Austenitic stainless steel (Types 304, 316, 321, and 347), Monel, and nickel alloy valves should have trim, gland bolts and nuts, and yoke bolting of the same nominal chemistry as the body.
Cast Monel valve material should be specified per ASTM A 494/A 494M Grade M-35-1 or Grade M-30C. Cast Monel valve materials for hydrofluoric acid service should be Grade M-35-1 with additional requirements as specified by the client company.
Limitations on the use of copper, and copper based alloys, should be as given below for the following services:
- Ammonia: Alloys with a copper content greater than 50 percent should not be used in ammonia service or in aqueous solutions containing ammonia where the pH exceeds 8.5.
- Caustic and alkaline: Alloys with a copper content less than 85 percent should not be used.
- Acetylene: Alloys with a copper content greater than 50 percent should not be used in services where acetylene in a wet environment is present.