Weld Joint Efficiency in Design by Analysis

In the original ASME Section VIII, Division 2, no consideration was given to partial weld joint efficiencies (values of the factor E less than 1.0) because that version required full radiography and only permitted weld joint efficiencies of unity. In the new (post-2007) Section VIII, Division 2, partial weld joint efficiencies as small as 0.85 are now permitted. Furthermore, much Design By Analysis work is performed on vessels fabricated to ASME Section VIII, Division 1 and the ASME B31 Codes, which all permit partial weld joint efficiencies. However, no guidance is provided on how to account for these values in Deign By Analysis to ASME Section VIII, Division 2, Part 5.This paper provides the technical justification for the proposed changes to ASME Section VIII, Division 2, Part 5 and API RP-579/ASME FFS-1 regarding weld joint efficiency. Guidance is also provided on how to incorporate this change into ASME Section VIII, Division 1 by way of U-2(g) and the B31 Codes.Copyright © 2016 by ASME