Mandatory appendix 28 show us alternative corner joint details for box headers for air cooled heat exchangers.
For lethal service categorie B and C welds shall be butt joint type (UW-2(a)(1)(b)) and has to be fully radiographed (UW-2(a))

Could appendix 28 also be applied for lethal service application?

Thanks for your feedback,

Denny

Denny,

The answer is no. See UW-2 of ASME Section VIII-1. UW-2 of Section VIII-1 take precedence over general requirements of other paragraphs.

leem817