Replies

1. 
   saschafer | Jun 07, 2008 09:50pm | #1

   My understanding is that Type M copper is not code-accepted for compressed gases. You need to use either Type L or Type K.

   -Steve

    

1. 
   dloc | Jun 08, 2008 05:57am | #3

   PEX tubing is compressed air rated. Simple to work with, easy to run.

1. 
   Tinkerer3 | Jun 08, 2008 07:36am | #4

   I have PEX for my heating system.  The ends where they clamp onto the fitting seem loose but still hold the water.  I've wondered if that connection would hold air under pressure

2. 
   RickL | Jun 08, 2008 09:46pm | #5

   All the PEX I've seen in not air rated. In fact it must kept from sunlight or it breaks down. It would be best to provide links to validate points.
   Ipex sells Duraplus which is an ABS plastic for airlines. Also rated is Duratec.
   http://www.environmental-expert.com/STSE_resulteach.aspx?cid=8136&idprofile=7575&section=2
   Over simplification of information is a dangerous thing.

1. 
   dloc | Jun 08, 2008 11:26pm | #6

   If you want to know what PEX from a specific manufacturer is rated for, call them and ask. Ratings are done by third parties so a rating costs a mfg money.

   <!----><!----> <!---->

   Here are some examples of what PEX is used for http://pex-solution.net/default.asp?p=Faq.asp

   Domestic hot and cold water supply which includes all forms of central heating and under floor heating <!----><!---->

   Domestic and industrial natural gas supply outdoors and within buildings <!----><!---->

   Natural gas supply in extreme ambient conditions <!----><!---->

   Carrier pipe in RTP Reinforced Plastics Pipes for high pressure gas applications <!----><!---->

   District heating systems <!----><!---->

   Air-conditioning systems <!----><!---->

   Solar energy systems <!----><!---->

   Automotive and ship-building <!----><!---->

   Transport of industrial gases, compressed air and fluids (Including fuel oil, gases, acids and alkalis and other chemicals) <!----><!---->

   Process engineering and other specialized applications <!----><!---->

   Buried pipe using ‘as-dug’ backfill, a significant cost saving compared with sand bedding <!----><!---->

   Plumbed a 500k GPY biodiesel pilot plant (so explosive & hazardous) in PEX and SS. PEX was used for acid and caustic lines, organic solvents, high pressure compressed air, low pressure control valve air, high purity gas lines, potable water, cooling water plus transport for oil, biodiesel and glycerin. We purchased from several manufacturers to get the colors we wanted but had no problem in finding rated tubing.

   <!----><!----> 

   The last time I looked, even the PEX tubing stocked by the local Menards lumber yard carried a compressed gas pressure rating. That tubing also contained UV inhibitors to allow for outdoor use.

    

   Yes, fact checking is important.

1. 
   RickL | Jun 09, 2008 12:14am | #7

   My point exactly. Not all Pex is rated equal for all applications. One should always get documentation from the manufacturer to verify your application. To generalize in the forums that Pex is rated for air will lead the less research minded individual to grab the cheapest Pex for airlines.

2. 
   dloc | Jun 09, 2008 12:41am | #8

   "All the PEX I've seen in not air rated." The inference you made is that no PEX was rated for air.  Indeed, I don't remember anyone finding any PEX that wasn't rated for at least 125 PSI in compressed gas use up to 3/4". A "rating" and suitability for use are two different concepts. PEX specifications are pretty tight so any PEX made from resins from a reputable manufacturer and made using approved extruders differs little (if any) across manufacturers. They may or may not chose to rate it.

3. 
   Jerry18 | Jun 09, 2008 06:38am | #9

   Great info.Any recommendations for connectors when using PEX for compressed air.Jerry

4. 
   dloc | Jun 11, 2008 09:12pm | #10

   PEX is made to a standard so fittings are interchangeable across brands of tubing. But you do want to use fittings designed for PEX tubing. No reason to put in anything other than brass in an air line but you can get a variety of materials if you want. We settled on the use of SS compressed bands because one tool could be used on all of the sizes. Back then, external compression rings which were physically compressed each required a separate compression tool. If you are only running a few drops, you can get fitting that you can screw on by hand.  They are expensive but less expensive than buying a tool. PEX has become so common in water systems that my local hardware store rents the  tool for compressed bands out. A wide variety of fittings are available so check around as every store carries a different subset. There are T's, L's and straights in all of the standard pipe sizes.

5. 
   Jerry18 | Jun 12, 2008 06:09pm | #12

   I ran about a mile of PEX in my own home for radiant heat so I have some PEX and fittings left over. I'll give it a try for air.Thanks for the info,
   Jerry

2. 
   RickL | Jun 08, 2008 04:20am | #2

   There is an ABS plastic from Chem-aire that IS airline rated. Also several others make an ABS for airlines. Kaeser and Garagepak make an aluminum aIrline rated product.

3. 
   mike4244 | Jun 12, 2008 03:34am | #11

   Go with type L. The cost difference isn't enough to worry about unless you're shop is 2000 sf or more.

   mike