This. This right here. The difference in liquids and gases is covered in, what, week 2 or 3 in HS physics?
Go back to class and try again.
PEX marketed as COMPRESSED AIR line.
- Thread starter fflintstone
- Start date
This. This right here. The difference in liquids and gases is covered in, what, week 2 or 3 in HS physics?
Go back to class and try again.
mygarageone
Well-known member
I was never arguing the issues about failed pipe and the results of stored energy . My whole point was if the pipe is rated for X # of lbs then it will hold that pressure. Does it or can it fail of course . But so can steel pipe and figs , I have seen malleable iron elbow ,tees and couplings fail under pressure and no matter what the sorce is creating the pressure and if it has a steady supply and source , there all. Dangerous . I am sure you have seen the devastation high pressure water at 80 - 100 psi can do , slice you hand wide open.
icenfire01
Well-known member
PVC= Shrapnel when it explodes. Don't use. It will kill you.
PEX= No shrapnel when it explodes. Don't use. It will kill you.
Rubber Hose= No shrapnel when it explodes. Everyone uses it. It will kill you.
Black Iron Pipe= Wont ever explode, will rust shut, ruin your tools and eventually kill you.
Copper= Will out last your children. Costs too much. Mafia hit man will kill you when you cant pay.
Pretty much sums it up.
PEX= No shrapnel when it explodes. Don't use. It will kill you.
Rubber Hose= No shrapnel when it explodes. Everyone uses it. It will kill you.
Black Iron Pipe= Wont ever explode, will rust shut, ruin your tools and eventually kill you.
Copper= Will out last your children. Costs too much. Mafia hit man will kill you when you cant pay.
Pretty much sums it up.
MP&C
Well-known member
Going on ten years now without any issues...... 
rlitman
Well-known member
PVC= Shrapnel when it explodes. Don't use. It will kill you.
PEX= No shrapnel when it explodes. Don't use. It will kill you.
Rubber Hose= No shrapnel when it explodes. Everyone uses it. It will kill you.
Black Iron Pipe= Wont ever explode, will rust shut, ruin your tools and eventually kill you.
Copper= Will out last your children. Costs too much. Mafia hit man will kill you when you cant pay.
Pretty much sums it up.
Where do galvanized, aluminum and stainless fit into this?
Lead pipe will kill you in the billboards room. Or is that the candlestick?
mygarageone
Well-known member
PVC= Shrapnel when it explodes. Don't use. It will kill you.
PEX= No shrapnel when it explodes. Don't use. It will kill you.
Rubber Hose= No shrapnel when it explodes. Everyone uses it. It will kill you.
Black Iron Pipe= Wont ever explode, will rust shut, ruin your tools and eventually kill you.
Copper= Will out last your children. Costs too much. Mafia hit man will kill you when you cant pay.
Pretty much sums it up.
Well might as well list everything that can kill , you are stating it will kill you but most likely won't .if people are that fearful of things they had better quit driving a car , flying in planes, using nat or L.P gas . The chances of the air system killing anyone is slim to non , you are closer to being killed every day just being in a car . In fact I would say , your chances of your car failing and being a problem is much better traveling down a hwy at 75 - 80 mph .
I do not feel one bit troubled by using Pex for air.. Because I already do and it has given me no trouble what so ever.
Hell the approved air pressure rated vibration isolation hose blew out with in 6 months of service
It was made and designed for this very thing.
icenfire01
Well-known member
More research is needed on all these other materials but the initial reports aren't looking good...
You don't even want to know what we found out about crossing the street before looking both ways, smoking, and bacon. (they will all kill you!)
rburke65
Well-known member
And don't forget the horrors of coffee and butter!!
finn
Well-known member
There'sa reason Russian Roulette wasn't a medal sport at the Winter Olimpics, although from some of these posts I looks like we would have fielded a full team,
bigredmf
Well-known member
My response to a previous discussion is below. Take it as you may but below is all facts.
What people need to understand is that PVC is rated for pressure based on it being used with a non compressible fluid.
Because air is compressible the working pressure drops dramatically.
Medium pressure NFPA hydraulic cylinders share designs with NFPA air cylinders yet their nominal working pressures are 1000 psi and 250 psi respectively.
Sure your PVC may work but make sure you do not nick it or damage it. The results could be damaging to your family, friends or your personal health, ride or your shop.
Further more you are playing into the design factor of the tubing. The NFPA severely derates air when used in a fluid conveying device.
