PEX question

[Torque1st]

I'm seriously not trying to stir the pot, start a ******* match or cause unneeded drama and I totally understand why PVC & CPVC should not be used for a pressurized air system, I just want to be shown hard evidence & logical documentation (not just hearsay based on personal opinion) on why PEX is not safe for an air distribution system.

Thanks.

If you really totally understand why PVC and CPVC are not safe for air systems why is it such a stretch for you to understand why PEX would not be safe?

Do your own research, spend your own money. Just call an application engineer that works for a PEX manufacturer, not a salesman or distributor, and ask whether you should use PEX for your air distribution system. Then call your local and state fire marshals and ask what they think. Call the ASME and ask for documentation and opinions. Ask for a copy of the Uniform Plumbing and Mechanical Codes. Be prepared to back up your request for their time and information with $$ because information and knowledge cost $$ to accumulate.

You will not easily find industry documentation or detailed written discussions on misapplications because no knowledgeable or reasonable individual would consider such a thing. Why would the manufacturers waste advertising or literature space on non-applications for a product? Why would regulators spend their time listing all the materials that are unsafe or useless for a particular use, -rather than what materials and methods are approved? Manufacturers spend millions getting their products approved for applications. They seldom waste their time and money on applications they know are unsuitable.

People do misuse and misapply materials all the time. It does not mean that it is safe or reasonable to do so.

 

[Daddy_Rabbit]

If you really totally understand why PVC and CPVC are not safe for air systems why is it such a stretch for you to understand why PEX would not be safe?

Because they are nowhere alike or similar in any fashion concerning base material chemical make-up or mechanical properties.

Do your own research, spend your own money. Just call an application engineer that works for a PEX manufacturer, not a salesman or distributor, and ask whether you should use PEX for your air distribution system. Then call your local and state fire marshals and ask what they think. Call the ASME and ask for documentation and opinions. Ask for a copy of the Uniform Plumbing and Mechanical Codes. Be prepared to back up your request for their time and information with $$ because information and knowledge cost $$ to accumulate.

You will not easily find industry documentation or detailed written discussions on misapplications because no knowledgeable or reasonable individual would consider such a thing. Why would the manufacturers waste advertising or literature space on non-applications for a product? Why would regulators spend their time listing all the materials that are unsafe or useless for a particular use, -rather than what materials and methods are approved? Manufacturers spend millions getting their products approved for applications. They seldom waste their time and money on applications they know are unsuitable.

People do misuse and misapply materials all the time. It does not mean that it is safe or reasonable to do so.

so you're not going to back up your "PEX is unsafe" claims?

 

[ptschram]

Nah, I did the same thing running a PVC airline across the street

This sounds safe. Particularly given the way PVC airlines respond to being crushed (like if a vehicle were to drive down the street and crush the line).

I think I'm gonna cut down all of my airlines and run everything in black iron. Just how I'm gonna get the things I'm trying to work on positioned to my hardlines is an issue I'll have to overcome. Filling tires will be a bear to say the least.

It sounds like you have disdain for any flexible line used with compressed air.

 

[Torque1st]

Because they are nowhere alike or similar in any fashion concerning base material chemical make-up or mechanical properties.

Would you list those properties that are nowhere alike that they would have no similarities in performance in an air system? Compare those properties with the properties of materials that ARE approved for compressed air distribution systems.

so you're not going to back up your "PEX is unsafe" claims?

Answer the question above. I am retired, I am no longer an ASME member so you WILL have to spend your own money for written research & documentation. I don't "claim" anything. I have done my research and have gained my knowledge the hard and $$$ way. I am just giving the group the benefit of years of knowledge, education, and experience. I know it is not "fair" but life seldom is. If my materials knowledge is no better than the average dog catcher I most abjectly apologize. Feel free to consult with him/her on material properties as you choose.

 

[Torque1st]

This sounds safe. Particularly given the way PVC airlines respond to being crushed (like if a vehicle were to drive down the street and crush the line).

My cheap PVC air hose held up just fine to the weight of several vehicles including a semi. You must have confused the properties of air hose with hard PVC pipe.

I think I'm gonna cut down all of my airlines and run everything in black iron. Just how I'm gonna get the things I'm trying to work on positioned to my hardlines is an issue I'll have to overcome. Filling tires will be a bear to say the least.

It sounds like you have disdain for any flexible line used with compressed air.

