Anyone ever see compressed air for a workshop run through copper pipe and sweated joints. I saw a general contractor do just that. I told him it would never hold up at 125psi. but he just looked at me like I had horns growing out of my head and said,”sure it will”. I told him black iron pipe and treaded elbows. I’ll take any insight you might have.
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The correct answer is: "Sure it will".
I have heard of people using 1/2 CPVC which will work just fine until you give it a sharp bump and it shatters.
or when it gets really cod and brittle...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!Forget the primal scream, just ROAR!!!
FWIW, most of the air lines in the big Aerospace company I work for final assembly buildings are sweated copper.
A thousand little air leak or pipe corrosion tool fouling leads to literally millions of $$ a year in losses.
PS: all my air hoses were bought at company surplus store, some have tiny leaks if the connector is bent at a hard angle. In a production setting (pressure 24/7), it pays to throw the whole air hose away. Just bought another 50 ft hose 3/8" hose toady for $2.72, the few hours a week my compressors run aint gonna kill me with a little leak.
PPS: surplus store is closing Dec 21st for ever ...sad.
PPPS: Own house has about 500 ft. of black iron (rejects/refits from the surplus store) and without very good moisture separators coupled with occasional use there is interior corrosion and rust particles that make the fittings leak. I'd NEVER use black iron again in own shop/house. Heck, I'd use PVC first behind 2x4 shields.
You lost me-
*your place of employment uses sweated copper and suffers a million little leaks
*Your rubber hoses leak
*You'd never use black pipe in a million years
So..... what's your suggestion for plumbing aIR?
Thanks,
Dick J
Copper, braze it with silphos if worried.
re: your place of employment uses sweated copper and suffers a million little leaks
What I said was: A thousand little air leak or pipe corrosion tool fouling leads to literally millions of $$ a year in losses.
OK, should have said WOULD lead to
I used sweated copper, no problems 15 yrs later. Strikes me as the best of the choices. Running my compressor at 125 psi with an added 80 gal tank (140 gal total) to give me enough air for sand-blasting. Avoided needing 175 psi that way.
My spare compressor has a 500 psi (working pressure) tank, unsure what plumbing that called for but unlikely I'll find out.
Forgot to mention that I heard similar predictions when I ended up running my residential water supply 80/100. That hasn't been a problem either.
PAHS Designer/Builder- Bury it!
Edited 11/15/2007 7:35 am ET by VaTom
Copper works well.
I know PEX MFG's don't rate their product for air...but has anyone done it? What's been the result?
I have been running my compressor with polybutelene pipe (the grey stuff with brass fittings) from one building to another underground for eight years with no problems.( My compressor never operates above 125 psi and is 2HP)
The Moving Finger writes; and, having writ,Moves on: nor all your Piety nor WitShall lure it back to cancel half a Line,Nor all your Tears wash out a Word of it." - Rubaiyat of Omar Khayyam
Most pex companies say to test with air in freezing conditions.
I ran my compressed air in my garage in pex, but I haven't put it online yet.
If it fails it will rip, not blow up like a frag grenede like pvc will.
"If men are so wicked with religion, what would they be if without it?" Benjamin Franklin
Copper is what most guys use. Use type m. If I remember right it is the thicker type.
Type m is the thinnest of the regular pipes. K is underground, L is a bit thicker (wall size) and M is the thinnest.
Oops! I always get those two confused. I meant type L. He could get the K if he really wanted. I don't think I've ever seen K. And I worked in hospitals where they had oxygen and nitrous oxide piped into the rooms. Even underground I've never seen K.
Must be really expensive.
I have heard the rational that in a fire, sweated copper will disassemble allowing your air compressor to fan the flames - same with plastic -
dunno - worth considering tho -
That's a good point.
I sweated copper for my own air system. The nuclear power plants I worked at all used extensive compressed air systems, all sweated copper. 125psi was peak operating pressures, and the only leaks were water at the coolers of the compressers.
"I am the master of my fate, I am the captain of my soul." Invictus, by Henley.
Medical offices use sweated copper- run at 120 psi for years
zero leaks or problems.
Our other house had a workshop in the basement. Plumbed to a 125psi air compressor with 3/4" schedule 90 (rated 300psi) pvc. We never had a problem, but it was scary to watch the pipe flex when disconnecting a line...
It's not the pressure that makes pvc fail, it's the oil that gets into the system, & pvc is a petroleum based product.
Your system will probably do just fine like most systems do that are piped in pvc, it's just if & when it fails it's really nasty.
"If men are so wicked with religion, what would they be if without it?" Benjamin Franklin
Was looking at a pvc manufacturer site for another reason but they specify that the testing of pvc systems should be tested with water NOT air, and up to 1 1/4 inch pvc can be tested with up to 370 psi. They say if you have to test with air, use a maximum of 6 psi, yes, that is a six. Water is essentially non compressible so if you get a catastrophic failure in the pipe the pressure goes away very quickly but with air and a failure, you have a boat load of volume behind it to throw the pieces ever which way. There is lots of information and formulas etc on air and air systems in the little pocket reference books.Nobody gets in to see the wizard...not nobody...not no how!
"I told him black iron pipe and treaded elbows."
Black iron is OK and it is probably cheaper than copper nowadays. But copper doesn't rust and it's easier to run. I use 3/4" copper lines in my shop at 125 PSI and have had no problems.
