Hazen-Williams Flow Calculator
Calculate flow rate in pipes using Hazen-Williams equation
About this calculator
The Hazen-Williams Flow Calculator determines flow rates and velocities in pressurized water pipes using the widely-accepted Hazen-Williams equation. This empirical formula accounts for pipe diameter, length, roughness coefficient, and head loss to provide accurate flow calculations. Essential for hydraulic engineers, water system designers, and plumbing professionals, it helps optimize pipe sizing, predict system performance, and ensure adequate water delivery in municipal water systems, fire protection networks, and building plumbing installations.
How to use
Enter your pipe parameters including diameter, length, and the Hazen-Williams roughness coefficient (C-factor) for your pipe material. Input either the head loss to calculate flow rate, or enter the desired flow rate to determine head loss. The calculator instantly computes the results along with flow velocity, helping you analyze your piping system performance.
Frequently asked questions
What is the Hazen-Williams C-factor?
The C-factor represents pipe roughness: new smooth pipes have higher values (120-150), while older or rougher pipes have lower values (80-120).
What units does this calculator accept?
The calculator typically accepts feet, inches, and gallons per minute (GPM) for US customary units, or meters and liters per second for metric.
When should I use Hazen-Williams instead of other flow equations?
Use Hazen-Williams for water flow in pipes with turbulent flow conditions. It's most accurate for water temperatures between 40-75°F in full-flowing pipes.