Mexstan

Have just been asked to plumb a workshop for compressed air and am looking for opinions from the opinionated folks here.

They have a 5 HP compressor that I think I will mount on the wall to provide more floor space. Working pressure will not be over 150 psi and more likely about 100 psi. Going to need 200 - 250 feet of line with maybe 6 outlets. I know how to plumb a compressed air line with the water drains etc, but my question is what material is best for the line? Leaning towards copper pipe, but could consider black or galvanized pipe too. Definitely going to stay away from any 'plastic' type of pipe. Am allergic to shrapnel.

If I use copper pipe, is type L safe enough? Type K I am sure is OK, but is more pricey. Not even going to consider type M. Of course, all the connections will be soldered.

Equipment used will be mainly nail guns and spray guns. Most of the time it will only be one tool at a time, so air volume will not be that high. Considering a 250 foot run, thinking that maybe I should use 3/4" pipe for the manifold and then 1/2" for each outlet.

Cost is a big factor as these folks do not have much money (an orphanage) so want to do it as cheap as possible while still keeping things safe and with low future maintenance. Don't want rusty air like is possible with black iron. Have already bought a few HF air regulators and filters.

Any suggestions will be appreciated.

sherod

I still use hoses, but my best friend has his entire shop plumbed with schedule 40 PVC. I have used every bit of pressure his system will provide. He has a 40 gallon and a 60 gallon plumbed in different areas. We have never had a failure or leak in the PVC. Someone smarter than me may provide the PSI rating for it, but in my experience, it has worked fine.

Justwannabeme

tools run at 45-90cfm pvc 3/4 for that run will have to pressure up to 120lbpsi. 140ppsi limits out the schd 40..... I am a hose fan. predictable.

j_martin

FYI, PVC is not allowed above 3/4" and 40 PSI. The reason is that the failure mode is explosion, and the flying shards can be deadly.

I saw a section of 6" schedule 80 fail at 100 lbs. Pieces flew a hundred feet or so. Maintenance chief was going to replace it with more plastic till I put a copy of the OSHA regs on his supervisors desk. They put in steel, and dug up several hundred feet of buried plastic and replaced it with steel.

Type M copper is good for several hundred pounds working pressure. Use 95/5 or silver solder for the joints. 50/50 is a little on the weak side. Threaded steel pipe is the usual material used.

The whole pipe acts as an accumulator, so you don't need as large a size as you'd think. 3/4" with 1/2" drops should be plenty for up to a dozen hand tools. You might need larger for a 1" air wrench or something like that.

sherod

I knew someone would have the exact answer. Thanks from my end J!

Mexstan

Thanks for the answers so far. Good info. Will be starting on this job towards the end of the month and need to have it finished before the end of August.

Justwannabeme

I was reading JM's and thought I said that....till I read a "1" was put in there by a dummy. yes to confirm 40 is the limit. steel has too many pressure variables with condensation and HOSE IS LOWER COST!!!! but not teenager proof.

snicker

Stan, I should just live at the orphanage. I'd be used to it. lol

Colo_River_Ram

I used galvanized on my air manifold. My concern with plastic or rubber is the flash fire effect it could create if a fire ever broke out. I use 1" on the main manifold and 1/2" for the feeder pipes. I do run big impact guns at times with my setup though. keep in mind future needs and use a "T" or a Cross instead of collars and plug the unused ports. It will make things a lot easier to add to in the future.

Have your horizontal runs slightly off level and put a drain valve on the low end to remove moisture. Keep in mind most air tools are recommenced at no more than 90 psi and regulate accordingly. If you tie a hose reel into the system have a quick connect coupler on the feed hose to it or a shut off valve so it can be quickly isolated if / when a hose breaks.

A tank tied into the other end of the manifold will give you more volume and cut down on motor startup surges to your electrical grid that you have noted in the past. Drain the moisture out of your tanks / manifold daily or as needed to prevent things from rusting as you noted in your first post.

