WRC 107 / 537 Nozzle Local Stress Calculator
Calculate local circumferential and longitudinal membrane and bending stresses at cylindrical vessel-nozzle junctions subjected to external piping mechanical loads per WRC 107 / WRC 537.
Vessel & Nozzle Dimensions
External Mechanical Piping Loads
Stress Intensity & Compliance
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Frequently Asked Questions
What is the purpose of WRC Bulletin 107 / 537 in vessel engineering?
WRC 107 (and its modern update WRC 537) provides an analytical method to calculate local stresses in cylindrical and spherical pressure vessel shells caused by external piping mechanical loads (radial thrust, shears, and moments). Standard code formulas only consider internal pressure, whereas WRC 107 evaluates pipe thermal expansion reactions.
What are the ASME Section VIII Division 2 stress evaluation limits?
Local stresses calculated by WRC 107 are categorized per ASME Section VIII Div 2: Primary local membrane stress Pl must not exceed 1.5 * Sm, and primary membrane plus secondary bending stress (Pl + Pb + Q) must not exceed 3.0 * Sm. The 3*Sm limit prevents progressive plastic ratcheting and low-cycle fatigue failure.
When should WRC 297 or Finite Element Analysis (FEA) be used instead of WRC 107?
WRC 107 assumes a rigid cylindrical plug attachment and is valid for diameter ratios d/D up to 0.33 (or beta <= 0.5). For larger nozzles where d/D > 0.5, nozzle wall flexibility significantly redistributes stresses, making WRC 297 or 3D Finite Element Analysis (FEA) mandatory.