I want to run air lines for my compressor

Chief · Oct 6, 2008

I want to run some pipe around the walls of my garage.

I am thinking about using 1/2 inch galvinized pipe. Is this ok?

Also, since the pipes will be under pressure, what should i use to connect the pipes to make a good seal?

Let me know you thoughts.

Thanks

PAToyota · Oct 6, 2008

Quite a few discussions with many suggestions already posted. Might want to read through all of those.

Kevin54 · Oct 6, 2008

I would not go any less than 3/4" pipe. And there is a ton of threads on this. Do a search for airline, compressor lines, , compressor plumbing, etc and it will bring them up.

logical · Oct 6, 2008

Your search will tell you to run black pipe, not galv. either good quality teflon tape or pipe dope will work as long as the threads are cut properly.
3/4 is generally reccomended for main lines and 1/2 for the drops from it. Realistically, unless you are snading or something, 1/2 will be fine everywhere.

Matti · Oct 6, 2008

I just ran 1/2" copper lines in the walls for my 2 hp compressor. It's bigger than the hose I was using previously and should be fine. If I was using a 5 hp compressor to run a blaster, DA or other high volume tools I would definitely go bigger than 1/2". While copper isn't cheap the 1/2" isn't too bad and the fittings are cheap. Some of the specialty hoses and lines have very expensive fittings. Anybody can learn to solder and it's quick unlike learning how to be a pipe fitter/plumber (cutting and threading pipe) and buying/renting threading tools or running back and forth to the local building store to get them to do it. Soldered fittings don't usually leak but threaded fittings often do.

Torque1st · Oct 6, 2008

Codes usually specify black iron pipe. Galvanized will work and will reduce rusting but some locations or inspectors may not allow it. Some inspectors may pass it if it is painted black. Copper is not allowed in some localities because of fire codes.

A person does not need to be a pipe fitter or plumber or learn how to cut and thread pipe to use iron pipe. Plan your installation then go buy the pipe and fittings you think you need. Also buy a selection of extra short *******, fittings, and couplings etc. Just return the excess when you are finished. Use high quality pipe dope containing Teflon on the joints.

Use 3/4 pipe for the main line. Use a reducing T 3/4 run to 1/2 branch at each drop. Run the drop off the top or side of the main line, not the bottom. Each drop will also require 2 45° fittings, either 1 or 2 90° fittings, and either 3 or 4 short *******. Use the appropriate length pipe down the wall with a T for the outlet and a drip leg with a drain valve.

Some installations slope the main line back towards the reservoir tank where the main tank drain valve is used to drain the moisture. With this type of installation the moisture has to flow against the flow of air and seems to kick up more droplets of moisture into the air stream.

Some installations slope the main line away from the compressor so that the moisture flows with the air flow towards a drain leg at the end of the line. In some installations the end of the line is sufficiently close to the compressor that an automatic drain valve can be used otherwise the drain leg must be drained manually.

Some installations run the pipe from the compressor both ways around the shop coupling the runs together on the far side of the shop.

e-tek · Oct 6, 2008

I like Torques summary - very succinct, takes into acccount most of what has been beaten to death before on the suject - nice one!

Matti · Oct 6, 2008

I would also air/leak test before strapping the pipe to the wall (where possible). Unless you are just lucky and can mix and match ******* and fittings or you are not too particular about the routing you will need to cut and thread pipe. This is not insurmountable...just a little work.

Torque1st re: fire codes - I am very curious to hear why fire codes would be concerned with copper air lines. It surprises me that they are even covered. I realize you probably didn't write the codes but what are the perceived risks? I think if you're garage is burning down the integrity of a compressed air line is not your biggest problem. Does the code also cover aluminum air lines and hoses?

Torque1st · Oct 7, 2008

Matti- I have run into it a few times while doing research on the subject. As far as I know copper is excluded in some areas due to the fact that the soldered joints will fail when heated and accelerate the fire. Ever used a bellows on a fire?

I have done a number of threaded pipe installations without having to cut and thread pipe and they looked good. Of course when the pipe run has to meet very close dimensional specs it may be necessary. Usually there is enough positional latitude on jobs like running air lines etc that it does not matter.

rubadub · Oct 7, 2008

Heres some stuff you could look at.

http://www.1969supersport.com/draw1.html

http://www.1969supersport.com/airsand.html

Rob

http://www.1969supersport.com

Chief · Oct 7, 2008

e-tek said:
I like Torques summary - very succinct, takes into acccount most of what has been beaten to death before on the suject - nice one!

