings, probably for such reason.

roger55 · Apr 12, 2006

AZAV8 said:
shock waves, commonly called "water hammer" in water systems. A water hammer is a wave initiated by closing a valve too quickly that travels along the pipe to the end of the system and then reflects back. You can get the same thing in a compressed air system. I have seen and had to fix the results of the damage caused by these waves. You WILL break a PVC pipe system with one with the possibility of injuring someone. That is why I say it is a matter of when.
Phil

Sorry, I don't at all agree with this part. Water and air have completely different properties. Water virtually does not compress. Air, as we know, is easily compressed. Shock waves with air are dissipated instantly because of the compression property. In any case, "water hammer" does happen with water yet PVC pipe is recommended for water.

I still don't disagree with the fact that it shouldn't be used. It can and does injure, but the risk is from impact or vibration from an outside source (which is a real risk in a workshop environment).

The reason PVC is not dangerous with water is because water doesn't compress. If a PVC pipe fails with water under pressure, there is no stored energy from compression to cause the pipe to explode.

maa139 · Apr 12, 2006

I think that the bottom line is that ANY air system can fail. The difference between PVC failing and copper/iron failure is what happens in that instant of failure. Copper will most likely split to allow air to escape. Iron will probably start to fail through a small rust hole. PVC will explode, sending shrapnel through anything that gets in the way - your walls, fridge, toolbox, project car and YOU! Is it worth the risk?

It's also against osha regulations to use PVC in a comercial shop, so it's not a real good idea to use it in a home shop either.

I did my garage with black iron pipe. There's a drain on every drop, and unless the air is being used, there's a shutoff at the compressor that's turned off and there isn't any air in the pipe. I also burp the compressor just about every time I'm in the garage.

Every shop I've ever been in has used black pipe, so that's what I went with. Copper is good too, I just have no faith in my soldering ability...

Matt

Ramblur · Apr 12, 2006

20 some odd years ago while employed at a parts store/machine shop my
boss in the machine shop hung the radiator torch (which was normally left
in an idle mode with a small flame) on the backsplash of the water tank instead
of the usual stand on the front of the water tank. While eating lunch in another
room with everyone else the explosion was enough to knock all the dust out
of the rafters and into our lunch. Everyone followed the noise to the radiator
room where the 3/4" PVC air line was now in two pieces. Heat from the torch
which wasn't even that close to the air line allowed it to swell to the size of
a FOOTBALL before it failed. :eyecrazy:

Sure am glad no one was nearby when
that thing let go! Make mine copper or black iron...

comp · Apr 13, 2006

same here

roger55 · Apr 13, 2006

I just found this and it looks interesting.
http://www.ipexinc.com/Content/EN_US/2_0_Products/2_1_Industrial/2_1_4_Compressed_air.asp
I don't know what the cost of it is but it sure looks like it would be easy to work with.
Anyone heard of this before?

roger55 · Apr 13, 2006

I registered on the IPEX web site and downloaded the Technical Manual and posted it here:
http://home.austin.rr.com/ls1/Duratec_Technical_Manual.pdf

I am really impressed with this stuff. I also downloaded their price sheet and it is somewhat expensive.

3/8 inch is $78 per 100ft roll, 1/2 inch is $98 and 3/4" is $150. The fittings aren't cheap either but I don't think the average garage would need that many fittings.

The only negative that I can see compared to copper or steel pipe would be that it probably doesn't dissipate heat as well. (You want to your air to cool as much as possible to get the water to condense out.) Although the plastic jackets are thin so it's bound to dissipate heat better than PVC. However, if you're building an air system with a dryer or a cooling chamber, this might not be a big issue. I like the idea of a chamber anyway as the air velocity slows down at the chamber allowing the condensed water to fall to the bottom.

The fact that you can bend this stuff with your hands would make it really easy to install. (Tight bends can be done with a tubing bender.)

AndrewM · Apr 13, 2006

If you want to compare prices, when I bought my copper 3 weeks ago, Schedule L copper 3/4" 10 ft tube was ~$18.50, 1/2" 10 ft tube was ~$13. Solder fittings are reasonably inexpensive though. 1/2" 50 ft coil of soft copper was $48.

