Compressed Air Lines | NC Woodworker

Please avoid PVC like the plague for compressed air. When it fails (and it will eventually fail from either damage or old age) it fails explosively and has been the cause of many injuries over the years. It is not that PVC can not handle the pressures we run our compressors at, but rather that, at 150 PSI, the air in those pipes will instantaneously expand 11-fold when a break occurs, literally ripping the PVC to shreds and launching very sharp shards of PVC at anyone and anything in the vicinity of the break. Since even a seemingly innocent impact, such as when moving a step ladder or board, with a PVC pipe can set the stage for catastrophic failure, it is not uncommon for the operator to be in the vicinity of the break at the moment of failure. It is worth noting that even the PVC pipe manufacturers forbid the use of their product for compressed gas (incl. air) distribution due to the high risks associated with failure.

Traditionally black iron pipe has been used for compressed air distribution due to its rigidity, thermal mass and the fact that it is typically much cheaper than copper. However, with black iron pipe you are limited to using prefabricated lengths of pipe unless you have lengths custom made and threaded for you.

I am using copper for compressed air distribution in my shop. You should stick with type L Copper (medium wall) as the thinner/cheaper type M (thin wall) is not recommended. Copper does not have the same thermal mass as the black iron pipe, but it has better thermal conductivity than black iron. Copper also has much smoother interior surfaces and does not rust and corrode internally like black iron so it maintains better and more laminar air flow versus black iron. Copper can be easily cut and sweated and readily adapted to your shop.

With any compressed air plumbing, be sure to either slope your piping back towards the compressor (for single point drainage) or towards a drain tap at the far end of the run (in which case you will need to drain at this end drain tap and at the tank). All AIR drops should draw off the top of the main (perimeter) pipe run and then make a 180deg turn for the drop. Drawing air off the top of the line helps to ensure you are drawing dry air, allowing condensed water to largely remain in the main (perimeter) line. The accumulated water in your main/perimeter line will eventually flow towards its drain point depending upon how you sloped the main line (either towards an end-run drain or back to the compressor tank). If you slope the line back towards the tank, please take care to ensure that there are no dips or loops in your flexible hose connection to the tank that would trap water in the hose. You want the water to readily drain back into the tank unimpeded, not trapped in a hose and spit back into the main line. If you choose to slope your piping towards an end-run drain, this drain tap should be located at the end of the run and drawn of the bottom of the main line (unlike air drops, which draw off the top).

If you happen to have a conduit bender, you can bend hardened type L copper pipe, though you may need to anneal it to make a full 90deg bend (due to copper having more spring-back than steel). Where greater flexibility is needed, you can easily anneal it with a torch by heating the desired section until it achieves a dull glow (or, in bright light, momentarily takes on an almost polished steel color under intense heat). This will leave the copper softer (just like copper tubing) and more easily shaped. Annealed type L copper is still plenty strong enough for the compressed air pressures we run (typically no greater than 200PSI for a home shop).

Try to avoid as many sharp 90deg bends as possible (e.g. standard copper elbows) -- either use two 45deg where possible or bend the copper (as above) to reduce turbulence at the joint. You will still need to use some elbows (and that is Ok), just try to avoid them where practical. When mounting the copper piping to your shop walls, I recommend using spacers (just make suitable blocks of wood) to hold the piping atleast 1/4" off the actual walls. This spacer will ensure that any hammering within the lines (such as from surge loads like a blower) will not result in the copper lines beating against your shop walls and making a racket.

Use a ball valve at the actual tank connection to allow for depressurizing the entire system. If there are multiple drop locations, it is good practice to install ball valve shutoffs at each drop ahead of your filters and regulators to allow emergency shutoff to a damaged hose. At each drop, install a brass elbow (e.g. shower fixture) with ears to bolt it to the wall, then attach first your coallescing filter followed by the regulator and, if wanted, an oilled lubricator or dessicant filter. The coallescing filter will trap any liquid water or oil that makes it to the drop (as opposed to condensing in the main line).

An important safety reminder when plumbing your shop for compressed air: GROUND THE COMPRESSED AIR LINES. You can purchase, from most any electrical supplier (including BORG) pipe clamps with ground connector that you can attach to a convenient point along your piping, then ground with atleast #12 (#10 even better) copper. This will provide critical protection should your compressed air distribution lines ever become energized due to a wiring fault in your shop -- it will also dissipate any static accumulation.

