Shop airline setup, wanna try something a bit different

[psu927]

I've searched and done a good bit of reading about how I want to setup my airlines in my shop and want to see if you guys see any problems with my idea.

My shop is 40X64 and I am going to run a 3/4" copper line (up in the trusses) down the front, and turn and go down one side. It will have 1/8-1/4" of fall per ft, with a solid pipe drain leg with valve at the corner, and the end.

Here is where I think I want to go a bit different, I want to use 1/2" pex for all of my drops. (about 6 of them) coming off of the top of my main (for moisture) and dropping down inside my shop walls. when I finish the shop all lines will be covered.

As opposed to running 1/2" copper (or 3/4?) down the walls, the pex deal would be a lot easier, and I still have the copper main for moisture removal. The main line will be ran at 180psi with all of my drops regulated.

One question I have is, should I install a large filter/regulator for the main somewhere before my first drop or just do every drop individually as needed? (blast cabinet, air reel, plasma cutter are my main uses)

 

[MrSurly]

I'm sure the anti PVC/PEX crew will arrive shortly with actual reasons not to use the stuff, but I know it's rated for the pressure. The first concern that I think of is the simple mechanical locating of the end fitting. How are you going to provide a rigid, strong and *reliable* anchor or mount for your quick connect (without the help of a rigid pipe)?They have little tab-ear fittings, I know, but will they be up to the job?

 

[ejabour]

Will the PEX be exposed to light or completely behind the wall? The problem is that it breaks down when exposed to UV of any sort.

 

[Phantomd]

Pex-AL-Pex is another option, much higher pressure rating.

https://www.rapidairproducts.com has a complete kit, there are other vendors as well.

 

[finn]

I'm sure the anti PVC/PEX crew will arrive shortly with actual reasons not to use the stuff, but I know it's rated for the pressure. The first concern that I think of is the simple mechanical locating of the end fitting. How are you going to provide a rigid, strong and *reliable* anchor or mount for your quick connect (without the help of a rigid pipe)?They have little tab-ear fittings, I know, but will they be up to the job?

There’s a general misunderstanding among laymen that there’s a difference between qualifying something and rating it for pressurized liquids and pressurized gasses.

No amount of arguing the physics will help those ignorant of basic physics and engineering principles regarding energy stored in compressed gasses vs compressed liquids, especially when failure isn’t 100% certain and predictable over time. That’s where anecdotal evidence takes over because “ uncle Jim has used it for years and his hasn’t killed him...yet”

All I can add is that none of the commercial PEX products that I have looked into are rated for compressed gasses by their manufacturers. The market is potentially huge, so they must have reasons to not qualify and certify their products for use with compressed gasses.

I have plenty of PEX on hand, but when I expand my piping at the shop, I will either stick with the black pipe that plumbs the rest of the shop or go with an approved product like the RapidAir.

Life’s too short to save a few bucks taking shortcuts.

 

[MX15]

Instead of using PEX for the drops look at Air Brake Tubing. It is covered by SAE J844 and DOT FMVSS 571.106 and designed to be used in Class 8 and Class 7 truck air brake systems. In the case of 1/2 tube it has a minimum burst pressure of 950 psi. which gives you over a 6:1 working pressure to burst pressure if you run your air system at 150psi. It is heat and light stabilized so you don't have to worry about UV etc. It works with compression fittings and push to connect fittings as well. Just make sure you have either with an internal tube support as they are designed to work with Air Brake tubing. Eaton (Eclipse 3270), Parker (1120 Series), Accuflex(Endure 151) all make version of this tube. I believe you can purchase it at NAPA and even Amazon.

 

[psu927]

There’s a general misunderstanding among laymen that there’s a difference between qualifying something and rating it for pressurized liquids and pressurized gasses.

