Applies To
Product(s):	AutoPIPE Nozzle
Version(s):	ALL;
Area:	Warning
Date Logged & Current Version	Sept. 2018 08.11.08.33

Problem:

The following message appears when running an analysis in AutoPIPE Nozzle:

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Warning Message
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Pad width is smaller than 1.65*SQRT(RT) = 989.38mm
as recommended by WRC297 & ASME VIII
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OK
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Warning Message
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Pad width is smaller than 1.65*SQRT(RT) = 162.64mm
as recommended by WRC297 & ASME VIII

Pad width is smaller than SQRT(Rm * Tsheel)/1.285 = 76.71mm
as recommended for elastic beam behavior for the load attenuation method.
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OK
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Warning Message
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Pad width is smaller than 1.65*SQRT(RT) = 162.64mm
as recommended by WRC297 & ASME VIII
where Rm = Mean radius of the shell and T shell = Shell thickness

Pad width is smaller than SQRT(Rm * Tshell)/1.285 = 76.71mm
as recommended for elastic beam behavior for the load attenuation method.
where Rm = Mean radius of the shell and T shell = Shell thickness
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OK
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Why and how to avoid?

Solution:

If the width of the shell reinforcement (pad, plate, or insert plate) is less than mentioned, then conservatism would require that no credit be taken for the reinforcing material when calculating stress resultants at the junction. See WRC 297, section - A-5 Nozzle Reinforcement where this topic is covered in detailed.

Suggest to make changes to the model such that this warning does not appear.

Note, from WRC297:

Therefore, per the code nomenclature, D = Mean Diameter of the shell. Thus the code equation equations 1.65x √ (RT), variable R would be referring to the mean radius of the shell. The same holds true for Rm, however the nomenclature is clearer to understand, Rm = mean radius.

Example:

Vessel dimensions:

Outside Dia. (OD) = 2168mm

Thickness (T) = 9.0mm

Mean Dia (D) = OD - T

= 2168 - 9

= 2159 mm

Mean Radius (R or Rm) = D / 2

= 2159 / 2

=1079.5 mm

Condition #1

Pad width is smaller than 1.65*SQRT(RT)

= 1.65 x SQRT (R x T)

= 1.65 x SQRT (1079.5 x 9.0)

= 162.64 mm

Condition #2

Pad width is smaller than SQRT(Rm * Tshell)/1.285

= SQRT(Rm x Tshell) /1.285

= SQRT( 1079.5 x 9.0) /1.285

= 76.71mm