plumbing 4 air ?

[Diamondpilot]

I used pex and it works fine. I have a compressor in a pole barn and put quite a few work ports around the shop. I even dug a trench to the house and ran it into the attached garage, a first floor closet, and a second floor closet. Very handy and with pex there are very few fittings.

Chris

 

[john_bud]

I used PVC in the shop air supply for about 12 years. The compressor is in the non-heated part of the shop and the lines go thru the wall up high and distribute around. Was in the shop last winter (-20F or so outside) and while using the needle scaler there was a H*ll of an explosion behind me. I was wearing protective eye wear and hearing protection, but even so it was loud! Jumped up and spun around to see a huge cloud of vapor and a large hisssss.

Yep, the cold contracted the PVC and then when the air cycled up and down it expanded it and contracted it more. Guess it fatigued, don't know for sure. Do know for sure that a Y and a T and a 3' section blew apart and put PVC daggers everywhere. I'm still finding chunks and slivers. Next day went and bought a bunch of black iron pipe. The PVC is cheaper, easier and all that, but....when it lets go - you don't want to be there. Trust me on this one!

Oh, check the price of copper. You don't want to blow that kind of money !

jb

 

[plaindave]

I had planned on using black iron when I hit upon the idea of using air hoses. I wanted to use PEX but it was too expensive. Air hoses are rated for the pressure and easy to route.

No doubt I'm taking a chance that somehow a line could become compromised, but it't got to be safer than dragging them back and forth across the garage floors and stepping on them for the last 15 years.

1/2" rubber hose is pretty reasonable at Northern Tool and has worked for me for about 4 years now.

 

[AndyMA]

I used pex and it works fine. I have a compressor in a pole barn and put quite a few work ports around the shop. I even dug a trench to the house and ran it into the attached garage, a first floor closet, and a second floor closet. Very handy and with pex there are very few fittings.

Chris

Plastic pipe comes in many types. Crosslinked, UV stable etc are a few of the characteristics that you might want to look for in a compressed air system. I have attached a spec sheet for Duratec a type of plastic pipe that is designed for compressed gasses.

Andy

 

[ray66v]

I have experience with this. You will have problems with using PVC for air lines.
I suggest you do not use it.
That being said, If you are going to use it anyway, I suggest the following recommendations: Use a rubber hose from the compressor to the line to limit vibration. A piece of hydraulic hose will work great. Then, use schedule 80 for at least the first connectors. Run your pipe, then change to black pipe at least 3 feet before you want to put your air hose. And make sure the black pipe is well attached to the wall. This will eliminate the common failure points.
As always slope the pipe toward the drain(s) for condensation. they should be at each drop, (point where you attach the hose). Drop meaning run the hose high enough on the wall that you can have a vertical pipe dropping down for the hose, put a tee in the drop for the hose and continue down about 2' more and put a drain at the bottom. All this must be in black pipe. It also helps with condensation to run one more drop past the last one you plan to use. This is because the end drop gets the most water.

 

[patrick_g]

Yet more comments on PEX. Not all PEX is created equal. There are different manufacturing processes for cross linking and different UV stabilizations. NEVER buy PEX from a supplier that stores his bulk PEX outside. UV stabilization mostly reduces degradation, not eliminate it.

PEX can be severely weakened and sometimes embrittled by exposure to sunlight (especially UV.) I am not anti-PEX and I plumbed my current house with it as well as the hydronics (in-floor, in-ceiling, and some in-wall) but I wouldn't use it where it would be exposed to UV such as is in natural light. The weakening is cumulative over time depending on intensity of exposure and duration. PEX might work well for a long time but when will it rupture due to the long term effects of light if it is exposed?

I was planning on going with the traditional iron pipe and rely on a simple filters to handle any rust but after I finish reading the nice PDF file referenced in a previous post I might go with that plastic if price, availability and performance warrant it.

Lots of good reasons listed for NOT using PVC in this thread, I have excerpted them printed out the list of the most dire warnings to give in paper form to my friend whoi had his shop plumbed with PVC. Short of a commando raid to remove his PVC and install iron when he isn't looking, there isn't much more I can do.

Pat

 

[firemanpat2910]

wow, we have never had a problem, but I will see about replacing the pvc. At least any thats not in the walls. I dont think we will be ripping the sheetrock out anytime soon.

 

[john_bud]

wow, we have never had a problem, but I will see about replacing the pvc. At least any thats not in the walls. I dont think we will be ripping the sheetrock out anytime soon.

If it fails, you'll have the rock removed for you. How handy is that?

jb

 

[patrick_g]

I was wondering if anyone else tried to get info on the plastic pipe for compressed air. I downloaded their price sheets and other info in PDF but when I called them to find out where there was a distributor I got deeply enmeshed in their automated telephone system and never got a live person or the info I wanted. On one attempt I was able to leave a message but got no response. I hate it when you have to expend so much effort to try to get info on how to buy something. You'd think they would be interested in either selling it to you or telling you where you can get it.

