Case N-318-5 of ASME Boiler and Pressure Vessel Code

Procedure for Evaluation of the Design of Rectangular Cross Section Attachments on Class 2 or 3 Piping


This calculation is only a simplified estimation, and does not replace a detailed design calculation.


1. Input data

    1.1. Loadings
         Bending moment  ML   N·m
         Bending moment  MN   N·m
         Torsional moment  MT   N·m
         Shear load  Q1   kN
         Shear load  Q2   kN
         Thrust load  W   kN
         Internal design pressure  P   bar
         Peak pressure  Pmax   bar
         Loadings level     
         Resultant moment due to weig…  MA   N·m
         Resultant moment due to nonr…  MB   N·m
         Resultant moment due to ther…  MC   N·m
         Resultant moment due to sing…  MD   N·m
         Stress intensification factor  i   

    1.2. Geometrical dimensions
         Run pipe outside diameter  Do   mm
         Nominal run pipe wall thickn…  T   mm
         Thickness of the attachment  L1   mm
         Length of the attachment  L2   mm
         Height of the attachment  H   mm
         Welds penetration type     
         Weld thickness  aw   mm
         Weld section modulus (parall…  Zwl   mm³
         Weld section modulus (parall…  Zwd   mm³
         Torsional weld section modulus  Zwt   mm³
         Weld throat area  Aw   mm²

    1.3. Material properties
         Basic material allowable str…  Sh   N/mm²
         Basic material allowable str…  Sc   N/mm²
         Yield stress at temperature  Sy   N/mm²
         Stress range reduction facto…  f   


  1. Principal sketch

  2. Control sketch