Miscellaneous Tips
Another tip: If you wish the option placing drops anywhere you wish in your shop, consider running a continuous loop all the way around your shop perimeter (don't forget the slope the lines back towards the tank!). If you feed both ends of this line then you will also gain pressure balancing properties throughout the system AND you can opt for one pipe size smaller for the main line if you wish to save money because each drop will be provided air from both sides of the main line.

If you are only running a single drop then 1/2" copper is a good starting point. If you are going to do multiple drops then consider 3/4" copper for the main distribution line (you could do 1/2" if you do a full perimeter -- like the above -- and feed from both ends). If you need to provide more than 20CFM (sustained or surge), then run either a 3/4" perimeter system fed from both ends, or upgrade to 1" pipe if making multiple drops. In a shop setup, you risk losing more than you gain if you opt for anything less than 1/2" type L copper pipe.

FWIW, in my shop I am running about 60ft of 1/2" Type L copper pipe since I will only be feeding a single remote drop and my current setup is meant to be temporary (we're discussing building a new shop in a few years). If I were doing multiple drops or a longer run, I would have gone with 3/4" for the main line. In the future, if we build a new shop, I will install a 3/4" perimeter main line (fed at each end) with 1/2" lines for the actual drops.

I wish you the best of luck with your install. Let us know if you have any other questions -- including how to sweat copper fittings. Ok, my opinion on some of the questions asked since my post...

Firstly, please visit this Air Piping Layout for a diagram of a recommended compressed air plumbing strategy.

Why Type L (medium wall) versus Type M (thin wall) Copper?
The effective pressure rating for Type M copper will actually be approximately 400PSI rather than the 800PSI as Chis was inquiring. In the course of soldering -- especially for a beginner -- you are very likely to be annealing the copper line at the solder joints (particularly if using a MAPP gas torch vs. propane). Additionally, the line needs to be further derated because, during extremely heavy use, the air temperature towards the tank side of the line can reach 200-250F on air compressors without integral aftercoolers or refrigerated dryers. (NOTE: manufacturer recommended working pressures are further derated depending upon the type of solder used -- as little as 100PSI for certain types of Tin-Lead solder).

While Type M, even at 400PSI, is certainly greater than the 150-200PSI our compressors are likely to produce, I generally like to work with a 300% rating on pressurized systems. Additionally, I don't know if you have ever worked with Type M copper, but it is remarkably easily crushed and damaged compared to Type L. The thinner walls will also be subjected to a greater degree of expansion and contraction due to pressure fluctuations over the life of your install which will place greater stress on your solder joints -- so there is a greater risk of developing leaks at the various fittings with Type M (thin wall) copper versus Type L (medium wall).

Even with this strong preference for Type L, if I were choosing between PVC and Type M, I would choose Type M -- atleast you are not risking life and limb, so to speak, with the thin wall copper the way one would be with PVC.

Opinion on RapidAir (and the like)
I have nothing negative to say with regard to safety of the RapidAir setup. It is basically a reinforced flexible tubing system, so it does not have the same safety concerns as with rigid PVC piping. I do wish, however, that RapidAir had a greater working pressure rating as many air compressors are capable of exceeding the manufacturer's rated working pressure unless the compressor's pressure switch is adjusted to deliver a lower pressure. At least if their system fails you won't have the same dangers as associated with PVC -- just a compressor that's potentially left running 24x7 until the break is discovered (not a huge deal with 100% duty compressors, but a concern with compressors not rated at 100% duty cycle).

However, the RapidAir tubing is typically used in professional installations which typically include a refrigerated dryer and, as such, deliver already dry air to the user. Our typical shop setups do not tend to include refrigerated dryers, as such our systems provide much wetter air. Part of the function of a copper or iron piping system (the longer the better) is to provide the hot incoming air time to cool down and transfer its heat to the metal piping. This causes excess moisture to condense in the metal pipes and, provided we draw our air of the top of those metal pipes, allows for the delivery of considerably drier air than we would have obtained straight from the air compressor's tank. It still will not be as dry as air provided by a refrigerated dryer, but it is much better than what you would obtain without the cooling provided by the metal piping.

