Running long air line to shop?

[X53Gunner]

Ok, going to try and explain my question.
I have two buildings one storage and the other is my shop for reference.
I'm going to put my stand up compressor in the storage building that is 120' away from my shop and plum an airline underground between the two. I'm running a 1/2" pressurized pipe between the two buildings. This pressurized pipe is also in a 2" PVC pipe just for some protection. I'm not worried about any code issue I just want to know what will and will not work. If I"m thinking correctly, If I have 125 PSI at my stand up compressor in the storage building then in theory I should have 125 PSI in my shop via the 1/2" pipe. (i could be wrong) However do I loose volume in any way by constricting it to the 1/2" pipe while using Impact wrenches and such? The thing i'm wondering is if I'm using a impact wrench or larger air tool, for the air to keep up with the initial drop in air from using the tool, do you think I should run the 1/2" pipe into a separate 11 gallon air tank in my work shop to keep the volume going? I know it can't hurt just wondered if its necessary? Sorry for such a long winded question. Please let me know your thoughts on this if you have experience with running longer airlines before. Thanks so much for the help guys!
Scott

 

[shannonw]

i'm no expert on this, but your shop won't be at the same pressure as the compressor due to pressure loss

this is reelcraft doc, so hoses, i imagine hardlines are similiar or maybe slightly different

http://www.reelcraft.com/pdfs/tech_bulletins/TB0001.pdf


So i'm no expert but i expect it's ________ tool requires X cfm at Y psi, if you put a tank that would provide additional volume for a short time but the psi would still be less so the tool would not be working at it's maximum (assuming the psi at the end of the run was below it's maximum)...it would have the volume but not the pressure. But we'll see what the experts say on here

 

[sberry]

There would be a little loss with a big tool, probably affect a 1/2 impact very little and the tank at the end would compensate a little.

All my stuff has a 3/8 hose on it, either a 25 ft fixed whip or a 50 ft hose reel. We got engineers here can tell you exact figures but the 1/2 pipe (this could vary a little depending on type of pipe, steel is quite a bit bigger than 1/2, near 4 times the area of a 3/8 hose),, so figure 3 for fudge factor and error so a couple # loss in between buildings with a 1/2 impact and over 5 down a 25 hose,,, upping the size from building to building would save a pound or so.

How much does a 1/2 gun use anyway,, I forget. The 3/8 secondary hose is too small for a 3/4 gun, it and some sandblasting is the only time I bypass a hose reel with a section of 1/2 hose. Its pretty rare day though, in a home garage not a concern. Body work and painting cars all from 50 ft 3/8 hoses.

 

[X53Gunner]

Ok, thanks for the response's Will continue to watch and see what the consensus is. Maybe one of the Engineers will chime in. I know there are 100' 3/8's Hose people use so i was thinking it shouldn't be to bad running the 1/2" hose 120' or so to the shop. But then will be connected to a 50' hose from there to use around the shop. That's why i thought the extra tank may help. But I'm no engineer just a crazy retired helicopter gunner>>>lol
Scott

 

[sberry]

i'm no expert on this, but your shop won't be at the same pressure as the compressor due to pressure loss.

I am no expert either but this goes up with flow. No flow they are the same, use a little air not much pressure loss, open it wide open lots of loss. Most of the work in small shops doesn't involve wide screaming its lungs out open and not for extended times,, a little loss is usually no big deal.

 

[May Pop]

I run 3/4" buried between my small shop and front garage. At least 75' with no noticeable loss in pressure or volume. The 1/2" seams small to me but that only my opinion. I like the idea of protecting the buried pipe in a pvc sleeve.

Ron

 

[rodm1]

I think you would be ok if not regulated the 120ft. I'm running 50ft of 1/2 hose and its ok there is some drop. You might wont to adjust the cut on psi to be higher sow the shop doesn't drop bellow 90 psi. I would plan for a serge tank just in case.

 

[sberry]

We had a fire 20 yrs ago, burned the shop to the ground and I Mygyver makeshifted some old buildings, a small insulated truck box sitting next to a temp pole with air comp and pressure washer in. I ran 120 ft of old 1/2 pressure washer hose laying across the drive in to a makeshift shop, stuck a filter/ regulator, 2 or 3 ts maybe, hooked up plama and a couple outlets. We kept the water blown out.

