Pe Pressure Grades

Overview

Engineering reference data for Pe Pressure Grades 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	—

Advantages of HDPE Pipes

HDPE (High Density Polyethylene) pipes offer several key benefits for water conveyance systems:

• Chemical resistance
• Lightweight and easy handling
• Long service life
• Low internal friction loss
• Cost-effectiveness
• High flexibility and toughness
• UV resistance
• Excellent water hammer dampening capability

Pressure Nominal (PN) Grades

HDPE pipes are specified by their Pressure Nominal (PN) rating, indicating the maximum pressure in bars they can handle with water at 20°C.

Common available PN grades are *PN 2.5, *PN 4, *PN 6, *PN 10, and *PN 16.

Material Classifications and Strength

Polyethylene pipes are also classified by material grade, which defines their long-term strength. The Minimum Required Strength (MRS) at 20°C for a 50-year lifespan is defined by ISO 4427.

Application Overview:

• *PE 100: High-demand applications
• *PE 80: Gas distribution (≤4 bar), drinking water (≤16 bar), industrial
• *PE 63: Medium pressure irrigation and drinking water connections
• *PE 40 & PE 32: Low-pressure systems

Pressure Unit Conversions

For reference, 1 bar is equivalent to:

• $10^5$ Pa (N/m²)
• $0.1$ N/mm²
• $10.20$ m H₂O
• $0.9869$ atm
• $14.50$ psi

References

• Original Source