Air lines for compressor

[DRJDVM's '69]

I have a new Ingersol Rand 2 stage compressor on its way, so I've been planning out my air lines etc. I've looked at a couple of sites that give recommendations for how to set up your system. I went to Home Depot and Lowe's today to get some ideas, but some of the recommendations dont make much sense to me...

The compressor has a 1/2 inch NPT outlet, and I use 3/8 air lines for my tools. Do I really need to run 3/4- 1 inch hard air lines around the shop ?? The way my garage is set up, I only really need about 25-30 feet of hard line, and there will never be more than one tool working at the same time.

I understand the advantage of hard steel lines to get the air temp down and get the moisture to condense before my filter/water trap etc, but with a 1/2 inch outlet and 3/8 flex air line, what the point of having 3/4 inch hard line between them?? Wont 1/2 inch be just fine ??

If I want to run 3/4 inch line, its just going to take more step up/down adapters to get it to work. Seems like alot of "bottlenecks" in a system like that.

Second issue... the diagrams I've found for layouts all have flex lines form the compressor to the hard line on the wall... I cant find short hose lines other than 3/8 inch.

[parsonsj]

25 to 30 feet of 1/2" will constrict the air delivery a lot more than 3/4".

Are you using regulators and filters? If so, you'll want to mount those on a wall with a disconnect coming from them, and they'll be a lot easier to do with hard line coming from the compressor. Here's a couple ideas for you:

1. Do the hard lines in copper: it's cheap, safe (rated to 250psi minimum), and easy. You'll be able to get everything you need from your local Home Cheapo or Slowe's.

2. Use AN socketless hose for your flex line. It's not too expensive, and is rated to 250 psi.

jp

[DRJDVM's '69]

I looked at galvanized and black pipe at HD and Lowe's but not really the copper. I thought coppper pipe was more expensive. so I didnt bother to look at it. With the galvanized pipe, I'm probably looking at $60-75 with all the fitting/elbows etc etc.

So John are you talking about using the same socketless AN hose that you would use in a car ?? What about the fitting for the connection to the compressor and then the hard line ?

Yes, I'll be running a filter/regulator, but I also have a hose reel, with about 50 ft of hose on it, so my quick disocnnect is on the end of that.

I understand the 3/4 inch will flow better, but the restriction is still at the compressor outlet and then the airhose again, so I dont see the big advantage of a big pipe inbetween.... maybe if I was plumbing a huge shop, but for a run of 25 feet it doesnt seem like it would be that much of a difference.

[parsonsj]

Suit yourself on the diameter and material.

As far as the connections, if you use copper, you can get pipe thread fittings that you sweat on. Then you use pipe to AN adapters, and you're golden. Oh, and yes, just ordinary AN hose you'd put on a car.

jp

[parsonsj]

A picture is worth a few hundred words ...

[DRJDVM's '69]

Thanks John for you help... I especially appreciate the pix...

Ned

[69slotcar]

Definitely go with Copper !

[Modo Innovations]

Hey Doc,
You can use the cheap method that I have been using for sometime now. I used 3/4" pvc pipe. It works very well, what I did do for the outlets is run about and 18" piece below the quick disconnects with a radiator petcock on the bottom so I can drain the moisture.
I plumbed my whole shop at home (20x30) for about $30 including quick disconnects.
My 2 cents

[Bowtie]

Ned,
Please do not use PVC plastic pipe. When (not if) it lets go it will shatter, sending shrapnel flying. I hope you and your nice car are not around when it does. It is an OSHA violation to use it in a place of business. In a home garage it’s up to you.

Listen to JP, use ¾” copper. An IR 2 stage compressor is expensive. Why cheap out on tubing to save a few bucks? Plumb it right! Think about your future needs and add additional drops now instead of later. If you are set on pipe use black pipe before galvanized. Both will rust internally over time. Use a good pipe dope as threaded fittings can leak. If you use copper solder it with 95-5 Tin-Antimony solder. Home Cheapo does not sell it; go to a plumbing supplier.

[Modo Innovations]

Ned,
Please do not use PVC plastic pipe. When (not if) it lets go it will shatter, sending shrapnel flying.

