Proof ? Sorry I don't have the names of any of the Insurance Inspectors or town or city code enforcement inspectors that asked to see what was being installed .
I have just done a I was trained when working for a large compressor company covering all the new england states .
Here are some resources you can read through .
http://www.engineeringtoolbox.com/astm-copper-tubes-d_779.html ( Notice Type M is Not listed for Compressed Air Use )
Also the Copper Tube Handbook by the Copper Development Association (
www.copper.org )
http://www.copper.org/applications/plumbing/cth
Taken from the above handbook
" The copper tube handbook,available FREE from the Copper Development Association (
www.copper.org) provides the following information:
1. Annealed (soft or coiled tubing) has a lower pressure rating than drawn copper tubing("copper pipe".
2. Even for the annealed type, in the 1/2", 3/4" range, 150 PSI is well below the basic pressure rating of the tubing itself, by at least 1/2.
however:
3. Brazed joints have a HIGHER mechanical strength than soft solder, but brazing considerably LOWERS the pressure rating of the system since brazing temperatures anneal the tubes and fittings. Brazed system has a pressure MAX of about 120 PSI.
4. The type of soft solder alloy used also affects the system rating:
a. Soldered with 50/50 Sn/Pb(tin-lead), types K,L,M in any size to 1" have a system rating of 150PSI MAX at 150ºF.
b. Soldered with 95/5 Sn/Sb(tin-antimony) the rating is 400 PSI at 150ºF.
So, you are potentially right at the outside limit of your materials . "
Please Note
What ever copper you use , only use 95/5 solder
Or just give up on copper and see if Hazard Fraught Tools is having a sale on hose's .
http://hooniverse.com/wp-content/uploads/2012/09/HF2.jpg
Bob