ANSI/MSS SP-143-2012

This Standard Practice establishes the minimum requirements for the application, design and installation oflive-loaded stem packing systems for valves designed in accordance with ASME B16.34, having rising and/or rotatingstems. It applies to valves with flexible graphite, polytetrafluoroethylene (PTFE), or other packing stem seal material,regardless of frequency of operation. This Standard Practice does not apply to valves that include a lantern ring(s) as partof its packing system or to self-energized packing.