scope:

This Bulletin focuses on the background of blister damage, HIC, and SOHIC. A review of WRC Bulletin 396, "Research Report on Characterization and Monitoring of Cracking in Wet H2S Service," along with detailed analyses of laboratory tests undertaken on steel removed from severely HIC damaged vessels are included. In addition, the results of round robin NDE testing of HIC damaged plates in the MPC FFS Joint Industry Program are discussed. The results of testing and WRC Bulletin 396 indicated that HIC damaged steel has considerable remaining strength. However, with HIC comes the added uncertainty of potential for SOHIC. Therefore new rules were developed for API 579-1/ASME FFS-1 that include both the recognition that HIC damaged material has remaining strength, but also the need to perform cracklike flaw calculations. A commentary on the new rules in Part 7 of API 579-1/ASME FFS-1 issued in 2007 is also included in this paper