Operating Torque Values for Seating of Mark VIII® Shutoff and Regulating Valves
The table below is a list of the Maximum torques which may be encountered.
Most generally the actual operating torques are 10 to 20% less than these figures depending upon the fluid flowing through the valve, the stem lubrication, and the condition of the seat.
For operating pressures less than 3000 PSI the torque values are less. It is recommended that the listed values be used for operating pressures between 1500 and 3000 PSI. For pressures of 1500 PSI and less, two thirds of the listed value may be used. Torque values are maximum and under actual conditions they may be less.