Another Compressed Air Line Question

[JOHNMAN]

In my newly acquired shop, I am planning on plumbing in air lines. In hindsight, I should have taken down my prior air lines from my old shop prior to moving away.

I had 3/4" copper run as the main line.

I have been pricing copper and prices are a bit higher than the last time I did air lines.

I will still be using copper, but I am strongly considering using 1/2" copper as opposed to 3/4 due to price.

Anyone have an opinion on the use of 1/2" copper instead of 3/4" copper?

If I had access to a free pipe threader and knew how to thread a pipe, I would probably look at using black iron pipe instead of copper.

 

[jeepgod]

i think if you stay below 100' run, 1/2" should be fine.. not sure how long you need your runs.. but that is what will dictate the size.. and copper should be getting cheaper..

 

[larry4406]

Harbor Freight has an electric pipe threader for about $150-175 (not "free" as you asked for), comes with dies for 1/2 thru 1-1/4 I believe. Works extremely well and even uses replacement cutters from Rigid. I had never threaded before either, but was up and running in less than 30 minutes, very easy to do. I used it to run all of the black pipe propane lines in my house and detached garage, as well as the 1-inch black pipe air line in my garage. Use Rector Seal on the threads for sealant. Make a sketch of the system you really want, price it in copper vs black pipe, determine the cost difference and see if you have enough left over to justify the tool purchase or a rental. Make sure you do a fair comparison not only with the materials, but also the tools you will need (tubing cutter, torch, solder, flux, crocus cloth vs threader, rector seal, pipe wrenches, hack saw/sawzall).

 

[Torque1st]

A person can easily use iron pipe without a threader. Just buy an assortment of pipe lengths and return what you do not use to the store. If you know you need some odd lengths just have them threaded at the store. They are not returnable tho.

 

[Industrial Concepts]

In my newly acquired shop, I am planning on plumbing in air lines. In hindsight, I should have taken down my prior air lines from my old shop prior to moving away.

I had 3/4" copper run as the main line.

I have been pricing copper and prices are a bit higher than the last time I did air lines.

I will still be using copper, but I am strongly considering using 1/2" copper as opposed to 3/4 due to price.

Anyone have an opinion on the use of 1/2" copper instead of 3/4" copper?

If I had access to a free pipe threader and knew how to thread a pipe, I would probably look at using black iron pipe instead of copper.

When deciding what size pipe to use for your airline,you have to answer the following:
What size compressor-pressure & cfms?
How long of a run?
How many drops, elbows & offsets will be needed?

The bigger the pipe size is always better, more volumn & storage.

 

[5wndwcpe]

When deciding what size pipe to use for your airline,you have to answer the following:
What size compressor-pressure & cfms?
How long of a run?
How many drops, elbows & offsets will be needed?

The bigger the pipe size is always better, more volumn & storage.

Plus you're only going to pay for it once. If you downsize it now and come to regret it, chances are slim you'll rip out the 1/2" and replace it with 3/4".

 

[JOHNMAN]

A few more parameters to add to the mix:

I am using a 5HP compressor. Upright 80 gallon receiver tank.

My shop is 40'x64' with 10' clear to the ceiling joists.

I will be placing the compressor centrally (24' along the 64' length and about 14' along the 40'). There will be a closet built to house the compressor (for noise).

My main consumers of air would be:

1. Sand blast cabinet located in another closet approximately 5' from the compressor.

2. Rim clamp tire changer (not yet located) up to 40-45 ft away. (it has it's own receiver tank)

3. General air tools located in a radius of 60 ft from the compressor.



I don't believe that I will have any runs that are more than 75 ft (unless you count hoses plugged into quick disconnects).

I am just not sure that 3/4" would be so much better considering that my hoses are all 3/8".

I may occasionally spray a car, but that would not be typical.

I am considering a main branch across the back wall 64' and making several drops (and extending one of those drops to the front of the shop across the top of my bench). A second branch would feed a couple drops across the front.

Here is another question:

Anyone use PEX?

 

[Torque1st]

For pipe size and layout check here:
http://www.oldsmobility.com/air-compressor-piping.htm
And here:
http://www.tptools.com/StaticText/airline-piping-diagram.pdf

For noise do not use a closet, -pipe the air inlet outside. There are a number of threads here on the subject of noise and compressor inlets.

Forget the PEX. It will go up easy but it will not condense water correctly and manage any water properly. Use the iron pipe either black or galvanized. Galvanized does not rust but you may initially get some dust from the coating. Black iron will give some dust and rust also. Copper may even give some dust initially. To use copper you will need the thicker wall tubing and brazed joints, not soldered. In some areas the building codes do not allow copper for air lines due to fire regulations.

 

[Steve in Mi]

To use copper you will need the thicker wall tubing and brazed joints, not soldered.

One can't give a pressure rating until the diameter is specified but certainly 3/4" cu in the thinest wall (even M annealed is good for greater than 200 psi in 3/4" @ 400 degrees F(see page 26 of pdf below)) will be fine for the 175 psi output of a 2 stage compressor. Soldered joints will be fine also (see page 28 for different solders and there pressure ratings in the following pdf.). I refer you to the "Copper Tube Handbook" which can be downloaded here;
http://www.copper.org/publications/pub_list/pdf/copper_tube_handbook.pdf

In some areas the building codes do not allow copper for air lines due to fire regulations.

If anybody ever finds this to be the case I'd like to be copied on it so I can learn why it would be a concern. Thanks in advance.

 

[Torque1st]

The industry references I have seen list the type L as required and disallowed standard soldered joints. Look around and you will find the references.

Also the fire codes for several localities I have run across list the copper prohibition. Apparently due to the blowtorch effect if a joint fails in a fire. Iron pipe was their desired material for fire resistance. Try some searches with Google etc.

Pressure ratings of tubing and joints are not the entire story or PVC would be allowed. I have a copy of the copper handbook.