Enter the density (lbs/ft^3) and the velocity (ft/s) into the calculator to determine the Surge Pressure. 

Surge Pressure Formula

The following formula is used to calculate the Surge Pressure. 

Psurge = .8 * D * V
  • Where Psurge is the Surge Pressure (psi)
  • D is the density (lbs/ft^3) 
  • V is the velocity (ft/s) 

To calculate the surge pressure, multiply the density by the velocity, then multiply the result by .8.

How to Calculate Surge Pressure?

The following two example problems outline how to calculate the Surge Pressure.

Example Problem #1:

  1. First, determine the density (lbs/ft^3). In this example, the density (lbs/ft^3) is given as 50.
  2. Next, determine the velocity (ft/s). For this problem, the velocity (ft/s) is given as 125.
  3. Finally, calculate the Surge Pressure using the equation above: 

Psurge = .8 * D * V

Inserting the values from above and solving the equation: 

Psurge = .8 * 50 *125 = 5000 (psi)

FAQ

What is Surge Pressure?

Surge Pressure, often referred to as water hammer, is a pressure change that occurs in a piping system when there is a sudden change in the flow velocity of the fluid within the pipes. This can happen due to the rapid closing or opening of valves, or the sudden start or stop of a pump.

Why is it important to calculate Surge Pressure?

Calculating Surge Pressure is crucial for the design and operation of piping systems to ensure their safety and reliability. High Surge Pressures can cause damage to pipes, valves, and other components, potentially leading to system failure, leaks, or even hazardous accidents.

Can Surge Pressure be mitigated or controlled?

Yes, Surge Pressure can be mitigated or controlled through various methods. These include the installation of surge tanks, air chambers, or valves specifically designed to relieve pressure. Additionally, gradual changes in flow velocity and careful operational practices can help reduce the risk of surge pressure spikes.