Volume (Minimum Flushing) and Time (Minimum Flushing) in Flushing Results Browser


 Product(s):Bentley WaterGEMS, WaterCAD
 Version(s):08.11.06.58 and later
 Area:Output and Reporting

Problem

How is the "Volume (Minimum Flushing)" and "Time (Minimum Flushing)" calculated, in the Flushing Results Browser?

Solution

The "Volume (Minimum Flushing)" result in the Flushing Results Browser is the total volume of the pipes in the pipe run for the respective event.

The "Time (Minimum Flushing)" is the minimum flush volume divided by the hydrant flow.

For example let's say you have six 12 inch pipes in your pipe run, with a total length of 1000 feet and a hydrant discharge of 1000 gpm (2.23 ft^3/s). The minimum flushing volume would then be 0.5^2 * 3.14 * 1000 = 785 ft^3. The minimum flushing time would then be 785 / 2.23 = 352 sec = 5.9 minutes.

You will need to enter a pipe run for these results to be available. To do this, open the flushing event and click the Select Elements button.

In the Select toolbar, click Add Pipe Run Elements, then select the pipe run you want to use. When you have selected the elements, click the Done button.

When you computing the flushing event, results for Volume (Minimum Flushing) and Time (Minimum Flushing) will be available.

The results for Volume (Minimum Flushing) and Time (Minimum Flushing) are also used to calculate the Volume (Recommended Flushing) and Time (Recommended Flushing). These results are calculated by multiplying the Volume (Minimum Flushing) and Time (Minimum Flushing) results by the Safety Factor added to the flushing area.

See Also

Conducting Flushing Studies in WaterGEMS and WaterCAD