Can holes be made in the short sections of the shell for type B flat-weld flanges?
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When reviewing design drawings for shell-and-tube heat exchangers, it is observed that when type B flat welding flanges are used for the equipment tube box flanges, openings appear within the total height H of the flange. Is it permissible to make openings within this total height H when standard type B flat welding flanges are used as tube box flanges?
Since the type B flange stub directly resists flange bending moments, its own strength and stiffness are crucial; making holes in it reduces its overall stiffness. Therefore, I believe holes should not be made in it (even if the reinforcement is sufficient), unless a stress analysis is conducted to determine whether the area affected by the holes overlaps with the area affected by the flange bending moments, so as to ascertain whether the stub can still meet the requirements regarding flange strength and stiffness after the holes are made.
Since the type B flange stub directly resists flange bending moments, its own strength and stiffness are crucial; making holes in it reduces its overall stiffness. Therefore, I believe holes should not be made in it (even if the reinforcement is sufficient), unless a stress analysis is conducted to determine whether the area affected by the holes overlaps with the area affected by the flange bending moments, so as to ascertain whether the stub can still meet the requirements regarding flange strength and stiffness after the holes are made.
After making the openings, the thickness of the flange, as well as the size and number of bolt holes, need to be recalculated