Ball valve calculation vs ASME B16.34

[BFZHA]

Hi,
While reviewing a calculation note for 2 pieces ball valve, I have asked Manufacturer to check the inner and outer ligament of body.
His reply was that according to ASME B16.34 Clause 6.1.2 (c) the ligament calculation is not required for 2 pieces valve construction design.
The clause cites 3 pieces ball valves but do not provide any exclusion for 2 pieces ball valves.
However, in ASME B16.34 interpretation for the following question "According to para. 6.1.2(c) of ASME B16.34-2009, would a two-piece ball valve design qualify as being a multi-piece construction?" the answer is No; That means 2 pieces ball valve is not concerned by this Clause.
So, my questions are:
1- Is this interpretation correct ie ligaments calculations are not required by ASME B16.34?
2- If it is the case, how, then, we can check that the thickness of ligaments are safe and do not constitute a threat to valve failure in this area.
Thanks.

 

[BFZHA]

Just an information

Clause 6.7 "Wafer and flangless valves" and fig 17 can be used to check inner and outer ligaments for ball valves body. Body having no flange on the side of closure.


I think it is a good approach to define the thickness of the ligaments in a safe manner.

If anyone can advise, he will be helpful

Thanks.