Joint Efficiencies

[z9rjword]

Part UW-12 (d) of ASME Section VIII states that E=1.0 for circumferential stress calculations when the requirements for UW-11(a)(5)(b) are met, and E=0.85 when UW-11(a)(5)(b) is not met or when the welds are types 3-6.

Does this cover both type 1 and 2 welds? Is there any situation where the circumferential stress calculations on a seamless vessel section or head would have an E=0.65 due to non-radiographed Category B, type 2 circumferential welds (UW-12 (d) does not specifically identify type 2 welds as it does with the others)?

Thanks,

z9rjword

 

[abbver98]

I think the UW-12(d) covers type 1 and 2 welds. I argue as the longitudinal weld generate more risk than the circumferencial one. In the case you mention we are more safe than in vessel with cat. A weld. Perhaps, ASME had explicitly to clarify this.

According to Table UW-12, you can use E=0.65 for type 2 cat. B weld with no ray examination.

 

[prex]

Not sure to understand what you are in doubt for.
UW-12(d) states that E=1.0 if (in brief) the circumferential welds (be them of type 1 or 2) are at least spot radiographed, E=0.85 otherwise.
This is applicable to calculations that involve the circumferential stress in shell. When you calculate the thickness of the shell based onto the longitudinal stress, you'll take for E the value applicable to the circumferential weld, whatever is it (possibly 0.65). prex

http://www.xcalcs.com

Online tools for structural design

 

[LSThill]

Dear z9rjword (Mechanical)

Please go to the following

http://www.nooter.com,

download the ASME Quick Reference Guide. ASME SECTION VIII DIV 1, Pressure Vessels, by Nooter Fabricators.

Leonard

 

[alan54]

To Isthill,

Nooter no longer offers that ASME Quick Reference Guide. Could you email me a copy (alan@pce-inc.com) or do you know of another location. Thanks,

alan54

 

[LSThill]

RE: Guidebook for the Design of ASME SECTION VIII PRESSURE VESSELS: PAGE 246 APPENDIX A FIG A.1 ASME Quick Reference Guide ASME SECTION VIII DIV 1, Pressure Vessels, by Nooter Fabricators.