The issue I have with respect to RapidAir (and comparable setups) is quite simple. The RapidAir piping has a much greater insulation value and far poorer thermal conductivity than that of either copper or iron piping. You will still benefit from some cooling within long runs with RapidAir piping, but nowhere near the same extent as with metal piping. It is also much more challenging to ensure a consistent slope with the more flexible RapidAir piping than with copper or iron piping. Everywhere there is a dip in the RapidAir piping there is an opportunity for condensed water to accumulate. The only thing worse than an air tool spitting a little water is an air tool spitting LOTS of water -- remember RapidAir is usually installed in professional setups that include a refrigerated drier which means NO water condensing in the lines, so this is a matter of some concern to me.

Use of Mounted Air Hose for Distribution
See RapidAir comments above, they are largely similar concerns

Comments on Black Iron Pipe - a Possibly Cheaper Solution
If concerned about the price of copper (it is not cheap these days), black iron piping is a traditional distribution system and is often cheaper than copper. Due to the rougher interior, use a minimum of 3/4" black iron for the main distribution line to reduce the losses in pressure and air speed. You will have to invest more time in a black iron pipe system since there are many fittings that must be well sealed with either Teflon tape (use yellow Gas tape) or suitable pipe dope.

Install periodic unions throughout your black iron pipe setup so that if you are plagued with an unwanted air leak down the road you will not have to disassemble your entire distribution system just to tighten the troublesome connection. Without unions the act of tightening one pipe connection invariable loosens the next connection -- with unions you just need to retighten all the joints within the affected section to correct the leak. Fixing a leak can still be a lot of work, but I would rather retighten or re-do 1/4 or 1/3 of my distribution system (up to the unions) than 100% of it!

Keep in mind, air leaks much more easily than water, so Teflon tape and/or pipe dope will be your best friend in this application. You can get by with traditional white Teflon tape, but you will need at least 3 times as many turns of the white Teflon tape versus the yellow Teflon tape to achieve the same result

Comments on Galvanized Piping
Although it looks nicer than black iron piping, many suggest avoiding Galvanized steel pipe due to zinc flaking off and plugging the air filters in coallescing filters. Personally, I'm not sure that this is really any worse than rust flakes from black iron pipe. Either way, don't ever use a blower to clean up unless that blower is drawing air through a coallescing filter with either an integral fine paper or sintered brass air filter -- you do not want flakes of zinc or rust embedded under your skin!

Closing Comments
These are my opinions and are based upon extensive research I did when planning my setup. Ultimately, you will need to install whatever setup works for your shop and within your available budget. The only *really* strong opinion I have is the avoidance of PVC distribution systems as they are just too unsafe. Woodworking can be a dangerous enough hobby with all our sharp hand and power tools without introducing homemade overhead IEDs into our shops!

HTH Ken,

If I understand correctly, this is the RapidAir kit you purchased with 2 outlets, distribution block and 100ft of hose?

If you can possibly do so, try to get at least 20+ft of copper/iron pipe between the tank and the distribution block. This will allow much of the water to condense from the warm air while also protecting the RapidAir tubing from the high temperature air (and oil) that a compressor can generate after it has been running for awhile. This will be more effective than running the RapidAir piping direct to the compressor -- even if you have to make zig-zags with the copper/iron to get to the 20ft mark. (Note: If you go the zig-zag route, keep drainage of the assembly in mind -- don't trap the water in a maze.)

With regard to your question as to where to locate the coallescing filter... Skip the 45deg fitting and purchase a combination coallescing filter plus pressure regulator. A combo unit will provide the two functions in a more compact package then seperate coallescing filter and pressure regulator components would otherwise allow. You could still use invidual components, but as two units they (combined with the quick connect) can protrude up to a foot out from the wall. A combined unit will cut 4-5in off that protrusion.

You can then either mount the quick connect direct to the pressure regulator or install the 45deg fitting and then the quick connect. Or you could do like I seem to like doing, and install a 3-way tree fitting, allowing for up to 3 quick connect fittings at a single outlet (e.g two Universals/Type-M and a Type-T).

Be sure to adequately secure the RapidAir tubing so that pressure differentials can not cause it to 'thump' within your walls. Clamping the tubing will also restrain it if a an end ever comes lose -- you don't want to get spanked by your own compressed air line! I have read some interesting stories about what a damaged air hose can do to a parked car over a lunch break!

