Shop Floor Talk  

Go Back   Shop Floor Talk > Welding and Metalworking Forums > Shop & Safety

SFT Search:   
Reply
 
Thread Tools Display Modes
  #1  
Old 05-10-2009, 12:26 PM
Lu47Dan's Avatar
Lu47Dan Lu47Dan is offline
Connoisseur of Old Iron
 
Join Date: Mar 2006
Location: N/W Pa.
Posts: 5,971
Default Thoughts on copper tubing for compressed air piping .

This thread is not meant to start arguments over which is better , copper /steel/pvc/or pex , but to give the reader a better understanding of planning and installing copper tubing in an air system .
Planning the system .
In planning the layout of the system there are a lot of variables , length of runs , air demand of existing and future tools & equipment , ceiling height and shape , ,multiple users , and how to mount the tubing .
Length of Runs .
This factor ties directly into the sizing the tubing , the longer the total run the larger the main size should be . In a 24' X 24' two stall garage you can get close to 100' of tubing up just by putting in a "G" shaped main to have "convenience" connections around the perimeter of the building .
When the building size increases the total run length also increases . I started out to put in air lines in a friends 40' X 60' shop . It originally was only supposed to be along the back wall and be black iron pipe . What it turned into was a totally different animal .
After installing the compressor inside the shop and having to wait for him to save the money for the pipe and fittings , two months of having the compressor running inside the shop was enough for him . It was decided that the compressor had to be moved outside , which was done by adding a 6' X 8' shed onto the building for the compressor .
Once the compressor was set up for the second time , and the piping run into the shop , the wait to do this job started again . Once he had the money for the pipe and fittings to do the back wall , he wanted to add a air connection between the overhead doors so he could pull up outside them to air up tires without dragging 100' of air hose from the back of the shop . Once that was added in to the total run of just the mains we had added approximately 80feet of 1/2" copper to the length of the mains .
Being leery of that much main line in 1/2" copper , the main size was increased to 3/4" copper . It would have been better to have known from the start that he wanted a air chuck between those doors , but use taught him better than I could explain that to him . In the end he now has a complete loop system in his shop with regulators on each drop .
This system has approximately 230 feet of 3/4" copper and more drops then you can shake a stick at .
What do you ask , does this story have to do with planning a system ?
The moral of this story is , that plans change with time and experience .
Sizing the main will be the next installment in this series .
Dan
__________________
Tools to Men are like Shoes to Women , you can never have too many !!
Used diesel engines are an adventure anyway you look at them !!
Miller XMT-304 Multiprocess
Miller 10-E Wire Feeder
Miller Spectrum 2050 Plasma Cutter
Hobart AC/DC stick welder
Hobart 175 Mig
Craftsman O/A set
Turbo torch and B-tank
Reply With Quote
  #2  
Old 05-10-2009, 01:01 PM
moe1942's Avatar
moe1942 moe1942 is offline
Voice of Experience
 
Join Date: Jun 2004
Location: Alexandria, Louisiana
Posts: 10,957
Default

Now Dan you know this isn't a fun thread til someone mentions PVC....:evil

Carry on Dan..
__________________
Don't pick a fight with an old man. If he is too old to fight, he'll just kill you... John Steinbeck

"If we ever forget that we're one nation under God, then we will
be a nation gone under". ~Ronald Reagan

We should have picked our own cotton...

I love my women hot and my beer ice cold..
Reply With Quote
  #3  
Old 05-10-2009, 01:20 PM
Lu47Dan's Avatar
Lu47Dan Lu47Dan is offline
Connoisseur of Old Iron
 
