MSS Banner The Technical Voice of the Industry
View Larger Image


Standard Marking System for Valves, Fittings, Flanges, and Unions (ANSI-approved American National Standard)

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.
The markings specified within this Standard Practice 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.


Today is: Thursday
July 16, 2020

MSS Member Login

MSS Scholarships
(Now Accepting 2020 Applications)
Deadline Extended

MSS Apparel

We Accept:
VISA  MasterCard  American Express
Discover  Diners Club 
Site Secured by:

Like us on:

Accept Credit Cards Online