Agreed, thanks a lot. Very Helpful.

alberto · Oct 7, 2008

rubadub said:
Heres some stuff you could look at.

http://www.1969supersport.com/draw1.html

http://www.1969supersport.com/airsand.html

Rob

http://www.1969supersport.com

If I read your drawing correctly, you are running the pipe the full length and back to where you have your air out. Is the sole purpose of this long of a run to cool the compressed air? I don't see any other air take out connections, and that's the only other reason I can think of for making the run that long. What is about the total length of pipe run you have?

Thanks for the links and posting this on your site, good stuff.

Alberto

Torque1st · Oct 7, 2008

The tank is the main water condenser in any compressed air system. The lines just act to collect any residual moisture that may form in them. The walls of the reservoir must remain cool and should not be enclosed. Some people try to reduce compressor noise by enclosing the compressor in an insulated enclosure or closet but that is a mistake. The noise from most belt driven compressors comes mainly from the air intake. Moving that intake outside may help but annoy the neighbors. Using a muffler and bends in the intake pipe may help damp out some of the intake noise.

There are also coalescing filters available that can help remove water at a point of use.

High volume industrial systems frequently use chillers or large diameter main lines to help cool the air and condense moisture. Home shops should not need those provisions.

I have seen pictures of a small tank covered with ice in an ice chest that was used to remove water. Running a line thru the old lady's chest freezer is not advisable tho...

rubadub · Oct 8, 2008

alberto said:
If I read your drawing correctly, you are running the pipe the full length and back to where you have your air out. Is the sole purpose of this long of a run to cool the compressed air? I don't see any other air take out connections, and that's the only other reason I can think of for making the run that long. What is about the total length of pipe run you have?

Thanks for the links and posting this on your site, good stuff.

Alberto

I have three hose reels, one in the overhead, three drains, you should be able to see all of them here. http://www.1969supersport.com/paintroom.html

Yes long runs to cool the hot air out of the compressor.

Just guessing here, maybe 70 feet out of the compressor before it goes into three filters, then I have another maybe 60 feet going into the paint room with another filter. Then 25 feet going down another side wall, unfiltered at the end of that.

Rob

http://www.1969supersport.com

akdiesel · Oct 8, 2008

Torque1st said:
High volume industrial systems frequently use chillers or large diameter main lines to help cool the air and condense moisture. Home shops should not need those provisions.

I will be doing somthing similar to what you are talking about. I will be using a 3" x 2' ss pipe sch 80 capped off with a valve in the middle for the air intake and an exit out the top. This will act as a knock out drum used as you said for knocking out any extra liquids the main tank does not collect. There will be a valve on the bottom for draining as well.
The reason for ss is because I will be using 3/4 ss tubing and Swagelok Parker fittings for the main run and 3/8 and 1/2 for the hose reel drops. The ss will give me the ability to extend and/or include any future add ons by simply splicing into the line with a "T".

rubadub · Oct 8, 2008

Some installations slope the main line away from the compressor so that the moisture flows with the air flow towards a drain leg at the end of the line. In some installations the end of the line is sufficiently close to the compressor that an automatic drain valve can be used otherwise the drain leg must be drained manually.

========================================================

Automatic drains are nice, as long as you drain the end of line filters by hand.

Heres what happened to me. At the end of the day I always drain the filters (water traps).

I drained them and (they have little wingnuts on the bottom) and after I tightened the wing nuts back up, I noticed my finger tips felt slippery, did the sniff test and figured something let loose in the compressor pump.

If I would have had an automatic drain, I probably would have saturated my air lines pretty good. I bought another compressor, This is the third compressor in I guess 12 years.

The first one went 10 years and the second two years now I have the third one. I buy the $750.00 plus tax type, 2 stage pump up to 175 lbs.

I know I should have sprung for a good one for around $1500.00 in the first place.

These $750.00 compressors will run a 100 lb pressurized sand blaster pot, or any air tool with out a problem, also I guess I could mention that I had a black max, then ingersol ram, 10 years on the black max, 2 years on IR, now I have a porter cable, but all three pumps look identical.

I'm also a hobbist, although I use them quite often, you would think they would have lasted longer, I changed the oil with regular compressor oil like they called for, even change the oil and filter more frequently then they call for.

