Weld Path Strength Calculation for Boilers

[pvrerate]

A NPS 2, set-on nozzle (Figure PW-16.1(a)) is being installed on a Steam Drum Head. Neither PG-38 nor PG-52 applies. The AI is asking for weld path strength calculations. Such calculations show that the nozzle fails following Figure PW-16.1(a). Is it the Code's intent that these calculations be done even though the nozzle is exempt from reinforcement calculations?

As per PG-32.1.3.1 and PG-32.1.3.1.1, "no calculations need be made to determine the availability of compensation for a single opening not covered by PG-38 or PG-52 in shells, headers, or formed heads whose inside diameter is not less than four times the diameter of the opening and" which is welded, not larger than NPS 2, and attached in accordance with the applicable rules.

Is the preceding sentence or some other area of the Code implying that weld path strength calculations are not required in this instance.

Thanks very much for your advice.

 

[metengr]

Yes. Compensation for reinforcement and nozzle load path calculations are two different animals under Section I. Load path calculations show the nozzle weld attachments have been sized correctly to avoid failure in service. Reinforcement calculations pertain to ensuring the shell or head where a hole is placed has not been weakened.