Just finished installing a new air compressor in my garage and I noticed that the outlet from the tank would take 1/2", not 3/4" pipe. Does the diameter of the pipe matter to the air tools? Should I run 1/2" pipe or install an adapter and run 3/4" pipe?
3/4 would give you a bit more volume in the lines but I don't think you will gain much if any flow due to the 1/2 outlet on the compressor.
They say to use the biggest you can afford. And a lot has to do with how long you are running the line, too. Yes, there will be a restriction in the fitting were it leaves the tank, but you have to think of the line as not just a conduit for the air, but it's volume is a small tank unto itself. I have a 5-hp, 220 volt compressor in my loading dock, and run a 3/4" to 1/2" to 3/8" down the 150 foot length of the dock. At the very end, where the trucks park, I cannot successfully run a 3/4" impact gun. It turns, but there isn't enough volume of air to give it enough torque to remove even a typical lug nut. The 1/2" drive impact guns and grinders and such work fine. If I need to use the 3/4" drive, I run a 1/2" hose to where the hardline is larger, bypassing the 3/8" section. That is the only restriction-caused problem I've ever run into. And the 3/8" line is lots smaller than the smallest you were considering. Check different locations on the tank. Mine has several bungs of varying sizes around the tank. The mainline comes off one side (via flex line), while my sandblast cabinet attaches to the other side through a regulator. The mainline has no regulator -- it's whatever the pressure of the tank is. The regulator gets installed at the end where the tools connect.
Agreed! Run the largest pipe you can afford. Consider 1½" galv schedule 40. Ebay is full of fittings and valves. Check with your local plumbing/mechanical/industrial/irrigation/pump supply houses for pipe pricing. You will be stuck with 20-22 ft lengths and you might have to rent some threading equipment if you have odd lengths to run, but well worth the storage capacity. .
I might add, the routing of the lines is critical to control moisture in the lines. Run them up high with 1/8" to the foot slope back to a drip leg with a ball valve at the compressor. Any condensed moisture will eventually end up there to be drained off daily. Each drop should also have a drip leg at the bottom and the ball valve to drain it. I have always been told air lines should be black iron not galvanized. Anybody know why? I like 1" laterals with 3/4" or 1/2" drops. Nothing smaller. Only use ball valves. the screw kind won't last the summer without corroding up. I use a large Ingersol-Rand with I believe and 80 gallon tank, and a Devilbis moisture trap. If you are going to spray paint off the same lines never run an oiler for your tools. Once the oil is in the lines it is impossible to get it all out and fisheyes are a way of life. Just my observations.
chek to see if the tank bushing is removeable , if it is you can up size the outlet on it , when I had the shop ( trucking co) we ran a 1 1/2 line out as a feeder with 1" drops for out hd impacts ( which used a chicago twist fitting ) and had smaller qc hook ups for air lines , the tool room were they did repair work on smaller stuff and car work we used a 1/2 line. and always try to run a filter on the lines if you use any type of ferrous pipe to catch rust , scale and sometimes galv flakes. copper isn't as bad but its expensive , and NEVER USE PVC for one its not rated for air/gas usage and 2 .its deadly when it breaks from the shrapnel . and not worth the risk !
NEVER run galvanized pipe for air line! I'm going to hear you've done it for bla bla years and never had a problem. Small bits of the galvanizing can break off and clog small orifices in air tools and become projectiles out of a blow off tool, usually when you're blowing the dust out of your face. Use sch 40 black pipe, or sil flossed sch K copper (never sch "M" drain copper). If you have the pipe pitched correctly and enough drains and dirt legs you won't have a problem with rust. The bigger the better for mains. the drops can be 1/2" or 3/4".
I ran 3/4 inch plastic pipe with threaded connectors for the air fittings from my compressor all around my 24x24 garage. Glued everything together and did not spare on the glue, so far 22 years with no leaks and I have run all my tools. It runs from compressor to water separator to plastic lines around garage.
