Air Compressor Lines

[ch47dpilot]

Wasn't sure what forum to put this question under but thought this may be the best place. I've decided to run my shop with copper type "L" copper lines. I have 2 questions.

I'll have some runs that are close to 80ft long. My compressors outlet is 3/4". Will I lose pressure or CFM with these long runs? If so will running 1" mainlines help or will the 3/4" compressor's outlet be my limiting factor?

None of the fittings I can find list their letter rating. I know the lines are color coded by rating how are the fittings labeled? Are all the fittings the same rating?

 

[murphy1244]

Why are you using copper for air lines?

 

[RPW]

Not sure about the copper but for the price involved I would consider the rapidair line. They now have a 3/4" setup with 100' of line 2 T's and 3 outlets for under $200.00 through Notherntool. I've seen the system and it's real easy to run.

Good luck.

 

[Egon]

I'll have some runs that are close to 80ft long. My compressors outlet is 3/4". Will I lose pressure or CFM with these long runs? If so will running 1" mainlines help or will the 3/4" compressor's outlet be my limiting factor?

The 3/4 outlet will give a slight pressure drop. The rest of the pressure drop will be dependent on the line diameter, length, roughness factor and flow velocity.:thumbsup:

 

[ray66v]

You don't lose pressure with undersized pipes, you actually lose volume, which in turn, causes the pressure to drop under a large load.

Yes you should use a larger size, unless the runs are less than 50 feet. And slope each line to a drain point, below where you have your take off for an air hose.

No, having a small outlet won't hurt you, but keep in mind every time you force air through a smaller opening, it can condense water on the other side, so you want to to limit these.

A vibration isolator between the compressor and the pipe would be a good idea. A length of hydraulic hose will work well here.

BTW: I hate you, for getting to fly CH47's, while the rest of us can't.

 

[rec]

why dount you use pvc for your air lines. my compresssor runs 175 psi on 3/4 pvc through the shop with no problem

 

[ray66v]

why dount you use pvc for your air lines. my compresssor runs 175 psi on 3/4 pvc through the shop with no problem

Please read up on the internet about pvc air lines.

As discussed in may threads on TBN, pvc is NOT rated for compressed air.

It is dangerous, and people have been injured. I know this from personal experience.

 

[ch47dpilot]

Why are you using copper for air lines?

I am planning on using copper for mainly two reason:

at 175 you need to use scheduled 80 black pipe and that cost more than similar sized copper.

Black pipe: Pipe, 1 In, 6 Ft L, Schedule 80, Blk Steel - Black Pipe - Pipe and Tubing - 1CPV5 : Grainger Industrial Supply $16/ft
Copper: Tube, Type L, 1 In, 5 ft - Copper Pipe and Tubing - Pipe and Tubing - 4WTJ3 : Grainger Industrial Supply $6/ft

easier to install, I have a pipe threader and pipe cutter for black pipe but it's just more time consuming than copper.


Originally was going to use PVC but like ray66v said I found that not to be a good idea.

 

[Garybake]

Type L will handle your pressures but over time I would rather have threaded joint seams with pipe sealant but if a joint does leak it is easy enough to cut and fix once you locate it. My pet peeve is the small leakdown that requires repressure run after a couple days off and away.

 

[grsthegreat]

NEVER use pvc for pressured air.....i was witness to one that exploded ... luckily no one was hurt. There were large shards of plastic embedded THRU a steel wall of the shop.

I have 1" type l for the main runs in my shop. with 3/4" tees every 12' or so.

the system is about 6 years old...no issues. should last forever.....knock on wood

 

[SpringHollow]

If there are no branches off of that 80' run, use something like jack hammer hose. It worked well for some 50' runs I needed.

Ken

 

[jenkinsph]

I would prefer the 1" type L in 20' sticks, makes a neater install and should be available at most plumbing supply houses. I would also recommend you use the hvac long turn elbows where possible as they have less friction loss. Be sure to fasten down the tubing securely to prevent any movement, this will reduce the chance of brittleness in the tubing. Use a good hose between the compressor and the copper tubing to dampen vibration.


You can use rolled soft copper too, it is harder to install and get it straight imo. I just checked before posting and Ferguson quoted $4.95/ft for 1" type L hard copper.

A properly installed copper line should last a long time with little or no problems with air leaks.

 

[EddieWalker]

Good choice going with Copper. It's going to be more money, but in the long term, you will never have any problems with it like you will with PVC or iron. Every time I think about doing that, I end up just using air hose.

