Permanent air lines

[pat32rf]

Long time ago in a past life it was explained to me why I shouldn't use copper water pipe for air lines. My memory's good, but short. Does anyone else know why?
Got lotsa 1/2 copper but iron pipe is a pain to thread. Its just for my own garage and basement....Plan on having about 125lb pressure.

 

[kennyd]

Copper is perfectly suitable for air line use. I prefer to use the "L" copper versus the "M" copper because it is thicker walled. Just stay away from PVC.

 

[Egon]

If materials are not purchased yet there may be flexible plastic lines and connectors that are suitable for air use.

No idea as to cost or availability.

 

[atgreene]

Most heavy trucks have copper air lines, or at least pieces of copper.

 

[Scooby074]

personally, I dont like copper. Mid wall copper is all right i suppose, but you need to use the right fittings, or its only as strong as the thin wall. And heavy wall wont be much if any cheaper than black pipe.

My system is plumbed in Black pipe.

THere are new nylon flexable systems available. One is called Rapidair. Last price ive seen was around $79 for 100ft. This doesnt include any fittings. Certainly a lot quicker than pipe though and likely cheaper when all is considered.

Theres also aluminum pipe, called Garage Pak, but you should be sitting down when you get the price.

 

[CurlyDave]

The only real drawback i can think of is that you will have solder flux in your air supply for quite a while.

The flux is water-soluble and flushes out of water lines quickly, but it sure isn't air-soluble, so a little bit will be coming out for a long time.

I have always wondered about the need for hard-plumbed air. I tend to put my big compressor in the garage/shop and leave it there. Rubber hose gets me everywhere I want to go. For air somewhere else, which can be another room, a job site, wherever, I have a portable compressor which can go anywhere.

 

[Scooby074]

My system is a single run to all points of use.

Im wondering if i complete the loop around the perimeter of the barn, would i have more volume at each point of use? or is it a waste of pipe?

 

[EddieWalker]

I'm with Dave. I have two regular, ruber hose lines coming off of my compressor. One line goes out through the wall and is kept on a garden hose type holder. The other line is inside my shop, and is also stored on a garden hose holder. The outside hose is 100ft long and I can get to any of my tractors with it. The inside hose is 50ft long and can also get to any location inside my shop. If I wear out a hose, or cut one, it's a simple matter of buying another one. My long hose is 20 years old, but short line is five years old. The only reason that I can see for hard lines around a shop is if there are multiple people using the air and you need the tools available for them in each area of the shop. For me, and what I do, it's never been needed.

Eddie

 

[PILOON]

I had an aviation facility with multiple work bench stations.
We ran copper to each bench with 2 fittings at each station.
Dual as we used rivit guns and air drills.
At each dual station in we ran about a 6-10 inch drop (sump) with a valve to act as a sump drain and as well draining the compressor daily.
That installation served us well for 10 yrs or so without any problems at all and the compressor was a monster with mega CFM's as well as sustained over 100 PSI.

 

[hydrovane218]

I have been in the compressed air service industry for almost 17 years. My two cents is as follows.
I have done my share of piping, copper and black malleable schedule 40. Not having priced stuff recently, one would naturally assume that copper would be more in materials, but is easier for the average guy without a threader to do. I haven't ever had copper burst or blow apart at the joints.
The advantages to copper are:
1/ It doesn't rust so it won't bung up your tools downstream
2/ It doesn't rust so it won't restrict air flow over time by reducing the inside diameter of the pipe
3/ It transfers heat better so you will have more moisture removal downstream during more moderate work loads(assuming you have a filter/trap at point of use)
The ideal way to pipe is in a loop from compressor, around shop, and back to compressor in order to eliminate noticable pressure drop. In most cases for a small shop and a small compressor, this may not be a noticable advantage. Also, the extra pipe, especially in larger sizes like 2", increases system volume which is easier on a cycling compressor like a piston, as it will run slightly longer and stay off longer.
While a long hose directly from the compressor may get the job done, it is a pain to constantly roll/unroll the hose, especially for the quick jobs like blowing something off or filling one tire. With a piped system and multiple outlets, a much shorter hose can be used in most cases.(and it looks much better/neater)
One way or the other, we all seem to get the air where it needs to be in order to get the job done.

 

[Hooked_on_HP]

My shop at home and at work are plumbed with pvc.Both have been this way for over 10 yrs with no problems. What are the draw backs Kenny.
Bill

 

[CurlyDave]

What are the draw backs

When PVC fails it fractures into semi-sharp fragments which are propelled throughout your shop by the compressed air. PVC is not rated for air pressure for this reason. They can be big pieces and propelled quite fast.

If you don't mind the chance of taking something that looks a lot like the spear that Oog the cave man used on miscellaneous game, right through your gut, there aren't many drawbacks.

The other problem is that the failure is not always rupture from internal pressure. If something hits the pressurized PVC pipe it can let go from that.

