Compressed air supply line

[Brad Buchanan]

hello all!

I am reaching the point that I have to decide what I will use for the air supply lines in the shop.

Most of the runs will be horizontal along a poured concrete wall app. 150 foot.

I want to run 3/4" pipe. The air will be used for general shop use and occasionally painting.

I looked at and priced pex, black iron, schedule 40 pvc and copper. pex, iron and copper were in the same ballpark in price (counting fittings) and pvc was about a third of the others.

Advice, opinion or thoughts would be appreciated.

Brad
 

[Puddles]

Don't use PVC! Numerous horror stories on the net about using it. I used galvanized pipe in my shop, 12-years now with no problems.
 

[Ken-Pa]

Several years ago , I worked general maintenance for a large Auto/truck parts & supply store . He also sold all types autobody shop equipment & supplies . He set me up as air compressor installer & maintenance plus occassionaly if the customer wanted to do his own installation , my job was to go to that particular body shop or garge to give the guy instructions & ideas for piping & safety. All compressor companies we dealt with at that time demanded 3/4" Galvanized pipe & fittings , with an inline drain valve for draining water buildup . Black pipe is for gas & is dangerous for compressed air usage . If other than Galv pipe was installed , the company voided the warranty on the compressor . HTH ! God bless, Ken
 

[DH in Carolina]

Schedule 40 black and schedule 40 galvanised pipe both are rated for 150 lbs working pressure. Black pipe with malable fittings is fine for air line. My Quincy compresser is factory piped to the tank with black pipe.
 

[WvaJim]

Might take a look at this:
Rapidair

 

[Ken Macfarlane]

Only issue I know of with plain steel pipe is corrosion. Have to keep and eye on it and have filters if painting.

I had 3/4 copper in the last shop, liked it alot. New shop hasn't been hard plumbed yet. Planning on either transport air line (pex) or conventional pex with a starter piece of copper for cooling.
 

[Charles (in GA)]

If you really want to start a long ugly, nasty thread just say you plumbed your shop with PVC and it has lasted for years and its OK..........

Google PVC air plumbing or similar.......

PVC is not designed or approved for compressed air and will shatter under pressure and send lots of plastic flying everywhere. Other materials will simply rupture, but not shatter.

Its been an OSHA violation since about 1988 in commercial use.

Charles
 

[Flex. Aluminum..John,PA]

Recently I visited a supply house where they specialize in air compressors and air delivery systems for commercial and industrial installations.

They now have a new (to me, at least) a flexible ALUMINUM pipeing system. Color of the pipe is blue. All connectors are "push-on" type. 1/2 in. and 3/4 in.
The pipe is not PEX.

So, you might look around your area for such a supply house and ask about the new stuff.

I do not recommend using PVC. As the PVC gets some age, it seems to lose flixibility and will shatter, instead of bending or simply cracking. If in doubt, remove a piece of "aged" PVC and do a sample bending of the pipe. Becareful of flying debris.

Only problem with black pipe might be the collection of moisture and rust inside the pipe.

Water drains should be installed according to the Codes.

Hope this helps.

John,PA

PS: Like all new products, I will wait awhile and see how that new flexible aluminum holds up.

Meantime my rubber hose system will work for me.
 

[David G]

PVC is not recommended, and actually discouraged for compressible gasses. I will not get into more discussion than that.
 

[Smart Arse guy]

Just use Schedule 40 PVC for all lines and fittings. Whats the worst that can happen?
 

[David G]

Death
 

[algar]

Proctor and gamnble uses soldered copper and SS for mains no rust particles
 

[old_bc]

Do not use schedule 40 plastic for air pipe. The biggest problem is that the glue is incompatible with the synthetic compressor oils. I am speaking from experience.
 

[Brad Buchanan]

What a great response!

I found the replies extremely helpful and they helped me know the issues and do the proper research.

I forgot to add two more factors: Needs a working pressure of 175psi and am shooting for a 20+ year durability.

Brad
 

[Puddles]

Brad my compressor is 175-PSI too. As someone already mentioned the pipe is rated at 160-PSI, which I believe is true, but at what safety factor. 3 to 1, 5 to 1? Pay close attention to a lot of pictures of guys tractors, a lot of their hydraulic lines are plumbed with regular old black iron pipe! In fact I have some on the out riggers of my backhoe.

http://www.osha.gov/dts/hib/hib_data/hib19880520.html