Because the RapidAir system has a maximum working pressure rating of 150PSI, you may need to dial down your air compressor's cut-off pressure (and possibly adjust the cut-in pressure as well) -- say 120PSI cut-in, 145PSI cut-off. Most pressure switches will have 2 or 3 adjustment screws for setting these two parameters (on 3-screw setups, one screw will be coarse adjustment, the other fine adjustment). Be careful some of the screws under the pressure regulator's cover are HOT, so use an insulated screwdriver in case you accidentally contact one of them!

I don't know if this is obvious or not, so heregoes: The RapidAir lines will ideally run at your full unregulated tank pressure. It is best to distribute high-pressure air to the outlets and then install a regulator at each outlet -- especially since you already need a coallescing filter at each outlet. This provides the best possible/practical pressure regulation by reducing the unwanted effects of line losses. It is possible to get by with a single central regulator installed at the tank, but your line losses will be more unpredictable since the amount of loss will depend upon a given application's air consumption. Without installing a gauge inline with the remote tool, you will have to guess the proper regulator setting. For nailers this isn't terribly difficult -- set the regulator for 100PSI -- the normal air reserve in the lines themselves will handle the brief surge of a nailer. But, for higher demand tools, you would need a gauge installed near the tool to know what regulated pressure at the tank outlet corresponds to a given operating pressure at the remote tool. This is why I encourage installing a regulator at each outlet and running the distribution line at full tank pressure -- it takes a lot of the guesswork out of the equation! Seperate regulators at each outlet also allows you to set a custom pressure at each outlet matched to the tool in use at that outlet (e.g. HVLP outlet at 40PSI; nailers at 90-100PSI).

In use, you will want to drain all the drain legs pretty religiously. Unused taps should not have much condensate, but you should expect condensate at the distribution block's drain (esp if you install metal piping ahead of it) as well as the drains at whatever taps you have used for the day (and don't forget the tank drain). It will help to concentrate condensate at the distribution tap's drain if your remote outlet piping draws off the top-side and has some vertical elevation as it leaves the distribution block -- this way the drain leg is well below the level of the outgoing remote air lines.

I'm not an expert on all of this, but I did spend many hours studying all the related topics and discussions for my own setup. These are my opinions on the topic based upon what I have learned tempered with my experiences along the way. Hopefully this information will prove helpful to others as well.

If you have any other questions, feel free to ask.

The problem with those quick aluminum setups is making modifications, extensions, or fixing leaks a few years from now when the company that made them has gone out of business. Many businesses fail and many more will fail over the next few years. Iron pipe and fittings will be available for our lifetimes.

I sale & install quit a bit of Prevost ALR pipe. The aluminum pipe is great product, there various mfg. making & marketing aluminum air piping systems. Each brand has their pro & cons. I don't see the big players going out of business. I can't image Ingersol Rand going out of business.

The product is easily modified. You can add a drop easily, most cases no cutting of the pipe. Cuts with a tubing cutter. As far as leaks, most brands are sealed with an O-ring.

Pricing on the average is between Black Iron & Copper K.

I personally don't believe in using black iron for compressed air. I'm in the business to provide clean, dry air. I like copper, but not black iron. Not everybody agrees. Aluminum pipe systems have negatives also, but the positives out weigh the negatives.

You dont follow, as usual.

Why would you even think of relying on 0-rings, when a threaded/sweat-soldered connection is so damn bullet-proof?

And you do know that there are MANY grades of O-rings, right?

Bullet-proof, my ass. I fixed about 10 gas leaks at the house today, and have about another 15 joints to fix in the morning.

I tried plumbing my air compressor with Lowe's fittings, fat fucking chance. I tried pipe dope, pipe tape, pipe tape and pipe dope, waiting 24 hours for pressure, none of it worked. I ended up buying high dollar US fittings to get no leaks.


As far as fire, if it gets hot enough to melt solder or aluminum, or even an o-ring for that matter, there's nothing left at that point, anyway. You can play what-if's, all day long, but shit will happen either way. If it hits temps to melt solder, all my paint cans will blow up, all the aerosol sprays will blow up, the gas cans will melt, the oil jugs will have melted, the acetone/mek/mineral spirits will have gone up, my wood work bench will have gone up, adding air is a moot point by then. Have any of you ever used a bellows on a fire? The air stream makes things burn very fast and very hot. That is why fire and building codes specify iron pipe. The fire has to be really hot to hurt it. It just gives the fire dept and your family some additional time to save things and the differences were well documented in testing. There are good reasons for those codes.