Ah, you misunderstand. I have used miles of the stuff in applications where it was useful and a good fit with the application.

Let us know how you rig your compressor for filling tires with hard pipe. Personally I use some hose with an air chuck. I just usually don't have to go across the street.

 

[Daddy_Rabbit]

Personal knowledge, education, and experience is nothing more than opinion without hard evidence.

 

[Torque1st]

Did you answer my question and compare properties?

Well, lets see your personal knowledge, education, and experience. Do you have any background in engineering or science? Do you or have you belonged to any professional organizations in the field of materials or engineering?

You can do the research yourself but it will cost you $$ to post it.

 

[nissan_crawler]

So, if I have a 50' air hose plugged into my compressor, versus a 25' "plastic" distribution line of some sort, and a 25' air hose, what's the difference?

 

[59 wagon man]

OMG.....
While I wouldn't use PEX in my shop because Ithink there are better alternatives (though lots of people have issues with black pipe too!), I do what I think is REASONABLE - and as such I wouldn't really have issues with using PEX for air..... if it wasn't for the long-term UV exposure problem!

i can see the headlines now man killed when exploding airlines kill him . widow sues for $100,000,000,000 lawyer says the maqnufacturerswarning wasn't good enough. we are here to promote safe practices ,sure you could use pex andi personally have hydrostatically tested it in new homes to 200psi ,but why take the chance when there are so many other products which you can use safely?

 

[akdiesel]

I see two reasons for not using PEX, PVC, and / or rubber hose for a perminate air system.
One is simply for safe practice. I will admit I have not heard of any accidents resulting in the use of PEX and it will probably act like a rubber hose in that it will not send shrapnel when compromised because of its material, but PVC is a whole other beast for reasons mentioned.
Two is that it does not transfer heat like metal piping and it will have low spots in the horizontal runs creating liquid drop out.
I have hose reels that incorperate rubber hoses but these are at the ends of the lines and so any moisture in the system will be blown out in any low spots in the hose, but I have not seen any liquids in the air system so this is a mute point for me.

 

[Daddy_Rabbit]

Well, lets see your personal knowledge, education, and experience. Do you have any background in engineering or science? Do you or have you belonged to any professional organizations in the field of materials or engineering?

You can do the research yourself but it will cost you $$ to post it.

I'm not the one here giving out advice based on unsubstantiated claims.

 

[ptschram]

My cheap PVC air hose held up just fine to the weight of several vehicles including a semi. You must have confused the properties of air hose with hard PVC pipe.

The PVC air lines that I have used in the recent past have all been cut into short pieces and thrown in the trash as tight bends and crushing result in collapsing, kinking and breaking resulting in whipping hoses. They have all been replaced with flexible "rubber" hoses from my local hydraulic supplier-they are made specifically for use in such an application.

Running air lines across traveled roads is NOT a safe condition, yet you have made multiple comments about the safety of various materials of construction for air lines.

There are other "retired" engineers here. In my case, I was an environmental, health and safety engineer in fortune 500 (at the smallest ) companies. I would not have permitted the use of flexible airlines (especially PVC) in an application where it was reasonably likely they would be driven over as it is likely to result in an unsafe condition and there are certainly ways to avoid an unsafe condition.

One of my undergrad degrees is in chemistry. I can also discuss physical and chemical properties with a degree of knowledge, confidence, experience, and competence.

 

[Steves32]

I think people will continue to use what they want to in their garage- even when the manufacturer says otherwise.
Is PEX dangerous for air? Don't know.
Has it caused any injuries or death? None that I'm aware of personally.
Is it an approved piping method for air distribution? No, but that never stopped DIY's in the past.
Does the manufacturer recommend Pex for air? Not the stuff that's being discussed here.

If you go back a few years- these are the same discussions that were going on with PVC. Guys were saying they had it in their garage for 10 years w/o incident. Guys who personally never saw a failure. Guys who didn't care if it was or wasn't approved for air delivery. Then, the tide changed. The difference was- PVC did fail & did injure people. It was documented.
In some areas, PVC is approved if it's installed inside a protective sleeve. Talk about a band-aid fix!

As a plumbing contractor that installs air lines & medical gasses for a living- I follow code & manufacturer's guidelines. I have to. I follow the same at my own home (all my air is copper). Your results may vary though.

This isn't about re-engineering a product to fit your guidelines- it about approval.
At least for me.