Schedule M copper (thinner wall) was ~$13 for a 3/4" 10 ft piece.

xtremes · May 20, 2006

What I did with my air lines. I went to the local NAPA add bought 1/2 air line that is used on a tractor trailer truck for the air breaks. Then went to a hardware store and bought some compression fittings and things. It's rated at 2000 pounds. Had it in my garage for about 3 years now. No problems at all.

comp · May 20, 2006

xtremes said:
What I did with my air lines. I went to the local NAPA add bought 1/2 air line that is used on a tractor trailer truck for the air breaks. Then went to a hardware store and bought some compression fittings and things. It's rated at 2000 pounds. Had it in my garage for about 3 years now. No problems at all.

good idea

Kruse · May 20, 2006

I have a feeling that some of these systems reported to be PVC could have been ABS. I am not sure that you can spot the difference that easily.
The big difference though is that ABS is approved for compressed air, PVC is not.

A related thread regarding the Alu alternative for piping compressed air.
http://www.garagejournal.com/forum/showthread.php?t=4371

Cropped from above thread:
::
Some opinion and observations:
As I am only happy to see alternatives to "black" pipe in Compressed Air systems, the price is always a factor.

Alternatives:

Copper though it is getting more expensive, is still the most beautiful.
In case of a fire in your shop, copper is the only pipe-system that will not spring a leak from exposure to heat.
(A leaking air supply system will feed a fire very effectively.)
----
PVC - Is not an option. Not secure as everybody, even the industry points out. It is very unsafe.
I believe some of the confusion regarding PVC pipe for shop air may relate to some of those systems that "worked for years, no problem" could have been ABS systems. Not always easy to spot the difference I would assume.
----
ABS - This plastic is safe and some pipes are approved for compressed air.
IpexInc has a system: DuraPlus.
Length of pipes: ?.
Sizes: 1/2 : 3/4 : 1 : 1-1/2 : 2 : 2-1/2 : 3 : 4 :
Must be glued. Has nice easy curved corners. Very smooth inside.
Probably not too expensive. (Register to get the data sheets and prise list)
----
HDPE-Alu-HDPE - IpexInc has a system: DuraTec. Pipe/coil is blue.
http://www.ipexinc.com/Content/EN_US..._2_Duratec.asp
HDPE inside and outside of the pipe/coil, Alu in the middle.
Length of pipes/coil: 100feet and 300feet.
Sizes: 3/8 : 1/2 : 3/4 : 1 :
Insert-twist the nut. Dual O-ring seal.
Nickel-plated brass or stainless steel connectors.
Extremely smooth run.
Somewhat sharp corners, but the alu-pipe/coil can easily bend/straightened.
The pipe/coil is cheap. (Register to get the data sheets and price list)
----
Alu - Ingersol-Rand has a system: SimplAir EL and SL.
http://www.irtools.com/partsandacces...air_piping.asp
Length of pipes: 10feet EL and 16feet6inch SL
Sizes: EL: 5/8 : 1 : 1-1/4 : SL: 1/2 : 1 : 1-1/4 :
Insert-twist the nut.
Reinforced plastic connectors on EL. Metal connectors on SL
Smooth run.
Very sharp corners, but the alu-pipe can be bend.
Price: ?.
--
Alu - (Also comes as Stainless steel pipes.) TransAir from Legris (French)
(The system used by http://www.garagepak-midwest.com )
http://www.transair.legris.com
For Catalog: click [TransAir Offer], then [Catalog] etc.
Length of pipe sections (includes 1 (2*1/2) connector: 10feet and 20feet.
Sizes OD: 5/8 (16,5mm) : 1/2 (25mm) : 1-1/2 (40mm) : 2-1/2 (63mm) : 3 (76mm) : 4 (100mm) :
Lots of innovative connectors, looks like plastic but are metal.
Pipes are enamel baked blue or grey(for Vacuum). Pipes can be bend.
Insert-twist the nut.
Price : ?.
----

Lots of choices. Smoother run than steel pipe, less loss of pressure.
No contaminants in the lines.
-
One thought on those thick pipes for main lines...
If it is just a small system, you can regulate early and use small dia pipe.
For larger systems, or where more users are tapping air at the same time,
using larger pipe with higher pressure "extends" your "tank" capacity lessening
the pressure loss down the line. If drawing air from nabouring connectors with local pressure regulators , a thicker supply line will see less intermediate pressure loss

Pete Lech · Nov 30, 2006

What about schedule 80 PVC? It seems to have ample safety margin even at high temperatures.

I was in a HIGH END factory race shop recently and saw that they used plactic air pipes. It started me thinking about plastic again.

Randall Edge · Nov 30, 2006

Pete Lech said:
What about schedule 80 PVC?

I'm sure it will last longer than SCH 40, but the things that cause SCH 40 to fail will most likely make the 80 fail as well. Heat, cold, vibration, & pressure fluctuations will probably eventually kill it.

REFLEXX · Dec 1, 2006

I'm going to use PVC, so there!

mikeyr · Dec 1, 2006

REFLEXX said:
I'm going to use PVC, so there!

