1/2" ball valve psi?

[Piper]

so a local natural/propane gas installer went out of business and I bought about 10 - 1/2" ball valves. I plan on using them for my new air compressor plumbing.

The writing stamped into these valves is really tiny and there are a ton of numbers and symbols etc but it seems to say "1/2 psi" on them. Is this right? Could this valve only stand a half psi??

I looked on the valve on my compressor right now which looks identical and it says 250 psi.

Are these natural gas valves only for gas and not air?

 

[cortez]

so a local natural/propane gas installer went out of business and I bought about 10 - 1/2" ball valves. I plan on using them for my new air compressor plumbing.

The writing stamped into these valves is really tiny and there are a ton of numbers and symbols etc but it seems to say "1/2 psi" on them. Is this right? Could this valve only stand a half psi??

I looked on the valve on my compressor right now which looks identical and it says 250 psi.

Are these natural gas valves only for gas and not air?

Believe it or not but most valves are for all fluids (technically speaking) and either water, gas, and air are within their range.

What is their range? I would say at least 250 pounds minimum--Notice that this may not be the rated number but 30 plus years in the industrial field I have only seen one Chinese valve go bad on a hot water line (but only after trying to remove it with a cheater bar on a pipe wrench).

If you read the old catalogs they definitely state that all their valves (ball, "gas" or whatever) are made for "Fluids" period (see the awe inspiring Mc Master Car catalog to get their true ratings, I am sure you will find your type of valve listed) .

Thus I think that an ordinary valve can handle most applications. The real problem is installing a brass valve that has been radically over tightened!!! This is the problem as they have tapered threads and are easily installed leak-proof as long as they are not over tightened.

 

[jbarila]

Valve 101,
Valves will be marked WOG, which means "water, oil or gas" with the rating. Normally brass valves are rated to 200 psi unless otherwise stamped on the valve. That would be WOG200. I would think that the valves you have can easily handle a compressed air system in a Garage.