normal

[OSCAR$]

Good morning.
I am using asme manuals, in particular section 8 (pressure tanks) and section 2 part d (materials with values in si).
I found discrepancies in the values read on some articles and those provided by the tables.
In particular, in the articles reference is made to creep life, in tables no.
the values of the admissible tensions, at various temperatures are inserted in tables 1a and 1b, at the end of the text there is an appendix (photo).
I do not understand whether it is how the legislation has determined the values or how these should be "correct" from those present in the tables.

 

[davidex]

the asme bpvc ii part d gives you the eligible values to use in formulas (designed with letter s "maximum allowable stress" (which corresponds to what in the en 13345-3 is designated with symbol fd "nominal design stress").

is in practice what in Italian on other regulations is usually called admissible voltage, already weighed with various risk factors. the en 13445-3 tab 6-1 tells you how to calculate this fd value, starting from the yielding voltage, breaking and other parameters of the material (typically for carbon steel is the minimum between the yielding at the project temperature (ts) divided 1.5 and the break at room temperature divided 2.4. Therefore it is simple enough to calculate, but the values are not then given in the en 13445-3, but you have to search them directly on the norms of the materials (for example for the tubes la en 10216 from the yielding to different temperatures, then the parameter is interpolated to the project temperature ts). alternatively there are software that already give you the correct value once you define the material and the project temperature ts.

the asme instead does not define the yield values at the temperature in the norms of the material (astm or asme bpvc ii part a and b), but directly gives the finite value s without having to do any calculation, in tables 1 (for vii div. 1) and 2 (for vii div. 2) and 3 (for tiranti and bolts) of the asme bpvc ii part d.
the yield and breaking voltages at the temperature then do not find them in table 1 or 2, but in table y (for yield) and u (for ultimate), but cmq then you would miss the creep and I think other parameters. essentially, however, with the asme you do not have to use Appendix 1, but only the values already tabled in the relative tables (1 for div. 1 and 2 for div. 2), so you do not need to calculate anything.