Compressed air piping for my 911s garage

[dweymer]

Hi all,

Anyone familiar with this: http://www.garage-pak.com/?

It looks better than black steel, is removable, and has push type connections.

I am moving this week and want to start planning my garage.

Thanks,

Don

[Steve 82SC]

A friend of mine put this in his garage. Very easy to install or modify and it works perfectly.

Steve

[Dixie]

I've used plastic Schedule 40 PVC piping for years. It's easy and cheap to install and modify, readily available, and even paintable.

A couple tips:

• Make sure you prime and glue the snot out of it to avoid leaks at the joints.
• There are nice, sweeping, 90-degree bent PVC sections in the electrical section of Home Depot.
• Layout your pipes so they all have a slight tilt back to the compressor. (Condensation will flow back to the tank.)
• Mount the regulator and filter a good distance from the compressor. They will be more effective. (While mine are only 5 feet from the tank, the tubing loops back. There is about 15 feet of tubing.)
• I've found you only really need two, maybe three, places to connect to.

[K.B.]

The salesman at Home Depot said go ahead and add as much line as you want. Some people put the compressor in another building to get rid of the noise. The advantage of a lot of line is it adds capacity to the system. your 60 gal tank could be up to 70 if you add enough line.

[vlocci]

I've seen it in use, but frankly it gets kinda pricey quick.

Run far away from PVC, while cheap and easy to work with, it is not designed for an air pressure use such as this. The constant hammering from a compressor takes its toll and the stuff is dangerous if you accidentally whack it with something solid. Many people use it, until they see the stuff explode first hand. You will walk away with a newfound respect for the energy stored in a compressed gas form.

Cheapest solition is regular copper pipe. 1/2 or 3/4 is typically plent and as an added beneift is serves to radiate a bit of heat over its length, aiding in condensing water out of the air. A propane torch is a worthwhile 20.00 investment and soldering is easy. (My local HD even sells joints with the solder preapplied... just flux the joint push things together and heat)

Put some slope in your pipe and a provision for draining condensed air.

Check out http://www.tptools.com/statictext/airline-piping-diagram.pdf

to see how it should be laid out. Mimic this layout but feel free to use copper.

Vin

[scottb]

The fittings look suspiciously like the "quick repair" plumbing fittings you can buy at Home Depot. Basically, you put your pipe into each end of the fitting, and then tighten down on a compression bushing, which provides the seal. I suspect the fittings at HD are a lot less spendy than Garage-Pak.

[Grady Clay]

Don,

I recommend some research on this product and find some who have used it locally for quite some time. My general feeling is that plastic compression fittings have a relatively short life span and are very dependent on the manufacturer staying in business. To be fair, I’m sure that isn’t true in all cases.

The classic is black iron threaded piping.

[The current least expensive is PVC. - - EDIT OUT based on recomendations below.]

The cool (and more expensive) is soldered hard copper.


There are some important issues when installing an air system. There are some good books on the subject. See if your library can order them up. I’ll see if I can find mine.

My first recommendation is to not have the compressor in the garage. It is very obnoxious to have that noisy thing cycling while you work, listen to music, watch the game, or try and carry on a conversation with other Pelicans. Put it in the garden shed or somewhere away from the house. If that isn’t practical, many have it portable on a pigtail so they can move it outdoors some distance when in use.

Depending on your climate, a big issue is moisture in the system. Many commercial systems have a refrigeration plant to cool the compresses air and automatically drain the condensed water. This is also very important for a home garage system. If nothing else, drain the tank regularly.

I remember the spec to have a larger diameter pipe (iron or copper) go straight up from the tank as far as possible. This reduces water droplets from going up and gave them a large surface to return to the tank. From the top, it is all down hill. Each tap comes from the top of the distribution pipe and then down to a drain. The tap comes from the side of that pipe. At that point most good systems have a pressure regulator, an air-water separator with a drain, and then a cartridge filter. At the end of the distribution pipe is a drop with another drain. There should never be a “low point” that can collect water or debris until the end.