No amount of arguing the physics will help those ignorant of basic physics and engineering principles regarding energy stored in compressed gasses vs compressed liquids, especially when failure isn’t 100% certain and predictable over time. That’s where anecdotal evidence takes over because “ uncle Jim has used it for years and his hasn’t killed him...yet”

All I can add is that none of the commercial PEX products that I have looked into are rated for compressed gasses by their manufacturers. The market is potentially huge, so they must have reasons to not qualify and certify their products for use with compressed gasses.

I have plenty of PEX on hand, but when I expand my piping at the shop, I will either stick with the black pipe that plumbs the rest of the shop or go with an approved product like the RapidAir.

Life’s too short to save a few bucks taking shortcuts.

I am using type M copper, and regular solder so I'm sure that's not "approved" as well, however none of the tubing is subject to impact, and if it fails, the worst thing that can happen is a joint blow apart. Even that is unlikely considering the number of straps I have. I feel the same about pex,

however it really wouldn't be that big of a deal to reduce to and run 1/2" copper for my drops.
Or 3/4", which should I use?

 

[GMCGarage]

I am using type M copper, and regular solder so I'm sure that's not "approved" as well, however none of the tubing is subject to impact, and if it fails, the worst thing that can happen is a joint blow apart. Even that is unlikely considering the number of straps I have. I feel the same about pex,

however it really wouldn't be that big of a deal to reduce to and run 1/2" copper for my drops.
Or 3/4", which should I use?

3/4" Copper is prefered so you get the volume if needed. Working pressure of copper is about 700 psi, Pex about 160 psi. use the copper.

or, find some hydraulic line that works for you behind the wall.

 

[matt_i]

I'd just run the drops with 1/2" Cu, its not much more work.

The type of copper is immaterial for the pressure rating, I'd suggest Stay Brite #8 solder for its extra strength and much easier flow into the joints.

 

[ZipSnafu]

I am using type M copper, and regular solder so I'm sure that's not "approved" as well, however none of the tubing is subject to impact, and if it fails, the worst thing that can happen is a joint blow apart. Even that is unlikely considering the number of straps I have. I feel the same about pex,

however it really wouldn't be that big of a deal to reduce to and run 1/2" copper for my drops.
Or 3/4", which should I use?

Depending on what your running the air on 1/2" copper should be fine.

 

[sberry]

Also,,,, figure out how to simplify this and leave a spot to get on hi pressure air if needed and run a regulated line or even 2 to where its needed. Air is not quite the same as electric which can have a lot of parasitic hookups or dozens of devices plugged in. A basic rule of thumb is 1 or 2 drops up to 1200 sq ft and another per 1000 and leave a T or extra port after the fil/reg so a guy can tap it if needed for a whip or plumb a plasma on. 2 reels here, set one up so it can be fed outside if needed, about a hundred feet of pipe, maybe less and a couple drops. You will find you use 2 in the end, 2 good ones beats several poor and a good system has no hose moves from hydrant to hydrant but to a reel with the only connectors being on the tool end. One of my regs feeds a couple reels and a couple whips, paint booth, another feeds a reel and the plasma.
Another thing, you don't need to reduce it, you can, at these distances even 1/2 is well adequate for common shop work until we get to multiple men in a commercial environment with larger comps or heavy impacts. My shop is 80x80 and both long runs are 1/2 pipe. Even has a T to feed a convenience reel out to one apron.

 

[GrayFlattop]

Instead of using PEX for the drops look at Air Brake Tubing. It is covered by SAE J844 and DOT FMVSS 571.106 and designed to be used in Class 8 and Class 7 truck air brake systems. In the case of 1/2 tube it has a minimum burst pressure of 950 psi. which gives you over a 6:1 working pressure to burst pressure if you run your air system at 150psi. It is heat and light stabilized so you don't have to worry about UV etc. It works with compression fittings and push to connect fittings as well. Just make sure you have either with an internal tube support as they are designed to work with Air Brake tubing. Eaton (Eclipse 3270), Parker (1120 Series), Accuflex(Endure 151) all make version of this tube. I believe you can purchase it at NAPA and even Amazon.

