Air line materials?

[woodlot]

I need to run a hard line for my air compressor. I'm unsure what kind and size of pipe to use. I'd like to keep it as small as possible. The line will run from my basement to my attached garage. It will be 30 ft. max. and will be out of the weather. The max. pressure my compressor gets is about 120 psi. Also, sould the line be pitched or have a drain to remove mositure?

 

[Jagmandave]

I've used just good ole PVC water pipe for my air compressor for years, even tho it's printed right on it that it's not suitable for air. I can't understand why tho, since it's rated for 600 lbs burst pressure and, like yours, my compressor only gets to about 120 lbs psi. Anyway, use it at your discretion, but it's cheap and easy to use, I have it running all over my garage for over 10 years with no problems.
Obviously, copper would be the first choice if you're up to soldering it all up, and don't mind the extra cost. I put a ball valve about 1 foot below the air outlet for my tools, and I drain whatever moisture out there, I also have a water separator and regulator right at the outlet too.
There are lots of sites online that discuss how to run air lines, pull from the top of the pipe for your drops etc. One thing about plastic, it never rusts or corrodes.........

 

[tc35dforme]

I'm no expert, but the concern with PVC is cold brittleness and shock impact due to slugs of condensed water. PVC is very brittle when cold and an impact may cause it to shatter. Combine this with the impact of a speedy slug of condensed water and you could blow out an elbow. I agree that PVC is okay if it is installed with a good pitch and the pipe is not running in a location that will allow a lot of condensation.

On the other hand, copper is excellent to use and won't suffer as much from the occasional water slug.

Remeber to account for pressure drop in the line. If the line is small and the flow is high, you may not get the air you need.

 

[PitbullMidwest]

I know a lot of guys use PVC and haven't had a problem with it. But, about 10 years ago a company that I worked for used PVC as air line and had a failure from over pressure. The pressure relief valve failed to open on the compressor and the pressure continued to build until the pipe exloded like a bomb.

Spend a little more money and do it the right way.

Curt

 

[woodlot]

Thanks Kurt, I don't like the PVC idea either. Your reply: "do it the right way"......Thanks exactly what I'm asking....What is the right way?!

 

[budman72]

I have seen some special PVC pipe that can be used for air lines, sorry I don't know the name or where to find it. Try Google??

The best way to run the line is using steel pipe.

JMHO,

Bud

 

[jheady]

I plan on using copper for my lines when my building is completed. If I don't use copper I would be using black pipe, and I wouldn't advise using PVC. Depending on your run lengths and volume needed 1/2" or 3/4" copper would work great. Make sure you plumb drops below your outlet points to fix a drain (like stated above) to release any captured moisture. Keep in mind if you use copper that it can't be touching any other metal as it will cause corrosion.
SCH 40 PVC does have the strength when new, but sunlight, age, and being exposed to the elements can cause weakness in the pipe. It may work fine for a while, but then just rupture for no apparent reason. It would definitely need to be protected and secured. Movement in the pipe could cause it to crack or worse. You could also drop a hammer or material on it and cause immediate problems too.

 

[Bird]

</font><font color="blue" class="small">( sould the line be pitched or have a drain to remove mositure? )</font>

Yes.

 

[TOMLESCOEQUIP]

I needed to run air over to a addition I built onto my barn. The distance was about 50'. I used 1/2" hydraulic hose to make the run. It was really easy to run from the compressor up thru the rafters & into the lower shop & I know I won't be having any problems with it blowing out @ the 175 psi I use. I used the 1/2" & haven't had a problem with loss of volume going that distance. Just thought it may give you another option to think about.........Tom

 

[Spiffy]

I've seen the hydralic hose used for airlines too and it works great. Also, for sandblasting I bought a 50ft X 1/2 airhose; works great w/ negligible losses even at 20cfm.

However, the biggest reason to stay with metal on your "hardline" is water knockout [I should had re-read the intended uses, but I'll go broad]; this is imperitive, if you're pressure blasting or painting. Moisture is not good for airtools either, but a little preventative maintanence after use will counter this.

Two reasons for metal: its heat transfer condenses the water and it is easier to slope without sags [which collect moisture]. Black is recommend over galvanized under the theory that zinc flakes are more likely than rust. I slightly dispute that and have used both on occasion. Don't be at all afraid of a heavy gage copper either though [just be real careful about proper sweating], a place I used to work at checker-boarded 80000sq feet with it, problem free. Even with a prefilter, refridgerating water separator, and coalescing filter, you still got water from the drain each month.

Air-lines

These guys diagram it better than I ever could, but I do like a prefilter. Just remember if you run a FRL for a prefilter [right at the first horizontal of metal]: do not fill the Lubricator, you'll change your applications the day after; just run a separtate FRL at the end point(s) for your air tools. Oh, a 1/2 inch coalescing [or desicant works too] right before your "softline" is spendy, but oh is it a "lifesaver". /forums/images/graemlins/smile.gif