Asme section ii part D- choosing the scale factor from table y-2 for Leak sealing

[psotil]

I am looking to use A240/316L as a flange/lug material for a leak sealing clamp. From reading section ii part D, this material has note (G5). The note states that this material is not recommended for applications where small deformation can cause leaks. Which is why I want to know the acceptable limits.

Note G5 refers to applying a scale factor listed in Table Y-2 to the YS and TS from Table Y-1.

The table has two columns:
1) %Strain
2) factors

I want to know how to determine the appropriate scale factor? Is there a calculation?, is there a method listed in the code which I may have missed.

I read a similar thread (thread794-391000), which referred to Appendix 1 which is a larger version of Note G5. This section does not explain how to determine the appropriate scale factor.

Any ideas?

 

[r6155]

It is easy to understand. Read again and again general note in Table Y-2.
Also you can use stress in line 17 of Table 1-A for SA 240 316 L (note G5 not applied)

Regards
r6155

 

[psotil]

I understand the concept of multiplying by a factor as described in the general note. What I want to know is how to choose the appropriate factor? the %Strain column ranges from 0.01-0.1%. I Want to know what is good engineering practice when selecting this. Is there a method? rule of thumb etc. The range of factors is 0.63-0.9 so the correct/appropriate choice makes a real difference to the final figure.


Secondly, the duplicate material listing is also confusing. the general data for this is the same except for the allowable stresses at temperature and the note (In this case the G5 note). Is there a clarification as to why we choose line A over Line B of the same material listing? I wouldn't think that we can choose the one that suits us in terms of allowables, there must be a reason why there are multiple listings of the same material.

Regards
PSotil