Any chance I could get a life insurance policy on you with me as the beneficiary ?

PAToyota · Dec 1, 2006

The simple fact comes down to that when PVC does fail, it shatters. If a copper pipe fails, it will split and burst but no shrapnel. Beyond that, you can argue the merits of either one ad infinitum (or ad nauseam)...

Stuart in MN · Dec 1, 2006

Pete Lech said:
What about schedule 80 PVC? It seems to have ample safety margin even at high temperatures.

I was in a HIGH END factory race shop recently and saw that they used plactic air pipes. It started me thinking about plastic again.

(sigh) As my mother used to say, if all your friends wanted to jump off a cliff would you do it too?

PVC plastic is PVC plastic...it's not designed for use with compressed air and it's not approved for use with compressed air. Do that high end race shop a favor, and report them to OSHA before someone gets hurt.

maa139 · Dec 1, 2006

Stuart in MN said:
(sigh) As my mother used to say, if all your friends wanted to jump off a cliff would you do it too?

PVC plastic is PVC plastic...it's not designed for use with compressed air and it's not approved for use with compressed air. Do that high end race shop a favor, and report them to OSHA before someone gets hurt.

+1. It may have been a HIGH END shop, but that doesn't mean that they're doing it right. Every REAL WORLD shop that I've ever been in has used black iron. There's a reason for it. You can beat on it with a hammer and it won't shatter. Plastic will, all you need to do is bump into it the wrong way. Period. End of story. (hopefully) end of discussion. Please don't use plastic pipe. It's not a question of if it will break, only when....

Matt

sharpshooter · Dec 1, 2006

Just because something is cheaper, or easier to work with doesnt mean its better, hell for that matter it doesnt even mean its safe (PVC) for those of you all thinking of using PVC for your air lines why is it you are considering it? because you want to save a few dollars?? Im sure this being some what of a DIY'ers website most of us have all tried to cut corners to save a little money and what typically happens in the end is that it usually bites us in the a$$ and cost us 3 times what it would have origannly cost us to do it right in the 1st place. So ppl do it right on the first try because there might not be a second try

MyDomain · Dec 1, 2006

What about cross-linked polyethylene, PEX? It is fairly cheap and easy to work with. It comes in a type with an oxygen barrier that should maintain air pressures well. The standard PEX is rated for 160 psi at 73 degrees. When I do my system I think I am going to use PEX as the interconnect. It is cheap enough that if it doesn't work I can scrap it and use black pipe or copper.

I have a scrap piece from my domestic water piping...maybe I'll rig a test section.

Uncle Buck · Dec 1, 2006

MyDomain said:
What about cross-linked polyethylene, PEX? It is fairly cheap and easy to work with. It comes in a type with an oxygen barrier that should maintain air pressures well. The standard PEX is rated for 160 psi at 73 degrees. When I do my system I think I am going to use PEX as the interconnect. It is cheap enough that if it doesn't work I can scrap it and use black pipe or copper.

I have a scrap piece from my domestic water piping...maybe I'll rig a test section.

Did you miss all the good advice in the previous posts against the use of plastic? The only plastic suitable for compresses air applications is marked as such. I guess some folks just have to defy the odds! Kinda like doing a half *** wiring job, then wondering if your house is gonna burn down! :lol_hitti

MyDomain · Dec 1, 2006

No, I did not miss the previous posts that spoke of hard, brittle plastic pipe. I was wondering about the use a plastic pipe that has an elasticity to it. I cannot imagine PEX shattering.

OldCarGuy · Dec 1, 2006

I have been in and around the plastic industry for over 50 years and I definitely oppose the use of plastic for high pressure air lines,,, particularly PVC.

The best options are copper, black pipe, or aluminum.

PAToyota · Dec 1, 2006

PEX does not have the dangers of PVC - shrapnel, that is. One issue is that 160 psi is fairly low.

carguy123 · Dec 1, 2006

Cool Pex is easy to work with. I was wondering about the Pex but didn't have a piece handy to see the pressure rating.

Why do you think 160 psi is low?

Now how about connections. Are they readily available?

byrdman · Dec 1, 2006

also, the compressor will be kicking out air that is higher than 73°.

MyDomain · Dec 1, 2006

carguy123 said:
Now how about connections. Are they readily available?

Yes, the Home Stores now have a limited supply or you can get them off the net.

I am going to cap the end of a roll and connect a fitting to the other end. Crank up the pressure and see what happens. I would imagine it would work fine...the walls of PEX are fairly thick.

Pvc Pipe Or Copper For Air Line?

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