MSS SP 25
Standard Marking System for Valves, Fittings, Flanges and Unions
|Publication Date:||1 January 1998|
This marking system applies to valves, fittings, flanges, and unions used in piping connections which include (but are not limited to) flanged, soldered, brazed, threaded, or welded joints.
These specified markings serve to identify the manufacturer, the rating designation, materials of construction and special service limitations imposed by the manufacturer. They are used for product identification and to assist in proper application.