 

[shannonw]

i'd think 1/2 should be plenty i run sanders and mini buffers off 3/8 probably 125-150 feet with a 10 footer after that for hours at a time...if i read the chart right that maybe assuming they use 10cfm @90 would be 4psi / 50 foot. So if i pressurized the line to 125 ...at the end of the run i have 113 (i guess).

I don't notice a difference in that or running it right next to the compressor..though technically that distance maybe it's borderline for 3/8 as they recomend 1/2 at that cfm.

 

[sberry]

Look at running power tools on 20A circuits, somewhat similar. An electric drill and a 100 watt lamp doesn't dim it but put a heavy chop saw on and it dims. The saw still works, loses a little power and is even helped a little if you take off the 100 watts. The efficiency loss is minor since you make a few cuts a week. Only in extreme cases would the pipe size difference here matter much.

 

[shannonw]

I am no expert either but this goes up with flow. No flow they are the same, use a little air not much pressure loss, open it wide open lots of loss. Most of the work in small shops doesn't involve wide screaming its lungs out open and not for extended times,, a little loss is usually no big deal.

That's how i read that doc. The psi loss is all dependent on the cfm flow.

 

[sberry]

A 6 inch da probably running 12 or better. You are losing some down this small hose at that distance. Running hi pressure to a regulator would help some, if this was a real regular event might consider some improvement,,, but its obviously working.

 

[X53Gunner]

So do you guys think the Surge tank would help in some of this lose? Or just give me more air storage?
Scott

 

[Nowater]

The buried line will lose pressure due to friction and might add a gallon or two of storage. Tell me the specs on your pipe and I can calculate the storage if you need it. For any given pressure in the storage shop, there will be less pressure where you use it.

I suggest putting a pressure regulator in the working shop.

By the way, the hot pressurized air will lose pressure due to being cooled by the earth and air around the PVC pipe as well. When that air cools, moisture will condense. The water will collect at any low spot and may try to leave that pipe will the same velocity as the air that is pushing it. Might actually be quite dramatic if it exits while you are working!

Is there any way to drain the buried pipe once in a while? I suggest that if the pipe is black iron, that it will rust out on the inside. Then the pressurized air will escape somewhere, hopefully underground, when it fails. Not sure about galvanized, as the water will lay there for a long time. Copper pipe might last the longest. Is there any plastic pipe safe to run under pressure and with the oils that are usually found with compressed air?

 

[sberry]

It will do a bit of both under some circumstances depending on the applied load,, its more of a question of,,, do you need it?

Is there reason to think you will use air at such a rate it isn't going to be sufficient? Are you going too run a 3/4 impact? For rotary tools only a bit more stored energy for the most part.

 

[X53Gunner]

Its a car and bike / fabrication shop so just your typical air tools
Scott

 

[sberry]

Its ok to work on the theory here but as a practical matter to the end user it wont mean a pinch of **** and not worth losing sleep over.

 

[Sureshot]

I ran semi-truck airline from my shop to garage. You can get it in many sizes. I would try it and then see if you need the tank. I ran 1/4" line as I only wanted it for filling tires and occasional air nailer use. I have since added a sand bio-filter system for our water and use it to backwash the sand and it has no issues keeping up. I have about 175'.

If I ever built a house or another acreage that airline would be in every trench to everywhere in the yard.

http://www.easternmarine.com/Air-Brake-Tubing-Bulk-Lengths/

 

[X53Gunner]

sberry that's what I'm after is the end result and if its not enough to worry about then i wont.....just trying to set it up right the first time.
Scott

 

[X53Gunner]

Nowater
Yes i will be able to drain it as it is running up hill to the shop so I'm setting up a water trap with drain in the lower storage barn.
Scott

 

[72Anthony]

How big is your compressor and what type of tools/equipment are you looking to run? Single user or will you have multiple people running tools simultaneously?

 

[X53Gunner]

Single user, Hang on I will go look at the cfm and stuff and report back.
Scott

 

[CNGsaves]

This underground between buildings setup would be ideal for one continuous flexible pipe like RapidAir . . . . yep me of all people said go with RapidAir.

