Select and determine the pressure grade of the stainless steel pressure vessel flange, taking into account the material type, medium properties, and operational status. Specific requirements are as follows:

(1) The pressure class of the container flange should not be lower than the allowable working pressure of the flange material at the design temperature.

(2) The pressure class of the container flange in a vacuum system should generally not be less than 0.6 MPa.

(3) When handling media that is brittle, explosive, or toxic, it is recommended to use a flange of one higher grade.