There are also issues when the system is in freezing conditions. You don’t want ice to form in the tank or system. Many compressors need a crankcase heater below some temperature.


There are serious reasons for all this effort. When checking cylinder leak, do you want water or rust contaminating your 911 cylinders or gauge? When you air up your tires, do you want any moisture at all? When you blow off transmission or engine parts do you want some media (rust, water) in there? Of course not.


I could carry on for quite awhile on this subject but there are good books out there. The art is having the right mix of function and cost. I’ll be glad to add more if anyone wants. Others please chime in.

Best,
Grady

EDIT for content - safety.

[Dan in Pasadena]

Despite what Vin says (which I am sure is true in the wrong circumstance) I would/will use Schedule 40 PVC in a heartbeat. My brother-in-law has had a system in his garage for decades with no problem. Now, he mounted one continuous loop at the top plate level and put "drops" on each wall, plus on overhead center drop. He put quick disconnects on each.

Yes, copper would be stronger, though more costly (though probably cheaper than this system you asked about) and is more difficult to install, especially in a garage with exposed typically old dry lumber and uses a propane torch. I might do it, but better have a fire extinguisher handy!

[HarryD]

I do industrial piping as an engineer. Part of my job is failure analysis. When under pressure, PVC Pipe fails by shattering into lots of small, sharp pieces. Under pressure, they can fly a long way and easily inbed themselves in soft things like wall board and skin. The failures are often catastrophic with little warning.

Frankly, ultimately, it's your life and your choice but I would not go into your garage with that stuff on the wall.

[scottb]

Originally posted by HarryD
I do industrial piping as an engineer. Part of my job is failure analysis. When under pressure, PVC Pipe fails by shattering into lots of small, sharp pieces. Under pressure, they can fly a long way and easily inbed themselves in soft things like wall board and skin. The failures are often catastrophic with little warning.

That's enough for me. If I ever do permanent piping in my garage, I'll probably do copper because it's lighter and easier to install, though likely more expensive than black pipe.

[dweymer]

I would never consider pvc for this task, but it is nice to have someone who knows his pipe chime in. Copper was my first choice, and the layout is pretty simple, three drops and a reel. Filter, seperator and dryer. Can't locate unit outside, but I may "modify" an enclosure for marine generators to keep the noise down. Keep ' em coming..

[widebody911]

I've heard these stories about PVC pipe exploding and killing entire families, but what pressures are they running? I've seen a lot of systems plumbed with PVC, and still can't swallow the ticking-time-bomb story.

FWIW, I did mine in galvanized, with my compressor outside in it's own shed, with the air piped underground and up into the shop. Pix on line @ http://www.rennlight.com/shop/

[Grady Clay]

Don,

You might consider having the compressor only in the garage and well insulated for noise, vibration, and heat. The compressor will need to be kept cool – it generates a lot of heat. Have an outdoors dissipation of the compressed air heat, and put the storage tank in an inside (air conditioned) location, like a utility room. From there you could plumb as above.

There are automatic drains that give a small “fitz” when the compressor cycles.

I agree with Harry about PVC. I will edit out of my above post. On the other side I see many low pressure (<60psi) PVC systems. What is the crossover with safety?

The best way to maintain a constant pressure is to have the system at ~150 psi and regulate it down to what you need (say 100psi?) This prevents variations in the pressure you use and also helps remove more moisture if done properly.

The compressed air connection out of the compressor should be a fluted SS hose with a SS over braid designed for this application. This is very hot air and severe vibrations. The compressed air to ambient radiator is fairly standard rigid line with fins. More is better. Remember the admonition about low points. Periodically there should be flexible connections and unions in the system.

With some research and creative thinking, you should be able to develop a home system that is: safe, useful, serviceable, and expandable so it can meet your needs.

