Appendix 28 for lethal service application?

[Dennysurf]

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

 

[CodeRef]

The following Interpretations give me reason to doubt that the alternatives outlined in Mandatory Appendix 28 apply to Lethal Service Vessels.
Another key against using APP. 28 for Lethal Service is the requirements for Fabricated Lap Joint Stub ends described in UW-2(a)(1)(c) and FIG. UW-13.5 FABRICATED LAP JOINT STUB ENDS FOR LETHAL SERVICE.

The two interpretations listed below are identical and thus, the same question is answered two times.

Do you want to try for a third time specific to App. 28? Go ahead and submit your inquiry to ASME. I would take a guess that this would be strike three..... But, who knows.

What does your AI/AIA say?

Interpretation: VIII-79-70
Subject: Section VIII, Division 1, Fig. UW-13.2 Sketches (b) and (c)
Date Issued: November 14, 1979
File: BC-79-639

Interpretation: VIII-80-02
Subject: Section VIII - Division 1, Fig. UW-13.2, Sketches (b) and (c)
Date Issued: January 14, 1980
File: BC-79-639

Question: Is the joint configuration illustrated in Fig. UW-13.2 sketches (b) and (c) of Section VIII, Division 1 acceptable when used to join side plates in a box header designed for lethal service?
Reply: No. The last sentence of the first paragraph of UW-2(a) lists the types of joints which may be used with various categories of welded joints. The three categories of joints which are used to join the sides of a box header in lethal service and the type of joint are: Category A (Longitudinal welded joint) must be Type 1 (butt) Category B (Circumferential welded joint) must be Type 1 or Type 2 (butt) Category C - same as Category B Since the joint must be a butt joint, the types shown in Fig. UW-13.2 sketches (b) and (c) are not permitted for lethal service.


FAQ731-376