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Mechanical Engineering2D

Friction Loss Calculator

Calculate friction head loss in pipes per 100m using Hazen-Williams C-factor for water systems.

Inputs
Enter your values below

New steel: 120, PVC: 150, Old cast iron: 80-100

Result
Friction Head Loss
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Enter values and click Calculate
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Formula
10.67 × flow^1.852 ÷ (c^1.852 × diameter⁴.8704) × length
Result unit: m

Hazen-Williams (SI): hf = 10.67 × Q^1.852 / (C^1.852 × D^4.8704) × L. Q in m³/s, D in m, L in m; result in meters of water head loss.

Introduction

Calculate friction head loss in water pipes using the Hazen-Williams formula, commonly used in water distribution and fire sprinkler system design. C-factors: new steel=120, PVC/HDPE=150, copper=140, old cast iron=80-100.

How This Calculator Works

Hazen-Williams (SI): hf = 10.67 × Q^1.852 / (C^1.852 × D^4.8704) × L. Q in m³/s, D in m, L in m; result in meters of water head loss.

Step-by-step process:

  1. Enter your input values in the calculator above
  2. The engine converts all inputs to SI base units (meters, kg, Pa)
  3. The formula is evaluated: 10.67 * flow^1.852 / (c^1.852 * diameter^4.8704) * length
  4. Result is formatted with the appropriate unit and precision

Calculation Example

50 m³/h through 100mm C=120 steel pipe: ~4m head loss per 100m.

Inputs: flow=50, c=120, diameter=100, length=100
Result: 4.05 m (of water)

Engineering Applications

  • •Water distribution
  • •Fire sprinkler design
  • •Irrigation systems
  • •Plumbing design

Frequently Asked Questions

What C-factor should I use?

New steel pipe: 120; PVC/HDPE: 150; copper: 140; 20-year-old steel: 100; old cast iron: 80. Conservative design uses lower values.

When is Hazen-Williams applicable?

Only for water at 40-75°F (5-25°C) in turbulent flow. Use Darcy-Weisbach for other fluids or higher accuracy.

What is the difference between friction loss and head loss?

Friction loss is the pressure drop caused by pipe wall friction, usually expressed in bar, psi, or kPa. Head loss is the same energy loss expressed as an equivalent fluid column height in m or ft. They are related by h_f = ΔP / (ρg), so for water 1 m head ≈ 9.81 kPa.

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Engineering Disclaimer: Calculations are for reference and educational purposes only. Always verify results independently for engineering design. See full disclaimer.
Reviewed by: Industrial Engineering Team
References: ASME B31.3, ASTM A36, Perry's Chemical Engineers' Handbook