Join Date: Mar 2006
Location: N/W Pa.
Posts: 5,971
Default Sizing the mains

Sizing the mains
In sizing the mains in a Compressed Air Piping System I am prejudiced against 1/2" copper tubing . It has more restriction then 3/4" copper tubing . It is fine for drops and drip legs but I frown on using it for mains . Also it has limited future expansion possibilities . There are various formulas out there that will tell you when you have reach the flow limit of a certain sized tube but they are way too complicated for this discussion .
In that I mean you put up 1/2" mains for your 3Hp compressor and they work swell for inflating tires and running a impact once in awhile , but a few years later you get a killer deal on a 5hp compressor and want to add air hungry equipment like a bead blast booth , pot sandblaster , etc . The 1/2" lines become problematic . with a pot sandblaster you are probably running at least 50' of 3/8" hose to get it away from the shop . The combined total of the main and the hose are more like 100' . Adding length to any air line adds resistance to it .
In the long run starting with 3/4" copper tubing makes monetary sense . You purchase the tubing once .
Drops
Sizing drops , all drops are not created equal . For standard air tools and air nozzles a 1/2" drop will be more then adequate , for air hungry applications a 3/4" drop works better . In my own shop I run dedicated a dedicated air chuck for my bead blast booth with another air chuck to run air tools from . This saves wear and tear on chucks and also saves time when I need to do a quick blast job .
Drip legs . when installing drip legs I add a valve above the leg and about 12" below the tee for the air chuck . The drip leg is usually 12" long or long enough to stop just inside the height of a five gallon bucket . The valve is operated then closed to send any condensate into the drip leg . There are a few ways to terminate a drip leg in a copper system , one a C X MNPT and a cap , a C X FNPT fitting with a plug or a C X FNPT fitting with a petcock .
When selecting plugs and caps for the drip leg , buy brass and used teflon tape on the threads.
I prefer C X FNPT fittings with a plug .
  1. C = Copper tubing size
  2. MNPT = Male threaded
  3. FMPT = Female threaded
  4. F = Fitting sized that end
The next several installment will be on fitting terminology , or how not to look like and idiot while purchasing copper fittings. .

Moe , I am figuring on several hijacks before this thread is finished .
__________________
Tools to Men are like Shoes to Women , you can never have too many !!
Used diesel engines are an adventure anyway you look at them !!
Miller XMT-304 Multiprocess
Miller 10-E Wire Feeder
Miller Spectrum 2050 Plasma Cutter
Hobart AC/DC stick welder
Hobart 175 Mig
Craftsman O/A set
Turbo torch and B-tank

Last edited by Lu47Dan; 02-06-2010 at 08:46 AM.
Reply With Quote
  #4  
Old 05-10-2009, 02:23 PM
moe1942's Avatar
moe1942 moe1942 is offline
Voice of Experience
 
Join Date: Jun 2004
Location: Alexandria, Louisiana
Posts: 10,957
Default

Quote:
Originally Posted by Lu47Dan View Post
Sizing the mains
In sizing the mains in a Compressed Air Piping System I am prejudiced against 1/2" copper tubing . It has more restriction then 3/4" copper tubing . It is fine for drops and drip legs but I frown on using it for mains . Also it has limited future expansion possibilities . There are various formulas out there that will tell you when you have reach the flow limit of a certain sized tube but they are way too complicated for this discussion .
In that I mean you put up 1/2" mains for your 3Hp compressor and they work swell for inflating tires and running a impact once in awhile , but a few years later you get a killer deal on a 5hp compressor and want to add air hungry equipment like a bead blast booth , pot sandblaster , etc . The 1/2" lines become problematic . with a pot sandblaster you are probably running at least 50' of 3/8" hose to get it away from the shop . The combined total of the main and the hose are more like 100' . Adding length to any air line adds resistance to it .
In the long run starting with 3/4" copper tubing makes monetary sense . You purchase the tubing once .
Drops
Sizing drops , all drops are not created equal . For standard air tools and air nozzles a 1/2" drop will be more then adequate , for air hungry applications a 3/4" drop works better . In my own shop I run dedicated a dedicated air chuck for my bead blast booth with another air chuck to run air tools from . This saves wear and tear on chucks and also saves time when I need to do a quick blast job .
Drip legs . when installing drip legs I add a valve above the leg and about 12" below the tee for the air chuck . The drip leg is usually 12" long or long enough to stop just inside the height of a five gallon bucket . The valve is operated then closed to send any condensate into the drip leg . There are a few ways to terminate a drip leg in a copper system , one a C X MNPT and a cap , a C X FNPT fitting with a plug or a C X FNPT fitting with a petcock .
When selecting plugs and caps for the drip leg , buy brass and used teflon tape on the threads.
I prefer C X FNPT fittings with a plug .
  1. C = Copper tubing size
  2. MNPT = Male threaded
  3. FMPT = Female threaded
  4. F = Fitting sized that end
The next several installment will be on fitting terminology , or how not to look like and idiot while purchasing copper fittings :evil: .

