How to Convert a Pressure Drop into an Equivalent Length

How to Convert a Pressure Drop into an Equivalent Length Using PIPENET

PIPENET provides several ways of converting a pressure drop into an equivalent length. This operation is most likely to be performed in the PIPENET Spray/Sprinkler Module. Therefore, the examples below are based on Spray/Sprinkler Module calculations.

1. Data:

Let us suppose that we have an item such as a strainer in a fire protection system.  The known data is the following:

Diameter = 100 mm nominal size of Schedule 40 pipe

Pressure drop = 0.3 bar

Flowrate = 1000 lit/min

2. A PIPENET Spray/Sprinkler Module calculation using the following data:

Input a pipe with a diameter of 100 mm and length of 100 m.

Set the inlet pressure to 10 barg and the outlet flowrate to 1000 lit/min.  Perform a calculation.

Note that the pressure drop is 0.4988825 bar

3. Calculate the Equivalent Length:

A Length of 100 m gives a pressure drop of 0.4988825 bar.  So the length which will give a pressure drop of 0.3 bar is 100 x 0.3 / 0.4988825 = 60.1344 m

4. Alternative Approach:

A simpler method might be to use the general pressure loss model of PIPENET Spray/Sprinkler Module.  The dialog box is shown below.