Here's my best advice, until we get ISO 14692 implemented at some future date.
ISO 14692 is an extension of the UKOOA code. Major differences between the two are:
1. SIFS are different for bends for piping diameters below 16”.
2. Failure envelopes for ISO-14692 can be slightly more detailed (and therefore less conservative) often being defined by one more data point (having pentagon shape rather than trapezoid shape).
3. Allowable stress levels may be increased for Operating and Occasional load cases, by 24% and 33% respectively, as compared to Sustained load cases.
4. Failure envelopes are defined for different types of joints in ISO 14692.
5. The “f2” term is excluded from the bending stress in ISO-14692, vs. included in UKOOA.
So I would suggest to you:
1. Model and analyze the system in CAESAR II using the UKOOA code.
2. Make sure that the checkbox for “Exclude f2 from UKOOA bending stresses” is checked in the Configure/Setup.
3. If you have ISO 14692 failure envelopes, construct a trapezoid that will fully fit within those envelopes, and use those to get the values you need for UKOOA (Sa(2:1) and R).
4. Use a system factor f2 of 0.67.
5. Calculate the bend SIFs as per ISO-14692 and manually enter any of those which significantly differ from those of BS-7159 (which is what UKOOA references).
6. After analyzing your model, compare your Sustained stresses to 100% of the allowable, your Operating stresses to 124% of the allowable, and your Occasional stresses against 133% of allowable.
7. Where joint strengths may govern, check them manually against the forces from the CAESAR II local force report.
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Tom Van Laan, PE
COADE, Inc.