Section VIII circumferential ligaments

[BigTank]

Is there a properly described Section VIII method for calculating circumferential joint efficiency?

UG-53 uses the term 'circumferential ligaments' in some of the wording for the calculation of diagonal ligament efficiency, but makes no mention of how to apply the paragraph to an array of holes in a plane perpendicular to the shell axis.

I would have assumed that using the circumference at the mean vessel diameter in conjunction with the circumferential opening size and spacing with the longitudinal ligament efficiency equation would have been correct, but a search of the boards yielded one opinion that explicity indicated that this is not correct.

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[ATriple]

BigTank,

UG-53(d), (e), and (f) allow for the calculation of circumferential efficiencies. You would calculate them the same way you calculate diagonal ligaments, using 90 degrees as your "angle with longitudinal". Depending on your specific setup you may need to use either Figure UG-53.5 or UG-53.6; read paragraphs (e) and (f) to see which one applies to you.