Quick Guide
How to use this calculator ▼
1. Define the pipe system
Select the pipe basis for the primary section using Metric PN / DN, Rural Pipe, or Custom Manual. Then enter the straight length. Enable Section 2 and Section 3 only if the system has additional suction or discharge pipe runs.
2. Enter operating conditions
Enter the Duty Flow and Specific Gravity. For water, leave SG at 1.0. Use the suction condition for lift or flooded suction, then choose how to define discharge static head using either a manual head value or RL points.
3. Set the discharge requirement
Use Required Discharge Pressure when the system must maintain pressure at the outlet, such as a sprinkler, valve, or delivery point. The calculator converts this pressure into head automatically.
4. Add friction and minor losses
Pipe friction is calculated automatically for each active section. Add fittings under Minor Losses using either Equivalent Length or K-value Method. Assign each fitting to the correct pipe section so the loss is based on the right diameter and velocity.
5. Read the main pump results
The key outputs are Total Dynamic Head, Pump Input Power, and the System Curve. These are the main values used for centrifugal pump selection and checking the likely duty requirement.
6. Use pump curve overlay
Turn on Pump Curve Overlay and enter flow/head points from the pump data sheet. The calculator estimates the operating point where the pump curve crosses the system curve. If there is no intersection, the shown pump curve does not suit the calculated system.
7. Use the NPSH check separately
NPSH is not the same as TDH. TDH is the system energy requirement. NPSH is a cavitation check. Enter the manufacturer’s NPSHR at the duty point, then review NPSHA, NPSH Margin, and NPSH Status.
8. What to look at first
For quick review, focus on the highlighted tiles: Flow Velocity, Total Dynamic Head, Pump Input Power, Estimated Operating Flow, and Estimated Operating Head. These are the fastest indicators of whether the system and pump are in the right range.
Project Details
Fluid and Pipe Inputs
Primary Pipe Section
Select a pipe option to populate the internal diameter.
Additional Pipe Sections
Suction and Discharge Head Requirements
Manual discharge elevation head is currently active. TDH uses discharge static head plus suction lift, or minus flooded suction.
Pump Inputs
Suction / NPSH Check
NPSH is a separate cavitation check. This uses the suction condition plus suction-line friction from the section named "Suction Line" or Section 2 if enabled.
Motor Selection
Installed power recommendation applies a service factor to either the drive power or pump input power, then rounds up to the next standard motor size.
Minor Losses
Counts below are converted to equivalent length using factor x D. Override values are editable.
Pump Curve Overlay
Enter flow and head points for the pump at the base RPM. In Auto-solve mode, the calculator adjusts speed up or down using pump affinity laws so the adjusted pump curve intersects the current duty point. Manual mode is also available for user-entered RPM.
| Point | Flow (L/s) | Head (m) |
|---|---|---|
| 1 | ||
| 2 | ||
| 3 | ||
| 4 |
Results at Duty Point
Pipe Section Summary
| Section | Length (m) | ID (mm) | C | Velocity (m/s) | Pipe Friction (m) | Minor Basis | Minor Loss (m) |
|---|
Minor losses are now assigned to individual pipe sections and calculated using that section's diameter and velocity basis.
System Curve
| Flow (L/s) | Pipe Friction (m) | Minor Losses (m) | Static Head (m) | Pressure Head (m) | TDH (m) | Hydraulic Power (kW) | Pump Input (kW) | Drive Power (kW) |
|---|
Calculation Breakdown
Enter the inputs to see the results.
Disclaimer
This calculator is provided as a guide only. It is the responsibility of the user to verify inputs, assumptions, and results, and to ensure the calculations are correct and suitable for the intended application.