ASME B31.4 Compliant | Joukowski Equation, Wave Speed & Surge Pressure
Common Liquids:
• Water (60°F): 62.4 lb/ft³, K = 300,000 psi
• Crude Oil (35°API): 53.0 lb/ft³, K = 200,000 psi
• Diesel: 52.0 lb/ft³, K = 210,000 psi
• Gasoline: 46.0 lb/ft³, K = 150,000 psi
Guidelines:
• Typical liquid velocity: 3–10 ft/s
• ESD valves: 2–10 sec closure
• MOVs: 15–120 sec closure
• Pump trip: instantaneous (0 sec)
Understand water hammer, Joukowski equation, wave speed, and surge mitigation
Valve closes faster than the critical time (tc = 2L/a). The full Joukowski pressure rise occurs because the pressure wave cannot complete a round trip before the valve is fully closed.
Application: Emergency shutdowns (ESD), fast-acting valves, safety analysis
Given: Pipe geometry, liquid properties, flow velocity, closure time
Calculate: Maximum surge pressure, wave speed, hoop stress
Water hammer is a pressure surge caused by sudden valve closure or pump trip events in pipelines, analyzed using the Joukowski equation.
This calculator performs water hammer and surge analysis per ASME B31.4.
It calculates surge pressure, wave speed, and pipe stress from valve closure or pump trip events.
The calculator supports quick valve closure (full Joukowski), slow closure attenuation (Allievi model), and pump trip transient analysis modes.
Flexible pipe materials like HDPE and PVC produce lower wave speeds and therefore lower surge pressures than rigid materials like steel. HDPE may experience only 25-30% of the surge pressure that steel pipe would see.