Shop Air Compressor Piping?

[Steve Mathews]

Part of my efforts to reorganize and setup a shop in my barn includes running air compressor piping. My thought was to run a loop around the entire inside exterior walls, which amounts to a little over 200 ft. After doing a little reading it looks like my logical choices for the type of pipe are black steel, copper and the coated aluminum pipe specifically for compressed air. I'm able to do the black steel and copper easily enough but still haven't decided which direction to take. I like the idea of copper for the ease of making changes if necessary. The black steel is of course cheaper but adding future outlets would be difficult. It's also not as clean as copper. The specialty aluminum stuff sounds good but I'm a little concerned about the plastic fittings and cost. Any suggestions or advice would be appreciated.

[Bill Adamsen]

Steve ... for the same reason you are considering copper (familiarity and flexibility) I chose to use copper for my pneumatic system. The materials were not particularly expensive in total (I had quite a bit of used pipe and new and used connectors) and my familiarity, and locally available materials made fast work of it. I liked that it was rated for the pressures I sought to use. The system is designed to gravity drain any condensation buildup. No complaints.

[Malcolm McLeod]

A loop or ring is very common in industrial settings, but of course will use more material. If you decide to go this route, consider 'up-sizing' the loop pipe. It is surprising the amount of air storage you can get in this volume of pipe and it reduces cycling on the compressor. However, the biggest justification for the loop is that it helps balance air flow to multiple users around the loop. This may be of little consequence in your usage plans.

As for materials, if you plan well, the black iron pipe should be easy to expand or change. I'd run the loop around the barn up high on the walls (just below ceiling), install a tee at every drop you wish to install, as well as at every potential 'growth spot', or even use tees instead of pipe couplings. Point the tees down the wall. For those you aren't using, put a plug in the tee.

At the tees you want to use now, drop a pipe leg down the wall and terminate it as you see fit - - put another tee to branch horizontally to FRLs, tools, or other points of use. Put a drip leg on the 'run' of this tee with a small valve to drain condensate.

Never used copper (for air) or the aluminum, so (I ) will stay away from (offering opinions on) that.... Hope the rest is some help.

[Sam Layton]

Hi Steve,

I used copper in my shop. I do not have experience with black pipe, nor the aluminum pipe. This is my second shop that I have used copper. I have had very good experience with it in both shops.

Sam

[Steve Mathews]

I forgot to ask about sizing. Based on the 200 ft. loop and only one person using the shop, what size piping should I use?

[Malcolm McLeod]

I forgot to ask about sizing. Based on the 200 ft. loop and only one person using the shop, what size piping should I use?

What are your points of use? What CFM is recommended/required by tools? What compressor? For what I do (tires, small stain/paint sprayer, nailers), 1/4" is plenty. On the other hand, if you have a tire changer 200' from the compressor .... well, as the preacher said, "Organist, play some check writin' music!"

Edit: This is handy and simple look at pipe sizing (http://www.industrialaircompressors.biz/files/943922/uploaded/how_to_determine_Pipe-Size_chart_2-18-11.pdf). It assumes you want the full volume & pressure capacity of your compressor delivered to point of use. You could figure the 2 worst cases: 1) longest run to a particular use point (with volume & pressure at that point) ; and, 2) run to the largest volume use point.

[Steve Mathews]

Malcolm - Good point. The compressor I currently have is just 5 hp with a vertical 60 gal. tank. I don't know the CFM. I don't have many pneumatic tools but can see using a paint/stain sprayer, impact wrenches, brad/nail guns and nozzles to blow off stuff. No sand blasting, tire changers, etc. The point of use could be anywhere on the loop. Copper can get really expensive when you reach 1" so I would like to keep it below that.

Edit: CFM rating on the compressor is 12.4 at 90 psi.

[Steve Mathews]

Malcolm - Thanks for the link to the pipe sizer. Based on that it looks like 3/4" is more than sufficient. It doesn't mention what friction loss coefficient is used in the charts but copper would be the better case scenario. I'm leaning toward 3/4" copper at the moment.

