Smoke Compartment calc

[TapaTapa]

Can someone provide an explanation of how to calculate the required refuge area for a smoke compartment per CBC 407.5? I understand that the required refuge area is Non-A x 30 SF + A x 6 SF. But how do I determine the amount of "non-A" and "A" occupants? Also, are employees included in the "A" occupants since the CBC states "and for other occupants"? also, Does the total occupant load calc per chapter 10 have to be equal to "non-A" + "A"?