Shop Air Compressor Piping?

[Doug Filo]

I used a rapidair Maxline I used 3/4" loop around the ceiling and 1/2 for the drops it is somewhat flexible so I only have connections at the drops I also have 10hp 120 gallon 65cfm compressor. When I compared it to copper a few years ago it was cheaper. Also I have 14' ceilings so this was a lot easier than copper in the ceiling.

[Mike Cutler]

Steve

I like copper. I've been installing copper tubing for pneumatic systems for over 30 years. It's a little bit more $$$$, but I like it. The black pipe available generally has so much "gunk" in it and on it, that it has to be cleaned and flushed before you ever use. It's good stuff, but there is some upfront prep that needs to go into it.
Installing it in a loop minimizes the pipe inner diameter penalties. a 200ft loop of piping is actually 100 ft. on the tables. Based on what you are giving for compressor specs, which is actually kind of small, you should run a 3/4" header and size your drops at 1/2" . You could also just go 3/4" all the way and think towards possibly installing a larger compressor sometime in the future. ( Piping diameters change size to maintain pressure, or flow. It depends on what you need. Same in a fluid system.)

I don't know if you plan to braze, sweat, or use compression fittings. If you braze, or use compression fittings, you're good to go. If you sweat the pipe, make sure to pic the correct solder. Plumbing solder, 50/50 is the incorrect solder and has a a rating of about 200psi, for 3/4" copper pipe. 60/40 will give you about 400 psi for the same joint.

[roger wiegand]

Mine is a one person shop with a maximum run length of 50 ft os so. "5hp" 60 gal Borg-sourced compressor. I use nailers, air to blow chips around, and not much else. Half inch copper with no loop is completely adequate for this level of use. While I was building out the shop I found that my little Hitachi compressor wouldn't start with the voltage then available in the barn, so ended up running 250 ft of 3/8" hose from the house. That kept up with a framing nailer without difficulty, even with rapid fire bounce nailing.

[Steve Mathews]

Steve

I like copper. I've been installing copper tubing for pneumatic systems for over 30 years. It's a little bit more $$$$, but I like it. The black pipe available generally has so much "gunk" in it and on it, that it has to be cleaned and flushed before you ever use. It's good stuff, but there is some upfront prep that needs to go into it.
Installing it in a loop minimizes the pipe inner diameter penalties. a 200ft loop of piping is actually 100 ft. on the tables. Based on what you are giving for compressor specs, which is actually kind of small, you should run a 3/4" header and size your drops at 1/2" . You could also just go 3/4" all the way and think towards possibly installing a larger compressor sometime in the future. ( Piping diameters change size to maintain pressure, or flow. It depends on what you need. Same in a fluid system.)

I don't know if you plan to braze, sweat, or use compression fittings. If you braze, or use compression fittings, you're good to go. If you sweat the pipe, make sure to pic the correct solder. Plumbing solder, 50/50 is the incorrect solder and has a a rating of about 200psi, for 3/4" copper pipe. 60/40 will give you about 400 psi for the same joint.

Thanks for the info. on the solder pressure ratings. I completely forgot to consider that.

[Alan Schaffter]

Everything you ever wanted to know- grades, fittings, pressure ratings (grades of pipe and various fittings), etc. can be found in the Copper Tube Handbook- a great reference. You can use either annealed (soft, ductile) or drawn (hard), Type M (thinnest wall, and cheapest, red colored printing.)- whichever works best. Pressure ratings are higher than any consumer-grade compressor you can buy.

The biggest air hogs are pneumatic ROS and HVLP sprayers. You'll want either big lines or short runs to the sprayer drop. Another issue with sprayers- ensure you have both oil/moisture traps/separators. All horizontal runs should have a slight slope to allow moisture that condenses there to flow and the bottom portion of each drop should have a sump with drain valve. If you have an assembly table or spray table, mount a hose reel to the ceiling above it. If your shop is large, consider having a regulator and oil/water traps/separators at each drop.

[Bruce Wrenn]

Steve

I like copper. I've been installing copper tubing for pneumatic systems for over 30 years. It's a little bit more $$$$, but I like it. The black pipe available generally has so much "gunk" in it and on it, that it has to be cleaned and flushed before you ever use. It's good stuff, but there is some upfront prep that needs to go into it.
Installing it in a loop minimizes the pipe inner diameter penalties. a 200ft loop of piping is actually 100 ft. on the tables. Based on what you are giving for compressor specs, which is actually kind of small, you should run a 3/4" header and size your drops at 1/2" . You could also just go 3/4" all the way and think towards possibly installing a larger compressor sometime in the future. ( Piping diameters change size to maintain pressure, or flow. It depends on what you need. Same in a fluid system.)

I don't know if you plan to braze, sweat, or use compression fittings. If you braze, or use compression fittings, you're good to go. If you sweat the pipe, make sure to pic the correct solder. Plumbing solder, 50/50 is the incorrect solder and has a a rating of about 200psi, for 3/4" copper pipe. 60/40 will give you about 400 psi for the same joint.

I've been in the plumbing business most of my life. I haven't seen any 50/50 in years as it was ruled illegal to use on water lines. All the new soldier is lead free. Do yourself a favor, and go by a plumbing supply house (not Lowes / HD) and pick up a jar of LA-CO soldiering flux. It's self cleaning, which means most fittings don't need to be sanded/ brushed prior to soldiering. Slope your lines AWAY from the compressor. You can run one line, and cap the end. Come back later and add other line, remove cap and connect together. Be sure take offs are from TOP of trunk lines, with both cut off and drain valves

[Malcolm McLeod]

... Be sure take offs are from TOP of trunk lines, with both cut off and drain valves

A couple of posts have mentioned tapping 'up' off a trunk line. I had forgotten this detail (its been a day or 6 since I was in this end of the industrial world), but recommend it highly. Thanks for the reminders.