^THIS^ We use it all the time for short runs in our busy manufacturing environment. SAE rated nylon air brake tubing holds up to a lot of abuse and is very oil resistant.

But it will never look neat and clean and straight as copper or black iron will. And in terms of saving time - if your main run is already going to be copper, just keep going with copper. Honestly it's such an easy material to deal with and is a great solution. If I was doing my home shop over again, I would use copper instead of black iron.

 

[psu927]

Thanks guys, as usual a ton of great info. Quick question... My flex line from the compressor to the hard lines.... a lot of guys use hydraulic line (tractor supply?) but I looked today and their 1/2" line (with 3/4 fittings on it) The I.D. of the pipe has to be close to 1/4-3/8", which I feel is too much of a restriction.

Anyone have recommendations of something readily available that I could use? (3/4" line w/3/4" fittings.)

 

[sberry]

You can use 3/4 hose with 3/4 barbs but the 3/4 hyd will work good. You are using 2 stage, the short 1/2 id of the line wont hurt a thing at that distance. The only time line size has much to do with anything for this crowd would be the use of 3/4 or larger air guns and even at that a 3/4 gun really wont be effected. Almost all the loss for these applications is in the secondary,,, after the reg and thru the hoses.
The goal here isn't to see how fast you can dump air but to have adequate supply when needed. These types of comps are the limiting factor. A 3/4 line can deliver a 100 cfm with minor losses at these distances, this is connected to a comp can make 20with tools that have an ultimate demand of 30 tops, screaming wide open to a hose that can cause a # a foot loss with heavy 1/2 gun depending on a couple factors.
We go to great pains to reduce drop by a couple #'s on the main where its going to hoses and regs to get it down 40#'s on the secondary. With common tools would even be difficult to measure the differences in losses between 1/2 and 3/4 main.

 

[38Chevy454]

I ran 3/4 copper around and then 1/2 copper for all of my drops. I used easy 3/4-3/4-1/2 tees where the 1/2 was the leg perpendicular to the main line. Made it easy and 1/2 copper is a lot less than 3/4. The various fittings for 1/2 are also lower cost since they are smaller.

 

[Dan in Pasadena]

....No amount of arguing the physics will help those ignorant of basic physics and engineering principles regarding energy stored in compressed gasses vs compressed liquids, especially when failure isn’t 100% certain and predictable over time. That’s where anecdotal evidence takes over because “ uncle Jim has used it for years and his hasn’t killed him...yet”

....Life’s too short to save a few bucks taking shortcuts.

Save your breath on “MrSurly” - appropriately named it seems.

Some guys can’t hear anyone who has knowledge of a subject they consider themselves “knowledgeable enough” about because there is a pressure rating stenciled onto a gazillion feet of Chinese made PVC.

 

[teamextreme]

Ya, don't forget the ever persuasive anecdotal evidence as well...Uncle Jim used it for 20 years, never had an issue. Analogous to "I've been driving without seat belts for 20 years and never had an issue". Therefore it must be safe.

 

[Red 17]

Air vs. liquid: Air compresses, becomes a giant spring behind whatever cuts loose:

http://www.ejprescott.com/media/reference/PresTestwAirvsWaterR-25.pdf

 

[OccupantRJ]

I am using type M copper, and regular solder so I'm sure that's not "approved" as well, however none of the tubing is subject to impact, and if it fails, the worst thing that can happen is a joint blow apart. Even that is unlikely considering the number of straps I have. I feel the same about pex,

however it really wouldn't be that big of a deal to reduce to and run 1/2" copper for my drops.
Or 3/4", which should I use?

I would use 3/4” going to a blast cabinet.