An approved cabinet for storing flammables will help also. They are expensive but I found a 30 gallon unit for $100 at a freight salvage place with only one small scratch and no dents.

Make sure your local fire department knows where you store flammable items like paints, gas, welding gas, solvent based insecticides, etc as well as where your compressor tanks sits.

BTW, those cheapo import threaded fittings ARE a nightmare. Save yourself a headache and buy the good stuff. The stuff at the home box stores can be OK at times but check them. The import stuff has improved greatly over the last 10 years.

Bullet-proof, my ass. I fixed about 10 gas leaks at the house today, and have about another 15 joints to fix in the morning.

Just to make you aware, I am NOT talking about black iron. Did you not read that?

I sure hope you are not running gas in copper.

Either way, it isnt the pipes fault the installer did a half-ass job.
Pipe fittings/joints last a LONG time. I have done propane to natural gas retrofits in homes that have 30+ year old black iron systems in them. More often than not, the system passes a pressure drop test as-is.

I tried plumbing my air compressor with Lowe's fittings, fat fucking chance. I tried pipe dope, pipe tape, pipe tape and pipe dope, waiting 24 hours for pressure, none of it worked. I ended up buying high dollar US fittings to get no leaks.

So... whats the problem again?

You buy cheap fittings, and Ill assume cheap pre-threaded nipples, and you are complaining that they are crap?

No matter really, Ill bet money that it was operator error again. If you were working with steel pipe fittings, Ill bet you simply did not have the fittings tight enough. Pipe threads only seal when TIGHT.

Have any of you ever used a bellows on a fire? The air stream makes things burn very fast and very hot. That is why fire and building codes specify iron pipe. The fire has to be really hot to hurt it. It just gives the fire dept and your family some additional time to save things and the differences were well documented in testing. There are good reasons for those codes.QUOTE]

Correct. If a fire starts to break out in the garage/shop it can burn up the oxygen with in the room but stay in a smoldering state. It can still be hot enough to melt solder though and if there is approx 150# of presure wanting to seperate the copper lines it will aid in it, thus feeding the smoldering fire and then it can take off and spread rapidly.
Never store flamibles close to water heaters, furnesses, or items that create sparks.

Just to make you aware, I am NOT talking about black iron. Did you not read that?

I sure hope you are not running gas in copper.

Either way, it isnt the pipes fault the installer did a half-ass job.
Pipe fittings/joints last a LONG time. I have done propane to natural gas retrofits in homes that have 30+ year old black iron systems in them. More often than not, the system passes a pressure drop test as-is.




So... whats the problem again?

You buy cheap fittings, and Ill assume cheap pre-threaded nipples, and you are complaining that they are crap?

No matter really, Ill bet money that it was operator error again. If you were working with steel pipe fittings, Ill bet you simply did not have the fittings tight enough. Pipe threads only seal when TIGHT.

Other than at the end, copper isn't threaded connections (and not even then, sometimes), hence why I thought you were talking pipe.

These lines are probably 15-20 years old, I doubt it's an installer issue. One fitting is leaking to where you can smell it when you're close (I had my nose about 5" away from it while working on something), the others I couldn't smell, but the detector shows it. It could easily pass a pressure drop test, but it's still not acceptable to me.

I know how pipe fittings seal, these didn't. when you're heaving on 24" pipe wrenches on 1/2" line and it doesn't seal, they're junk. I got tot he point of stripping a few fittings and finally gave up on them, no operator error. the other fittings went right on, no leaks, first time around. I probably had the system apart 10-15 times witht he other fittings.

Hardly splitting hairs.

Lets take a specific example, that would apply to 90% of this board.

Say a fire erupts in the garage/shop. Oily rags thrown into a barrel that self-ignite. That fire needs FUEL, the primary one being Oxygen, secondary being that of some sort of combustible material.

A roaring fire runs out of oxygen FAST. You should know this, if you have ever burned wood in an air-tight wood stove.

Get a good fire going, then shut the damper and choke it down.

What happens when you open the door

Yeah, except a garage is hardly air-tight, and even if it was, has a lot of air in it. By the time it's used up air, it's burned a hole through to air anyway. Also, how much air would a 60 gallon 150 p.s.i. air compressor add? I doubt it would be that much.

