Hazen-Williams Equation Calculator

Here’s a comprehensive table summarizing all you need to know about the Hazen-Williams Equation:

Hazen-Williams Equation Overview

Aspect	Details
Purpose	Calculates head loss due to friction in water pipes
Formula	hf=10.67×L×Q1.852C1.852×D4.87hf​=C1.852×D4.8710.67×L×Q1.852​
Parameters	hf: Head loss due to friction (m) L: Pipe length (m) Q: Flow rate (m³/s) C: Hazen-Williams coefficient (dimensionless) D: Internal pipe diameter (m)
Units	SI units (metric)
Applicability	Water at ordinary temperatures (40°F to 75°F or 4°C to 24°C)
Advantages	Simple to use, fewer parameters required
Limitations	Less accurate for large pipes, high flow velocities, and varying temperatures

Hazen-Williams Coefficients (C)

Material	C Value
Cast Iron (unlined)	100
Cast Iron (lined)	130
Ductile Iron (cement lined)	140
Steel	130
PVC	150
Copper	130

Key Points

1. Usage: Commonly used in designing water supply systems, fire sprinkler systems, and irrigation networks.
2. Accuracy: Less accurate than the Darcy-Weisbach equation but simpler to use.
3. Temperature Sensitivity: Does not account for water temperature or viscosity changes.
4. Flow Regime: Best suited for turbulent flow in relatively smooth pipes.
5. Calculation Tools: Many online calculators and software tools are available for easy computation.
6. Alternative Forms: The equation can be rearranged to solve for different variables, such as pipe diameter or flow rate.
7. Industry Standard: Widely accepted in the water industry, especially in North America.
8. Limitations: Not suitable for fluids other than water or for extreme temperatures.

By understanding these aspects of the Hazen-Williams Equation, engineers and designers can effectively use it for water system calculations while being aware of its limitations and appropriate applications.