150 psi 3/4" galvanized pipe?

[RT66DOC]

Does anybody know if 3/4" galvanized pipe will hold 150 psi? I have a 135 psi 60 gal air compressor and need to set up a supply line. Any suggestions? TIA

 

[JohnE]

Yes, but you should use black iron for air systems. The expansion and contraction of the pipes may flake off the zinc plating (galvanize) and plug regulators, orifices, etc.

A serious air system should have a cooler and dryer, too.

 

[RT66DOC]

Thanks for the reply, JohnE. Why did I figure you were going to say black iron? Probably because it's the hardest to find around here, eh? Home Depot and Lowes sure don't have it. Why a cooler? I planned on a dryer for a paint spraying line but not for air tools, etc. Do I need a dryer there too?

 

[B.G. Smith]

Specs

Go ahead and use the galvanized, you will have less trash than with black iron. Our plant spec was galvanized for all air lines, breathing, instrument and plant air. bgs

 

[RT66DOC]

Thanks for the info, bgs.

 

[AKAMAC]

http://home.carolina.rr.com/unclejoe/pipe.html

Go here. I have used pvc for years and I love the low cost.

 

[Elite1]

PVC will hold that pressure no problem as long as you use high quality glue (I prefer wet r' dry). Use sch. 40. I believe in 3/4" the sch. 40 is rated at 400 psi. Heck even the thin wall 3/4" is rated at 200 psi. , the thin wall 1/2" is rated at 315 psi... . but I would use schedule 40. It won't rust... guaranteed!

 

[Eric_77]

Second vote for PVC. I run mutiple valves so any area of the shop can be shut down if it springs a leak(not often and we run 120-150 PSI in 1 1/2 line for last 15 years), fittings need to be replaced or line added etc. We have "low spots" designed into system so any water condensating will accumulate there and can be drained without worry of corrosion of pipes.



Other way to reduce water content and to have "cool" air is to build lots of pressure(also adds reserve to system) in tank then reduce line pressure 30-50 PSI but that now puts even more water into tank which should be drained regularly to keep rust away.



Prime and glue all joints one part glues do not seem to be as good as two part prime/glue

 

[Piston Slapper]

PVC here too

We have PVC in my dads shop been there 12 years regulator set on 175 lbs. We work on Heavy equipment.

 

[RT66DOC]

Awesome info, guys. Thanks. Had another gent at work tell me today he's used sched 40 PVC in his shop for years with no problems.



BTW, Piston Slapper, what kind of a dog is a "white faced blue pointer" anyway?

 

[JohnE]

PVC is great until the time you impact it. It will explode and send shrapnell everywhere. Yeah, it will never happen to me!

Make sure to cover the exposed pipe with something.



A cooler may be built into your compressor unit.

Cooling the air adds more overall capacity to the system. If you pump hot air in at 160 psi the air tools will deplete it much faster than a cold 160 psi. Simple Boyle's Law.

 

[RT66DOC]

Ah yes... Boyle's Law. Dispersion of gasses, etc. , etc. It's all coming back to me now - like a bad dream. Physics 102. Comes in handy when calculating how long one should wait before entering a men's room after some other guy drops a bomb in there.



OK, Boyle's Law I can handle. Let's just not push it and start talking acid-base balance - Henderson-Hasselbach equation and related stuff. Thank the Lord we don't need much of acid-base balance to deal with the Dodge Cummins - in a practical day-to-day sense.

 

[lil red cummins]

have had 3/4 galvanized in my shop for over 15 years. we have a basic moisture trap by the compressor. have had no problems at all. no flaking, no rust, no problems. there are 6 lines - each one between 50 and 100 feet long with taps about every 12 feet.



i also have a high pressure line running at 150 psi in copper. it is by far the cleanest way to go. it just needs more protection against bumps and i put it up high so nobody hangs stuff on it.



the galv. has stuff hanging on it everywhere, but it is no problem because we put hangers approx. every 5 feet.



jim