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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: David Anderson on December 05, 2011, 10:54:05 AM

Title: air lines for my bus garage
Post by: David Anderson on December 05, 2011, 10:54:05 AM
I am getting close to actually building a bus garage/woodshop for the Eagle and my other Tim the Toolman endeavors.  I was wondering about running some 1/2" plastic lines under the slab and stub up in various places in the shop for compressed air.  My fear is too much moisture accumulating in the lines and going through my tools.   When I built my house 15 years ago I laid about 80' of pvc line under my slab and stubbed up in a couple of places.  It works great but I do get annoying moisture out the blow gun. 

Should I forgo this and just run everything overhead?  Overhead allows placement of moisture trap drip legs.   Underground doesn't.  Any ideas of suggestions?

David
Title: Re: air lines for my bus garage
Post by: desi arnaz on December 05, 2011, 11:01:44 AM
run a 2 inch grey PVC under the floor and then snake a hose inside that,then you don't have to worry about the PVC breaking due to high pressure.
Title: Re: air lines for my bus garage
Post by: RJ on December 05, 2011, 11:02:34 AM
David -

Years ago I ran air lines in my garage, even tho I was working on Corvairs at the time.

I ran all mine overhead, with moisture filters, thus never any gunk in the tools.

Of course the slab was already there when I started. . . but I still would have kept the air lines above ground.

If anything, put hydronic heat in the floor!

FWIW & HTH. . .

;)
Title: Re: air lines for my bus garage
Post by: bevans6 on December 05, 2011, 11:09:50 AM
Well. you probably know that PVC isn't rated for air unless it's buried.  The stories about exploding PCV are legendary...

Black pipe up high and downward stubs with drains is classic old-school.  I don't know why you couldn't use copper with soldered joints.  Thinking out loud, I don't know why you couldn't use 1/2" flex air line from a bus!

Brian
Title: Re: air lines for my bus garage
Post by: luvrbus on December 05, 2011, 11:24:08 AM
Why isn't PVC not rated for air unless buried keep the temp down it does good 600 psi is 600 psi regardless only the temperature will affect the bursting pressure 1/2 in sch 40 pvc is 600 lbs @ 73 degrees the 1/2 cpvc is 100 psi at 180 degrees anything below 180 or 73 degrees will increase the psi ratings


good luck
Title: Re: air lines for my bus garage
Post by: bevans6 on December 05, 2011, 11:40:23 AM
Apparently it can shatter, explode with shards/shrapnel and otherwise become objectionable.  I think there is also an issue with flame resistance/melting.

Anyway - http://www.osha.gov/dts/hib/hib_data/hib19880520.html (http://www.osha.gov/dts/hib/hib_data/hib19880520.html)

With that said, I wouldn't be at all surprised if there are modern "PVC equivalent" products that can be used.  I was just taught that plain old Home Despot PVC like you buy for your water drains and supplies wasn't good to use.

Brian
Title: Re: air lines for my bus garage
Post by: luvrbus on December 05, 2011, 11:50:51 AM
Times and methods of manufacturing PVC since 1972 when that was written Brian, only a Canadian would link us to a OSHA site lol seriously they are using the stuff about for everything now that and poly pipe

good luck
Title: Re: air lines for my bus garage
Post by: Len Silva on December 05, 2011, 11:51:57 AM
I found that same OSHA link (damn gummint regulators), and within that link is this explanation:

QuoteColonial Engineering Inc.
Thermoplastic Piping Systems

To Whom It May Concern:

From time to time, I receive inquiries as to the suitability of using PVC pipe land fittings in compressed gas piping systems. While the benefits of use may be enticing, it is a very dangerous and, in some states, illegal thing to do. For example, MIOSHA (Michigan's branch of OSHA) prohibits the use of PVC plastic in compressed gas systems unless properly encased in steel, cement, or some other approved material. Please check your local and state regulations.

The main problem with using PVC pipe and fittings for compressed gas is not that it spontaneously explodes but that PVC is a brittle material that can be broken or shattered with external force unless properly protected. Compressed gasses can be best described as being analogous to a coiled spring. When a PVC pipe or fitting fails when under stress from compressed gas it literally explodes like a bomb, sending shards of plastic flying several feet in all directions. Liquids, on the other hand, being compressed by only 1/10th of 1% contain very little stored energy. When pressurized systems with liquids fail, the energy is dissipated very quickly, thereby creating a much lower potential for hazard.

