Usually we weld all our openings (nozzles, tubes, fittings, etc.) on vessels by means of full penetration welds even if it is not required or neccessary. We think this way is more stiffer and can withstand much more loads, etc.

Every time our AI require us to calculate and check on vessels the minimum dimension of the weld tw or tc (see UW-16). But if the welding details are according to figg. UW-16.1 sketchs (a), (b), etc. UW-15 (b) write it is not required or not?

Best regards

AMinati

Strength calculations for nozzle attachment welds for pressure loading are not required for
Figure UW-16.1 sketches (a), (b), (c), (d), (e), (f-
1), (f-2), (f-3), (f-4), (g), (x-1), (y-1), and (z-1),

Read UG-41(b)
and
UW-15 quoted here below
(b) Strength calculations for nozzle attachment welds
for pressure loading are not required for the following:
(1) Figure UW-16.1 sketches (a), (b), (c), (d), (e), (f-
1), (f-2), (f-3), (f-4), (g), (x-1), (y-1), and (z-1), and all the
sketches in Figs. UHT-18.1 and UHT-18.2; see L-7.1 and
L-7.7;
(2) openings that are exempt from the reinforcement
requirements by UG-36(c)(3);
(3) openings designed in accordance with the rules
for ligaments in UG-53.

Fillet weld size of joints (UW16 figures) should be calculated and mentioned on drawing.