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Pressure Loss Plastic Pipes

Reference data and engineering information about pressure loss plastic pipes for fluid mechanics applications.

pressurelossplasticpipes

Overview

Engineering reference data for Pressure Loss Plastic Pipes in fluid mechanics.

Key Formulas

Reynolds Number

Re=ρvDμRe = \frac{\rho v D}{\mu}

Ratio of inertial to viscous forces — determines flow regime.

Bernoulli's Equation

P+12ρv2+ρgh=constP + \frac{1}{2}\rho v^2 + \rho g h = \text{const}

Conservation of energy for steady, inviscid, incompressible flow.

Continuity Equation

A1v1=A2v2A_1 v_1 = A_2 v_2

Conservation of mass for incompressible flow.

Darcy-Weisbach

ΔP=fLDρv22\Delta P = f \frac{L}{D} \frac{\rho v^2}{2}

Pressure drop due to friction in a pipe.

Variables

SymbolDescriptionUnit
ReReReynolds number—
ρ\rhoFluid densitykg/m³
vvFlow velocitym/s
DDCharacteristic dimensionm
μ\muDynamic viscosityPa·s
PPPressurePa
ffDarcy friction factor—

Friction Head Loss Data Table

18 rows
Friction Head Loss (ft H₂O per 100 ft pipe) in PVC Schedule 40 Plastic Pipes. Calculated using the Hazen-Williams equation with c=145.
Flow (GPM)(GPM)
Flow (GPH)(GPH)
3/8 in(ft H₂O/100ft)
1/2 in(ft H₂O/100ft)
3/4 in(ft H₂O/100ft)
1 in(ft H₂O/100ft)
1-1/4 in(ft H₂O/100ft)
1-1/2 in(ft H₂O/100ft)
2 in(ft H₂O/100ft)
2-1/2 in(ft H₂O/100ft)
3 in(ft H₂O/100ft)
4 in(ft H₂O/100ft)
6 in(ft H₂O/100ft)
1603.31.10.3
212011.83.810.30.1
424042.513.73.51.10.30.1
530064.220.75.31.60.40.2
6360297.42.30.60.3
848049.512.63.910.50.1
1060074.7195.91.60.70.20.1
20120068.621.25.62.60.80.30.1
30180011.85.61.70.70.2
40240020.19.52.81.20.40.1
50300014.44.31.80.60.2
60360020.162.50.90.2
7042007.93.31.20.3
80480010.24.31.50.4
90540012.65.31.90.5
10060006.52.30.60.1
12575009.83.40.90.1
15090004.81.30.2

Source: engineeringtoolbox.com

Hazen-Williams Formula for Plastic Pipes

The head loss in the table is calculated using the Hazen-Williams equation:

hf=10.67⋅L⋅Q1.852C1.852⋅d4.87h_f = \frac{10.67 \cdot L \cdot Q^{1.852}}{C^{1.852} \cdot d^{4.87}}

For PVC, PP, PE, and similar plastic pipes, the Hazen-Williams roughness coefficient CC is commonly taken as *145. The table uses a simplified, direct relationship derived from this equation.

Important Note: The calculated head loss values in the table represent friction loss in straight pipe sections only. The minor losses from fittings (elbows, valves, tees, etc.) must be calculated separately and added to determine the total dynamic head loss in a piping system.

Unit Conversion Factors

Key conversion factors provided in the source data:

Volume Flow:

  • 1 U.S. gallon/min (GPM) = 6.30888×10−5m3/s6.30888 \times 10^{-5} m^3/s
  • 1 GPM = 0.227 m3/hm^3/h
  • 1 GPM = 0.0631 dm3dm^3 (liter)/s
  • 1 GPM = 2.228×10−3ft3/s2.228 \times 10^{-3} ft^3/s
  • 1 GPM = 0.1337 ft3/minft^3/min
  • 1 GPM = 0.8327 Imperial gallon (UK)/min

Pressure Head:

  • 1 ft H₂O = 0.3048 m H₂O
  • 1 ft H₂O = 0.4335 psi
  • 1 ft H₂O = 62.43 lbs/ft2lbs/ft^2

Example Calculation

For a flow of 10 GPM in a 2-inch PVC pipe, the friction head loss from the table is: hf=0.2 ft H2O per 100 ft of pipeh_f = 0.2 \text{ ft H}_2\text{O per 100 ft of pipe}

This means for every 100 feet of 2-inch PVC pipe, you will lose 0.2 feet of water column (or about 0.087 psi) due to pipe friction alone.

Interactive Charts

Lined Pipes - Pressure Loss vs. Water Flow

References

Source: engineeringtoolbox.com