Do it once and build it to last. I'd go with 3/4" or 1" RapidAir inside the 2" PVC between buildings and you'll never have to worry about that segment, except of course draining water, which OP says he has covered on the lower end.

Of course, once the airline system is above ground, it's your call whether you'll stay with RapidAir, or go with copper or black pipe steel !!

 

[X53Gunner]

6HP
60Gal
14.6 SCFM @ 40 PSI
11.1 SCFM @ 90 PSI
125 Max Pressure
Probably not the best but its what I have for right now till I upgrade.
Single user
Mostly body work, paint and fabrication shop.
Scott

 

[HMCFab9]

If you are ever going to sandblast.... go with 3/4" or more, preferably 1".
I have a 7.5 hp / 80 gal / 32.6 CFM compressor & it runs quite a bit while working.
I have about 20' of pipe to my regulator / filter & then to my air hose.
I use it to sandblast & even with a small tip, it runs quite a bit. It will keep up to a D.A. sander or air tools very well, but still kicks in pretty often.
Being in Michigan, i'd worry about water / condensation in the air & very cold air in the winter. (cold air isn't a big deal, but it will make D/A sanders, etc uncomfortable to hold)
I'd add a tank in the shop for a reserve just to be sure. you can pick up an air tank pretty cheap.

 

[X53Gunner]

Hmmmm was just thinking I have a 100 pound LP tank that is like new and I don't use anymore. Wonder if I could just use that as surge/reserve tank. Smell might be an issue but I'm sure I could fill with water to purge it and then fill with a bleach mixture to get rid of the smell.
Scott

 

[rodm1]

You could use that but it will take probably months to years to eliminate the smell. Some of the guys have done it hear. If you can post a list of tools you plan to use that would be helpful. If you plan to paint, sand blast, DA sander no way will it work. The compressor you have on its best day won't work well for those. IMHO you better look for another compressor 5HP or 7.5HP time is money and you are going to need lots of it.

If someone could calculate the drop for you regulate it down to that and try doing some REAL WORK with all of your tools that should give you the answer you need.

When I had a 125psi compressor I never used a reg didn't need it with 50ft 1/2 rubber and 25ft of 3/8 hose the presser drop I believe whose 100psi while running.

 

[OccupantRJ]

Hmmmm was just thinking I have a 100 pound LP tank that is like new and I don't use anymore. Wonder if I could just use that as surge/reserve tank. Smell might be an issue but I'm sure I could fill with water to purge it and then fill with a bleach mixture to get rid of the smell.
Scott

I would go with 3/4 line. You never know what you may need to use later. The smell in a propane tank can be reduced by rinsing with tomato juice. A surge tank would be a plus if you have the room, if not, it could be added later if needed. You need to be able to drain water from it. A friend installed 3/4 PEX underground 100 feet to another building that originally had 3/8 hard pipe that had rusted out after 46 years. The available free flow volume difference is astounding. He has had it in place for about 6 months and is very happy with it.

 

[stonesfan68]

Assuming a straight run of 1/2" SCH40 pipe you will loose about 4 PSIG. If you run a 1/2" hose between the compressor and shop then the pressure drop will be +15 PSIG. The flow rate will remain the same if there are no leaks. I would recommend installing a tank and pressure regulator at the shop where the air tools will be used. Inserting the metal pipe inside of PVC is a good idea to help prevent corrosion.

 

[ABADWILLYS]

you should have cool, dry air to your paint guns being that far away!
will you have to bury that pipe and pcv below frost line? thats 4 feet where i live, i see yourin Michigan, gotta be cold there too

 

[westom]

So do you guys think the Surge tank would help in some of this lose? Or just give me more air storage?

A surge tank will only help in short bursts. Relevant here is not air pressure. Relevant is how much air is consumed by the tools. An experiment will easily determine this.

Get a 100 foot air hose. Connect the tools that might be used simultaneously and a pressure gauge. Turn on all tools simultaneously. How low does the pressure drop? You should know what is 'too low pressure'. The longer the hose, the more pressure will drop from 125. If the drop is too large, then the pipe from compressor to tools would have to be larger.

Some numbers. A 3/4 inch pipe would ballpark to about twice as much airflow as a 1/2 inch pipe. More airflow means less pressure drop.