The flow is approximately the square of the diameter difference so 3/4" pipe flows 2.25 times what a 1/2" pipe flows. A 3/8 dia air hose also flows 2.25 times a 1/4" ID hose... these are for equal length runs. For longer runs, the bigger pipe is better. Rapidair has a decent chart http://rapidairproducts.com/flowrate.asp
Plastic gets brittle over time, especially if there are airborne chemicals or oil in the space. I've personally seen the aftermath of PVC failing (using extra glue does no good as most failures aren't at a glue joint) and you do not want to be around when it does. You've been lucky for 22yrs
I have a friend that ran a 4" sch 40 PVC header in his shop and used 2" sch 40 for all the drops. He did the math - I forget how much it increased his storage capacity, but it was a lot. Really reduced the frequency of run time on his compressor too. He did this about 15 years ago - its still in service with no issues.
4" PVC in Schedule 40 has a water working pressure of 220 psi at 73deg F. At 100 deg F it derates to 136 psi. PVC pipe is a bomb when handling gasses. UV light deteriorates the stuff.
His is probably operating up to about 120 psi - its inside a climate controlled building and has been in working service for 15 years. No issues. Many people have done this.
I have used 1/2 inch plastic in my shop for 30 years with no problems. It is rated for 400 plus pounds. The first 40 feet is copper all slanted toward the compressor(zig zag style) to act as a water separator. Black iron pipe is required for gas installs because it has few defects. Galvanized is used to seal the defects.
I am just about to hook up my new compressor so I appreciate this conversation. I think I will go with 3/4" black pipe and take advantage of the suggestions offered.
My home shop/garage has 3/4in blue (L) copper for the main runs with 1/2in drops. Black iron rusts and can be a PITA to work with.
black pipe is not a good idea in my area.....to much humity....copper or galvanized is the only way to go. Mine is 3/4" rubber hose from the tank to the wall then its copper for about the first 10 feet then galvanized 3/4" and I have about 40' of sloped run that goes outside my garage then comes back inside for the first takeoff...all are off the top and go up 6" then turn down for 12" with a ball valve drain. The long run lets the metal pipe cool the air and condense the moisture out.
Do not use pvc for compressed air, it breaks down with time due to exposure to UV rays. When it fails it will spread shrapnel flying and cause you to possibly experience a bad day at the ER. Galvanized pipe at one time was known to flake off but with new technology it no longer happens. Copper works very well and is very clean if you flush the flux out of it. Other plastic hoses may hold pressure but can fail when sparks from the welding and cutting process land on it. If you can afford it copper, else galvanized works well. Coming from a Pipefitter for 35 years.
Sorry I forgot to address the question, Run the pipe the same size or one size larger than what is coming of the tank of the compressor. When adding tees to the line point them up and at the end of the run point an elbow down with a blow down valve.
Having been a Boilermaker for several years, I never thought I would agree with a Pipefighter on anything but you're absolutely right.
The prices for pipes certainly were cheaper 10 years ago. Can anybody even afford to plumb a shop these days ?
I've been putting it off for a couple years....but then I also don't seem to need to use air as much as I used to.
Before I realized this is a ten year old thread I was going to say RapidAir has a flow calculator on their website. But here anyway, maybe it will help someone: https://www.rapidairproducts.com/te...0An9E3DyGiASJYw43Pn6FPSLRE76tZNBoC850QAvD_BwE
I use copper pipe for all my personal air lines and have never had a problem. I use L type. M-type piping is the thinnest residential copper piping variety, and typically lasts for 20-50 years. L-type copper pipes are of medium thickness and can last for 50-100 years. As the thickest variety of copper piping, K-type pipes can last for over 100 years. Sweat fitting the joints is so easy that even a boilermaker can do it with enough practice.
We used the kit form Northern tool in the equipment dealer ship I work for . was cheap and easy to put up and looked good its aluminim wiht a blue coating on it . comes with aluminum blocks with three ports and all that . has been in service 10 years running tools every in a heavy equipment shop t . by the time you screw around with other stuff you can buy these kits and have them up much faster . they even had a tool to cut the line . it uses kind of a pex type compression fittng and was 3/4" as I recall big enough to run the 3/4 " air guns RapidAir MaxLine 3/4in. 100ft. Master Kit Compressed Air Piping System, Model# M7500 | Northern Tool We used a couple of these and added in line ball valves to be able to shut a section down if a hose reel hose let go . was a deal IMO
Saw a guy get hurt from a PVC line it let go when they threw open a ball valve fromt the compressor and the initial surge was all it took . Guy had a chunk of pipe in his neck
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