Pat

 

[sugarmaple]

In the fwiw dept:

I really like the idea of isolating the compressor in a separate structure, the stronger the better. I believe this is OSHA mandatory in industrial settings. Every now and then you hear about someone's compressor blowing up and doing a world of damage and/or causing physical harm. In the do as I say and not as I do dept., my compressor is in the shop and I regularly worry about the integrity of the tank. Automatic tank drains help those inclined to forget draining.... I still drain, but run a piece of quarter inch pipe out from under the tank so I don't have to stand on my head to reach the drain valve. The good news is that most tank failures are not catastrophic, manifesting themselves, rather, as pinhole leaks.

McMaster-Carr has nifty braided flex hose connections rated for compressed air that make an excellent transition to ridgid piping for the purpose of vibration isolation.

My compressor guru also strongly suggests setting the compressor on rubber using pieces of mudflap. (McMaster also has nifty vibration absorbing rubber mounts that might be a little more elegant. I used them on a rotary 3 phase converter and they made a huge difference in quieting the racket.) This will diminish the amount of vibration translated down to and back thru the compressors feet which is especially desirable with the vertical units that have a longer moment arm between the pump and the feet. He does a lot of industrial compressor connections and is also in the L copper contingent for reasons of rust contamination and ease of installation.

On the concern about putting the compressor out in the cold, my guru seemed more concerned about the motor bearing grease hardening in the cold than the pump bearings being starved for oil. Not sure if I agree 100% on this; I think some heat source, perhaps a little ceramic heater, switched inside the shop, in an insulated enclosure would be desirable for those of us in the frosty north. A maplesugar producer friend who has even more stringent temperature concerns about his reverse osmosis machine, is able to heat his quite large, but well insulated enclosure adequately with a light bulb. The belt and suspenders contingent might rather use two bulbs. Ingersoll Rand makes a synthetic compressor oil that may be a little more forgiving of the cold. Remember to use non-detergent oil if you are not using compressor specific oil.

 

[sugarmaple]

PS: Thinking about the bulbs for heat suggestion made me think about the potential for vibration in the enclosure damaging the filament....hmmm

 

[patrick_g]

Sugarmaple, Good comments. I intend to put my vertical compressor on the other side of a wall from the shop. Hadn't really thought about containment for a potential tank failure.

A sheet of fairly thin sheet metal(not too thin, at least 20 ga but 18 is better) laminated between the sheetrock and a piece of OSB or ply will stop some very energetic debris. I will put it on the "other" side of the wall, not in the shop.

You should fasten the laminations to the studs in the wall. You don't have to do a large area. I intend to do a 4x8 which will cover the "angles of interest." Any debris thrown in other directions will not be likely to encounter people, just things, insured things.

Pat

 

[dbdartman]

I was wondering if anyone else tried to get info on the plastic pipe for compressed air. I downloaded their price sheets and other info in PDF but when I called them to find out where there was a distributor I got deeply enmeshed in their automated telephone system and never got a live person or the info I wanted. On one attempt I was able to leave a message but got no response. I hate it when you have to expend so much effort to try to get info on how to buy something. You'd think they would be interested in either selling it to you or telling you where you can get it.

Pat

I really wish I'd saved it, but a few (probably 5 or 6) years ago I ran across a web page with work-arounds of automated phone systems. What I remember being the most used ways to get around the systems are:

For automated voice systems (where they ask questions & you respond by voice) you should just mumble. After a few tries the system should direct your call to a real person.

For the automated response systems (where you're asked to press 1 or 2 etc.) you DO NOTHING! Eventually you should be transferred to an operator. Another thing to try with these systems is to simply press "0" (I remember you can also try repeatedly pressing "0" or "9").

I went through the same thing as you, Pat, when trying to ask a question of my health insurance company a few years ago. Their automated voice system kept me rolling around their labyrinth of a phone system for some 6 calls over 2 days. Finally, out of frustration, I called again & just mumbled obscenities at their system & after a couple minutes of trying it finally said it couldn't understand my responses & would connect me to an operator. HALLELUJAH!!!! If my question had been a simple one, I would have found the answers in one of the novels they regularly send me explaining benefits, rather than spend hours getting frustrated by their lousy, useless, & complicated phone system.

Oh, concerning PVC compressor piping, here's my story: I installed an argon distribution system in a small manufacturing facility. Since the gas was regulated to something like 40psi, I used PVC (it's what they wanted, not steel or copper). Just to be safe, I used schedule 80. The problem with that is, there is no such thing as schedule 80 FITTINGS! Something like 18-24 months later I heard that one of the fittings exploded during the night. Then some time later I heard it happened AGAIN! Don't know if they're still using the system today.

