how to calculate nozzle thickness in Api 620 1

[shakila21]

hi
I need to calculate nozzle neck based on Api 620.
the related part in API 620 is 5.19.2 Minimum Thickness of Nozzle Neck which says:
a. The thickness of a nozzle neck shall be computed for the applicable loadings in 5.4, using allowable stresses as specified in 5.5, and to this thickness shall be added the corrosion allowance. The minimum thickness of nozzle neck to be used shall be at least equal to the required thickness so obtained in no case shall the net thickness of the nozzle neck, excluding corrosion allowance, be less than the smaller of the following thicknesses:
a The net thickness, excluding corrosion allowance, of the tank wall adjacent to the nozzle, disregarding any added thickness that serves as reinforcement for the opening.
b The thickness of standard-weight pipe see ASME B36.10M.

so I need to know how to calculate neck nozzle thickness since there is no formula.it is just mentioned "The thickness of a nozzle neck shall be computed for the applicable loadings in 5.4, using allowable stresses as specified in 5.5, and to this thickness shall be added the corrosion allowance." but how? does it mean with shell formula t=pr/S ??

 

[JStephen]

If there are no other loadings on the nozzle, then just calculating T2 and associated thickness would suffice.
In most cases, the minimum thickness requirements will control, so don't be surprised if your calculated thickness comes out very small.

 

[shakila21]

Thank you Stephan