Best,
Grady

[Zeke]

I think of a subject like this when buying house paint. It takes some effort to use a gallon of paint, especially on trim. So, the ratio of man hours to the cost of a gallon has never convinced me to buy nothing but the best on the shelf. The difference may be as much as $10/gal. Big deal. If it lasts one more year than the cheaper stuff, it's worth $50/gal more.

I would buy the best pipe I could for the same reason. You can spend a lot of time hanging $100 worth of material. If there is ANY question, why would you use less than the best? What is your time worth in relation to the labor vs. materials? Well , I guess you're not getting paid to work on your own garage, but the principle is the same. So, what is your safety worth?

It could be that the difference in material costs is insignificant in the face of safety. If that doesn't sway you, think of the benefits of a metal system to control and expell condensation.

[dweymer]

Milt,
That's one of the reasons this system appealed to me vs. copper pipe: Ease of assembly(less labor, tools, etc), reconfigurable. The fittings seem to be the weak link, maybe the pipe engineer can comment on them? I buy the best paint too , I hate painting trim twice.

[ozz]

Harry - I'm not questioning your professional experience nor opinion but rather trying to understand the condition of the failure you warn against. While I do agree with many of the above posts, I already have PVC pipe plumbed on the regulator side of my compressor and want to understand the issues before tearing it all out and replacing with black or copper.

Various PVC manufacturer/reseller sites I visited show pipe available at pressure ratings of 150 - 1250 psi. The pipe I have has 600psi in blue ink on the pipe. Since its on the regulated side, it sees roughly 100 psi (+/- a little for regulator inaccuracy). This is just over 16% of rated maximum capacity. Again, I'm not looking for an argument just trying to understand the probability of mechanical failure given the application is well below rated maximums. If there is other than anecdotal reasons that I'll end up with PVC shrapnel, the stuff is coming down this weekend and getting replaced

[Porsche_monkey]

I used steel hydraulic tubing and flared the ends, then used JIC fittings. Cheap, safe to over 1000 psi.

[RickM]

Don, Interesting product there.
When I purchased my Duro retractable air hose reel the gentleman who owned the company recommended a "plastic" hydraulic tubing used in the trucking industry. It's easy to cut and comes with push on fittings. It's rated at a very high PSI. It was important that it was easy to run as my old Craftsman compressor is in a cement crawl space under the garage and the reel needed air supply through the attic. This stuff worked perfectly (as promised by the seller who mostly sells to commercial shops).
However, now that I have a much larger compressor and want to effectively do some media blasting I'm thinking the volume capability may not be there.
Depending on what your setup and use will be this could be an option.

[Porsche_monkey]

If you want cheap and SAFE plastic fittings go to SMC and buy 'one-touch' fittings and nylon hose. Or, go to Legris and buy brass push fittings.

[vlocci]

Maybe I spoke to quickly regarding PVC.

My take on PVC failure lies in the difference between compressed air and a compressed fluid. Understand that PVS doesn�t fail simply because it is under pressure, if it did you would not see the 600 psi rating on the side. For arguments sake, lets compare air under 150 psi of pressure vs water under the same pressure. Water is virtually incompressible, as compared to a gas like air which compresses significantly. When a PVC airline holding compressed air fails the gas expands explosively, causing PVC shrapnel to go flying. This incompressibility of water is one of the reasons that when testing a pressure vessel of any kind water is used instead of compressed air initially. I�d much rather a stream of water shooting at me than a hunk of tank following an explosion.

Having said this, PVC is fine for the pressure etc. but bump it with something hard, whack it when it is cold (i.e. below freezing) or tug a little too hard when trying to make that air hose reach and you might add just enough stress to the pipe to get that initial crack to form, followed by a destructive decompression.

for those interested in OSHA's take (for whatever that is worth) read

http://www.osha-slc.gov/dts/hib/hib_data/hib19880520.html