Pipeline Head Loss Calculator
Calculate friction loss in pipes using the Hazen-Williams Equation
Understanding Pipeline Head Loss
Head loss refers to the measure of the reduction in the total head (sum of elevation head, velocity head, and pressure head) of the fluid as it moves through a pipeline. This calculator uses the Hazen-Williams equation, which is widely accepted for water flow in pressurized pipes.
Energy is lost due to friction between the moving fluid and the internal walls of the pipe. Higher flow rates, smaller diameters, and rougher pipe materials all contribute to increased head loss.
The Hazen-Williams Formula
The metric version of the formula used in this calculator is:
- hf: Friction head loss (meters of water)
- L: Length of pipe (meters)
- Q: Volumetric flow rate (m³/s)
- C: Roughness coefficient
- D: Inside diameter of pipe (meters)
Common Roughness Coefficients (C-Factors)
| Material | C-Factor Range |
|---|---|
| PVC / Polyethylene / ABS | 140 – 150 |
| Copper / Brass | 130 – 140 |
| New Ductile Iron | 120 – 130 |
| Galvanized Steel | 100 – 120 |
| Concrete | 100 – 120 |
Why Calculate Head Loss?
Engineers calculate head loss to ensure that pumps are sized correctly. If the head loss exceeds the pump's capacity, flow will decrease, or the system may fail to deliver water to higher elevations. Additionally, excessive friction loss can lead to high energy costs and potential erosion of pipe materials if velocities are too high.
Example Calculation
If you have a 500-meter length of 100mm (0.1m) PVC pipe (C=150) carrying water at a rate of 40 m³/h:
- Convert Flow Rate: 40 m³/h / 3600 = 0.0111 m³/s
- Apply Formula: hf = 10.67 × 500 × (0.0111 / 150)1.852 / (0.1)4.87
- Result: Approximately 4.45 meters of head loss.