[John K Jordan]

Black iron pipe can rust inside and contaminate things. Copper is great.

I installed RapidAir flexible plastic pipe and fittings in the walls and ceilings. I installed eight outlets with quick connect fittings in the wood shop, machining area, little weld shop, maintenance bays, and outside. No leaks in two years of use. Ain't gonna rust. Runs impact drivers and random orbital sander, my biggest air suckers, and everything else I've used. 5hp 60 gal Ingersol compressor.

JKJ

[Steven Hosler]

Steve,

It sounds like I have a setup similar to yours. I ran 3/4" copper pipe for the loop, and then 1/2" for the drops. I choose copper for the same reasons listed above, but also because any water in the system can rust out a black pipe system over time (also risks of rust flakes in sprayers). I have also noted (as Malcolm stated), that this system seems to expand my air capacity more than I expected.

Good luck

[Brian Henderson]

I had 3/4 copper in my old shop and it worked just fine. I'll use that in my new shop, once I get around to building the shed for my compressor and dust collector in the spring. I do end up using two 1/2" 50' air reels that reach pretty much anywhere in the shop, plus a couple of dedicated drops, such as at my main workbench and in my finishing room. I put one reel at each end of my shop and I have never found anything I couldn't reach.

[Bob Wingard]

I too ran a giant loop of copper completely around the perimeter of my shop. It is a few feet in from the stud cavities, so I can get to it if/when necessary. The entire loop is gently sloped toward one corner for condensate drainage. Each takeoff starts with a "t", a 90deg. fitting and a short stub of vertical pipe ... then, a 2' or so horizontal pipe to get just over the stud cavity, and finally, the drop actually down & into the stud cavity. I have 10' ceilings, and the drops are all about 5' from the ceiling. Once inside the stud cavity and down the 5', I installed a "t" fitting and ran the piping horizontally to whatever the next obstruction might be. This large inverted "t" runs completely around the shop at about 5' from the floor. If I ever need to add on to the plumbing, I just have to remove a piece of paneling (Hardiboard in my case) ... make the required changes ... replace the paneling and cutting any necessary holes in it. I basically have compressed air available for the full perimeter of the shop, and it is not very difficult to access it. Also, there are three hose reels mounted at the ceiling, and one fitting mounted on the outside wall so I have air to inflate a tire without having to even go into the shop.

[Robert Delhommer Sr]

Just wondering if PEX piping would work? Not expensive but I have no idea what the pressure ratings, ect. are.

[Jim Becker]

Just wondering if PEX piping would work? Not expensive but I have no idea what the pressure ratings, ect. are.

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.

[Malcolm McLeod]

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.

Somebody has-been-there-wondered-that: http://www.sawmillcreek.org/showthread.php?16795-Pex-pipe-for-air-lines

[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 (https://www.copper.org/publications/pub_list/pdf/copper_tube_handbook.pdf)- 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 (http://www.parker.com/literature/Literature%20Files/pneumatic/Literature/FRL/0700P-E_B%20Global%20Air%20Preparation.pdf) (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:

http://www.essentialhardware.com/media/catalog/product/cache/2/seo_image/239x/9df78eab33525d08d6e5fb8d27136e95/2/9/2904142.jpg

[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.

[Martin Wasner]

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.

It's what I have in my shop for air lines. It's ugly and does nothing to cool the air. It is cheap, is very easy to modify, and takes very little skill to install. I had all the air lines and drops installed in two days. Maybe 400' of pipe.

I'm torn whether to do copper or aluminum pipe in my new shop. It depends which will be cheaper. The aluminum is pretty easy to install, the pipe is significantly cheaper, but the fittings are spendy. Prevost is the brand of aluminum pipe I've been looking at.

[Mike Cutler]

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.

Bruce
Same here in CT. 95/5 is used in plumbing. The core changed from acid to rosin. Corrosive, versus non corrosive.
If you go to the Home Depots up here they have the rolls of solder all together. Most of it is labeled pretty poorly. If a person doesn't work with solder a lot, they'll usually just grab the cheapest roll which will be 50/50. The plumbers don't buy it, but I doubt someone in that business is buying many products at Home Depot.

