Velocity
The velocity of water through pipes is calculated using the below formula:
Velocity (m/s) = (Flow Rate (L/s) / 1000)/((Pie*Radius of internal diameter (mm)^2)/1000000)
This spreadsheet contains the formula that is used for the H2X calculations.
All pipe materials and sizes available in H2X have been verified against the above spreadsheet. You can check the verified results for our standard pipes here.
Note:

There can be a difference between the spreadsheet and the H2X result due to the rounding up of multiple decimal places within the calculation. The difference generally occurs by the third decimal place in the velocity result.