Calculators
Friction Loss Calculator
Calculate friction loss in fire sprinkler piping using the Hazen-Williams formula. Select your pipe material, size, enter the flow rate and pipe length, and the calculator returns the loss per foot, total loss, and pipe velocity.
Hazen-Williams Friction Loss Calculator
p = (4.52 x Q^1.85) / (C^1.85 x d^4.87)
How it works
This calculator uses the Hazen-Williams formula:
p = (4.52 x Q^1.85) / (C^1.85 x d^4.87)
- Pipe internal diameters are from ANSI/ASME B36.10M (steel), ASTM F442 (CPVC), and ASTM B88 (copper)
- C-factors default to NFPA 13 values: 120 for steel, 150 for CPVC and copper
- Override the C-factor field for aged pipe or special conditions (e.g., C=100 for corroded steel)
When to use
- Quick-checking a single pipe segment during design
- Verifying software output for a specific run
- Estimating whether a pipe size will work before running full calcs
- NICET exam preparation — practice Hazen-Williams problems
Not a substitute for full hydraulic calculations
This tool calculates friction loss for a single pipe segment. A complete NFPA 13 hydraulic calculation requires node-by-node analysis of the entire system, including fittings (equivalent pipe lengths), elevation changes, and device losses. See Hydraulic Calculations for the full methodology.
Related references
- Hydraulic Calculations — equivalent pipe length tables, K-factors, worked examples
- Pipe and Fittings — pipe material properties and joining methods