 

[OccupantRJ]

Thanks guys, as usual a ton of great info. Quick question... My flex line from the compressor to the hard lines.... a lot of guys use hydraulic line (tractor supply?) but I looked today and their 1/2" line (with 3/4 fittings on it) The I.D. of the pipe has to be close to 1/4-3/8", which I feel is too much of a restriction.

Anyone have recommendations of something readily available that I could use? (3/4" line w/3/4" fittings.)

I run my air system at 120 psi, so I bought 1” rubber airlhose from Dillon Supply around the corner, machined my own 3/4” steel pipe barb fittings for better flow than the necked down available ones, then attached the hose to them using 2 screw clamps on each end of the hose. I am getting ready to do it again for the second compressor.

 

[sberry]

You can do all that but,,, in the end you still have a 5 hp comp. In the end gonna shoot it thru a 3/16 nozzle for sandblast. A 3/8 hose will run down a 5 in a hurry blasting.
Not that it hurts to have larger piping but we should leave an accurate assesment of demand. It would be different if this was 50 hp.
I done a fair amount of blasting from 185 cfm comp and 3/4 hose. With my own shop have 1/2 to blast pot, can easily run the comps down.
This is similar to the 60A service serving your load. Without other loads running it would serve your comp and another one too.
Because wire and even pipe is sized at the code requirement doesn't mean all of it is inadequate. One it's 1 size up losses are almost negligible. We are commonly seeing 2 up or more with adamant insistance. Doesn't make it safer or work any better and certainly not noticeable.

 

[OccupantRJ]

My son and I are sometimes running both blast cabinets at once. I size my air jets to match the compressor output. Nozzle size on a suction type gun does not determine air flow requirements. The air jet does.

 

[KEH]

Not expressing an opinion or planning to use pex, but regarding the breakdown from UV, would it be possible to paint the pex to prevent UV?

KEH

 

[MrSurly]

Save your breath on “MrSurly” - appropriately named it seems.
Some guys can’t hear anyone who has knowledge of a subject they consider themselves “knowledgeable enough” about because there is a pressure rating stenciled onto a gazillion feet of Chinese made PVC.

I can indeed be a bit surly, on occasion.
I'm baffled at this point, though... as to why *I'm* being pilloried here.
1. This ain't my thread.
2. I never said use PEX (or PVC) in the guy's build. As stipulated, there are many Professional Sheepskin-Certified Government-stamped Experts are on duty here, chomping at their proverbial bits to dish out ALL the reasons not to use the stuff...there was no need for a Layman such as myself to attempt to enter that fray. I only asked how he would anchor the terminations IF he used it.
3. My point to the O.P. was *here's another reason NOT to use it.*
4. AFAIK, PEX is rated at at least 160psi (working, not burst) fluid pressure at room temp.
5. In O.P.'s application, will it survive? Probably. But I wouldn't use it anyway.
6. If the stuff WAS used for O.P.'s application, would it pose a danger of catastrophic shrapnel-hurling violent explosion? No.
7. Yes, compressed gases store significantly more potential energy than pressurized liquids; Laymen are allowed to know this.
8. PEX CAN rupture but it can't produce 'shards'. It would seem to present no massive danger. Feel free to explain how the uncontrolled release of air through a burst event with PEX would manifest itself with great violence.
9. In O.P.'s application such a rupture could cause what grand calamity? Air loss?
10. Again, I'm not going to use it or recommend it, so I don't know I'm being attacked. My own build has 120' of welded 1" 0.083 wall 316 stainless steel tubing that is likely NOT on the list of *approved* shop air line systems.

 

[teamextreme]

I assumed the objection was to PVC, but in re-reading finn's post he is lumping PVC and PEX in the same category, which may technically be correct from a ratings perspective, but I don't think it's valid to consider them as equally poor choices. I agree with McSurly's points on PEX. PVC? That's a whole different Darwin award story.

 

[kbs2244]

I like red 17's post on the things involved on the product labeling.

In short
Air pressure and water pressure are not the same.