Again, it could make a slight difference, but I have a hard time seeing it being significant. The wood walls in my den are probably as dangerous.

Hardly splitting hairs.

Lets take a specific example, that would apply to 90% of this board.

Say a fire erupts in the garage/shop. Oily rags thrown into a barrel that self-ignite. That fire needs FUEL, the primary one being Oxygen, secondary being that of some sort of combustible material.

A roaring fire runs out of oxygen FAST. You should know this, if you have ever burned wood in an air-tight wood stove.

Get a good fire going, then shut the damper and choke it down.

What happens when you open the door

This is getting a little off of subject, but very important notes to take.
This is correct, but a little correction. The fuel is the rag and chemical and those two make a reaction to create heat the third element in the Tetrahedron.

It takes three things to make a fire. Fuel(wood, gas, plastic, etc), Oxygen(self explanitory), and Heat(spark, fire, hot atmosphear), and now a fourth that takes place is called the chemical chain reaction. 66L78, Check to see if the aluminum system is ASME or ASTM tested and to what standards. Compare this to copper and threaded pipe. Remember that there is also welded pipe and pex to through into this discussion. I have seen pvc pipe used but would not recommend it because if there is a pressure failure there could be shrapnal produced which could cause additional injury. What you really want to know: is the piping system suitable for the application and enviroment? Additionally, us must identify the max working pressure of the pipe and if it is air compatable. Some piping systems and corresponding fittings are not.

In my opinion, most garages and small shops only require 3 to 6 drops and cost (unless you are really pinching pennies) between the best(most expensive) and the budget(least expensive) is very small. Only if you are going to change the layout frequently or impress you buddies would it be benefical to go the cadillac route. All of the industrial environments that I was responsible for in the past utilized black iron threaded or welded pipe. Proper piping techniques are required no matter what system you choose. You may want to use a conventional piping system for distribution and then go with the aluminum system for the drops. It is true that the "exposed pipe" would 'aid' in the cooling aspect of the compressed air. However this is a very small aspect. Piping in hospitals(breathing air) and other "clean" enviroments is located inside walls/ceilings. If moisture is a problem you should deal with that with a dryer located at the compressor. Otherwise install 'point of use' filter/dryers along with moisture pots. Proper pipe fall should also be adressed.

Hope this helps. You can PM me and I can share other air piping experiences.

... I have seen pvc pipe used but would not recommend it because if there is a pressure failure there could be shrapnal produced which could cause additional injury. ...

PVC is illegal per OSHA and other regulations. All of the PVC manufacturers I have checked have warnings on their websites or catalogs. There is a grade of ABS that is allowed but it must be approved and marked for the use. There are other plastic types but again in a fire they would be dangerous.

... It is true that the "exposed pipe" would 'aid' in the cooling aspect of the compressed air. However this is a very small aspect. Piping in hospitals(breathing air) and other "clean" enviroments is located inside walls/ceilings. If moisture is a problem you should deal with that with a dryer located at the compressor. Otherwise install 'point of use' filter/dryers along with moisture pots. Proper pipe fall should also be adressed.

Hope this helps. You can PM me and I can share other air piping experiences.

The gasses used in hospitals are dry to begin with since most are supplied as liquids. Compressed air lines in a shop should be run in free air. Moisture removal is a large part of the function of the distribution system in a shop which is why pipe fall is important. Of course very large shops with high volume air use may install a mechanical chiller etc but there are few home shops where that would be warranted.

66L78, Check to see if the aluminum system is ASME or ASTM tested and to what standards. Compare this to copper and threaded pipe. Remember that there is also welded pipe and pex to through into this discussion. I have seen pvc pipe used but would not recommend it because if there is a pressure failure there could be shrapnal produced which could cause additional injury. What you really want to know: is the piping system suitable for the application and enviroment? Additionally, us must identify the max working pressure of the pipe and if it is air compatable. Some piping systems and corresponding fittings are not.

