Arc Strike on ASME VIII U-stamped Vessel
Arc Strike on ASME VIII U-stamped Vessel
(OP)
I have an ASME Section VIII vessel that was fabricated and U-stamped in accordance with the 2001 edition of the code. It was shipped by the vendor to a module assembly shop, contracted by my company, and then sent to our site. Post receipt, it was noted that the vessel has several arc strikes that we plan on removing by grinding. I indicated the travel path simply to note that we don't actually know when the arc strike occurred.
NBIC Interpretation 98-30 notes that grinding operations that reduce the outside diameter, length, and thickness of a pressure retaining item are not considered alterations and are not required to be performed by a holder of an "R" Certificate of Authorization, provided the changes do not affect the pressure-containing capabilities of the vessel.
ASME PCC-2, Article 3.4, Section 4.1.3 requires NDE to be performed following the removal of a flaw or defect. We will also need to perform UT to verify that min wall is not violated after defect removal.
Two questions on this situation:
1. Does the subsequent NDE need to be performed by a holder of an "R" Certificate of Authorization?
2. What involvement, if any, is required by an Authorized Inspector certified by the National Board?
NBIC Interpretation 98-30 notes that grinding operations that reduce the outside diameter, length, and thickness of a pressure retaining item are not considered alterations and are not required to be performed by a holder of an "R" Certificate of Authorization, provided the changes do not affect the pressure-containing capabilities of the vessel.
ASME PCC-2, Article 3.4, Section 4.1.3 requires NDE to be performed following the removal of a flaw or defect. We will also need to perform UT to verify that min wall is not violated after defect removal.
Two questions on this situation:
1. Does the subsequent NDE need to be performed by a holder of an "R" Certificate of Authorization?
2. What involvement, if any, is required by an Authorized Inspector certified by the National Board?





RE: Arc Strike on ASME VIII U-stamped Vessel
2. None unless weld repair is required to restore the wall thickness.
RE: Arc Strike on ASME VIII U-stamped Vessel
RE: Arc Strike on ASME VIII U-stamped Vessel
You may need to confirm the removal of heat affected material by etching or hardness testing.
RE: Arc Strike on ASME VIII U-stamped Vessel
Regards
r6155
RE: Arc Strike on ASME VIII U-stamped Vessel
RE: Arc Strike on ASME VIII U-stamped Vessel
Not necessarily. Section IX defines an arc strike as an "inadvertent discontinuity..."
It's up to your company to define an arc strike as a defect in your specifications. See the definitions of defect and discontinuity per section IX.
My thoughts on vendors that question the need to remove arc strikes are that they need a good education on the potential problems arc strikes may cause, and leaving them on a pressure vessel just screams of lack of workmanship.