Replies

1. 
   RickL | Jun 06, 2008 03:55pm | #1

   You assumed it was PVC which it might be. Hopefully he is smarter than that and used ABS plastic for the airlines. Chem-aire and http://www.ipexinc.com/Content/EN_US/2_0_Products/2_1_Industrial/2_1_4_1_Duraplus.asp

   make such systems. Also Kaeser and garagepak make aluminum systems for air.

   Here's a piping diagram, T's go up then down. A commonly overlooked detail.

   http://www.tptools.com/StaticText/airline-piping-diagram.pdf

2. 
   JohnWW | Jun 06, 2008 06:15pm | #2

   The Marc Adams School is presumably staffed by furniture makers, they may not know anything about the safety of air piping systems.

   The placing of something dangerous "out of harms way" is a poor approach to safety in any case, and a blow out would still risk harming people in the shop with flying shrapnel. An over stressed pipe wouldn't need to be hit to shatter it could do so spontaneously.

   John White

3. 
   [email protected] | Jun 07, 2008 07:02am | #3

   The problem with PVC, as a compressed air line, is that it fatigues along the residual stress left from the extrusion process, gets brittle and fails by breaking into sharp, little shards.  Which if I remember correctly are very hard to find on an x-ray.  Copper, steel, or flexible plastic tubing, or rubber hose are all safer choices. 

   I worked in an auto body shop years ago, that had run all the lines with rubber hose, barbed fittings, and hose clamps.  It was actually quite convenient, because they could modify it quite easily to add drops where needed.  (Plus it as lots easier to route around above the exiting suspended ceiling.)  The owner figured, that he could just run the main lines, and a drop for the paint booth, then the guys could cut in drops where needed.  He said that when/if the rubber wore out he would put in a copper system, but then he would know where it made sense to put the drops. 

   
   

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   Edited 6/7/2008 12:05 am ET by Jigs-n-fixtures

4. 
   miter | Jun 07, 2008 04:21pm | #4

   When I installed air lines in my shop I had 10 foot sections cut (small shop could use 5 foot) and threaded so I could install a "T" pointed up at every joint. Just put a threaded pipe plug into the "T" you will not use.This will allow you to change air usage locations in the future with minimum time and grief. Be sure to set your main line pitch so that condensed water can drain and install a valve at the lowest point to allow draining every day. Each tap should go up from the "T" 6 to 10 inches up then 2 elbows then down to your coil hose. This will help keep water out of the downstream line. Elbows and "Ts" are cheap when you are building your line,throw a couple union fittings in to allow for possible future layout changes. Use unistrut and uinstrut pipe clamps to secure the line to the wall or ceiling every 10 feet and enjoy a trouble free system. Please don't waste your time on PVC like I did the first time and then need to rework all the lines. If you ever saw PVC shatter ( I did) you would not consider it in you shop. My PVC lines were about 10 years old and I have skylights in my shop --UV from sunlight will degrade PVC and makes it brittle. I hit the PVC line with a board and the PVC flew apart in some seriously sharp pieces -no injury- but I stopped and put in iron pipe.  Home depot can supply all the pieces if you dont have a plumbing supply close by.

   
   

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   Edited 6/7/2008 9:23 am ET by miter

1. 
   Jfrostjr | Jun 08, 2008 04:41pm | #5

   As I have attended many classes at Marc Adams School, I thought I would check with him to see what product he used for his airlines. Here is his response:"it is a schedule 40 PVC and was professionally installed by a licensed plumber/electrician who tested and re-tested the system before we put air into the lines. He also did research to verify with his supplier that PVC would work for our application."It would appear that PVC is suitable if it is the correct grade. Frosty"I sometimes think we consider the good fortune of the early bird and overlook the bad fortune of the early worm." FDR - 1922

1. 
   saschafer | Jun 08, 2008 05:51pm | #6

   "...who tested and re-tested the system..."

   That misses the point. The safety issue with PVC has absolutely nothing to do with the ability to hold pressure.

   http://www.osha.gov/dts/hib/hib_data/hib19880520.html

   -Steve

    

   Edited 6/8/2008 10:56 am ET by saschafer

2. 
   RickL | Jun 08, 2008 09:29pm | #7

   There is no suitable PVC. There are ABS plastics air and gas rated.
   http://www.plasticsystems.co.nz/abs.html

   Edited 6/8/2008 2:37 pm ET by RickL