Based on Valve Size, Seat Material and differential pressure across the valve (in closed position), the amount of torque required by the ball valve can be determined by the following procedures:

1. Find the valve torque from the torque charts on the next page using the differential pressure across the valve in the closed position. Locate the differential pressure on the horizontal axis of the chart and move up until you arrive at the appropriate valve size, transfer the intersecting point across to the vertical axis of the graph and read the required torque.

 

2. Multiply this torque value by one or more of the application factor multipliers shown above.

FULL PORT BALL VALVES

When Determining torque requirements for full port ball valves, refer to the following table to identify which nominal port valve torque will be equal to the full port size, then follow steps 1 and 2.

Flow Coefficient is the rate of flow (Q) of water in US gallons per minute, at 60° F. (15.6 ° C) that will generate a pressure drop of one pound force per square inch across the valve.