In my opinion, most garages and small shops only require 3 to 6 drops and cost (unless you are really pinching pennies) between the best(most expensive) and the budget(least expensive) is very small. Only if you are going to change the layout frequently or impress you buddies would it be benefical to go the cadillac route. All of the industrial environments that I was responsible for in the past utilized black iron threaded or welded pipe. Proper piping techniques are required no matter what system you choose. You may want to use a conventional piping system for distribution and then go with the aluminum system for the drops. It is true that the "exposed pipe" would 'aid' in the cooling aspect of the compressed air. However this is a very small aspect. Piping in hospitals(breathing air) and other "clean" enviroments is located inside walls/ceilings. If moisture is a problem you should deal with that with a dryer located at the compressor. Otherwise install 'point of use' filter/dryers along with moisture pots. Proper pipe fall should also be adressed.

Hope this helps. You can PM me and I can share other air piping experiences.

Prevost ALR is certified by TSSA-TUV-it conforms to ASME B31.1. I am sure the other three major Aluminum Air Line Mfg. are to the same standards. These are products that are engineered & designed for compressed air. Most of these have a working pressure rating of 188 psi, which means with a burst rating of four times the working pressure it would take 752 psi to blow the pipe apart. That does'nt mean that if the airline is not installed correctly you won't have problems.

Aluminum does melt at a lower temp. than steel, that is why it is not allowed in the manufacture of spray booths.

In case of a fire or a line burst, etc. there are safe guards that you can put between the compressor & the airline tie-in to shut off the air supply. It is never a good idea to leave a compressor on or the ball valve open that would allow air to keep feeding air to a flame. I personally think that if this going into business then A. by code you may be required a fire supression system B. There are probally more things in your shop that will fuel a fire to worry about, or if this going into a home hobbiest shop chances you are not going to have much more pipe tan an air hose, air hoses melt. Some of the people here need to move forward 100 years or so...........

The factory I'm sitting in right now has literally thousands of feet of copper air line in it. In the 23 years that I've been here I've yet to see a failure in the hard line portion of the air system.

Black iron is simply a PIA and expensive to work with. Threading machine?? Yep, I've got 2 or 3 of those in my shop just waiting for the next time I need one. Tried to buy a decent pipe theading setup lately?? Prepare to spend some big dollars for one that does a better job of threading than the Chinese do.

Ever look inside any new production equipment, CNCs, tractor trailers??? Wanna guess what they use for air lines?? It ain't black iron, and it's all sealed with push-fit O-ring'd connectors. Again, rarely see a failure.

Compressed air fanning the flames?? I'll bet you've got the pressure relief valve on your tank plumbed outside don't you?? What happens when a fire starts near the compressor, flames heat the tank, the air pressure goes up and the valve pops?? Better plumb that valve outside.........

Have you seen the new crimped copper piping systems?? Guess what it's sealed with??
It ain't pipe doped, it ain't soldered, and it ain't threaded, yet I see it every day and it ain't leaking.

Your family needs to try to save stuff and escape the flames??
#1, saving stuff is what insurance is for, scew it, get the hell out. More people die trying to save stuff than failing to wake up.
#2 Any "working" shop containing anything but minor amounts of flammables should not be attached to the house, period.

Like the fire department is going to keep a list of what's in yout house and where it's located. There's simply now way for them to keep track of everyone's home garage.

And on and on.............

Use what you can afford and what you feel comfortable with installing and using. Breathing air in most hospitals is supplied by breathing air compressors located in central mechanical plants. I have personally installed these in hospitals and in medical facilities as well as medical vacuum systems(suction). Oxygen on the other hand "is" piped from a central liquid source.

I have a 20 cfm dryer in my shop that I use for my plasma cutter and all painting. I just expect my impacts, rachets, die grinders, etc to spew water and air thus resulting in increased tool maintenance and failure.

The ability to condense water vapor out of compressed air is a function of several factors and is essentially relative to the ambient air temperature, compressed air temperature, compressed pressure and initial(pre-compression)relative humidity. At pressure and say 75 degrees ambient, no length of pipe will cause a temp drop sufficient to condense the water vapor and knock it out of the stream because as the pressure rises the dew point decreases. Then when the pressurized air is dropped across a regulator the dew point rises and some water is condensed and this is where a filter/seperator or knockout pot comes into play. But there is still water in the air stream. The balance then enters the tool, at regulated pressure and more water is knocked out when the regulated air is reduced to atmospheric pressure as tool exhaust. At each pressure drop there will be a temp drop resulting in condensation. The cooler the ambient air and/or the more volume of air the worst this situation gets. A dryer will reduce the temperature of the compressed air to 45/50 degrees F before it enters the piping system and will condense most all the water out of the air stream. Without a properly sized drying system, some condensation will occure during cooling within the piping system but the piping system itself is not considered a "drying system". It is ideal to dry the air before it enters the piping system because you really never want water in the piping system. In practice it occurs "ONLY" because there never seems to be enough money or foresight to properly dry the air before it enters the piping system. Pipe fall, knock-out pots, filter/dryers, etc are all required because it is extremely difficult to remove all the moisture but by themselves do not constitute a "drying system". These "secondary" stratagies are insurance when used in conjunction with proper post-compression drying. All the dryers that I have worked with were refrigerated dryers.

