API 617: Governing Thickness for Impact Tests

[newweldeng09]

API 617 Standard, Par. 2.2.1.15.5 states that the governing thickness used to determine impact testing. My company welds nozzles on P1, Gr. 2 compressor cases, (these are not castings). The cases are nominally 8 inches thick. My interpretation of this section is that this thickness is to be used to determine impact testing because it is greater than the nominal thickness of the largest butt-welded joint and is greater than 1/4 of the nominal flange thickness. Using this thickness in Section VIII, Fig. UCS-66, the thickness is off the Figure. UCS-66, lists exemptions for welded and non-welded construction. This case is welded, but since the nominal section for pressure containment is the governing thickness, is API 617 treating this as a non-welded case? This governing thickness would require impact testing of the materials. Is this correct?

 

[nickelkid]

It appears to me that regardless of construction, weld or non-welded, API 617 governing thicknesses for impact testing on a “Low Temperature” case is what you have interpreted.