This error message informs the user that their nozzle design exceeds the curve limits set by the WRC standard (107 or 537) and that WRC 537 is not valid for use. 

The parameters used for evaluating curve boundaries are reported under "Opening (Nozzle ID)>  Local loads on xxxx shell..."

Example:  

 

Avoidance:

To resolve this, the nozzle parameters must be adjusted so that the calculations for the necessary variables are within the ranges depicted in the standard's graphs.

These modifications would include;

• • Rm = mean radius of spherical/cylindrical shell
  • rm = Mean radius of hollow cylindrical attachment
  • T = thickness of spherical/cylindrical shell
  • t = thickness of hollow cylindrical attachment
  • r0 = outside radius of cylindrical attachment
  • Radius/perimeter of your attachment.
  • etc..

In addition, consider modifying any of the other variables that are taken into account for calculating gamma and beta

Scenario #1:

Figure 1C has some extrapolated values below. When the WRC was asked what the correct value of Y, when gamma = 50 and beta = 0.45  ?

We asked if we could use the Y value obtained using the equations and coefficients from WRC 537 which is 0.194

We asked if we should use the last known data point for gamma = 50 which is 0.05 (which competitive software does to just to get a stress value to plot out).

WRC's response was that we should not use either option because WRC 537 cannot be applied, the design is outside the curve boundaries.