MSS SP-42-2009
1. SCOPE
1.1 This Standard Practice covers Classes 150, 300and 600 corrosion resistant alloy gate, globe, angleand check valves with flanged and butt weld endswhich are constructed of pressure containing parts,including materials that conform to ASME B16.34.
1.2 This Standard Practice covers additionalconstruction requirements for corrosion resistantvalves not covered by ASME B16.34. Such valvesare made from corrosion resistant alloys whoseproperties are uniquely suited to the service intowhich they are placed. Chemical process andcryogenic fluid service constitute two suchapplications.