The Manufacturers Standardization Society (MSS) of the Valve and Fittings Industry announces that SP-151-2021, Pressure Testing of Knife Gate Valves, has been revised and published by MSS.

Standard Practice (SP)-151 was originally published in 2016 for the purpose of providing a uniform means of testing knife gate valves commonly used in the "full open" and "full closed" type of service for isolation (not control). The standard establishes requirements and acceptance criteria for shell and seat closure pressure testing of resilient, non-metallic (e.g. ceramic), and metal-to-metal seated knife gate valves of all types. SP-151 continues to be maintained under the consensus of MSS Technical Committee 409, Knife Gate Valves.