Moe , I am figuring on several hijacks before this thread is finished .


Dan I just couldn't help myself. Want me to delete that???
__________________
Don't pick a fight with an old man. If he is too old to fight, he'll just kill you... John Steinbeck

"If we ever forget that we're one nation under God, then we will
be a nation gone under". ~Ronald Reagan

We should have picked our own cotton...

I love my women hot and my beer ice cold..
Reply With Quote
  #5  
Old 05-10-2009, 08:14 PM
Team DeSade's Avatar
Team DeSade Team DeSade is offline
Elite Member
 
Join Date: May 2005
Location: Acworth, Ga.
Posts: 1,124
Send a message via AIM to Team DeSade
Default

Thanks for the info Dan. I'll be following this one.
__________________
---------
Terry
Reply With Quote
  #6  
Old 05-11-2009, 08:06 AM
terry lingle's Avatar
terry lingle terry lingle is offline
Something's Fishy ...
 
Join Date: Aug 2004
Location: Birch Island, BC, Canada
Posts: 5,278
Default

There are some neat tricks that I use when doing an air distribution system.
First where possible I run a ring around the perimiter which has the same effect as using a larger pipe size because the air comes to each drop via both pipes.
Second I like to add a second air reciever in the middle of the loop ( the point furthest from the compressor). As long as it is set up to be self draining it is an install and forget thing. It adds no moisture to the system but again makes air delivery to the drops much better. I generaly match the size of the main reciever where possible.
Third I make it a point to get the air as dry as possible before it gets to the storage /distribution part of the system.
__________________
Life beats the alternative hands down.
Reply With Quote
  #7  
Old 05-11-2009, 10:12 AM
Lu47Dan's Avatar
Lu47Dan Lu47Dan is offline
Connoisseur of Old Iron
 
Join Date: Mar 2006
Location: N/W Pa.
Posts: 5,971
Default Copper tubing , fittings and fitting terminology

