I need to clarify description. Openings have a minimum lintel depth of 8" from ceiling and the total width of the openings in each wall not to exceed 8'.
I understand this to consider a 12" deep x 12" thick lintel over a 12' opening will combine two rooms into one compartment because even though it exceeds the minimum lintel depth, it is over the 8' maximum opening. Others consider this two compartments just because it has a lintel over 8" in depth.
To further complicate things. Across the room is the same size opening (12' wide x 12" thick opening). But even though the openings are 9' high, the ceilings are 19' high. No chance of heat activating sprinklers on opposite sides of the wall unless fire is in the opening. Logically the ceiling height would divide this into two compartments. But to stick just to the definition, these three rooms would be one compartment with two continuous obstructions. What is your interpretation?