Permanent air lines

[patrick_g]

last i checked the PVC is just pressure tested to some PSI. air, water it really doesnt matter.

PVC under 100PSI of water pressure will exhibit the same failure type as 100PSI of air.

Other than its increased propensity of failure due to external forces, if such forces are limited the advantages of its ease and speed of installation, and cost can be compelling.

What is really compelling is the damage caused by the compressibility of the air in the PVC. You store a lot of energy in the compressed air and if a PVC pipe ruptures the air acts like an explosion and accelerates the shards to tremendous speeds.

On the other hand, at the pressures within the ratings of PVC, water can be considered incompressable. The PVC may expand and store a minor amount of energy but the water under pressures within the ratings of the PVC will store only a negligible amount of energy and if the pipe ruptures there is very little force applied to the shards to accelerate them and make them potentially deadly shrapnel.

Comparing water under pressure to air under pressure, is at best, an apples to oranges comparison but closer to an apples to BBQ ribs or baby diapers comparison.

Pat

 

[ray66v]

last i checked the PVC is just pressure tested to some PSI. air, water it really doesnt matter.

PVC under 100PSI of water pressure will exhibit the same failure type as 100PSI of air.

Not to pile on, There is much more to choosing a suitable pipe than checking the pressure rating. Temperature plays a big part. That is why plain PVC is not suitable for hot water. A pipe will fail at a lower pressure as the temperature is increased. And, compressed air can be very hot, especially at the discharge point of the compressor.

There are other factors that have been know to cause PVC to fail, when used for compressed air; vibration, chemicals, (like paint solvents), being sucked into the intake of the compressor, and then pumped into the pipe, and stresses put on the pipe by air hoses being pulled or tripped over.

Using PVC for air, often combines these factors, which greatly increases your chances of a failure.

OSHA has banned PVC use on compressed air, for a reason. It's because of many years of multiple failures, some causing serous injuries.

 

[777777]

Hi.

Fast, easy, safe and not to spendy way to run air lines :

Compressed Air Piping, Compressed Air Systems, Do It Yourself Air Tool System

Or

Eastwood Company - Search and search for air lines.

Have a great evening

 

[pat32rf]

When we pressure test tanks we fill them with water and "hydro-stat" them. The PSI may be the same as air, but if they fail the results are a LOT different...

 

[kennyd]

last i checked the PVC is just pressure tested to some PSI. air, water it really doesnt matter.

PVC under 100PSI of water pressure will exhibit the same failure type as 100PSI of air.

Other than its increased propensity of failure due to external forces, if such forces are limited the advantages of its ease and speed of installation, and cost can be compelling.

What is really compelling is the damage caused by the compressibility of the air in the PVC. You store a lot of energy in the compressed air and if a PVC pipe ruptures the air acts like an explosion and accelerates the shards to tremendous speeds.

On the other hand, at the pressures within the ratings of PVC, water can be considered incompressable. The PVC may expand and store a minor amount of energy but the water under pressures within the ratings of the PVC will store only a negligible amount of energy and if the pipe ruptures there is very little force applied to the shards to accelerate them and make them potentially deadly shrapnel.

Comparing water under pressure to air under pressure, is at best, an apples to oranges comparison but closer to an apples to BBQ ribs or baby diapers comparison.

Pat

Not to pile on, There is much more to choosing a suitable pipe than checking the pressure rating. Temperature plays a big part. That is why plain PVC is not suitable for hot water. A pipe will fail at a lower pressure as the temperature is increased. And, compressed air can be very hot, especially at the discharge point of the compressor.

There are other factors that have been know to cause PVC to fail, when used for compressed air; vibration, chemicals, (like paint solvents), being sucked into the intake of the compressor, and then pumped into the pipe, and stresses put on the pipe by air hoses being pulled or tripped over.

Using PVC for air, often combines these factors, which greatly increases your chances of a failure.

OSHA has banned PVC use on compressed air, for a reason. It's because of many years of multiple failures, some causing serous injuries.

This was WELL covered in the links I posted above in post.BIG difference between air and water.

You are DEAD wrong on this Schmism.

 

[gasbag]

wineslob, why not use gav ??

 

[mjncad]

Yes it is but in our system here in CA we get 5+ gallons of condensate a day. Our humidity is usually in the 15% range. So depending on how much air you use it can and will vary, but it will always be there unless you get rid of it.
I've been designing and installing compressed air systems for 20+ years. All have been commercial. The one I installed at work is in a 100,000 sf building. The entire perimeter is in 2" black pipe with 1" branches and 1/2" drops. Our main compressor is 100HP and can provide over 400 CFM @ 120 psi.
You can use some of the "rules of thumb" for a small system installed in a garage or shop.

You can use copper but, as has been stated, use heavier schedule pipe. The preferred pipe is schedule 40 black iron up to 2". Any bigger and copper is eaiser to work with. Never use galv or PVC.
Anytime you can, do a perimeter loop, it will insure that from any drop used you will get maximum air flow.
Always halve the drops compared to the mainline IE: Mainline is 1" use 1/2" drops.
If you can, invest in a drier, even if it's the one from HF. Water will kill air tools, and ruin a paint job. At the very least get a filter with a auto drain.
As has been stated use "T's" and go up and over and back down on the drops.
You will always need more CFM than you can afford.

You definitely are designing heavy duty high capacity systems. My compressor is in the 22-gallon range, and at best I get about a tablespoon or two of water out of it when I drain it at the end of each day. For my needs the 1/2" copper has been just fine, and I use that size exclusively.

 

[Wineslob]

wineslob, why not use gav ??

There is the possibility of the galv scaling off of the insides of the pipe.

 

[jsborn]

There is the possibility of the galv scaling off of the insides of the pipe.

You need to be careful with black iron also it can rust inside and the rust scale off and do bad things to your body if it blows on you. I had a QA fitting break off in my hand and it took the Dr's about 3 hours to get all the rust out of my hand and arm.

Just another reason to keep the water out of yur system.

 

[Wineslob]

Just another reason to keep the water out of yur system.

Yuppers! Notice that most, if not all, manufacturers of air tools, machines, motors, etc., specify clean, dry air.