Copper Tubing & Fitting Terminology :
Copper tubing is measured by internal or "nominal" dimension , in other words a 1/2" copper tube measures 5/8" on the outside diameter .
  • Nominal - Actual
  • 1/2" - - - - -5/8"
  • 3/4"- - - - - 7/8"
  • 1"- - - - - - 1-1/8"
Copper tubing that is generally available ranges in size from 1/8" to 2" . It is available up to 8". DWV tubing and fittings should not be used in a pressurized system as SOP . DWV is short for Drain , Waste , Vent .
There are several types and grades of copper tubing available on the market today
Types include stick copper and coiled copper ;
Stick copper can be purchased in two hardness's , as drawn or drawn (hard) and annealed ( soft ) , drawn copper is usually what you find at hardware , home and plumbing supply stores in the stick form . In this thread , drawn stick is what we will be discussing .
Coiled copper at the hardware , home and plumbing supply store will most likely be annealed , annealed copper is soft and bends fairly easily and is mainly used for installations that require no joints when it is installed . One example of this would be a water line from the house to the water main , another would be a water line under the concrete floor of your garage , no joints equals no leaks (in theory) . Exposed piping can be done with coiled but hard drawn stick tubing ends up looking nicer than coiled does .
Grades of copper include K , L , M, DWV, ACR , And the Medical Gas Grades . We will concern ourselves with K , L , and M
K - copper is the heaviest of these three grades .
L - copper is the standard weight
M - copper is the lightest weight copper
Each grade of copper has an identifying color code for it .
K - Green lettering and stripe .
L - Blue lettering and stripe .
M - Red lettering and stripe .
When using copper tubing for air lines K would be the best choice , but L will work fine .
Fitting Terminology
Copper fittings come in two types , water and drainage , and in wrought and cast copper , and copper alloy pressure fittings .
If the copper fitting is designed for drainage do not use it in a pressurized system .
Fitting ends are classified as copper or fitting ;
Copper (C) the bell of the fitting slips over the outside diameter of the tubing .
Fitting (F) will insert into the bell of a standard C X C fitting
The best example of this is a street elbow (image 1) .
All copper fittings are designated this way
Couplings & Related Fittings
Couplers are the simplest fitting in use today , there are two types straight (my term) and reducing couplings ,
Straight couplings join two tubes of the same type , but are available with or without stops . Stops do what it sounds like , they stop the insertion of the tube at a set point in the fitting .
A coupling without stops is used when a repair or addition of a fitting is required , it can be slid back onto the tubing to allow for easier installation of the repair piece or fitting then slid over the joint . Care must be exercised when doing this to insure that the tubing ends are cover by the coupling equally . This usually means marking one or both tube ends before the coupling is slid in place .
Couplings are C X C ------ 1/2" X 1/2" (image 2)
Reducing Couplings do just that reduce from one pipe size to a smaller on in a straight line .
They are C X C ----------3/4" X 1/2" (image 3)
Bushing reduce the size of a fitting , there are two types .
Bushing and Flush bushings .
Bushings use a fitting end to fit into the bell of another fitting to reduce its size without a piece of tubing between them . This eliminates one joint that would need solder and one possible leak point . (image 4)
Flush bushings are inserted into a bell of a fitting to do the same thing as a regular bushing but end up flush to the end of the bell . (image 5)
More tomorrow. Dan
Attached Thumbnails
Click image for larger version

Name:	copper-fitting-90-street-elbow.jpg
Views:	933
Size:	11.4 KB
ID:	45687   Click image for larger version

Name:	copper-fitting-coupling.jpg
Views:	636
Size:	9.0 KB
ID:	45688   Click image for larger version

Name:	copperfitting-reducing-coupling.jpg
Views:	625
Size:	8.5 KB
ID:	45689   Click image for larger version

Name:	copperfitting-bushing.jpg
Views:	651
Size:	9.6 KB
ID:	45690   Click image for larger version

Name:	copperfitting-flush-bushing.jpg
Views:	665
Size:	8.2 KB
ID:	45691  

__________________
Tools to Men are like Shoes to Women , you can never have too many !!
Used diesel engines are an adventure anyway you look at them !!
Miller XMT-304 Multiprocess
Miller 10-E Wire Feeder
Miller Spectrum 2050 Plasma Cutter
Hobart AC/DC stick welder
Hobart 175 Mig
Craftsman O/A set
Turbo torch and B-tank

Last edited by Lu47Dan; 05-17-2009 at 11:28 AM. Reason: To hilite the coupling section
Reply With Quote
  #8  
Old 05-11-2009, 10:44 AM
Lu47Dan's Avatar
Lu47Dan Lu47Dan is offline
Connoisseur of Old Iron
 
Join Date: Mar 2006
Location: N/W Pa.
Posts: 5,971
Talking

Moe , no , maybe it will be enough that it was mentioned .
Terry , glad you are interested .
Terry Lingle , a Loop or ring main is the best system as you say it allows air to flow through both sides to a single drop , but it also has the benefit of allowing another device to be used without serious reduction to a downstream device up to the rated CFM of the compressor . At least in theory .
I will cover this more later but I also pitch the main to a drop that is basically a drip leg if the system has or does have a water problem . Adding a receiver to the system equal distant would help with heavy intermittent use .
Dan
__________________
Tools to Men are like Shoes to Women , you can never have too many !!
Used diesel engines are an adventure anyway you look at them !!
Miller XMT-304 Multiprocess
Miller 10-E Wire Feeder
Miller Spectrum 2050 Plasma Cutter
Hobart AC/DC stick welder
Hobart 175 Mig
Craftsman O/A set
Turbo torch and B-tank
Reply With Quote
  #9  
Old 05-12-2009, 09:56 AM
Lu47Dan's Avatar
Lu47Dan Lu47Dan is offline
Connoisseur of Old Iron
 
