Dear all!

I understand in B31.1 2004 CASE 173.1 that Code considers acceptable the use of ASME Sec. II Part D maximum allowable stresses (based on a material safety factor of 3.5) instead of the allowable stresses of Appendix A of B31.1 (based on a material safety factor of 4), as long as material is listed in B31.1. Am I right? Or is there any limitation to the use of this bigger allowable stress?(I had never used it)
And, is it possibble to consider this increased allowable stress in CAESAR automatically or must I modify myself all the allowable stresses?

best regards,

CAESAR II does not consider this automatically. If you want to use the allowables from Sec. II, you'll have to input them manually.

Carletes

Essentially you are conceptually correct (but the devil is in the details). A complete reading of B31 Case 173 is essential because, yes, there are limitations (see B31 Case 173, (d) for example). Also remember that not all the materials that have been used previously in the B&PV Code will qualify for the 3.5 factor of safety. So you must use the maximum allowable stress magnitudes as provided by the Section II, Part D, 1999 Addenda, Tables 1A and 1B.

The above is only my opinion and not that of ASME or any ASME Code Committee.

Regards, John.