Even sharp bends can decrease that pressure. Again, to ballpark. A sharp bend in the pipe may be equivalent to 10 feet of pipe. Gentler curves cause less pressure drop. Just a few concepts to better understand the problem or what may only be a fear. Nobody can really answer your question without knowing the airflow demands of each tool and how many tools are being used simultaneously (the numbers).. The above experiment is probably an easiest answer.

 

[X53Gunner]

Ok you guys are awesome! There will be no tools used simultaneously as I'm retired and doing things in the shop by myself. The tools will be Paint Spray Guns, DA sander, Air ratchets, Impact wrenches and so forth was also going to build a Sand Blast Cabinet....However by reading the post by HMCFab9 Looks like I'm going to have to save up for another compressor. I will still be able to plum all the lines and hook this one op for the time being and use it for what I can then when I get the new one just drop it in place and everything will be all set to go..Thanks guys for all the information and help that is why I love this site!!!
Scott

 

[D KRAGER]

So do you guys think the Surge tank would help in some of this lose? Or just give me more air storage?
Scott

Yes this will help. Any time I'm spray painting out in the yard, I set a big air tank out closer to my work area, takes away the pressure drop from the long hose.

 

[kspwski]

I think that you can look at two scenarios to accomplish what you want and provide capacity for the future sandblaster. Option 1, run 3/4" hose and a small tank (your 11 gal) in the shop. Option 2, run 1/2" hose and a larger tank in the shop. Having an aux tank in the shop is going to help in a big way.

For the record, I think that the 1/2" hose and 11 gal aux tank will provide 90% of the performance it seems you need. Maybe you end up occasionally waiting when sandblasting, but no big deal.

It may also be a good thing to put some sort of auto disconnect on the compressor that would power down in case of a leak and the compressor started running for hours. I'm picturing the compressor in a back shed where you don't see it/hear it.

My 2 cents!

 

[westom]

... I set a big air tank out closer to my work area, takes away the pressure drop from the long hose.

Tank does not take away a pressure drop. It simply slows that inevitable pressure drop. How much longer does it take pressure to drop? Same experiment can be conducted with that tank using some air driven devices, a pressure gauge adjacent to those air consumers, and a long hose.

That test is best conducted with one more air driven device than expected. For example, if only one air driven device is to be used, then the test is done with two. A resulting gauge pressure will be always be less than 125 psi but should remain just above a minimum acceptable pressure. Then that line will always provide more than sufficient pressure when using any one air driven device.

Pressure drop may not be harmful when sand blasting. But it might be harmful to workmanship when spray painting.

 

[X53Gunner]

Thanks everyone for the wealth of information. I will put it to good use!
Scott

 

[sberry]

A bigger hose wont hurt especially if it is a hose, it would help even more under demanding loading especially since this is a small low pressure comp, it would add a pinch of poop with an impact for a split second, a real body tool requires 30% more than the comp even makes.

Run your hose hook it up, you can add a tank later. Just do it.Put a 3/8 hose on the end and probably wouldn't need a regulator for a body tool.

 

[X53Gunner]

ok thanks
Scott

 

[sberry]

I had 3 hp 2 stage with 100 gallons of tanks and you can do body work with it especially if a guy is a little thrifty, can manage his time. If you really want to work its not enough, the 5 hp will run a sander steady. The Op is going to have more of a comp issue than a line problem. My single unit system had near double the stored energy.

I have over 200 gallons of tanks, maybe 220 and 300 ft of 3/4 line and some secondary. I have the old 3 as the master and an additional 5 on as backup and ji demand. I finally turned the breaker off to it the other day. It came on once a year blowing some piping down and on rare occasion getting on a sander or wire wheel and to sandblast a couple things. An hour or 2 of run time in the year.

 

[sberry]

The Op seems like a guy setting up a hobby shop as he goes, probably doesn't have extra hundreds hanging out of his pockets he doesn't know what to do with but is retired,,, wants to fiddle and fix some cars. You don't have to toss an extra 300 in the wind every step along the way.

In some sense it would make sense to have adequate electric to make it where needed but putting it out of the way near power is good too. Noise reduction is a plus but you are only going to be able to sand a couple 3 minutes anyway no matter what size line is on it.