How to Calculate Maximum Operating Pressure from Rod Load

Formula:
P_MAX = F_RL × 4 / (D_P² × π)

Where:

P_MAX = Maximum Operating Pressure* in pounds per square inch
F_RL = Rated Maximum Rod Load in pounds
D_P = Plunger Diameter in inches
π = Pi = 3.14159

Maximum Operating Pressure [PSI] = Rated Rod Load [lbs] × 4 / {(Plunger Diameter [in])² × 3.14159}

Example:
Rated Rod Load = 10,000 lbs
Plunger Diameter = 6.5 Inches
Calculate: 10,000 [lbs] × 4 / {(6.5 [in])² × 3.14159} = 301.36 PSI

*The maximum operating pressure calculated here is for the power end only. The maximum operating pressure calculated from the rod load should be compared to the fluid end’s maximum pressure. A check valve should always be correctly installed and set for less than the lower of the maximum operating pressures for the fluid and power ends of a pump.