Hello Stressers,

ASME B31.3 2016 now incorporates the use of B31J as an option for Stress Intensification Factors.

I have searched the B31.3 2016 and found 3 statements about B31J shown below:

1)
319.3.6 Flexibility and Stress Intensification
Factors. The flexibility factors, k, and stress intensification
factors, i, shall not be less than unity. In the absence
of more directly applicable data, the flexibility factor, k,
and stress intensification factor, i, shown in Appendix D
shall be used for flexibility calculations described in
para. 319.4.
Stress intensification factors may be developed in
accordance with ASME B31J.
For piping components or attachments (such as valves,
strainers, anchor rings, or bands) not covered in
Table D300, suitable stress intensification factors may
be assumed by comparison of their significant geometry
with that of the components shown. The validity of any
assumptions is the responsibility of the designer. If two
or more of the geometries shown in Appendix D are
combined, their combined k and i might be significantly
different from the values shown. Examples include trunnions
on elbows and branch connection fittings welded
to anything other than straight pipe.

2)
For branch (Leg 3 in Fig. 319.4.4B), use eq. (23b2) only
when l 1 or [0 is based upon i, i11 or i0 taken from
Appendix D; when both I; and /0 are determined by
experimental or analytical means, e.g., ASME B31J use
eq. (23b1).

3)
For branch (Leg 3), use eq. (20) when i; or i0 is taken
from Appendix D; when both i1 and i0 are determined
by experimental or analytical means, e.g., ASME B31J,
use eq. (19).

My question is how about the use of Flexibility Factor k? Is it also a part of ASME B31J and can be an option instead of using the Appendix D k values?

Many Thanks,

Cheers!!

Yes! The flexibility factor, especially for tees, is just as important as the SIF. This is what FEATools is all about (please listen to the Webinars on this website for details). If you are using CAESAR II v.10, you have B31 Essentials, this provides the ability to use the SIFs and K-factors from B31J.

The current B31.3 references the old B31J. The old B31J provides a method for determining SIF by experimentation (the "Markl" method). This has been around for quite a while.
Both B31.1 & B31.3 have proposals for their next editions that make reference to the NEW B31J and its flexibilities.

Thanks Dave and Richard. That clears my thoughts.