mtk-14
Mechanical
- Nov 12, 2019
- 2
Hi All,
Would appreciate if anyone could provide some guidance on when the requirements of ASME PCC-1 should be used as opposed to ASME B-16.5/B16.47 for assessing flange face defects.
The flange in question is 48" 150#, which has two defects from mechanical damage with radial length of 10 mm (Rd) separated by 15 mm along circumference. The depth of the defects is approx 0.1 - 0.2 mm.
Assessing the defects by ASME PCC-1, Appendix D finds w/4 < Rd < w/2 (w= Radial width gasket seating surface 23.9 mm), hence acceptable defect depth < 0.76 mm rating the defects as acceptable.
Assessing the defects by ASME B16.47, Table 30 finds as the defects are deeper than the height of the serrations the maximum defect radial length is 7 mm, hence the defect is unacceptable.
Additionally ASME B16.47 requires the defects to be separated by 4 times the maximum radial projection for multiple defects and ASME PCC-1 only requires the defects to separated by 1 time the maximum radial projection.
I believed that ASME B-16.5/16.47 should only be used on new flanges, and ASME PCC-1 on flanges in service, but i cannot find any technical justification to back this up.
Thanks in advance.
Would appreciate if anyone could provide some guidance on when the requirements of ASME PCC-1 should be used as opposed to ASME B-16.5/B16.47 for assessing flange face defects.
The flange in question is 48" 150#, which has two defects from mechanical damage with radial length of 10 mm (Rd) separated by 15 mm along circumference. The depth of the defects is approx 0.1 - 0.2 mm.
Assessing the defects by ASME PCC-1, Appendix D finds w/4 < Rd < w/2 (w= Radial width gasket seating surface 23.9 mm), hence acceptable defect depth < 0.76 mm rating the defects as acceptable.
Assessing the defects by ASME B16.47, Table 30 finds as the defects are deeper than the height of the serrations the maximum defect radial length is 7 mm, hence the defect is unacceptable.
Additionally ASME B16.47 requires the defects to be separated by 4 times the maximum radial projection for multiple defects and ASME PCC-1 only requires the defects to separated by 1 time the maximum radial projection.
I believed that ASME B-16.5/16.47 should only be used on new flanges, and ASME PCC-1 on flanges in service, but i cannot find any technical justification to back this up.
Thanks in advance.