What this tool does
Screen whether a candidate internal diameter creates unusually low or high velocity at the entered flow. Optional length and C-value inputs add a preliminary friction estimate.
When to use it
Use it before selecting a pipe size, when comparing real pipe schedules, or when checking whether a pressure-loss result is driven by velocity.
Inputs and supported units
Each labelled field explains the quantity it expects. Unit-system changes convert existing numeric entries once and keep calculations on a single SI internal basis. Supported shared units include L/min and GPM, metres and feet, kPa and psi, millimetres and inches, kW and hp, and °C and °F as relevant.
Calculation or decision method
The tool reports neutral screening language rather than treating a single velocity range as a universal legal limit.
How to interpret the result
Read the primary result with the supporting breakdown and warning. A plausible number is not evidence that every input, operating case or design constraint has been included.
Worked example
At 120 L/min through a 50 mm internal diameter, velocity is about 1.02 m/s. The same flow through a substantially smaller ID increases both velocity and friction rapidly.
Assumptions
Steady, full circular pipe flow; the entered diameter is the actual internal diameter.
Limitations
The status is a screening cue. It does not consider water hammer, noise criteria, solids transport, erosion, code or manufacturer limits.
Sources
- U.S. Army Corps of Engineers — EM 1110-1-4008
- Westlake Pipe & Fittings — Schedule 40 and 80 PVC Pressure Pipe
- U.S. EPA — Storm Water Management Model User’s Manual 5.2