Meana Petro

Instalaciones e integridad

Resistencia remanente B31G

A metal-loss defect assessed by both original and modified B31G, giving the failure pressure, the safe operating pressure and the longest defect your MAOP can carry.

Datos de entrada

0.72 for a Class 1 gas pipeline, 0.60 for Class 3.

Resultados

Cargando el cálculo…

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Cómo se calcula

  • Original B31G: parabolic defect area, flow stress 1.1·SMYS, Folias factor M = √(1 + 0.8z) with z = L²/(Dt); for z > 20 the defect is treated as infinitely long.
  • Modified B31G (0.85 dL): flow stress SMYS + 10 ksi and the two-part Folias factor, which is the form normally used today.
  • Safe operating pressure is the failure pressure times the design factor you set.
  • The allowable defect length is found by marching the length out until the safe pressure falls below MAOP.

Estándares que habla

Dónde deja de ser cierto

B31G is a Level 1 screening method for blunt, isolated, internally or externally corroded areas in ductile pipe under internal pressure only. It does not apply to cracks, gouges, dents, girth-weld defects, seam defects, or corrosion in a bend or under external loading — and it assumes the defect profile is a single smooth patch, where a real corrosion cluster has to be assessed as interacting defects. A pipe that fails B31G is not necessarily unfit; it is a candidate for a Level 2 effective-area or Level 3 finite-element assessment, which routinely clears pipe that B31G rejects.

Herramientas relacionadas

  • Espesor de pared y MAOP

    Required wall thickness and maximum allowable operating pressure under B31.3, B31.4 or B31.8, with the class location, joint and temperature factors applied.

  • Caída de presión en tubería

    Single-phase liquid by Darcy–Weisbach with a real Colebrook friction factor, and gas by Weymouth with both Panhandle equations alongside it.