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Mechanical EngineeringP0

Pressure Loss Calculator

Calculate total pressure loss in a pipeline including friction losses and fittings (K-factor method).

Inputs
Enter your values below

Sum K for all fittings: elbow≈0.9, globe valve≈6

Result
Total Pressure Loss
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Enter values and click Calculate
Formula
(friction × length ÷ diameter + k_total) × density × velocity² ÷ 2 ÷ 1000
Result unit: kPa

ΔP = (fL/D + ΣK) × ρv²/2. K-factor method sums minor losses from fittings: elbow≈0.9, gate valve≈0.17, globe valve≈6, tee≈1.8.

Introduction

Calculate total pressure loss including both straight-pipe friction and minor losses from fittings, valves, elbows, and entrances/exits using the K-factor (resistance coefficient) method.

Calculation Example

50m pipe with K=5 fittings, water at 2m/s: 30 kPa total loss.

Inputs: friction=0.02, length=50, diameter=100, k_total=5, density=1000, velocity=2
Result: 30 kPa

Engineering Applications

  • •Pump head estimation
  • •Piping system design
  • •Fire protection systems
  • •HVAC hydronic design

Frequently Asked Questions

What are typical K-factors?

90° elbow: 0.9, 45° elbow: 0.4, gate valve (full open): 0.17, globe valve (full open): 6, ball valve: 0.05, tee (through flow): 0.9, tee (branch): 1.8.

What is the difference between K-factor and L/D?

Equivalent length (L/D) methods convert fittings to equivalent pipe length. K-factor method uses velocity head directly: h_loss = K × v²/2g. Both give same result.

Related Calculators

Pressure Drop Calculator (Darcy-Weisbach)Darcy-Weisbach Pressure Drop CalculatorFriction Loss Calculator

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Disclaimer: Calculations are for reference and educational purposes only. Always verify results independently for engineering design. See full disclaimer.