Calculation pressure

A theoretical pressure at least equal to the test pressure which, according to the degree of danger exhibited by the substance being carried, may to a greater or lesser degree exceed the working pressure. It is used solely to determine the thickness of the walls of the shell, independently of any external or internal reinforcing device (see also "Discharge pressure", "Filling pressure", "Maximum working pressure (gauge pressure)" and "Test pressure"). NOTE: For portable tanks, see Chapter 6.7.