Lack of penetration in existing nozzle welds. Where is this addressed in any of the codes?

[jeevesme]

We have a pressure vessel built to ASME Sect. VIII Div. 1. It appears that the bottom nozzle has been altered. The flange was cut off, and an elbow & small pup piece put in. I cannot find any documentation for this repair/alteration. It has Lack of Penetration on most of the welds that were done. I cannot find, in any codes, that address the requirement to fix this issue.

 

[metengr]

Inadequate penetration (IP) is not permitted by most codes and standards because this type of flaw is considered a pre-existing crack. I can't tell in the photos but the IP which you identify appears to be more like a parting line. This is acceptable as a nozzle weld joint detail provided the weld is a partial penetration weld from the OD surface, which I cannot tell from the one photograph. What does the OD surface look like at this location?

 

[metengr]

. Just as a side note, the IP referenced above is "incomplete penetration" to be absolutely correct in code space.

 

[jeevesme]

Thanks for the quick reply metengr. The issue is that I am recommending that it be fixed properly. However, I cannot find any reference for it in NBIC, API 510, ASME PCC's, or any other in service codes that would tell them that it MUST be fixed.

 

[metengr]

...and you won't find it because IP is rejectable, which means it has to be removed. The NBIC refers you back to the original code of construction, if applicable.

 

[Ripz]

UW-51 B (1)

(b) Indications shown on the radiographs of welds and
characterized as imperfections are unacceptable under the
following conditions and shall be repaired as provided in
UW-38, and the repair radiographed to UW-51 or, at the
option of the Manufacturer, ultrasonically examined in
accordance with the method described in Appendix 12
and the standards specified in this paragraph, provided the
defect has been confirmed by the ultrasonic examination
to the satisfaction of the Authorized Inspector prior to
making the repair. For material thicknesses in excess of 1
in. (25 mm), the concurrence of the user shall be obtained.
This ultrasonic examination shall be noted under remarks
on the Manufacturer’s Data Report Form:
(1) any indication characterized as a crack or zone
of incomplete fusion or penetration;

 

[Ripz]

UW-38 REPAIR OF WELD DEFECTS
Defects, such as cracks, pinholes, and incomplete fusion,
detected visually or by the hydrostatic or pneumatic test
or by the examinations prescribed in UW-11 shall be
removed by mechanical means or by thermal gouging processes,
after which the joint shall be rewelded [see
UW-40(e)].

 

[Duwe6]

Ripz is exactly right. And when somebody brings up the "Sect VIII" is for construction only, not in-service inspections: the two 'major' in-service Inspx Codes are NBIC [National Board Inspection Code] and API-510 [Boilers and Pressure Vessels]. Neither of them allows any more IP or Lack-of-Fusion than Sect VIII -- namely, ZERO. Tell 'em to quit crying and just fix it. If the welder can weld it from the ID, that repair can be made in an hour or two. Simple.