What is the time frame when your pvc goes into shatter mode?

[Todds69]

I dont want to steal this thread but I am thinking of using copper pipe as well, so my question is what is the difference between "L" and "M" on the copper pipe. I noticed one is thicker walled but wondered what the designation stood for? Thanks

[parsonsj]

I've always used the thicker wall stuff (don't remember which is which). It is "softer", so I figured it easier to work with. It's also more expensive, so I figured it would last longer.

I'd love to know if anybody knows more about it ...

jp

[parsonsj]

Google is your friend:

The difference is the wall thickness of the pipe and therefore the pressure it can handle. The exterior dimensions are identical, meaning you use the same copper fittings. You also use the same tools, materials and techniques to cut and sweat them. The beefier Type L is often used underground, in hot water heating systems, for commercial plumbing and for gas line (where permitted). Most plumbers use the less-expensive Type M for residential projects: One told me, “Type L pipe will last 300 years and Type M only 250.” But check with your building inspector; some areas require Type L.

From the website, The Family HandyMan.

jp

[Bowtie]

Everyone has their own idea on what is best. Both copper and black pipe are approved for compressed air systems. Black pipe is typically rated to 150 psi. The major issues with pipe are: it is heavy, it will rust, and installation is a pain if you do not have a plumbers pipe threading machine – you will be running back and forth to Home Cheapo to have them cut and rethread your pipe. I prefer copper for its ease of installation and lack of rust issues.

JP and Todd -
For more copper info than you will probably want or need refer to the Copper Tube Handbook, (sorry I don’t know how to link)
http://www.copper.org/resources/pub_list/pdf/copper_tube_handbook.pdf
Be sure to look at the tables.

Table 1 lists applications. Compressed air is not listed for Type M, it is for Types K and L. Home Cheapo does not sell Type K, only Types L and M. Like JP, spend a couple dollars more for the Type L.

Table 2 lists dimensions. Wall thickness for ¾”:
Type K = .065”; Type L = .045”; Type M = .032”

Table 3 lists rated internal working pressures.

Table 4 lists the pressure-temperature ratings of soldered and brazed joints. Use the 95-5 Tin-Antimony.

Table 5 lists actual burst pressures.

Shannon –
UV light is the enemy. Exposure to UV will cause the PVC to become brittle, the more brittle the bigger the issue. PVC is not approved for compressed air. How long will it last? I don’t know. Your system may work great for the next 50 years, but why risk it? I have a good friend who plumbed his garage with PVC 8 years ago, the pipes are hidden in the sheetrocked walls and ceiling (no UV exposure), he has a small compressor that he runs maybe 3 times a year. So far it is working great.

Check the following for some ideas on how to run the lines:

http://www.tptools.com/statictext/airline-piping-diagram.pdf

http://sharpe1.com/sharpe/sharpe.nsf/Files/YTCJYTCK/$File/pipe-layout.pdf?OpenElement

[Todds69]

Nice find, thank you.

[DRJDVM's '69]

I have no plans to even consider PVC pipe... I'm not crazy....... anyone thats using it for this kind of application is just asking for trouble. Maybe ""I've been doing it for years with no problems" is safe enough for you, but not me.....

The black pipe was the leading candidate, but now I'll look at the copper more before I decide. The good thing about my application with the black pipe is that the layout will match very well with the standard sizes/length of pipe, so I dont think I'll need to do any re-thread etc etc.

[digger1978]

Does 1/2" pipe flow enough? My compressor only has a 3/8" fitting coming out of the tank. I have it then stepped up to a 1/2" fitting. My filter and regulator have 1/2" fittings on them. My dilema is that my impact gun doesn't seem to work well. It won't even take off a lug nut. Yes I checked to make sure it was oiled and it is was set on the highest flow setting. Regulaor was set at 95psi. It works just fine at my fathers house with his compressor set up. I have tried two different impact guns. I currently have about 12 feet of black pipe, and then 50ft of 3/8" compressor hose. The compressor is a Sanborn 60gal, 7hp 220v. Do you think the 3/8" fitting on the tank is the problem? Should I get a regulator/filter combo instead of two separate units?