I have all kinds of solder, as I also used to do electronic board repair, for the day job. I don't normally buy solder at a Home Depot either.

PS
I installed a lot of tubing and airline at Catawba Nuclear Station when it was under construction. I lived in Charlotte at at the time. I've always missed living in NC. It's very pretty down there. Lot's of good memories from that time.:)

[Jim Becker]

Martin, I was hoping that "officially" PEX might be supported as I have some changes I want to make to my system. But no matter, I can stick with copper for these modifications. I already have the pipe I need, so it's just a matter of fittings.

[Steve Mathews]

It's what I have in my shop for air lines. It's ugly and does nothing to cool the air. It is cheap, is very easy to modify, and takes very little skill to install. I had all the air lines and drops installed in two days. Maybe 400' of pipe.

I'm torn whether to do copper or aluminum pipe in my new shop. It depends which will be cheaper. The aluminum is pretty easy to install, the pipe is significantly cheaper, but the fittings are spendy. Prevost is the brand of aluminum pipe I've been looking at.

Both Prevost and RapidAir systems are tempting but I haven't found a way of getting the rigid pipe in full lengths without paying a lot for shipping. Copper is fortunately readily available and only requires a little more effort to install.

[John K Jordan]

Both Prevost and RapidAir systems are tempting but I haven't found a way of getting the rigid pipe in full lengths without paying a lot for shipping. Copper is fortunately readily available and only requires a little more effort to install.

If you use plastic consider running a length of copper from the compressor itself and before the water separator, trap, and dryer. This will let the air cool far better than the plastic pipe. If the water separator is too close to to the compressor the hot, moist air will pass right through. From my research a typical recommendation is 25' of cool-down pipe. It should be sloped so water that condenses inside drains to a trap and doesn't pool anywhere in the pipe. I made traps from brass tubing. The compressor is in a closet for sound control so I brought all the controls, valves, and shutoff switch out into the main shop.

352382

JKJ

[Bruce Wrenn]

The cored soldiers are for electrical stuff. Plumbing soldier is solid, you have to add flux to joint before soldiering.

[Alan Schaffter]

and if you use the flux with powdered solder in it (if you can find it), the joint almost sweats itself and you hardly need to add any solid solder.

[Chris Stolicky]

I have run 3/4" pex for air in my shop. It is in the ceiling and in the walls. I think there are a couple of important factors to consider here - 1) when compared to metal, pex can be physically damage easier if it is exposed, 2) UV can degrade pex, so you probably do not want it run on the outside of walls, 3) pex manufactures are in the business of making pex for water (liquid) use, therefore, will not 'certify' it for a gas (or air), and 4) check to make sure the pex has an oxygen barrier.

I'm not surprised Sharkbite generically says "no" to compressed air. The standard pex is thinner and does not have the barrier. It is easier and less liability for them to simply say "no" because all pex is not make equally. In my case compared to copper and BI, the price was right and ease of installation was there. And, if it breaks, I'll just fix it... So far so good. Ironically, pex instructions do say to use air for a pressure test prior to putting it into service.

Note, the good thing about pex is that if it does fail, it is a very ductile material and will not shatter. It would be an elastic failure. This does not, however, prevent all of the pressurized air from blowing out.

Good luck in your decision.

[Chris Parks]

The use of a hose reel is also being considered.

There are hose reels and there are hose reels. I bought two cheapish hose reels with 3/8th hose which is the absolute minimum to run air tools with and it really should be bigger but I am not using them professionally so I live with it. When I got them I did not notice for a while but the power of the tools seemed to have dropped but I put it down to the hose diameter and lived with it. Then i got curious one day and pulled the reel aprt to have a look and found that the air inlet in both reels was only a 1/4" which is as useless as an ice cream in hell. So the lesson is check the specs for any hose reel and make sure you get what you pay for.

