air line runs in shop

[Max]

Yabbut, using 6" piping will be like having another reservoir

Max

[Mike O.]

ooops...60 FEET

Mike O.

[Robert Allison]

If you use 6", I would go with butt weld. 6" screw pipe requires two

72" pipe wrenches and is a real pain to run. VERY hard to get started, especially with long runs (over 20'). I have run alot of this and it is NOT easy.

[Max]

"Robert Allison" wrote

Thanks for the tip. Glad I have a welder.

Max

[Hoosierpopi]

"DO NOT USE PVC PIPE MADE FOR WATER LINES!!! "

Responded someone. I beg to differ. John and I had and John still has a shop fitted with schedule 40 PVC lines for his large compressor. The large I.D. of the PVC pipe serves as additional volume and the runs and drops provide access all over the shop.

Each outlet is fitted along a vertical drop that terminates in a weep valve below (for draining the lines.

We used automotive ROS, Grinders, Binks Spray Guns, die grinders for years and years without a problem. I can't recall the exact sprecs on the compressor, but it was a two-stage with an 80 gallon tank or damn close to it - Tall as I.

Air pressure is measured at the compressor, but should be the same if you moved the gauge to the end of the line.

Holding capacity is initially limited by the attached tank, but increases the moment you attach an air hose so the tank size never equals the working volume, now does it?

You let a little air out and nothing happens, a bit more and at some point the overall pressure in the lines and tank frops below the refresh setting and your pump begins to run to pump in sufficient air to raise the pressure to the high cut-off point.

Restrictions due to a smaller diameter hose (or PVC piping) could, indeed impact the performance. But you are going to use 3/4" PVC or larger and avoid such a complication.

My bet is that your little compressor is the only "choke point" in your planned approach and that will be remedied down the road when you can afford to connect a bigger, more powerful unit to the PVC piping installed to over yourself today.

Provide for drainage and filtration and you'll do just fine.

[Robert Allison]

I got fired from a job over 24" screw pipe. My helper let the backup wrench slip and we turned the building over.

[Robert Allison]

In remembering my old pipefitting days, I recalled a time when I was on a chemical plant job and told this old joke to my new welder and his very green helper. I finished the line about turning the building over and the helper asked: "Anyone get hurt?"

That was funnier than the joke.

And believe me, I really have run 6" screw pipe for fire suppression systems in the laboratories. The main run is 6", it really requires a

72" pipe wrench (which weigh about 75 pounds each) and it is all suspended in the ceiling to supply the fire sprinklers. The drain lines are the coolest. They are 2" pyrex (chemical resistance).

[Greg O]

Just because you are getting away with it does not make it right. I have seen PVC pipe explode for no apparent reason with 100 PSI air pressure. I guy I know has scars on his face from a different PVC pipe rupture. The stuff is dangerous. When it ruptures it goes off like a hand grenade spewing PVC shrapnel all over the room. Manufacturers and OSHA have warnings against it's use. I used PVC in the past, but never again after seeing the carnage when it fails. I know guys that go to the bar and drink until they can barely walk, then drive home. They have been doing it for years with no problems, so I guess it is ok. Greg

[dpb]

As well as just the simple bursting scenario, it is subject to similar disintegration failure on impact, etc., ...

--

[dpb]

Greg O wrote: ...

Seems like I've seen a clip somewhere of the resulting carnage -- don't recall exactly where; OSHA report, maybe???

--

[J. Clarke]

Sounds like a good Mythbusters. In fact I just suggested it.

[Tom Veatch]

Correct - the effect depending on how much of the larger diameter pipe is downstream of the restriction. The more pipe volume downstream of the restriction the larger the effective tankage.

A quarter inch orifice in the line will restrict the flow more than if the orifice wasn't there, but nowhere near as much as if the entire line were the diameter of the orifice. The larger the pipe, the less pressure drop per foot for a given flow rate - or - the greater the flow rate for a given pressure drop. And, ignoring start/stop transients, steady state performance is independent of where in the line the restriction/orifice is located.

Tom Veatch Wichita, KS USA

[clare at snyder.on.ca]

Do NOT use PVC. It is EXTREMELY DANGEROUS if it is shocked while under pressure . It fragments violently, and packs a FATAL blow if you are in the (rather extensive) range of fire. It also deteriorates in contact with oil, and you cannot guarantee your air is oil free. This makes it more brittle.

[Tom Veatch]

OK, as long as you don't have to satisfy any OSHA regs and aren't worried about flying plastic shards in the event that the pipe does rupture.

"(T)he Plastic Pipe Institute, in its Recommendation B dated January

19, 1972, recommends against the use of thermoplastic pipe to transport compressed air or other compressed gases in exposed plant piping." ... "It is our position that PVC pipe shall not be used as a means of transporting compressed air. This position follows the manufacturer's own statements that PVC is unsuitable for compressed air systems. "

Veatch Wichita, KS USA

[Greg O]

Check this out,

?p_table=INTERPRETATIONS&p_id=20202Greg

[J. Clarke]

papers have far less impact than seeing what really happens when the stuff goes bust.

[Lew Hodgett]

If you are close enough to see it, you are a fool who is too damn close.

Lew