Division 2.1.1 Calculation method

The minimum thickness of pressurised parts shall be calculated having regard to the intensity of the stresses and to the following provisions:

1. (a)

   the calculation pressure to be taken into account shall not be less than the maximum working pressure PS selected;

2. (b)

   the permissible general membrane stress shall not exceed the lower of the values 0,6 R_eT or 0,3 R_m. The manufacturer shall use the R_eT and R_m minimum values guaranteed by the producer of the material in order to determine the permissible stress.

However, where the cylindrical portion of the vessel has one or more longitudinal welds made using a non-automatic welding process, the thickness calculated as referred to in the first paragraph shall be multiplied by the coefficient 1,15.