 

[ptschram]

While I don't disagree with you Steve, OSHA hasn't issued guidance documents stating that PEX is not suitable, as they have W/R/T PVC.

While that might not be a singing endorsement, it is certainly less explicit than the prohibitions against PVC.

 

[cag310]

Can anyone say shrapnel cousin?

Some people/applications require approval; Some don't. Some people are very old fashioned and/or 'by the book'..trusting only what they know from experience; Some aren't.

I take information from a variety of sources and form my own educated opinions on what's the best solution to my problem. I think PEX may be the best solution for many others out there..but that's their decision.

..But what do I know..

And I'm not sleeving my PEX.

 

[BLUBAYOU]

And I'm not sleeving my PEX.

 

[cag310]

lol.

 

[peelman]

Running air lines across traveled roads is NOT a safe condition, yet you have made multiple comments about the safety of various materials of construction for air lines.

Hyperbole much? He said he ran a line across the street to help a neighbor inflate a tire. He did NOT say that he ran a flexible PVC line unprotected across an interstate for two decades. The dude is trying to relay experience, opinions, and a bit of educated guesstimates, and all you guys wanna do is play reductio ad absurdum.

As far as the rest of this FUD and retardation:

Traditional PEX (which was what the discussion started with) is not rated for air. If you're serious about putting up an air distribution system, then why *wouldn't* you go with steel, black iron, or copper? Other than laziness? You only put it up once. You have to do pretty much the same prep work. You still have to worry about condensation and water separation.

You're probably going to save some on the pipe, but you're going to take it in the *** on fittings, and then you have to cover it / protect it, not only from UV light, but from flying objects, heat, etc.

THEN if anything DOES develop a leak you have to chase it down through whatever cover you put over it (hope the cover is big enough to allow a PEX union...oh, and that's only like $9 or something).

 

[ptschram]

Hyperbole much? He said he ran a line across the street to help a neighbor inflate a tire. He did NOT say that he ran a flexible PVC line unprotected across an interstate for two decades. The dude is trying to relay experience, opinions, and a bit of educated guesstimates, and all you guys wanna do is play reductio ad absurdum.

As far as the rest of this FUD and retardation:

Traditional PEX (which was what the discussion started with) is not rated for air. If you're serious about putting up an air distribution system, then why *wouldn't* you go with steel, black iron, or copper? Other than laziness? You only put it up once. You have to do pretty much the same prep work. You still have to worry about condensation and water separation.

You're probably going to save some on the pipe, but you're going to take it in the *** on fittings, and then you have to cover it / protect it, not only from UV light, but from flying objects, heat, etc.

THEN if anything DOES develop a leak you have to chase it down through whatever cover you put over it (hope the cover is big enough to allow a PEX union...oh, and that's only like $9 or something).

And yet you continue the argument.

Running air lines across a traveled public road for any period of time is not safe. Crushing a PVC air hose will eventually result in its failure with resulting risk of a hose whipping around. Removing the tire and carrying it to the air source would have been much safer and we wouldn't be having this discussion.

As I used to tell employees in the factories where I worked, "if you have to ask me if it's safe, it isn't".

My shop is plumbed with nylon air brake line. I have an automatic drain to remove moisture from the tank before it gets to the line. As my shop is in a barn that was built around the time the war of Northern Aggression began, I make compromises. I regularly oil my air tools and do not spray paint-therefor, for my purposes, what I have met the requirements I have and that constitutes "good engineering practice". It's safe, functional and economical.

My last shop was plumbed in PVC because it was there when I moved in and at the time, in spite of having spent nearly 20 years in safety, I was unaware of the risk. I got lucky and now have my air system plumbed in a much safer manner.

 

[Torque1st]

ptschram-

HAHA, the air hose was across the road under construction (dirt) for a few minutes. The hose survived the three or four vehicles that ran over it. Removing the (front) tire or moving the vehicle was not an option. He drove it down to the shop and had it repaired afterward. It saved him the expense of having the tire truck out. It was my spare hose anyway and it does not appear to be any worse from the experience, no flattened or abraded areas. It gets used about once a year and it is expendable. I believe it will be just fine for a while yet. When it develops a leak it will be trashed. It isn't worth messing with.

My minor was in chemistry also. So you should be able to help out Rabbit with his physical properties comparison since he hasn't got a clue. My sister was in health and safety for Bendix for many years. You are correct about having to ask... The OP and others should have known "if you have to ask me if it's safe, it isn't".

