The Manufacturers Standardization Society (MSS) has announced the publication of the following revised Standard Practices: MSS SP-99-2016a, Instrument Valves (replaces 2016 edition), MSS SP-105-2016a, Instrument Valves for Code Applications (replaces 2016 edition), and MSS SP-120-2017, Flexible Graphite Packing Sealing for Rising Stem Valves.
The original SP-99-2016 and SP-105-2016 (published November 2016) have been replaced by this revised 2016a edition.