Join Date: Mar 2006
Location: N/W Pa.
Posts: 5,971
Default Fitting Terminology , Elbows and related fittings .

Elbows
There are three types of ninety degree elbows commonly available , the "standard" elbow , a street elbow , and the reducing elbow .
"Standard" Elbow
This is the regular 90* elbow that joins two pieces of copper tube of the same nominal size , it is used to turn corners , get around obstacles , from swings , and expansion loops in long runs . They are C X C
Reducing Elbows
These reduce the size of one of the legs , these fittings eliminate the need for a reducing coupling or a reducing bushing , thus eliminating extra solder joints . The fewer joints the less potential for leaks . They are C X C
Street Elbows
These are used to reduce the center to center distance to get a turn in the piping where space is tight . One end is nominal size , and the other end is belled to accept nominal sized tubing . They are C X F .
45* Elbows
There are two types of forty-five degree elbows commonly available , "standard" 45* elbow and street 45* elbow .
The "standard" 45* elbow is used mostly to make offsets in the piping system . I my opinion a 45* offset looks better then one made out of 90* elbows , but there is a time and a place for both types of offsets . They are C X C
Street 45's are used in the same way but are used directly out of a fitting . They are C X F
Related Fittings
There is a whole host of related fittings , but the majority of them are little use in a compressed air system . To name a few , drop ear ninety , Hyset elbows , these come in various designs mostly with female threads for attaching shower heads and the like .
  1. Elbow
  2. Reducing elbow
  3. Street elbow
  4. 45* elbow
  5. Street 45
Tomorrow on to tee's
Attached Thumbnails
Click image for larger version

Name:	copperfitting-90-elbow.jpg
Views:	607
Size:	10.2 KB
ID:	45763   Click image for larger version

Name:	copperfitting-reducing-90-elbow.jpg
Views:	612
Size:	8.7 KB
ID:	45764   Click image for larger version

Name:	copper-fitting-90-street-elbow.jpg
Views:	554
Size:	11.4 KB
ID:	45765   Click image for larger version

Name:	copperfitting-45-elbow.jpg
Views:	561
Size:	7.9 KB
ID:	45766   Click image for larger version

Name:	copperfitting-45-street-elbow.jpg
Views:	582
Size:	7.7 KB
ID:	45767  

__________________
Tools to Men are like Shoes to Women , you can never have too many !!
Used diesel engines are an adventure anyway you look at them !!
Miller XMT-304 Multiprocess
Miller 10-E Wire Feeder
Miller Spectrum 2050 Plasma Cutter
Hobart AC/DC stick welder
Hobart 175 Mig
Craftsman O/A set
Turbo torch and B-tank
Reply With Quote
  #10  
Old 05-12-2009, 12:33 PM
Paychk's Avatar
Paychk Paychk is offline
Project Phoenix
 
Join Date: Jun 2004
Location: Junction City, OR
Posts: 2,253
Default

Dan

I sure appreciate the time you're taking to post this thread, I've always planned on piping with copper when I build my shop. I wasn't aware of all the different types of fittings.

Thanks again

Alan
__________________
Ory-gun Boy!

Millermatic 200 w/ SKP-35 Spot Pulse Weld Panel, Tweco MIG-GUN #2, running ER70S-6 .035 wire on CO2, Spoolmatic 1 Spool Gun
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Web Search:

All times are GMT -5. The time now is 07:41 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.