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Dan Marx

Best air compressor lines

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Just bought a Speedaire compressor. (used, that is is the only way to afford this one). Is there an alternate compressed air line other than black iron? Thanks

Dan

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I used black iron pipe with a filter/regulator combo for each outlet. The pipes do rust inside, for a good permanent job people have painted the inside of the pipe with POR15. Use the largest pipe possible for good air volume. You might also try galvanized to try to fight the rust, but copper or PVC plastic are not considered strong enough to carry the PSI long term.

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Sure, there are plenty of options. Here are a few. Pick one that suits your application and installation capability.

You could use steel galvanized pipe. The down side of black or Galvanized is that you need threading capability or cut all your pieces and take them to the hardware store for threading. This can be a bit of a pain. These two offer the best physical protection for harsh environements.

Copper works well although I wouldn't use Type M. Type L is a little stronger. No corrosion and offers pretty good physical protection plus, it looks nice. It'll last as long as your building.

An easy and inexpensive option is schedule 40 PVC pipe. Working pressure for 3/4 or 1" dia PVC is around 450 psi more than enough for a home shop compressor. PVC doesn't offer as much physical protection from damage so depending where the line is, that may or may not be a concern.

Even easier but a tad less permanent is general purpose rubber hose. You'll need to convert to a rigid material at the point where the quick disconnect is unless its a line run to a permanent piece of equipment.

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I like the idea of Sched 40 PVC, any other comments on this. Has anyone used this. I agree the pressure issue is not a problem, max 175psi.

dan

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I used PVC going on two years now and no problems. Easy to install.

I have some galvanized fittings right off the compressor which I bought from the home store and they are rusting mad.gif on the inside. I will be replacing them with PVC unions soon.

Attach is a quick layout of my piping in 3d. This is what I do for a living. Piping design.

post-31137-143138076545_thumb.jpg

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PVC pipe not to be used in compressed air systems

The Department of Labor and Industries warned consumers and employers in May 1988 that plastic-polyvinyl- chloride (PVC) pipe cannot be used in compressed air piping systems without risk of explosion. By law, employers must protect their workers by avoiding the use of unapproved PVC pipe in such systems. Existing compressed air systems that use PVC piping must be completely enclosed, buried or adequately guarded according to specifications approved by a professional consulting engineer. Only Acrylonitrile-Butadiene-Styrene (ABS) piping was approved for use with compressed air, provided it was marked on the pipe as approved for compressed air supply.

In October 1989, the Plastics Pipe Institute (PPI) amended their original recommendations for thermoplastic piping in the transport of compressed air and other gases. WISHA's (Washington Industrial Safety and Health Act) Division of Consultation and Compliance Services now will accept thermoplastic compressed air piping that meets the following guidelines (recommendation B, to the PPI 1972 recommendation):

"The Plastics Pipe Institute recommends that thermoplastic piping intended for the transport of compressed air or other compressed gases be buried or encased in shatter-resistant materials, unless the piping has been manufactured from materials which shall resist shatter-type failures under the anticipated conditions. Specifically, above ground installations of thermoplastic piping should only be made using products which have been suitably evaluated and which are recommended by the manufacturer for the particular intended service.

"It is recognized that while adequacy of strength is an important element in the safety of a compressed gas piping system, consideration must also be given to the nature of failure should accidental failure occur, whatever its cause. Above-ground piping which fails by shattering can present a serious hazard to personnel by the resultant flying shards, or pipe fragments, which are rapidly propelled by the released energy of the suddenly decompressing gas. Because the inclination of a material to fail by shattering is determined not only by the nature of the material, but by pressure, pipe and fitting dimensions, and by the nature of the gas, the evaluation of shatter resistance should consider all these and any other pertinent factors."

NOTICE TO EMPLOYEES: If you suspect that a pressurized PVC piping hazard exists, bring it to the attention on your employer. If you do not obtain satisfactory results, you may file a confidential complaint with the Department of Labor and Industries. Complaints are investigated promptly. Call the Department's toll free number at 1-800-423-7233.

NOTICE TO EMPLOYERS: If you have questions about the suitability of a material for air system piping, call the Department of Labor and Industries Regional Office for a free consultation.

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DO NOT USE PVC PIPE FOR ANY COMPRESSED GAS OR AIR.

The reason is that when the PVC fails (usually from an impact of some sort) the PVC will shatter into bits like shrapnal from a pipe bomb. There have been reports of shards of failed PVC Pipe penetrating drywall and other seemingly solid surfaces. Can do nasty things to anyone and anything nearby when it fails.

There are plastics made for compressed air.

Just DO NOT USE PVC!!!!!!!

Here's a good discussion on air piping from garagejournal.com

Discussion on Air Piping from Garage Journal

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The negative points made about using PVC are good and should be considered based on the specific application. Any concerns relative to using Sch 40 PVC for air are centered around the physical damage aspect as was mentioned. I should have expanded more on the potential concerns.

Sch 80 PVC has much greater impact resistance however the cost starts to rise so you would need to compare it to other materials.

Another concern which I did not think of is the installation method of PVC. I incorrectly made an assumption that everyone would know the correct way to install it and did not warn against it. There is more risk using PVC if the joints are not cemented properly. Also if the pipe happens to be run in close proximity to a heater that would also weaken it.

I personally would have no problem using it in my own garage where I am in control of the environment and know it won't be subjected to damage. In commercial and industrial applications the dangers of physical impact are far greater and control of the environment and personnell is far less so thats why its often unapproved in those installations and understandably so.

I have worked on the operations side in various industrial manufacturing environments for the past 30 years and have seen PVC used extensively without incident as long as the installation was proper taking into consideration the properties of PVC pipe.

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Thanks to all who replied. Hope the info was helpful to others.

Ok, I like the idea of copper pipe. Can the compression fitting be used, or must all joints be soldered?

Dan

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