Colonial Engineering does not recommend the use of PVC plastic pipe fittings in compressed gas service.

If you have further questions regarding this matter please feel free to contact me directly.

Sincerely,

Jack Roach

That said, I knowingly used PVC in my shop, limited to 125 psi and had no problem.  I ran the first 8 feet or so from the compressor in steel pipe in order to give the air a chance to cool a bit before hitting the plastic pipe.

Title: Re: air lines for my bus garage
Post by: Len Silva on December 05, 2011, 11:55:45 AM
Quote from: luvrbus on December 05, 2011, 11:50:51 AM
Times and methods of manufacturing PVC since 1972 when that was written Brian, only a Canadian would link us to a OSHA site lol seriously they are using the stuff about for everything now that and poly pipe

good luck

I first became aware of the issue when I was doing my shop.  Walking through the Home Depot plumbing section and the boxes of fittings are clearly labeled "not for compressed air".

Pipes carrying compressed air will explode and shatter where the same pipes with water will just split and leak.
Title: Re: air lines for my bus garage
Post by: bevans6 on December 05, 2011, 12:55:08 PM
Well it was written in 1988, not 1972 when the pipe apparently became available, I guess implying that the stuff was OK for 16 years   ;D  Some one probably got killed or maimed by an explosion, that's how these things usually work...   :o

I do think that there are probably modern equivalents that install and look similar to PVC that are OK.  I wouldn't be at all surprised if PEX or a PEX equivalent wasn't rated for low pressure gas.  I shall look and see!

Brian
Title: Re: air lines for my bus garage
Post by: luvrbus on December 05, 2011, 01:00:12 PM
You are seeing SDR21 fittings in those places Len huge difference in PVC fittings I see people use waste pipe fitting on pressure pipe for  water they blow off or break they look the same but the collar part will be longer I use sch 80 fitting on everything it cost a little more most people, never read the glue can either tons of different glue for different sizes and PVC pipe types

.David can use poly pipe if he chooses it made from 1/2 inch to 48 inch they are using poly for high pressure gas lines and gravity flow sewer line it is fused together instead of glue.

I am not afraid of PVC I wouldn't use sch 20 or irrigation PVC or the fittings  
Title: Re: air lines for my bus garage
Post by: bevans6 on December 05, 2011, 01:05:22 PM
And here it is:  http://www.ipexamerica.com/Content/Products/Product.aspx?MarketSegmentId=1&SubMarketId=9&ProductId=93 (http://www.ipexamerica.com/Content/Products/Product.aspx?MarketSegmentId=1&SubMarketId=9&ProductId=93)

It's the PEX with the aluminium layer.  Sold as Duratec Airline.

I just use great heaping rolls of 3/8" or 1/2" air hose.  Simplest, dumbest, most labour intensive solution, but that is so me... ;D

Brian


Title: Re: air lines for my bus garage
Post by: luvrbus on December 05, 2011, 01:28:41 PM
Brain, I see that place sells ABS for air lines also I don't have PVC I have 1/2 steel but with todays prices on steel pipe PVC would be my choice fwiw

good luck
Title: Re: air lines for my bus garage
Post by: Len Silva on December 05, 2011, 01:42:39 PM
Quote from: luvrbus on December 05, 2011, 01:00:12 PM
You are seeing SDR21 fittings in those places Len huge difference in PVC fittings I see people use waste pipe fitting on pressure pipe for  water they blow off or break they look the same but the collar part will be longer I use sch 80 fitting on everything it cost a little more most people, never read the glue can either tons of different glue for different sizes and PVC pipe types

.David can use poly pipe if he chooses it made from 1/2 inch to 48 inch they are using poly for high pressure gas lines and gravity flow sewer line it is fused together instead of glue.

I am not afraid of PVC I wouldn't use sch 20 or irrigation PVC or the fittings  

Not to be overly argumentative but I was clearly looking at Schedule 40 PVC glue in fittings, not DWV or SDR21.

