API 1104 Appendix B question

[tonybka]

For Procedure Specification, section B.2.1.1.2 it states: For in-service welds, the pipeline operating conditions (pipe contents, flow rate etc) for which the procedure applies should be identified. Conditions may be grouped. Is there an industry standard that is being used for these groupings? Because, in B.2.2.1.2 it states that an increase of the severity of the pipeline operating conditions (in terms of cooling rates) above the group qualified constitutes an essential variable. Pretty vague requirements, to me. Thanks

 

[CWICWE]

The second concern is for hydrogen cracking, since
welds made in-service cool at an accelerated rate as the result
of the flowing contents’ ability to remove heat from the pipe
wall.

The flowing contents cause an accelerated rate of cooling the weld.

For hydrogen cracking to occur, three conditions must be
satisfied simultaneously. These conditions are: hydrogen in
the weld, the development of a crack-susceptible weld microstructure,
and tensile stress acting on the weld. To prevent
hydrogen cracking, at least one of the three conditions necessary
for its occurrence must be minimized or eliminated.

When qualifying a procedure,you can group the scenario of various flow rates, contents, although if you go outside of the specified scenario, you must re qualify.
So basically test for the most extreme of conditions. Water has an accelerated cooling rate in the test jig, as opposed to oil.