Hello,

I am reading the following book; Pressure Vessel Design Manual secnd. 2 by Dennis R. Moss. On page 41 "Design of Blind Flanges with openings" you can calculate the minimum flange thickness.

On this page below the next notes are standing:
1. XX
2. Options in lieu of calculating reinforcement
Option 1 - No additional reinforcement is required if flange thickness is greater than 1.414 to
Options 2- If opening exceeds one half the nominal flange diameter, the flange may be computed as an optional-ype, reducing flange.
Option 3 - No additional reinforcements is required if to is calculated substituting .6 for .3 in the equation for to(doubling of c value)

Does anybody knows if this options is based on the ASME? And where is it standing in the ASME VIII div.1?

Refer to ASME UG-39(d) that gives you an alternative to checking the reinforcement on the blind flange.

In PV Elite you have both options,

If you check the reinforcement, then add a nozzle on the blind flange.

If you want to check the alternative way, then after you modeled the blind flange then on the input screen, on the bottom there is an option for "Evaluate Uniform Patterned Holes". Check that and specify the input.