Steel Pipe Schedule 40 Friction Loss Diagram

Overview

Engineering reference data for Steel Pipe Schedule 40 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	—

Unit Conversion Factors

The following conversion factors are useful when working with friction loss calculations in different unit systems.

Imperial Units

Parameter	Conversion
1 gal (US)/min	$6.30888 \times 10^{-5}$ m³/s = 0.0227 m³/h = 0.06309 dm³/s = $2.228 \times 10^{-3}$ ft³/s = 0.1337 ft³/min
1 ft/s	0.3048 m/s
1 psi (lb/in²)	6,894.8 Pa = $6.895 \times 10^{-3}$ N/mm² = $6.895 \times 10^{-2}$ 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

SI Units

Parameter	Conversion
1 Pa	$10^{-6}$ N/mm² = $10^{-5}$ bar = 0.1020 kp/m² = $1.02 \times 10^{-4}$ m H₂O = $9.869 \times 10^{-6}$ atm = $1.45 \times 10^{-4}$ psi
1 liter/s	$10^{-3}$ m³/s = 3.6 m³/h = 0.03532 ft³/s = 2.1189 ft³/min (cfm) = 13.200 Imp. gal/min = 15.852 gal (US)/min = 792 Imp. gal/h
1 m/s	3.6 km/h = 196.85 ft/min = 2.237 mph

Applicable Standards

This data applies to ASME/ANSI B36.10/19 Schedule 40 steel pipes as specified in the American Society of Mechanical Engineers standards for welded and seamless wrought steel pipe.

References

• Original Source