The vertical drops do not need to have a goose neck on them, put the air connection above the end of the drop and have a drain valve under it so the condensate collects below the air connection. The bigger the pipe size used the slower the air speed, the slower the air speed the less condensate carried in the air stream.

[Brice Rogers]

I'm surprised that you didn't consider schedule 80 PVC pipe. It has a burst rating of around 600 PSI. I run around 100 psi in my shop and use irrigation ball valves at each station. The valves are perhaps the weak point (rated around 150psi but tested to 220 psi) but don't seem to leak at all after 10 years of use. When I assembled I used purple primer and a good quality PVC glue.

I bought the white PVC at the "big box" store. It is very inexpensive.

[Chris Fairbanks]

I'm surprised that you didn't consider schedule 80 PVC pipe. It has a burst rating of around 600 PSI. I run around 100 psi in my shop and use irrigation ball valves at each station. The valves are perhaps the weak point (rated around 150psi but tested to 220 psi) but don't seem to leak at all after 10 years of use. When I assembled I used purple primer and a good quality PVC glue.

I bought the white PVC at the "big box" store. It is very inexpensive.


someone should put their flame suit on now..... :)

Its not burst rating PSI that people worry about. As PVC is exposed to UV and as it ages, it gets very brittle. PVC is not rated to handle compressed gases. It is rated to handle no pressure or non-compressible things like water. One accidental hit with a piece of wood, a clamp, etc or just old age and its going to explode and send shrapnel everywhere.

[Jim Becker]

Yes, there have been lots of "PVC for air" threads over the years and while some folks have successfully used it, its properties can be somewhat dangerous in certain circumstances which is why it's not permitted by OSHA and other jurisdictions for compressed air.

[Martin Wasner]

If anyone wants to feel better about their choices, I just dropped about $4200 on air line pipe and parts. I ended up going with Prevost aluminium pipe. That includes almost $900 for filters at the compressor too.

[Doug Walls]

My thought was to run a loop around the entire inside exterior walls, which amounts to a little over 200 ft.


A loop or ring is very common in industrial settings, but of course will use more material.

I use to work in a shop that used a 2-1/2" black pipe loop through out the whole shop, Probably close to 800 feet or more in total length. It's surprising how much air that loop system held! We had to drain the loop system once to add a larger dia. section to one of the drops & it took quite a while to get all the air out.

Doug

[Dan Schmidt]

I used 1/2" copper in my last 2 shops. Love it. 3/4" is not needed for the use cases you have.

Dan

[Bill Dufour]

I read that OSHA has outlawed pex for compressed air within the last week. I would expect it is due to ageing since it is not allowed to see sunlight for more then 30 minutes or so before burial. It might also be that pressure cycling will cause it to creep off the fittings until it blows off completely.
Bill

[Bill Dufour]

Be aware if you use pex it is tube size not pipe size. so to be equal air flow to 1/2 copper pipe you need to use 3/4 PEX. one inch PEX is a s big as you can easily find. that is only 3/4 pipe size.

[Lane Hardy]

A horror story with compressed air piping!
i am a hobby wood worker, professional Corprate pilot flying Corporate Jets, with a degree in Electrical Engineering.
i had nothing to do with the design of this fiasco. I was merely a beer sipping bystander, 1989 a small town 18 miles North of Tallahassee, FL in GA. This town had a small manufacturing facility for small boxes and baskets and wood things that were sold to a big name company that sold these items for a 500% mark up. The owner of the manufacturing facility made very little on her investment. However she provided work for those in the community and the workers provided a quality product.
The company that bought her wares asked for more production with a cash infusion to expand an used part of her building! win Win.
she needed more Air for her pneumatic tools that the employees used on the assembly line.
I knew her husband from the airport that I flew out of, he was a private pilot a sharp individual, a retired civil engineer.
he mentioned the expansion of the facility and asked if I had any recommendations on how to expand the compressed air system. I told him that is not my area of expertise and suggested he consult with Ingersal Rand.
i was out of the loop.
4 months latter we ran into each other at the airport on a Sunday afternoon. I asked about the shop expansion he said he hired a guy to design the system and install it and they were going to fire it up and test today since no employees were present. He said he had the beer on Ice (you can't buy Beer on Sunday in GA)
Cool am game! (I had a Low beer light at my house) poor planning on my part.
We arrive at the shop, he shows me the compressor it is a twin cylinder 3 phase 480 volt compressor!
The cylinders must have been 5 feet in Diameter just kidding I asked what is the CFM and pressure output? He said he did know. But let's fire it up!

