The secondary or emergency relief pressure is to be the highest of those pressures occurring in the test of at least two of the same secondary or emergency relief devices. If
the secondary or emergency relief device pressures of two or more devices being tested vary from one sample device to another by more than 10 percent, the total number of
samples tested is to be increased to six. The maximum pressure is to be the highest observed during the testing of the six samples. In such a case, the lowest pressure of any
of the six samples is to be at least 85 percent of the maximum pressure determined by the above procedure