<VV> Re: Air compressor distribution lines - NO Corvair

[Frank DuVal]

>Message: 3
>Date: Tue, 1 Nov 2005 18:11:32 EST
>From: UltraMonzaWest at aol.com
>Subject: Re: <VV> Air compressor distribution lines - NO Corvair
>To: virtualvairs at corvair.org
>Message-ID: <1d7.48d0d7a9.30995024 at aol.com>
>Content-Type: text/plain; charset="US-ASCII"
>
>In a message dated 11/1/2005 11:52:58 AM Pacific Standard Time, 
>Rt66Vairs at aol.com writes:
>
>  
>
>>Honeywell did tests with PVC for compressed air in the early 70s.
>>
>>It failed to make the grade. 
>>
>>We were shown the results at classes  in Minneapolis that I attended in 
>>1974.
>>
>>I suspect PVC is PVC. In 1974 and 2005.
>>
>>    
>>
>******************************************************************************
>*****
>And in the 70's Corvairs still leaked oil!   [ BUNA M] !!!!!
>
>PVC  today is totally different......Sch. 40  has always been TOTALLY  
>different then sch. 125!!    What you're guys were surely testing....
>
>
>
>Matt Nall / Patiomatt / WCUH / Mr. DeckRug
>69 Monza Cpe., 66 Monza vert, 65 Crown v8 Cpe.
>Somewhere between Reno, NV and Coos Bay, Or.
>
>  
>
>  
>

In the 70's Clarks and others were selling/promoting silicone and viton 
O rings to Corvair owners. Buna-N was not a good Corvair O ring.  
Polyvinyl chloride is still polyvinyl chloride. If the formula changed 
significantly, it would have a new acronym. Like the newer products PEX 
and CPVC.

If you would do some research on the web you would see:

For those wondering what schedule 125 PVC is ( I had never heard of it 
and I worked in a plumbing supply warehouse in the 70's) I went to:

 From Jess Stryker's
Landscape Sprinkler Design Tutorial:  
http://www.irrigationtutorials.com/sprinkler13.htm

snip "PVC is the type most commonly used in warm winter climates. PVC 
pipe is rated by two different systems, the first is the "class" system 
(Cl) the other is the "schedule" system (SCH). It is not possible to say 
that one is always better than the other. Schedule pipe is rated by the 
pipe's wall thickness, while class pipe is rated by the pipe's operating 
pressure. All PVC pipe of the same size will have the same outside 
diameter, regardless of which type or rating they are, so the same 
fittings will fit all of them. Most PVC pipe is connected together using 
"PVC fittings" which are glued in place. The fittings are typically 
rated as SCH 40 (standard white PVC fittings), some are available as SCH 
80 (stronger and normally gray color). Sometimes PVC pipe has threaded 
ends just like steel pipe. PVC pipe and steel pipe have the same outside 
diameters, and threaded steel pipe fittings will fit on threaded PVC 
pipe." unsnip

Thus I learned PVC comes in schedule 40 and 80, and also class 125 (for 
125 psi rating). No schedule 125 PVC pipe. More searching produced class 
150 and class 200 pipes for water supply companies (large underground 
utilities).

For suitability of PVC pipe for compressed air I went to a manufacturer 
of PVC pipe,  http://www.charlottepipe.com/

Here on page 15 of their technical and installation manual for PVC 
pipe(http://www.charlottepipe.com/Documents/Industrial_Tech_Manual/Industrial_Tech_Manual/html/Industrial_Tech_Manual.html) 
it states:

"PVC AND CPVC PIPING PRODUCTS ARE NOT RECOMENDED FOR SYSTEMS WHICH 
TRANSPORT OR STORE COMPRESSED AIR OR GASES.  DO NOT TEST PVC OR CPVC 
PIPING SYSTEMS WITH COMPRESSED AIR OR GASES. ALWAYS BLEED ALL ENTRAPPED 
AIR FROM THE SYSTEM PRIOR TO TESTING."

For another manufacturers statement I went to  
http://www.harvel.com/piping-clear-pvc.asp


snip "Harvel Plastics, Inc. does not recommend the use of this product 
or other rigid PVC/CPVC piping products for the transportation or 
storage of compressed air or gases, nor the testing of these systems 
using compressed air or gases." unsnip

I could find no manufacturer that recomended PVC pipe in any form, 
class, or schedule for compressed air.

All you people using PVC for compressed air lines have been warned.  It 
could work for years, but when it fails.....There is a reason the ASME 
has testing procedure for compressed air tanks before they can be sold. 
Can you supply me with ASME data to support the use of PVC pipe or 
components in a compressed air system? ASME is The American Society of 
Mechanical Engineers 
<http://searcht.netscape.com/ns/boomframe.jsp?query=asme&page=1&offset=0&result_url=redir%3Fsrc%3Dwebsearch%26requestId%3Db08acba8ac2ccbaf%26clickedItemRank%3D1%26userQuery%3Dasme%26clickedItemURN%3Dhttp%253A%252F%252Fwww.asme.org%252F%26invocationType%3D-%26fromPage%3DNSCPToolbarNS%26amp%3BampTest%3D1&remove_url=http%3A%2F%2Fwww.asme.org%2F> 
. This kind of reminds me of those people using old water tanks to hold 
compressed air, another Don't!

Frank DuVal