IMO hard plastic lines are an accident waiting to happen.
I came across this hint years back...
Air brake hose for big rigs, rated 250 psi.
Would not put it in plastic. What is the pressure rating on copper?
The ToolBear
"Never met a man who couldn't teach me something." Anon.
Table 3. Allowable Stresses for Copper Tube as a Function of Temperature
Temperature (ºF)
Allowable Stress (psi)
Annealed
Drawn
100
6000
10300
150
5100
10300
200
4900
10300
250
4800
10300
300
4700
10000
350
4000
9700
400
3000
9400
"If men are so wicked with religion, what would they be if without it?" Benjamin Franklin
I think your "thinking" of natural gas piping.
had 20 years in at industrial laundry facility (lots of humidity) air lines origonally were black iron, lots of problems with pnuematic valves etc,. due to interior corrosion. Also had some lines run in cpvc, OSHA cited us for those. Apparently they can shatter if broken (like schrapnel!) We replaced all lines with copper. Decent qaulity hose is fine also, (look at its pressure rating)
About 2 years ago I had a pressure reducer fail on a very large pump, it shot my pressure up over 400psi on a 6" copper, no problem, although I did notice some of my offsets grew a little bit.
Here is the pressure rating for copper pipe.
Re; the table:
There may ba a tendency for some to interpret that as psi air pressure allowable, it is not.
The table is the allowable tensile strength of the copper itself. Pressure needs to be calculated based on hoop stress in the copper,
psi(copper) = psi of air*pipe ID/(copper area*2)
Sorry about that Art, I forgot that table needs
P =
View Image to figure the actual pressure rating.
Here is the table I should have posted.
Nominalor standardsize, in inches
Drawn**
S=10,300 psi100F
S=10,300 psi150F
S=10,300 psi200F
S=10,300 psi250F
S=10,000 psi300F
S=9,700 psi350F
S=9,400 psi400F
1/4
1850
1850
1850
1850
1796
1742
1688
3
1946
1946
1946
1946
1889
1833
1776
1/2
1534
1534
1534
1534
1490
1445
1400
5/8
1266
1266
1266
1266
1229
1193
1156
3/4
1466
1466
1466
1466
1424
1381
1338
1
1126
1126
1126
1126
1093
1061
1028
1-1/4
914
914
914
914
888
861
834
1-1/2
850
850
850
850
825
801
776
2
747
747
747
747
726
704
682
"If men are so wicked with religion, what would they be if without it?" Benjamin Franklin
Copper is common for compressed air.
I once piped two bicycle shops for compressed air with plastic pipe meant for it. PVC is not approved. This stuff was green.
A google search came up with this:
http://news.thomasnet.com/fullstory/804640
Very quick and easy but expensive material wise.
The green plastic piping is Chem-Aire by Nibco.
http://nibco.com/cms.do?id=2&pId=14
That's the stuff.
When I came out West, from Chicago, I was stunned to see copper used for air ... back East we used black pipe. I checked the codes, and - at least from a code perspective - almost anything is allowed for air piping.
I was present when a sweated joint on a main air line failed. No big deal - just a long time for the pressure to bleed off. I seems that no one EVER uses enough valves when they run air lines!
I'm very uncomfortable with PVC when used for air lines. I am thinking 'shrapnel' when the pipe goes.
Copper tubing seems to work well as air line. It IS nice to open the drain, and get relatively clean water ... rather than all the rust and crud that comes out of an iron line.
i hate to admit this in public but here goes so maybe one other person won't do it.
i had been to a auto painting seminar and they talked about not ever using pvc,no problem my shop was piped in iron. about 10 years later i bought a building that was all plumbed for air in pvc. well you know how this goes,i should change that ,but maybe next week.
about a year into being in that shop i came in one morning and the air line had blew. now i thought if it blew it would just split open and leak air.no thats not what happened. it took out about 24" of line and blew apart into shards about 8" long and 1/2 wide that were as sharp as a knife. stuff was blown every where with one piece sticking about 2" into a sheetrock wall! looked like someone had shot it with a bow and arrow.
if i would have been in the shop when this went and a piece hit me it would of without a doubt penatrated whatever it hit.[well maybe my head eould be ok,it's pretty hard]
to say the least my shop is plumbed with iron. i have had copper also with no problems.
IF YOU PLUMB AIR WITH PVC BE SURE YOUR HEALTH AND LIABILTY INSURANCE ARE PAID IN FULL.
larryif a man speaks in the forest,and there's not a woman to hear him,is he still wrong?
Thank you for that story. I had only been making a guess; your tale confirms my fears. Also ... materials used aside ... everyone should take this as a major caution as to just how much power is within those air lines. However simple a job may appear, remember the words of Admiral Farragut:"Pay attention to detail!"
Craig,
My present building which I have been in for 5 years and the previous building that I was in were both piped with copper. Our compressor runs at 175 lbs and we have never had any problems.
As far as PVC goes, I do not think that OSHA allows it, that should be a hint.
If you are not doing a big shop and want something real nice, but a little expensive, look at this stuff. It is availabel from a couple of sources:
http://www.garage-pak.com/
http://www.trident.on.ca/Transair-compressed-air-piping.htm
Bill Koustenis
Advanced Automotive Machine
Waldorf Md