Here's a note in the Configuration processor's Help: "When the piping code specifies hoop stress evaluation, the software uses the code's hoop stress calculation and ignores Base Hoop Stress On. For example, offshore or transportation piping codes, such as B31.4, B31.8, and DNV, specify hoop stress evaluation."
PD 8010-1 is another one of these Codes.
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Dave Diehl