To hell with "a few years". People STILL come on here and state that PVC pipe is safe for compressed air. Some add that it must be schedule 80 and want to argue "pressure ratings" when it is the material that is unsafe.

PEX will not fail by shattering like rigid PVC. PEX still has the same temperature limitations and low thermal conductivity in common with other organic materials and composites like nylon, PVC, PEX/AL/PEX, etc.

For a quicky job or temporary use there are many available materials, options, and "kits" available. If a person wants to do it right then use the approved materials.

I would be ashamed to have an air distribution system of PVC or PEX in my shop. It is similar to having zip cord and extension cords draped around the walls for the electrical system. I do have some gray PVC for electrical conduit though.

 

[Daddy_Rabbit]

a pretty good sign someone has lost a debate is when one resorts to name-calling instead of stating fact.

p.s. still waiting on that documentation and/or pictures of PEX systems that have failed resulting in injury, death or loss of property while being used in a pressurized air distribution system.

 

[mikeyr]

let me get in here with a few words, why would someone want to use PEX ? the cost difference between copper and PEX is not that great and copper has other advantages besides safety, like cooling the air and removing moisture. Yeah, I know copper is EXPENSIVE, I bought 12 10ft sticks this past Saturday along with bags of elbows and T's so I know exactly how expensive it was but a plastic/nylon/whatever air system would not have been much cheaper and the money savings would not be worth the disadvantages. Not even talking safety here since I don't know if PEX is safe for air or not, to me (and only to me) its plastic, just like PVC so not safe. Unless you are using PVC which is ultra cheap, all the others cost quite a bit and the difference is not enough to worry about especially if you plan on being in the shop for many years like I do.

 

[Torque1st]

a pretty good sign someone has lost a debate is when one resorts to name-calling instead of stating fact.

p.s. still waiting on that documentation and/or pictures of PEX systems that have failed resulting in injury, death or loss of property while being used in a pressurized air distribution system.

Keep waiting. I won't help you with your research. You will have to spend your own money. Maybe contact a forensic PE. There are some that list PEX explosion investigations with compressed air and injuries, -remember, bring your checkbook.

I am still waiting for your professional comparison of material properties.

 

[Hurricane_Whisperer]

I have used it and will be using it in my new garage. I used to work in a wood furniture manufacturing shop most of our equipment was pneumatic and ran polyethylene air hoses.

I never had a hose failure from bursting, only at a faulty joint.

Msc supply or grainger sells all kinds of polyethylene air hose.

I hope this doesn't turn into a thread like welding on a compressor tank

I doubt that was polyethylene. Polyethylene is not used for hoses. It kinks. It is used for tubing that won't be required to flex like a hose.

They do make hoses are made out of polyurethane or nylon.

 

[brianh]

I doubt that was polyethylene. Polyethylene is not used for hoses. It kinks. It is used for tubing that won't be required to flex like a hose.

They do make hoses are made out of polyurethane or nylon.

Look at the link here I have used at least a thousand feet of the stuff when I worked with pneumatic machinery and its polyethylene .
http://www1.mscdirect.com/eCommerce...Ctk=All_MSC&currentMSCtx=mode+matchallpartial
Or here
http://www1.mscdirect.com/eCommerce...Ctk=All_MSC&currentMSCtx=mode+matchallpartial

Or maybe here
http://www1.mscdirect.com/eCommerce...Ctk=All_MSC&currentMSCtx=mode+matchallpartial

This topic has spun way out by a lot of opinions by people that have not even worked with the material but thanks for telling me they don't make it.

The hoses on this machine I made are all polyethylene they move back and forth as the parts feed through

The air drill I added to the mortise machine cycles up and down with the hose moving with it.

 

[oldtractors]

Yet another thread about PEX that degrades into people shouting about PVC and other nonsense.

Come to my 30x50 shop. I will show you an air distribution consisting of 200' of 3/4 pex and about 75' of 1/2 Pex. I will show you the water that drains from the drains in the Pex line. I will show you how there is no water at the air fittings. I can also show you how I can add in a new drop in about 15 minutes without setting a wall on fire by soldering with a propane torch. And how It was at least half of what copper or iron would cost and I installed it all on a Saturday afternoon with no leaks.

I can also show you my power pipe threading machine, so I do know how to thread pipe.