Rob

http://www.1969supersport.com

Torque1st · Oct 8, 2008

Rob, check your inlet air filter etc for quality and leaks...

Do you use your 2-stage compressor for 125PSI service or run it up to 175 PSI?

rubadub · Oct 8, 2008

Torque1st said:
Rob, check your inlet air filter etc for quality and leaks...

Do you use your 2-stage compressor for 125PSI service or run it up to 175 PSI?

Its always pretty clean, and when I change the oil I clean it like they say, but most all the dirt in the air is in my paint booth so its getting pretty decent air.

I also keep tabs on the duty cycle and don't over work it.

I run it up to 175psi thats where it shuts off, I usually run 95psi off the inline regulator, but after sand blasting I will run the regulator up to 130 psi to blow the sand out of the body or whatever.

It shuts off at 175 psi and kicks in around 125 or 130.

Are you think I should set the on tank pressure switch to 130 psi or something like that?

Thanks Rob

http://www.1969supersport.com

gerryw · Oct 8, 2008

i have a 7 hp, 60gallon compressor, i run 1/2 copper lines.
It works very well for my needs (weekend warrior)
I also have a glass beading cabinet and it runs with no problems.I have the usual drills, impacts, die grinders, and a pnuematic motorcycle lift
As far as leaks go, i have enough of a air leak for the compressor to kick on every 5 days or so, so i never fixed the leak as i felt it would be good to run the compressor in the event that i am not using it over a extended period of time.(the leak is not in the copper, but at the quick connects)

Gerry

Torque1st · Oct 8, 2008

rubadub said:
Its always pretty clean, and when I change the oil I clean it like they say, but most all the dirt in the air is in my paint booth so its getting pretty decent air.

I also keep tabs on the duty cycle and don't over work it.

I run it up to 175psi thats where it shuts off, I usually run 95psi off the inline regulator, but after sand blasting I will run the regulator up to 130 psi to blow the sand out of the body or whatever.

It shuts off at 175 psi and kicks in around 125 or 130.

Are you think I should set the on tank pressure switch to 130 psi or something like that?

Thanks Rob

http://www.1969supersport.com

Your air filter, even in a clean shop, should get dirty. Look at any surface you haven't cleaned for a few months. It sounds like you are getting a lot of particulates into the compressor that is causing abnormal wear. The particles that will do that are so small you can't even see them. Many manufacturers will put on a small inefficient air filter to save money knowing that they don't have to worry about the compressor failing during warranty due to wear. An efficient filter will cause a pressure drop across it so oversize it to minimize the loss.

Running high air pressure then reducing it thru a regulator wastes $$ energy. You paid a ton of money to compress the air to 175PSI just to blow it away in a regulator. I would suggest running your compressor at 125 PSI and maybe adjust the hysteresis if possible to cut in at about 100PSI. Some pressure switches have an adjustment for that. A rap on the gun and a hose wiggle etc should clean out the system.

PAToyota · Oct 9, 2008

Torque1st said:
Running high air pressure then reducing it thru a regulator wastes $$ energy. You paid a ton of money to compress the air to 175PSI just to blow it away in a regulator.

You make it sound like the regulator just vents the excess air. Actually, you are storing significantly more air in the tank at the higher pressure. Granted, it takes more energy to compress that air to the higher pressure than having an equal volume at a lower pressure, but for most of us the size of the tank is an issue and a 300 gallon tank isn't practical. Further, having the extra pressure that is then regulated down allows the compressor to cycle less frequently and cool down between cycles.

Torque1st · Oct 9, 2008

PAToyota said:
You make it sound like the regulator just vents the excess air. Actually, you are storing significantly more air in the tank at the higher pressure. Granted, it takes more energy to compress that air to the higher pressure than having an equal volume at a lower pressure, but for most of us the size of the tank is an issue and a 300 gallon tank isn't practical. Further, having the extra pressure that is then regulated down allows the compressor to cycle less frequently and cool down between cycles.

No, the regulator does not vent the air, it does however release the energy that it took to compress the air. The compressor actually runs longer and works harder to compress the air to 175PSI. Check the air system design manuals for a better understanding. There are formulas and tables for figuring the HP loss thru a regulator. Never compress air more than needed, it is a big energy and $$$ waste.

I want to run air lines for my compressor

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