Steel Pipe Schedule 80 Friction Loss Diagram

Overview

Engineering reference data for Steel Pipe Schedule 80 Friction Loss Diagram in fluid mechanics.

Key Formulas

Reynolds Number

$Re = \frac{\rho v D}{\mu}$

Ratio of inertial to viscous forces — determines flow regime.

Bernoulli's Equation

$P + \frac{1}{2}\rho v^2 + \rho g h = \text{const}$

Conservation of energy for steady, inviscid, incompressible flow.

Continuity Equation

$A_1 v_1 = A_2 v_2$

Conservation of mass for incompressible flow.

Darcy-Weisbach

$\Delta P = f \frac{L}{D} \frac{\rho v^2}{2}$

Pressure drop due to friction in a pipe.

Variables

Symbol	Description	Unit
$Re$	Reynolds number	—
$\rho$	Fluid density	kg/m³
$v$	Flow velocity	m/s
$D$	Characteristic dimension	m
$\mu$	Dynamic viscosity	Pa·s
$P$	Pressure	Pa
$f$	Darcy friction factor	—

Operating Conditions

The friction loss calculations are based on the following conditions for water flowing through Schedule 80 steel pipes:

Parameter	SI Value	Imperial Value
Fluid	Water	Water
Pipe	Steel Pipe - Schedule 80	Steel Pipe - Schedule 80
Temperature	20.0 °C	68.0 °F
Density	998.3 kg/m³	62.0 lb/ft³
Kinematic Viscosity	1.004 × 10⁻⁶ m²/s (0.01 stokes)	1.08 × 10⁻⁵ ft²/s
Pipe Roughness Coefficient	4.5 × 10⁻⁵ m	—

Unit Conversions

Pressure Conversions

From	To
1 Pa	10⁻⁶ N/mm² = 10⁻⁵ bar = 0.1020 kp/m² = 1.02 × 10⁻⁴ m H₂O = 9.869 × 10⁻⁶ atm = 1.45 × 10⁻⁴ psi
1 psi	6,894.8 Pa = 6.895 × 10⁻³ N/mm² = 6.895 × 10⁻² bar = 27.71 in H₂O at 61 °F = 703.1 mm H₂O at 61 °F = 2.0416 in mercury at 61 °F = 51.8 mm mercury at 61 °F = 703.6 kg/m² = 2.307 ft H₂O

Flow Rate Conversions

From	To
1 liter/s	10⁻³ m³/s = 3.6 m³/h = 0.03532 ft³/s = 2.1189 ft³/min = 13.200 Imp.gal(UK)/min = 15.852 gal(US)/min = 792 Imp.gal(UK)/h
1 gal(US)/min	6.30888 × 10⁻⁵ m³/s = 0.0227 m³/h = 0.06309 dm³/s = 2.228 × 10⁻³ ft³/s = 0.1337 ft³/min

Velocity Conversions

From	To
1 m/s	3.6 km/h = 196.85 ft/min = 2.237 mph
1 ft/s	0.3048 m/s

References

• Original Source