david339933, this material was previously located in Mandatory Appendix 28 where it was particular to air cooler box headers. I have only a nodding familiarity with it in that context. It now apparently applies to corner joints in general, it gives relief from the "a + b = 2t" rule, but at the cost of additional requirements. See remarks below.
Now, answering your questions, based on my reading of the rules, and keeping in mind my lack of much experience with them:
Assuming a circular head.
"Is NDE required by UG-93(d)(3) required?" I'd say yes, per UW-13 (e), first sentence.
"Would C=.33 be an acceptable attachment factor for this connection?" I'd say yes, I'd interpret this detail as falling under Fig UG-34 Sketch (h) even though not called out there. (Committee take note)
"ts is double tr" this meets UG-34, not sure it has a bearing in Fig UW-13(s) & etc.
Remarks: You should carefully read UW-13(f) before proceeding with this detail. The additional requirements are detailed and extensive, including possibly through-thickness tensile testing.
Regards,
Mike
The problem with sloppy work is that the supply FAR EXCEEDS the demand