ASME BPVC Section VIII.2 Clause 4.3.12 Vs VIII.1 UG-32(g)

[PVDEngg]

Hello all,

Conditions of applicability for using DIV.2 rules for design of toriconal sections 'paragraph 4.3.12.2' are listed in equations 4.3.63, 4.3.64 & 4.3.65. These conditions of applicability are specified in UG-32(g)in DIV.1, together for toriconical heads and sections. Is it coherent to compare these conditions of applicability in Div.1 & Div.2 with each other, as Div.2 is rewritten from Div.1 (not all rules though, can this one)? Question is what is reason Div.2 allow smaller knuckle radius (1.5% of connecting shell or head skirt OD) as compared to Div.1 (6% of connecting shell or head skirt OD)? Any background information?

Thanks in anticipation, for enlightenment.

 

[TGS4]

The development is fully described (with appropriate references given) in ASME PTB-1.

For future reference, if you are ever wondering why rules are as they are in Div 2, ASME PTB-1 should be your first place to check.

 

[PVDEngg]

Thanks for your guidance, sir. I shall follow that advise every next time. After you advised, I checked it in PTB-1, it does not mention anything specifically about conditions of applicability as such. It directs to WRC-521, Pressure Area Method Application to Knuckle Joint and stress analysis method for discontinuity stresses. Basically, does not seems to address 'rewrite of conditions of applicability FROM UG-32(g) of Div.1 TO equations (4.3.63, 4.3.64 & 4.3.65) in paragraph 4.3.12.2 of Div.2. Some of the members of this forum, like you, sir, are esteemed ASME BPVC Code Committee members. So, apart from literature study, a second place to seek answers to such specific questions where probability of getting accurate solution is high because of participation in code evolution.

Requesting comments.
Thank you.

 

[TGS4]

The background information is provided in the WRC Bulletin.

Basically, new research was performed to validate the VIII-2 rules. At that time, there was no interest in updating the VIII-1 rules. And with Code Case 2695 (and the upcoming changes to the VIII-1 for the 2019 Edition) there is the availability to use the VIII-2 rules for VIII-1 construction. it is highly doubtful that the VIII-1 rules will be updated - it is more likely that they will actually be deleted and a referral/reference provided to VIII-2.

 

[PVDEngg]

Thank you for to the purpose resolution sir. To conclude this, we can say that these particular requirements from two divisions should not be correlated.