I have two 100' lengths of air line and a 50 ft line that I keep hooked up to the compressor. With all 250 feet of hose hooked up, I don't notice any loss of pressure or volume. I'm sure it's there, but its not something that is significant or noticable. I wouldn't think that you could tell the difference between a 3/4 inch copper pipe or a 1 inch copper pipe over 80 feet.

Eddie

 

[ak9]

as ray66v stated &.....copper is the best way to go .Graingers offered a fairly delailed schematic diagram years ago that helped me in building my shops' set up .Iron pipe and any steel fittings will rust over time ... even the steel spring(s) in some regs i've seen rust out over time
:2cents: keep your lines the same dia throughout the lenght or step it down smaller as you get to the end. Not wise to go ~ smaller ~ bigger this will cause volume/pressure drop.
My set up : two stage IR T-30 W/ constant speed unloader and pressure switch > 1.5" on/off Gas valve>1.5" flex line >200psi 1.5" reg w/gauge & filters > _slope drops W/ quick connects ( this is located at the compressor area)> then a 50' serpentine of 1.5" copper steam heat pipe(fins) that can be either heated or cooled > to another auto drain > 60' @1.5 copper sloping to service another shop ( paint) area > auto drains > 1.5" gas valve > Reg w/ gauge & quick connects>50' @1"copper sloping too> auto drains >1" gas valve> reg w/gauge filter /dryer > sand blast equip ,pressure & gravity w/ reclaimer ,cabinet ... my expansion on to this is going to be a 3/4"@ 50'
into an ajoining shop this spring . for this I will use a rubber air hose to a valve/ reg assmby
ak9

 

[timster2]

You may also consider a loop. One shop I worked in had smaller diameter copper tubing run around the perimeter of the shop with drops at the work benches and between the garage doors. Never had a problem with volume or pressure. Each fitting was fed from two directions. Three quarter tube with half inch drops, one inch line from the compressor to the tee in the loop. That was of course before the dramatic rise in the price of copper.

 

[ray66v]

A big factor in what size you need to run, is what tools your planning to use.

Most air tools don't have a high demand. A tool that uses 5-7 cfm is really not going to tax even a small diameter airline.

It's when you need to operate things like an air grinder, or a pressurized sand blaster, some of these can draw 30-40 cfm. That 's where you really need to be concerned about volume.

Also consider how many people are going to use the system at a time. Two people using a steady 7 cfm at the same time, will probably cause a drop in a smaller line. But, intermittently it probably will not be noticed.

 

[SPYDERLK]

Wasn't sure what forum to put this question under but thought this may be the best place. I've decided to run my shop with copper type "L" copper lines. I have 2 questions.

I'll have some runs that are close to 80ft long. My compressors outlet is 3/4". Will I lose pressure or CFM with these long runs? If so will running 1" mainlines help or will the 3/4" compressor's outlet be my limiting factor?

None of the fittings I can find list their letter rating. I know the lines are color coded by rating how are the fittings labeled? Are all the fittings the same rating?

Altho bigger feed pipe is always better, I would not be concerned with pressure loss at that distance with 3/4 tubing unless youre using very high flow ... say above 30CFM. That would take a 10HP compressor to sustain. Most home to 2 man shop use requires 20cfm or less. And I find myself usually using a 3/8 hose from feeder to the tool. A relatively huge pressure loss there, and notice it only with the big toos. Connectors are a big part of pressure loss -- quick connects particularly. Even the straight 3/4 to 3/4 out of your compressor tank is a relatively high loss compared to the tubing itself. At high flow that connection has the loss of ~10ft of like sized pipe. ... but still not all that much at 20 or 30cfm

 

[radioman]

Good choice going with Copper. It's going to be more money, but in the long term, you will never have any problems with it like you will with PVC or iron. Every time I think about doing that, I end up just using air hose.

I have two 100' lengths of air line and a 50 ft line that I keep hooked up to the compressor. With all 250 feet of hose hooked up, I don't notice any loss of pressure or volume. I'm sure it's there, but its not something that is significant or noticable. I wouldn't think that you could tell the difference between a 3/4 inch copper pipe or a 1 inch copper pipe over 80 feet.

Eddie

Same here- except I have 3 lines of 100' and no problem. Before I switched from a small portable hotdog compressor, I had more volume but longer repressurization. Now I have a large upright, I love setup even with a air drill.

 

[Egon]

As an alternative there are air certified plastic lines on the market. No idea as to cost.

 

[TRR]

Here is more information than you want to know about copper pipe. It does identify Type M as suitable for compressed air. And it talks about the effect of different solders on the pressure rating for the pipe and temperature vs. pressure rating. And a lot more:

http://www.copper.org/publications/pub_list/pdf/copper_tube_handbook.pdf