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Temperature Allowable Stresses Pipes

Reference data and engineering information about temperature allowable stresses pipes for fluid mechanics applications.

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Overview

Engineering reference data for Temperature Allowable Stresses 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—

Pipe Specifications

StandardDescription
A 53Pipe, Steel, Black and Hot-Dipped, Zinc Coated, Welded and Seamless
A 106Seamless Carbon Steel Pipe for High-Temperature Service
A 135Standard Specification for Electric-Resistance-Welded Steel Pipe
A 333Seamless and Welded Steel Pipe for Low-Temperature Service
A 334Seamless and Welded Carbon and Alloy-Steel Tubes for Low-Temperature Service
A 369Standard Specification for Carbon and Ferritic Alloy Steel Forged and Bored Pipe for High-Temperature Service
API 5LLine Pipe
A 335Seamless Ferritic Alloy Steel Pipe for High-Temperature Service
A 269Seamless and Welded Austenitic Stainless Steel Tubing for General Service
A 312Seamless and Welded Austenitic Stainless Steel Pipe
A 358Electric-Fusion-Welded Austenitic Chromium-Nickel Alloy Steel Pipe for High-Temperature Service

Unit Conversions

  • 1 psi=6895 Pa1 \text{ psi} = 6895 \text{ Pa}
  • 1000 psi=6.9 MPa1000 \text{ psi} = 6.9 \text{ MPa}
  • Temperature conversion: T°C=59(T°F−32)T_{°C} = \frac{5}{9} (T_{°F} - 32)

Example: Convert 20,000 psi to MPa: 20,000 psi×6895 Pa/psi=137,900,000 Pa=137.9 MPa≈138 MPa20,000 \text{ psi} \times 6895 \text{ Pa/psi} = 137,900,000 \text{ Pa} = 137.9 \text{ MPa} \approx 138 \text{ MPa}

Allowable Stress per ASME B31.3

For ASME B31.3 Process Piping, the allowable stress is determined by: σallow=St3\sigma_{allow} = \frac{S_t}{3} where StS_t is the tensile strength of the material at the operating temperature.

In contrast, ASME B31.1 Power Piping uses: σallow=St3.5\sigma_{allow} = \frac{S_t}{3.5}

B31.3 applies to piping systems in chemical and petroleum plants, refineries, and related facilities, covering fluids such as chemicals, hydrocarbons, gases, steam, and cryogens.

References

Source: engineeringtoolbox.com