Water is OK because it isn't compressible and doesn't propel things the way air does. Although, I don't think I will ever forget getting whapped by a piece of 1-1/2" PVC which pulled out of a fitting and swung around on the end of a rubber hose. The only reason it didn't break my leg is that it hit my rear end instead. Left a huge bruise, which in time turned many amazing colors.

 

[Scooby074]

The ideal way to pipe is in a loop from compressor, around shop, and back to compressor in order to eliminate noticable pressure drop. In most cases for a small shop and a small compressor, this may not be a noticable advantage. Also, the extra pipe, especially in larger sizes like 2", increases system volume which is easier on a cycling compressor like a piston, as it will run slightly longer and stay off longer.

Cool. My system is a mix of 1/2 and 3/4" black pipe. Total run right now is around 50'. If i was to complete the loop it would add approx 40' to the run.

My compressor is 18CFM at 90PSI 60Gal tank and my system pressure is usually around 130-140. And i use ALL those 18CFM... I wish i had a bigger comp.

All my current run is sloped to reduce condensation. With drains and t's on each end.

I do a fair bit of painting and blasting. So my concern would be my desiccant dryer. Right now its on the end of my run, where the air is coolest and dryest. If i looped my system, the new section would be only 15' at the most from my blaster. I noticed my air was much dryer after i installed the long length of black pipe.

Attached is a quick illustration of my layout. Any ideas for improvement from a pro?

I also have a 30? gal old compressor that i was going to plumb into the system to use as an additional air tank. Is there any benefit to this? I know it will add to my compressor cycle times but when im blasting, my compressor hardly cycles anyways.. (yes i know this is bad)

 

[mjncad]

I have 1/2" copper lines in my shop with 8 drops and no problems. I also have a drop in the outside pen where I keep the implements.

The compressor cuts out at 130-PSI, I have my circuits set at 100-PSI, and small regulators attached to all my blow guns.

 

[kennyd]

My shop at home and at work are plumbed with pvc.Both have been this way for over 10 yrs with no problems. What are the draw backs Kenny.
Bill

Do a Google search "pcv for air". Dangerous stuff! In post #20 of THIS thread I put some links in to OSHA.

 

[Egon]

my compressor hardly cycles anyways.. (yes i know this is bad)

Why is it bad? Most industrial set ups run continuously. Stop start would be considered bad by many.

 

[patrick_g]

One way or the other, we all seem to get the air where it needs to be in order to get the job done.

Ah, yup, but with varying degrees of ease and convenience. You can share a fork between multiple eaters but it sure slows down progress.

My vertical compressor is in the garage so I can usually have a wall between me and the noise. There is an outlet there for tires and air tools if needed. The refrigerated air dryer is plumbed so it can be bypassed if desired. Compressor to filter and then dryer is PEX and then black iron on to the 4 outlets in the metal shop (a hair over 1000 sq ft) and 3 in the wood shop (a tad under 1000 sq ft). Several of the outlets are dual outlets with one being filtered dry air and the other with a filter-regulator-oiler for air tools. (You do have to keep the hoses separate. I have some wall mounted retractable spring loaded drums which are super convenient for getting a hose pretty much anywhere you want it fast and convenient. (I need some for electric too.)

The compressor is set for 175 psi and the regulator on the comp's outlet is set for 110 psi for distribution. The regulators out at the ends of the runs can be set for 90-100 for air tools. I would distribute at a higher pressure BUT... the dryer is not rated for 150 psi working pressure.

When I ran electricity to my relocated 35x70 barn I also buried a small plastic tube (ice maker tubing...yes it is rated for the pressure) to supply air to a recycled 30gal compressor tank (motor died after only 25 years or so) It is not a fast recovery situation but to start with you have 30 gal @ 110 psi, good for topping off a tire.

Pat

 

[The Haymaker]

I've used PEX piping for my air supply in The GarageMajal. It works well, no failures, no leaks. Very flexible, takes a few minutes to plumb everything. Best part is if you need to expand, just cut, crimp in a "T", and go where you need it!

Mos heavy trucks don't use metal anymore. They use plastic. No corrosions and good anti-chafing properties. BUT, changing fittings sucks when it's -5f and the wind is blowing!

E

 

[varmint]

It may have been a mistake, but I used schedule 80 pvc for my airlines in my shop, but they are installed inside the wall, seldom used, and then at usually under 100 psi for nail guns. Seemed like a good idea at the time, 10 years ago. No problems, he said.

 

[Scooby074]

Why is it bad? Most industrial set ups run continuously. Stop start would be considered bad by many.

The key word in your post is INDUSTRIAL. Duty cycle on my compressor is 100% BUT:

My compressor never cycles because im using more air than i can generate (ie:bad). In use my line pressure will drop to around 40psi (bad) when i really want 90.

I really need a larger compressor for what i do.