Air line Q's (Not the Norm)

[fireplug]

Hi guys, I'm hoping for your opinions. I've posted a quick 'Paint' drawing of what I'm planning please critique away!

You'll notice that the line loops back on itself. The point of the hardline is simply to condense water for sand blasting and painting.

I'm planning on 3/4" Copper and the total length from compressor to outlet will be about 30 feet. Going any longer than that would be a lot more effort than it would be worth.

This is a hobby garage only.

The 'dead end' is for possible future needs.

Now some questions;

Am I correct in thinking that 3/8" airline fittings are the largest available?

What size thread does a 3/8 quick connect have?

Most of what I have read advises reducing from 3/4" to 1/2" at the drops. As I'm limited in overall length should I too reduce to 1/2" or stay 3/4"?

Despite everything I've read, I can't help but feel that ultimately the restriction at the outlet would make this short run of 3/4" pointless. Any thoughts?

All input would be greatly appreciated!

 

[kbs2244]

I would slant the runs down to the right in your drawing and put a tee and drip leg at the 11” raiser point. That will drain both horizontals.
You want large diameter on long runs because of the drag on the air as it flows through the pipe. The drag is at the wall, and the farther from the wall the faster the air can flow. The larger the diameter the less friction. If you are doing high air volume you want large diameter.
It is the same with water plumbing. They used to do whole houses in ½ inch pipe. Then code went to ¾ for any run over 30 feet. Now it is 1 inch over 30, ¾ between 10 and 30 and ½ to the fixture. All this to feed a 3/8 tube in the faucet or toilet. But the 3/8 is less then 24 inches long and has plenty of flow up to it so it is never starved for water.
The same idea for your air piping.
You can go too small but it is hard to go too big.

 

[fireplug]

Great idea on the drip leg at the right side I hope I can incorporate that.

Unfortunately I don't think I'll be able to do it, I'm going to have to look into that one. The big empty space below the horizontal lay, is my garage door.

Great example of friction loss! I'm pretty familiar with it as it applies to fire fighting, I guess this extremely short lay just has me fooled, I didn't know that about plumbing code...

 

[fireplug]

No thoughts on the drops? I'd like to start assembling this weekend so your input would be greatly appreciated.

To reiterate I'm wondering whether I should step down from 3/4" to 1/2" at the drops. It seems as though this is the norm but why?

I can't put in that dripleg that kbs2244 suggested but I was thinking that if I drop the mainlines to the left it should drain half the line to the compressor, and half the line to the last drip leg. Which should make EVERYONE here happy as the general opinion seems to be cut down the middle!

I really considered 1" when I bought the tube but I gave in to my gut feeling and as the compressor exits at 3/4" I figured I'd go that route for the whole thing.

 

[Charles (in GA)]

I'll probably go one inch on my runs when I install, but truthfully, 3/4 will do just fine, unless you are running a huge blast cabinet and spray booth at the far end. There is no real reason to use 3/4 for the drops, 1/2 inch will flow more air than you can use at one drop. Its kinda like electric wire to your house. Its a long run, so you need a large wire, but when you get inside, you don't need to continue that large wire to each small draw item. Air is a little different, you will only use one drop at a time unless you have a bunch of friends over, working, (that ain't gonna happen... working I mean). But for the long run, you want a large enough pipe that you don't experience losses as it flows 50 ft to the far end, however, for a short 10 ft drop, you really just don't need the 3/4 pipe. If you have it, use it........ It won't hurt.

Charles

 

[nkachur]

One other thing to consider is the added air storage in longer diameter pipe it is like getting a bigger tank on your compresser without buying a larger tank.

 

[fireplug]

Is there a rule as to what ratio your posts to others' posts has to be in a thread?!

I 'dry fit' the horizontal lay to visualize it all a bit better. What isn't evident in the pics is the transition from drywall to wood, and also the difference in 'depth' from the door frame to the block wall. Those facts together with an already 'busy' area require some extra care in laying it all out.

Obviously this isn't a great area to be doing this, but I'm adamant that the compressor be located where it is. With the compressor located there, the other option is to run the tubing to the left but that requires going into the corner behind the furnace (which wouldn't be the best place to cool the air in the winter).

 

[Charles (in GA)]

After looking at your initial sketch and the pic you posted above with the hose reel position, etc, and I see that the long run is simply a waste of pipe. I am running a blast cabinet on a 25 ft 1/2" rubber hose on the floor, directly off the regulator and water separator on the compressor and have not experienced any moisture problems. I personally feel that the need to condense out water in the airlines is way over exaggerated by many people on this board and if you have a good separator, you probably will have eliminated 99.8% of it right there. If you are running something critical, then add a second separator and filter at that device (blast cabinet or paint booth, etc).

I'm in Georgia, we have lots of moisture here, I get a fair amount from the compressor tank and the separator, but if there is any more left after that, I certainly haven't noticed it when using the blow nozzle, air tools or blast cabinet.

Charles

 

[volvo]

.
....Is there a rule as to what ratio your posts to others' posts has to be in a thread?! .....

Hell No, This is YOUR thread... Ask away, lets get you all the help you need to get your project up and going to its full potential....H

 

[fireplug]

After looking at your initial sketch and the pic you posted above with the hose reel position, etc, and I see that the long run is simply a waste of pipe. I am running a blast cabinet on a 25 ft 1/2" rubber hose on the floor, directly off the regulator and water separator on the compressor and have not experienced any moisture problems. I personally feel that the need to condense out water in the airlines is way over exaggerated by many people on this board and if you have a good separator, you probably will have eliminated 99.8% of it right there. If you are running something critical, then add a second separator and filter at that device (blast cabinet or paint booth, etc).

I'm in Georgia, we have lots of moisture here, I get a fair amount from the compressor tank and the separator, but if there is any more left after that, I certainly haven't noticed it when using the blow nozzle, air tools or blast cabinet.

Charles

I will admit, that I am being proactive so I haven't experienced problems to know that I need this set up. Got me thinking now...