Some of the people here need to move forward 100 years or so...........

The factory I'm sitting in right now has literally thousands of feet of copper air line in it. In the 23 years that I've been here I've yet to see a failure in the hard line portion of the air system.

Black iron is simply a PIA and expensive to work with. Threading machine?? Yep, I've got 2 or 3 of those in my shop just waiting for the next time I need one. Tried to buy a decent pipe theading setup lately?? Prepare to spend some big dollars for one that does a better job of threading than the Chinese do.

Ever look inside any new production equipment, CNCs, tractor trailers??? Wanna guess what they use for air lines?? It ain't black iron, and it's all sealed with push-fit O-ring'd connectors. Again, rarely see a failure.

Compressed air fanning the flames?? I'll bet you've got the pressure relief valve on your tank plumbed outside don't you?? What happens when a fire starts near the compressor, flames heat the tank, the air pressure goes up and the valve pops?? Better plumb that valve outside.........

Have you seen the new crimped copper piping systems?? Guess what it's sealed with??
It ain't pipe doped, it ain't soldered, and it ain't threaded, yet I see it every day and it ain't leaking.

Your family needs to try to save stuff and escape the flames??
#1, saving stuff is what insurance is for, scew it, get the hell out. More people die trying to save stuff than failing to wake up.
#2 Any "working" shop containing anything but minor amounts of flammables should not be attached to the house, period.

Like the fire department is going to keep a list of what's in yout house and where it's located. There's simply now way for them to keep track of everyone's home garage.

And on and on.............

Use what you can afford and what you feel comfortable with installing and using.

Well said...

The factory I'm sitting in right now has literally thousands of feet of copper air line in it. In the 23 years that I've been here I've yet to see a failure in the hard line portion of the air system.

As stated already, multiple times, copper lines work great.

Black iron is simply a PIA and expensive to work with. Threading machine?? Yep, I've got 2 or 3 of those in my shop just waiting for the next time I need one. Tried to buy a decent pipe theading setup lately?? Prepare to spend some big dollars for one that does a better job of threading than the Chinese do.

Just because you have a hard time with black iron, doesnt mean it is hard to work with. A good machine and sharp dies go a LONG way.

And no, I dont have my own machine. Whenever I need one, I rent one. I typical rent for a day cost me less than $50 It has never, and will never, make sense to buy one. Sounds to me like you have already made that mistake "2 or 3" times.

Ever look inside any new production equipment, CNCs, tractor trailers??? Wanna guess what they use for air lines?? It ain't black iron, and it's all sealed with push-fit O-ring'd connectors. Again, rarely see a failure.

So you have seen failures? On NEW equipment?

My thoughts exactly.

Have you seen the new crimped copper piping systems?? Guess what it's sealed with??
It ain't pipe doped, it ain't soldered, and it ain't threaded, yet I see it every day and it ain't leaking.

I have seen it. I have used it. I sell it at work.

But I dont trust it.

Trust takes time. Give those fittings 10+ years. If they are still holding fast, Ill CONSIDER them.

Again, I see no reason to use O-ring fittings based upon this logic:

It creates one more possible point of failure.

Sweat soldered/threaded joints WORK. I see no reason to change, other than installation convenience, which the O-ring setup targets.

Your family needs to try to save stuff and escape the flames??
#1, saving stuff is what insurance is for, scew it, get the hell out. More people die trying to save stuff than failing to wake up.
#2 Any "working" shop containing anything but minor amounts of flammables should not be attached to the house, period.

#1, Sorry, but I dont think ANYONE mentioned a concern for saving "stuff".

#2, Ill beta majority of this board will disagree with you on that one

And on and on.............

Use what you can afford and what you feel comfortable with installing and using.

Ill drink to that.