I chose to use them anyway in spite of the warnings but it was an informed choice.  That's all we are looking for here.
Title: Re: air lines for my bus garage
Post by: robertglines1 on December 05, 2011, 01:50:21 PM
I have pvc in shop for 20 yrs.  that said    put a piece in freezer for couple hrs then drop it on the floor.   Hasn't been a problem for me. My air lines are fastened down. rubber from outlets.    Bob
Title: Re: air lines for my bus garage
Post by: luvrbus on December 05, 2011, 02:37:40 PM
If you read the on fitting it will be a DS number and PVC1 sch 40 is the thickness that is all those fittings are junk at HD and Lowes they are not rated as much as the pipe

good luck
Title: Re: air lines for my bus garage
Post by: gus on December 05, 2011, 03:05:00 PM
My guess is the quality control for PVC is not that strict since it is produced in such large quantities, so an occasional weak bad spot can sneak through. Much less likely to happen with metal of softer plastic.

Also, some water could freeze in PVC and it sure doesn't take much ice to break it since it is so brittle.
Title: Re: air lines for my bus garage
Post by: Busted Knuckle on December 05, 2011, 03:11:29 PM
Well here I go again being a bad apple! In our 3 shops we were in in Union City 2 were plumbed for air in PVC before we rented them! The 3rd I plumbed myself and used PVC as well.
The shop we bought here in Huntingdon, TN was already plumbed when we moved in. Guess what it's plumbed in with?
So I know for a fact I've been using air systems plumbed with PVC for 12 yrs and ain't no tell'n how long any of the shops had been that way before I used them.

I see no problems with it as long as the pressure is kept @ 150 or so. (really why would any of us need more than 150psi anyway?)
;D  BK  ;D
Title: Re: air lines for my bus garage
Post by: Boomer on December 05, 2011, 03:38:03 PM
I agree with Brian.  In '97 I built a new 10k sq ft bus shop and plumbed the air system with OSHA approved plastic pipe and fittings from Harrington Industrial Plastics, Portland.  Sailed right through the inspections and was real easy to work with.  Don't remember much about the pipe except it was green and I believe a type of ABS.  Check out www.harringtonplastics.com (http://www.harringtonplastics.com) for all the industrial air piping and tubing stuff.  If I was not concerned about meeting regs and codes, or possible exposure down the road, I would use black iron pipe if it was cheaper. Just IMO.
Title: Re: air lines for my bus garage
Post by: David Anderson on December 05, 2011, 03:58:04 PM
Thanks for the replies.  I'm not afraid of PVC since I've had it below grade under my house slab for 16 years and I use it at my car wash business above grade for 26 years, so it does work and work well.  However, I fight the moisture problems.  It gunks up my solenoid valves at the car wash.  I've tried installing drip legs, etc. and it does help, but still annoying.

David
Title: Re: air lines for my bus garage
Post by: neverlearn on December 05, 2011, 04:49:25 PM
I am on year 5 of soldered copper in my garage with a constant 175 psi in it.  I mounted mine overhead, on a pitch, with low-point traps and drain valves.
After going through all the work of copper, I saw a city maintenance garage using flexible plastic (of some sort) lines with push-in fittings.  The lines and fittings looked like a larger version of that which came with my kenmore reverse osmosis under-sink water filter.  I bet it took them less time to run air in that entire maintenance facility than it took me to hook up my residential garage.
Title: Re: air lines for my bus garage
Post by: busguy01 on December 05, 2011, 05:17:36 PM
Built my "toy barn in 2002. Poured a slab outside and put a shed up with compressor inside of it. Ran a 2" flex line to building. Installed 2" sched 80 PVC in floor to many/several places. Still working good with no moisture issues. Also all the noise is outside! Did NOT connect shed Slab to shop slab.
Just my way -- your mileage may vary
JimH
Title: Re: air lines for my bus garage
Post by: fraser8 on December 05, 2011, 07:17:37 PM
I got a bunch of part rolls of PEX pipe from a local plumber who does hot water in floor heating. It works great for air and handles the pressure, I have two runs that are almost a 100'. PEX fittings and and squeeze rings fit tight. Works for me and it was almost free.
Title: Re: air lines for my bus garage
Post by: JackConrad on December 06, 2011, 05:10:17 AM
I plumbed our shop using schedule 80  PVC (rated for 300 PSI) about 15 years ago, no problems so far. Main line is overhead with several drops attached to the walls. Each drop has a moisture trap about 12" below the quick connect fitting. Also a moisture drain on the storage tank which started it's life as an air starter tank on a NJ Eagle.  My compressor kicks out at 130 PSI.  Jack
Title: Re: air lines for my bus garage
Post by: David Anderson on December 06, 2011, 11:16:07 AM
Looks like moisture traps around the fitting ends are the way to go.  Thanks for the ideas.