I am not ashamed of my PEX pipe either.

 

[Hurricane_Whisperer]

Look at the link here I have used at least a thousand feet of the stuff when I worked with pneumatic machinery and its polyethylene .
http://www1.mscdirect.com/eCommerce...Ctk=All_MSC&currentMSCtx=mode+matchallpartial
Or here
http://www1.mscdirect.com/eCommerce...Ctk=All_MSC&currentMSCtx=mode+matchallpartial

Or maybe here
http://www1.mscdirect.com/eCommerce...Ctk=All_MSC&currentMSCtx=mode+matchallpartial

This topic has spun way out by a lot of opinions by people that have not even worked with the material but thanks for telling me they don't make it.

The hoses on this machine I made are all polyethylene they move back and forth as the parts feed through

The air drill I added to the mortise machine cycles up and down with the hose moving with it.

That isn't hose, it's tubing. Yes, it has some flex to it and if you use a sufficiently long bend radius as you have done and use it on a machine that moves in a controlled manner that doesn't exceed the bend radius, you can get sufficient flex out of it.

However, if you look in the Parker manual, it recommends using urethane tubing for pneumatics where movement, kink resistance, and high flexibility is required. It does not make the same claims for polyethylene. It lists pneumatic use of polyethylene but it recommend urethane for use where movement or kink resistance is required.

Because polyethylene can kink, a minimum bend radius is given. The urethane tubing does not give a minimum bend radius because it is kink resistant, although bending too much will probably pinch it off.

Even the manufacturer of the flexible antimicrobial polyethylene tubing recommends polyurethane for use where flexing is required.

Also the working pressure of the polyethylene is low compared to other tubing such as polyurethane. The Parker polyethylene products have ratings that may be sufficient for the system depending on what it is regulated to and if it doesn't get hot.

You go on to state that you never had a failure due to bursting of the polyethylene "hose" only at a faulty joint. A tubing failure at a joint is still a tubing failure and not necessarily a fault of the joint. As a matter of fact, you will most likely see a failure of the tube at a joint where stresses are concentrated. That is why they make thinks like strain reliefs for use on hose or tubing near joints.

 

[cag310]

Yet another thread about PEX that degrades into people shouting about PVC and other nonsense.

Come to my 30x50 shop. I will show you an air distribution consisting of 200' of 3/4 pex and about 75' of 1/2 Pex. I will show you the water that drains from the drains in the Pex line. I will show you how there is no water at the air fittings. I can also show you how I can add in a new drop in about 15 minutes without setting a wall on fire by soldering with a propane torch. And how It was at least half of what copper or iron would cost and I installed it all on a Saturday afternoon with no leaks.

I can also show you my power pipe threading machine, so I do know how to thread pipe.

I am not ashamed of my PEX pipe either.

No big words there. Just facts.

 

[ptschram]

Yet another thread about PEX that degrades into people shouting about PVC and other nonsense.

Come to my 30x50 shop. I will show you an air distribution consisting of 200' of 3/4 pex and about 75' of 1/2 Pex. I will show you the water that drains from the drains in the Pex line. I will show you how there is no water at the air fittings. I can also show you how I can add in a new drop in about 15 minutes without setting a wall on fire by soldering with a propane torch. And how It was at least half of what copper or iron would cost and I installed it all on a Saturday afternoon with no leaks.

I can also show you my power pipe threading machine, so I do know how to thread pipe.

I am not ashamed of my PEX pipe either.

Personal real-world experience! How long have you had this system in place?

I really like the nylon set-up I have for the same reasons. I started with a Harbor-Freight system and ended up buying more presto-lok fittings from my hydraulic supplier (who BTW-had no reservations over using PEX for shop air systems) to add more drops. Now I solder together a handful of inexpensive fittings, screw them to the wall and run the hose to them. In a 48X64 shop, it's handy, realistic and inexpensive.

 

[cag310]

oldtractors, any recommendations on my setup?

http://www.garagejournal.com/forum/showthread.php?t=93565&highlight=cag310

 

[Torque1st]

Just remember, -just because it "works" does not mean it is safe or good:

 

[jam0o0]

i skipped the last 3 pages but someone said DOT air line wasn't available is sizes you want. i wanted to set that straight. i do not know anything about this site but it's the first place i found selling 3/8, 1/2, 3/4" DOT air line. http://gravity-werx.com/dotairline.aspx