Regarding the opening of the flathead following ASME Section VIII Div.1 1

[WRH_36]

I am checking the adequacy of the flathead with a thickness of 1 inch. Please find the attached figure.
There are three 4" and multiple 1" openings.
I checked the code UG-36 to UG-40 in ASME Section VIII Div.1 and confused some statements.
UG-36 (3) (-a) (-1) "finished opening not larger than 3.5 in. (89 mm) diameter—in vessel shells
or heads with a required minimum thickness of 3/8 in.(10mm) or less;"
There are three 4" holes, but the minimum thickness is 1" which is larger than 3/8 in. Not sure if I need to add the reinforcement?
UG-36 (3) (-d)
"(-d) no two unreinforced openings, in a cluster of
three or more unreinforced openings in accordance with
(-a) or (-b) above, shall have their centers closer to each
other than the following..."
I am not sure if my case fits (-a)?

Thanks,
WRH_36

 

[SnTMan]

WRH_36 you must refer to the rules in UG-39 for reinforcement of openings in flat heads.

You should be aware that in Code speak "reinforcement" does not necessarily imply added elements, but that it can be shown by applicable rules sufficient excess thickness exists to provide said reinforcement.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[WRH_36]

Hi Mike,

Thank you for your comments.

Regards,

WRH_36