David
Title: Re: air lines for my bus garage
Post by: neverlearn on December 12, 2011, 07:25:27 AM
Just saw this today.  It looks very similar to what I saw in use in that City maintenance facility:

http://www.northerntool.com/shop/tools/product_200367525_200367525?cm_mmc=Housefile-_-cm_cat=3DAY2FGC_121211-_-cm_pla=STANDARD-_-P20 (http://www.northerntool.com/shop/tools/product_200367525_200367525?cm_mmc=Housefile-_-cm_cat=3DAY2FGC_121211-_-cm_pla=STANDARD-_-P20)

(https://busconversionmagazine.com/forum/proxy.php?request=http%3A%2F%2Fwww.northerntool.com%2Fimages%2Fproduct%2Fimages%2F490500_lg.jpg&hash=16547b5900ffdb10b026258d3a58dc920c9c50e3)
Title: Re: air lines for my bus garage
Post by: kaptar on December 12, 2011, 10:28:11 AM
Stay with the line rated for air. Schedule 80 pvc can hold the pressure but if it ever does blow due to impact of weak fitting it will throw shrapnel like a grenade. Be safe and follow the codes to protect yourself.
Title: Re: air lines for my bus garage
Post by: junkman42 on December 14, 2011, 06:20:59 AM



there is a pvc material that is grey in color I do not remember the designation but is normally used with threaded fittings it is impervious to oil and does not degrade from most chemicals.  I used flex dot tubing like many of our buses use and I can tell You that the mice eat it faster in my shop than in the coach!  I also found that squirrels eat it also.  I plumbed air out to My pole barn and noticed the compressor running one day and discovered the lines or drops on the supports had been eaten!  Maybe I need a life time supply of dryer sheets!  Just My take.  John L
Title: Re: air lines for my bus garage
Post by: RJ on December 14, 2011, 08:15:09 AM
Quote from: junkman42 on December 14, 2011, 06:20:59 AM
. . .there is a pvc material that is grey in color. . .

John -

The grey stuff I use is called CPVC, and is Schedule 80 rated.

FWIW & HTH. . .

;)
Title: Re: air lines for my bus garage
Post by: Ericbsc on December 14, 2011, 08:21:12 AM
Our shop is 15k sq. ft. When we built it we ran air and power under the slab. As far as I know EVERY ONE of those have either been broken off at the floor, dragged, or bent flat by forklifts or what ever device of mass destruction the guys choose. I have everything overhead now.
Title: Re: air lines for my bus garage
Post by: junkman42 on December 14, 2011, 01:43:17 PM
RJ, You are corrrect, I am aged and slow I could not remember!  Will We see You at Aarcadia this year?  Regards John L
Title: Re: air lines for my bus garage
Post by: RJ on December 15, 2011, 12:11:23 AM
Quote from: junkman42 on December 14, 2011, 01:43:17 PM
RJ, You are corrrect, I am aged and slow I could not remember!  Will We see You at Aarcadia this year?  Regards John L

John -

Sadly, I'm going to miss Arcadia this year, have spent the travel budget on a trip to Kelowna, BC to be with the grandkids.

Tried to make it a FAT > YLW > TPA (or MCO) > FAT airport tour, thereby killing two stones with one bird, but alas, the airlines decided to price the journey such that only Bill Gates could afford it this year.  (Even if he used his own LearJet. . .)

Seems like every year that |@n, Buswarrior and Luke make it down, I don't. . .  Maybe Murphy has something to do with it?  :(

FWIW & HTH. . .

;)