If/when I run air in my garage, you can bet I'll be using black iron with forged fittings. There will be condensation drops with ball valves (for ease of use) at every outlet drop, & maybe a couple more just for insurance.

 

[ray66v]

wow, we have never had a problem, but I will see about replacing the pvc. At least any thats not in the walls. I dont think we will be ripping the sheetrock out anytime soon.

You will likely not have trouble with the sections inside the walls, the pipe is capable of handling the pressure no problem.

The common failure points as I outlined, are at the compressor and at the drops. Compressors like to move around, and vibrate. Both are not tolerated by pvc. Simply tripping over a hose, can cause breakage. I have even seen the rope from a overhead door loop around a valve and break it off when the door was opened.

I never saw it fragment, it does however, launch things with considerable velocity. Not necessarily deadly but, severe injuries are a very real possibility. Not to mention the loss of production in having to shut down for repairs.

There are alternatives to black pipe that are approved, one such is a system that is all aluminum tube with slip together plastic fittings. A friend has had it in their factory for 10 years or so and is very happy with it. It goes up fast and does not have all that weight. Of course its not cheap, however you can possibly save the difference in labor.

If you have employees, spend the money to get an OSHA approved system, you have a lot of liability with pvc.

 

[ray66v]

The problem with that is, there is no such thing as schedual 80 FITTINGS!

There is no such thing as schedule 80 fittings at Home Depot.
However, they are out there, I have used them. The ones I used were dark grey in color and much more expensive.

Google: Schedule 80 pvc fittings

 

[patrick_g]

PS: Thinking about the bulbs for heat suggestion made me think about the potential for vibration in the enclosure damaging the filament....hmmm

There are ceramic cones with coils of heater wire on them. These are available with a medium light bulb base (standard light bulb size) and they are way more tolerant of vibration. They work well in the aluminum clamp on reflector lights, directing the heat in a beam where yo want it and not wasting it all over. Of course in a confined space the heat will end up distributed pretty well. If you can't find one at a low enough wattage to suit you then wire two or more in series. For example if you have them rated at 100 watts but only need 50 then you use two in series and each will put out 1/4 of their rated heat for a total of 1/2 as much heat or 50 watts.

Alternatively you could wrap the important bits with thermostatically controlled heater tape which will avoid freezing temps but not waste power the rest of the time. You could wire a T'stat to the first heat elements I mentioned too. I think the heater tape would be the way I would go. They typically have a T'stat for about 40F.

The formula where:

P = Watts of power,
E = Volts (EMF, Electromotive Force), and
R = Resistance

is P = I2/R (I2 is read I squared or I*I or IxI)

So if you only wanted 33 watts you could use 3 of them in series. I think they are available under 100 watts too. Do use a ceramic light socket or one of the aluminum reflectors with the ceramic socket in it so as to be extra fire safe.

Pat

 

[patrick_g]

I really wish I'd saved it, but a few (probably 5 or 6) years ago I ran across a web page with work-arounds of automated phone systems. What I remember being the most used ways to get around the systems are:

Thanks for the reminder on phone systems. I know the dial "O" and don't respond at all to a voice system tricks. I did dial "O" for operator and got a voice mail system where I left a message but got no call back.

Regarding vibration. There are one size sort of fits all anti-vibration pads for putting under the feet of vibrating machinery. Way better are pads where you specify the weight on each pad and the approximate frequency of the vibration you are trying to isolate. I'm not saying to call Spectral Dynamics for a full up vibration analysis, just that you can buy pads that are much much more effective if you match their design characteristics to your equipment. Places like professional Onan generator sales outfits should be able to supply what you need. That was the way I last located some. All the engineering data you need is the weight on each pad and the RPM of moving masses (motor, compressor, number of cylinders, that sort of thing) and they should be able to get you a close enough match.

It can make a tremendous difference in the vibration and noise. Do not paint the pads or let them set tremendously buried in yuck. It will reduce their performance.

Ships in ASW roles and submarines too are interested in quieting their machinery. They go into the yard for retrofit, upgrade, and maint and come out fairly quiet with all new bearings etc. Over time the sailors paint over the anti-vibration pads and they then conduct sound into the hull (and the ocean) really well. That plus over time the machinery ages and bearings become noisier making the vessel easier to detect on passive SONAR.

Pat

 

[AlanB]

A good assortment of those pads are also available in heat and air shops like Johnstones or CC dickson.

Dad and I were talking about doing a system in Pex, it was interesting to see someone had done it.

 

[jcims]

Are there any specific length limitations to consider when running compressed air? I'm going to be trenching for utilities out to my barn and am thinking about tossing something (apparently not pvc, lol) in there for an air supply back to the house/garage (probably with a reserve tank at the house too). The run is going to be about 150'.

Copper might be the best bet ($$$) for this application b/c of corrosion? I suppose i could put it all in 4' conduit but that would get expensive too.