102.3 Allowable Stress Values and Other Stress Limits for Piping Components
102.3.1 Allowable Stress Values
The basis for establishing the allowable stress values in this Code Section are the same as those in the ASME Boiler and Pressure Vessel Code, Section II, Part D, Appendix 1...
302.3.2 Bases for Design Stresses
(4) 100% of the average stress for a creep rate of 0.01% per 1 000 h
(5) 67% of the average stress for rupture at the end of 100 000 h
(6) 80% of the minimum stress for rupture at the end of 100 000 h
These are same as ASME Section II, Part D, Tables 1A and 1B.
(b) At temperatures in the range where creep and stress rupture strength govern the selection of stresses, the maxi-mum allowable stress value for all materials is established by the Committee not to exceed the lowest of the following:
(1) 100% of the average stress to produce a creep rate of 0.01%/1,000 hr
(2) 100Favg% of the average stress to cause rupture at the end of 100,000 hr
(3) 80% of the minimum stress to cause rupture at the end of 100,000 hr
where
Favg%multiplier applied to average stress for rupture in 100 000 h. At 815°C and below, Favg p 0.67. Above 815°C, it is determined from the slope of the log time-to-rupture versus log stress plot at 100,000 h such that log Favg%=1/n, but it may not exceed 0.67.
n = a negative number equal to Delta log time-to-rupture divided by Delta log stress at 100,000 hr