RED
Sent from my iPhone using Tapatalk
What people need to understand is that PVC is rated for pressure based on it being used with a non compressible fluid.
Because air is compressible the working pressure drops dramatically.
Medium pressure NFPA hydraulic cylinders share designs with NFPA air cylinders yet their nominal working pressures are 1000 psi and 250 psi respectively.
Sure your PVC may work but make sure you do not nick it or damage it. The results could be damaging to your family, friends or your personal health, ride or your shop.
Further more you are playing into the design factor of the tubing. The NFPA severely derates air when used in a fluid conveying device.
RED
Sent from my iPhone using Tapatalk
icenfire01
Well-known member
Yes PVC is dangerous, please don't use it, but I'm still waiting for someone to explain why PEX is more dangerous than the rubber hose that is attached to EVERYONES air comp. I don't care if you use 10 miles of BIP or copper or galvanized, or aluminum you still have a rubber hose at the end of the line that one day will explode due to break down from UV exposure oil or just plain old age, and yet PEX is evil because it could rupture. Now someone will say rubber hose is rated for air and PEX is not yet the fact remains that your rubber hose that is rated for air will burst, and the PEX that is attached to it might. Kinda splitting hairs now aren't we???? 
Techie1961
Well-known member
I have read through this thread with respect and sometimes amusement. There are a lot of people here that have no experience with the full range of materials or have not seen them reach all of their failure modes. Even fewer seem to understand the difference between kinetic vs. potential energy and sustainable sources of energy vs. deplete-able sources.
The type of air line that was used to start this thread is common in a lot of industrial/commercial applications. Medical is a big target for them (nitrogen, oxygen, etc.) as well as food grade etc. Everything has a suitable application and needs full consideration. A black steel air line isn't going to be good for medical grade oxygen (lots of reasons) or transmission of food products. Most plastics don't do well as a barrier product (hygroscopic) while metals do. Metals don't do well where flexibility is needed, plastics do. Stainless steel is really expensive so other solutions are needed. Etc. Etc.
Use the correct material for the job and be willing to accept that time and engineering are going to change what is correct. Good yesterday doesn't mean good tomorrow. Science and medicine will continue to find lots of stuff that is bad for you. That's why engineering is a living changing discipline. We learn as we go.
Using a solution for gas vs. liquid has more to it than has been stated here. Not only can gas store the energy when compressed but it can also stop a lot quicker. When you don't have to deal with inertia, the material and design changes. Liquids don't store energy (unless from a sustainable energy source) but do wreak havoc on systems when stopping and starting are nearly instantly. Water hammer is an example of this and how to destroy even steel piping at low pressures.
There are a lot of dos and don'ts but not every do and don't in this discussion is gospel. Some of it just isn't true. Go with approved solutions that meet the criteria for the job at hand. You will be amazed at how you can think that you knew all the pitfalls of something only to get bitten in the **** by it. Trust me on this one, I have a lot of experience with finding failure modes in stuff and getting bit in the ****.
The type of air line that was used to start this thread is common in a lot of industrial/commercial applications. Medical is a big target for them (nitrogen, oxygen, etc.) as well as food grade etc. Everything has a suitable application and needs full consideration. A black steel air line isn't going to be good for medical grade oxygen (lots of reasons) or transmission of food products. Most plastics don't do well as a barrier product (hygroscopic) while metals do. Metals don't do well where flexibility is needed, plastics do. Stainless steel is really expensive so other solutions are needed. Etc. Etc.
Use the correct material for the job and be willing to accept that time and engineering are going to change what is correct. Good yesterday doesn't mean good tomorrow. Science and medicine will continue to find lots of stuff that is bad for you. That's why engineering is a living changing discipline. We learn as we go.
Using a solution for gas vs. liquid has more to it than has been stated here. Not only can gas store the energy when compressed but it can also stop a lot quicker. When you don't have to deal with inertia, the material and design changes. Liquids don't store energy (unless from a sustainable energy source) but do wreak havoc on systems when stopping and starting are nearly instantly. Water hammer is an example of this and how to destroy even steel piping at low pressures.
There are a lot of dos and don'ts but not every do and don't in this discussion is gospel. Some of it just isn't true. Go with approved solutions that meet the criteria for the job at hand. You will be amazed at how you can think that you knew all the pitfalls of something only to get bitten in the **** by it. Trust me on this one, I have a lot of experience with finding failure modes in stuff and getting bit in the ****.