IIRC, Parker (somewhere on their site) has a great deal of information on good air system piping design (regardless of material), air prep, and delivery components. If you are going to all the trouble to build loops, drops, etc - - it might be worth a glance.

[Steve Mathews]

Alan - Thanks for the link to the Copper Tube Handbook. Great resource.

Bruce & Mike - Thanks for the suggestions.

I really liked the idea of the RapidAir FastPipe but an all copper system beats it hands down in delivered price and availability. My plan now is to run the 200 ft. loop in 3/4" Type L copper pipe with long radius 90s in the corners and 1/2" drops where needed. I don't see any need for Type K or L copper for my application unless someone can point it out to me. I'm a little torn by whether to use a goose neck or drop straight down with the 1/2" connections. I see the additional value in the goose necks in preventing water from entering the drops but it would be awkward in my case because the loop will be fastened to the wall. Besides the RapidAir installations all show straight down drops. I'll be sloping the loop away from the compressor and providing drip legs with drain valves at the bottom of drops so maybe that's good enough. I'm also not sure about the cut-off valves at each drop. Why would they be needed?

I plan to use 95/5 solder with the LA-CO flux that Bruce mentioned. The use of a hose reel is also being considered.

[Malcolm McLeod]

... I'm also not sure about the cut-off valves at each drop. Why would they be needed?

Most plant air systems deliver air to the header at the rated pressure of the air compressors. Then each drop gets a FRL, etc - - to condition the air for the requirements of the individual point of use. Best-practice is to include a cut-off valve on each side of the FRL - one to isolate the FRL, so it can be serviced; the second, to quickly isolate the process equipment (if the FRL is set for a relatively low pressure, it might take an unacceptably long time to dissipate the hi-pressure air still 'in' the FRL - using the upstream valve only).

This may be gross overkill for the average hobbyist user.

[Steve Mathews]

Didn't take long to convince me to put a goose neck and isolation valve on the 1/2" drops. The cost and effort to install the additional control valve is minimal so I'll go ahead and do it. I just thought of a way of installing the goose necks even though the loop is fastened to the wall. I'll just arm back into the wall cavity. Fortunately the studs are currently open. That arrangement might actually be better because the drop would be out of the way from being hit. Thanks for keeping me on my toes and thinking this through better.

[Alan Schaffter]

Goose necks taps off the main can't hurt, but the main line still needs to slope and somewhere you still need a drop coming off the bottom so condensate can drain, you don't want water pooling anywhere. Remember, moisture can condense anywhere in the line.

My drops come off the bottom of the main and in place of goosenecks I put a "U" near the bottom. At the bottom of each drop I have a small drain valve. The tap is a few inches above the drain valve and turns up just slightly. The shut-off valve, regulator/moisture separator/gauge/quick connect are attached at the end of the turned up piece. Every drop has a shut-off because it allows me to do maintenance on the regulator assembly without bleeding down the entire system and it also allows me to isolate quick disconnects (and my ceiling-mounted hose reel) which are notorious for leaking, keeps the system from bleeding down.

_____________________3/4" type M copper main (on or near ceiling)______________________
|
|
|
| < drop (1/2" copper, except for HVLP drop which is 3/4")
|
|
|________| < turns up 1" - 2". Shut-off valve/regulator/separator/quick disconnect mounted at the top
|
|
| < this 6" section (approx) acts as a water sump
|
X < condensate drain valve

I use these to attach the pipe to walls and ceiling:

[Jerry Bruette]

Most plant air systems deliver air to the header at the rated pressure of the air compressors. Then each drop gets a FRL, etc - - to condition the air for the requirements of the individual point of use. Best-practice is to include a cut-off valve on each side of the FRL - one to isolate the FRL, so it can be serviced; the second, to quickly isolate the process equipment (if the FRL is set for a relatively low pressure, it might take an unacceptably long time to dissipate the hi-pressure air still 'in' the FRL - using the upstream valve only).

This may be gross overkill for the average hobbyist user.

We use self exhausting ball valves, upstream of the FRL, which will automatically exhaust all down stream air. No waiting for the line to bleed out or getting stinky, oily air out of the filter drain valve.

[Mike Cutler]

I've been in the plumbing business most of my life. I haven't seen any 50/50 in years as it was ruled illegal to use on water lines. All the new soldier is lead free. Do yourself a favor, and go by a plumbing supply house (not Lowes / HD) and pick up a jar of LA-CO soldiering flux. It's self cleaning, which means most fittings don't need to be sanded/ brushed prior to soldiering. Slope your lines AWAY from the compressor. You can run one line, and cap the end. Come back later and add other line, remove cap and connect together. Be sure take offs are from TOP of trunk lines, with both cut off and drain valves

Bruce
Lots of 50/50 still out there. They changed the core, but the 50/50 is everywhere.

[Bruce Wrenn]

Bruce
Lots of 50/50 still out there. They changed the core, but the 50/50 is everywhere.

What do you mean "changed the core?" Here in NC, you can only buy lead free for plumbing. The stained glass people still use 50/50, but not from plumbing supply sources.

[Jim Becker]

I've been wondering the same thing lately as I recently used PEX for a plumbing repair in the house. I have not had time to research that, however.

That said, my air lines are all copper with the exception of a short flexible loop between the compressor and the system for sound and vibration isolation.

Answering my own curiosity. From the FAQ at the SharkBite web site:

Q: Can I use PEX pipe for compressed air applications?
A: No, PEX pipe is not intended for compressed air applications.