As I was looking at this beast I saw that the pipe coming out of the compressor was 6 inches in diameter made of steel it disappeared into the ceiling through ceiling tiles and on to the work stations in the ne Facility. I was thinking that is a lot of volume not to mention available pressure.

Art said grab the Cooler we are going to be here a while the compressor builds up to the working pressure.

We pop the top on the beers Art starts telling me about the project and how it gone. The first contractor had a health issue and recommended another guy to complete the project. The second guy finished up and said he needed to be in Atlanta on Monday to start a new project and every thing was a go fire it up!
So here we are the Pressure is on! We started the compressor, we are sitting on the loading dock, feet dangling sucking down the beers, a cool November evening 6:30 ish quiet surroundings, talking about flying, the compressor has been purring in the background for about 45 minutes.
If you have ever herd a Sonic Boom this was about 20 times louder! And my body reverberated with the concussion of the air, and I was outside a100 feet from the rupture of the pipe. The failure was the 10 inch PVC pipe the second moron though he could inhanse the volume by adding 30 feet of 10 inch diameter pipe as a resivior (his words)
the fire department showed up thinking that the building blew up. Folks a mile away said there was an explosion here.
the point is don't use PVC for compressed air.

[Lane Hardy]

Part 2, I forgot to mention the moron that built the system did not speak English nor did he use pvc primer / solvent prior to glueing the pipes together, A chunk of The 10 inch PVC pipe blew through two Pieces of 1/2 inch drywall and impalled an office chair. The non English speaking person was better suited to conducting other task. I blame the guy that hired hired him. Not the poor guy doing work.

[John K Jordan]

... I blame the guy that hired hired him. Not the poor guy doing work.

My stars!!! My experience with such things is with pressure vessel inspection back in the '70s. The energy in a 30' length of 10" dia cylinder at 100+ psi is astounding. When we pressure tested vessels with air we first lowered them into an underground bunker with a heavy steel and concrete hatch. Hydro pressure testing with water is safe if it fails (and silent).

I do use extra length of hose to increase the reservoir volume - when using air tools on the farm with a portable compressor rather then run 100s of ft of electrical cord I run a short cord and 100s of feet of air hose. But PVC? Large diameter PVC? No. You can use PVC for vacuum reservoirs since the pressures are so low, but it has to be solid core not cell core PVC.

JKJ

[Chris Parks]

My welding teacher was also a investigator of industrial accidents surrounding welding and he used to relate to us how accidents came about through stupidity. One he related concerned a high pressure air tank that was being built, two welders were leak testing the tank by charging it with air, locating leaks, dropping the air pressure then repairing the leaks. This process took a lot of time and it was Friday afternoon and they wanted to finish before going home so they decided to short cut the whole thing and get out of there. They were working on top of the tank so they leak tested, found the leak and began to weld and it simply blew up. Apparently the marks their bodies left on the roof of the workshop could clearly be seen after the explosion. Compressed air is dangerous but few of us realise how dangerous.

[Lane Hardy]

Sorry for the thread drift but I wanted to add that 10 years prior to the stupid design incident I mentioned above, I had a part time job busting and mounting tires at an auto tire shop. I was airing up an automobile tire that had a blemish in the sidewall of the new tire, a foot operated valve on the tire changer stuck open when I released the foot pettle. Not knowing that the compressed air was still entering the schrader valve. The tire separated under right middle finger and blew the end of my finger off. Compressed air is dangerous!