Copper bearing alloys

[JLSeagull]

I often see a phrase in piping specifications etc. such as "no copper bearing alloys". This is typically associated with processes that contain stuff that reacts with copper such as various type amines, acetylene, etc. What does "copper bearing alloy" mean to you?

Does this mean that valves with bearing surfaces cannot be copper or alloy with over 50% copper?

Does this mean that all valve trim is to be copper-free or to contain zero copper?

If not zero is the amount to be less than 20%, 2% or 0.02% copper?

My opinion is that this means to propose alloys that are copper free, that contains 0.0 copper. However, some suppliers seem to think that it means something else.

 

[btrueblood]

JL, I would agree with your assessment. The presumption used by the spec. writers is that the copper may go away completely due to corrosion by the stuff in the pipe. Somebody proposing an alloy with some copper content had better be ready to explain to you/them why the alloy won't be affected by removal of the copper content during service.