Mexstan

JWBM, this place with the approx 80 kids they have there tends to break everything, so whatever I do it is necessary to think about the unskilled using things and how to make it teenager proof.

JWBM, come on down and live at the orphanage for a while. There is a place for you to live. That place could really use your talents. In fact, if anybody wants a break, or a 'vacation' of a different sort, come on down and give a hand. There are frequent work teams that come down to help. Most of these groups come from churches, but occasionally there are individuals or couples that come down for 7 - 10 days or so to help. A work group of 16 from Canada just left and a new group of 20 youth is arriving on Friday for 10 days. This next team will also have a mechanic, so he will be changing the transmission on an old Ford E350 15 pax van. Some of this new group will be laying paving stones, another will be painting, another will be doing carpentry work and the list goes on and on.
Everybody, come on down. This place really needs your help.

Mexstan

All good info. This place does not use any impact guns, but maybe could do so in the future, so my plan is to keep that in mind. The more I think about this, the more I think that I am going to use 3/4" copper for the long horizontal runs. It is very easy to plumb, plus as the air is not in constant use, there is less chance of accumulated water causing rust. Do intend to run the large horizontal line at an angle towards the end. All drops will go vertical before going down to keep as much moisture out of the drops as possible. Good idea about the tank at the end and had not considered that. Now need to find a cheap, small tank.

Scotty

Was one of the folks that came in the group of 16 named Art?

j_martin

I would install the main line so it slopes slightly downward to a T, drop from the T with a drip T and drain below the quick connect. Main continues onward, slightly upward, then downward (crowned, if you will) to the next T, etc. The slope needs to be very little. Just enough to see it if you look real close. Any more doesn't matter, thus you could hit a drop, then go upward and over an obstruction.

You want the water to go to collection points and be removed, not stay in the line indefinitely.

First drain could be an automatic one as it will get the most water, the rest could just be manual petcocks.

Any time you compress air, you squeeze the water out of it. Everyone has driven into a low spot with clear saturated air in it, and had their windshield instantly fogged over. That's what is happening, only with 6-10 times compression, it's much more. The heating of the air helps it to hold some of the water, and as it cools off going down line, it lets go of some more water. Thus no matter what you do unless you install a refrigerated drier, it'll always tend to be a bit wet.

Mexstan

Don't remember any Art, but have met - and promptly forgotten- so many folk that have come down to help. All the work crews recently have been from the Vancouver area.





Will do my best to ensure that no water stays in the line. Thought about a refrigerated dryer, but decided against it. Will be using a desiccant dryer next to the compressor and that is all.

signature600

Stan,

My shops are all plumbed in Copper. We use them daily, and the compressors are set to shut down at 165psi. 18,000 sq ft farm dealership shop.

Here's how ours are plumbed.

From compressor's 2" bung to 2" copper through a stainless flex coupler. That 2" header runs the 80' width of our shop, with a 1" line coming off at each end running down the wall. The drops down to the hose connections are all 1", bushed down to 1/2" couplers to 3/8" hoses. Each hose coupling is teed off, with a drain extending down about another 12" at the bottom of each connection.

Our other shop is similar, only without the 2" header. We just used 1" throughout as we connected the two buildings together by extending the 1" line in the old shop to the new.


I have 20 mechanics working daily in the shop, using impacts and assorted air tools, as well as 2 guys cleaning up machines most days using air wands to blow off the big stuff before they start washing.


The copper costs more as you well know, but in the 13 years we have been in the old store, we have had 1 spot crack that was outside, and the drain had froze. I don't forsee any other issues in the next 13, as we have that particular issue taken care of now.


Good luck.
Chris

6cylinders

Black iron pipe, but then I'm a pipe fitter

How I plumbed it may not makes sense but it did to me

I "T"d it right away with valves,one run along the wall with an oiler at the start
and outlets-every 8 feet.
The other run goes through a drier for painting
that is just before the one outlet .