MSS SP-91-2009 PDF

The purpose of this Standard Practice is to provide valve users with information for use in evaluating the manual operation of valves.

It must be understood that this information is general in nature and must be supplemented by specific operational data for the valve and service conditions to be experienced. The maximum and minimum torque ratings of specific valve and actuator types are not covered by this Standard Practice, but must be considered when applying manual input devices to any specific valve. Data from the valve and actuator manufacturers should be consulted regarding valve and actuator types and ratings.

This Standard Practice provides guidelines for the operation of manually actuated valves as affected by the valve operator's input.