Where do true limits lie when considering inner rooms?
Suppose we had an arena, capable of holding, say, 16,000 people in one space under one roof. Suppose that in the middle of that very high ceilinged arena a relatively small room is constructed. It has a relatively low ceiling and a number of exits leading in different directions and it is capable of holding 200 people. Suppose that we fill the room with 200 people. We won't put anyone in the outer space so let's say the outer walls of the room are entirely glazed, giving everyone in the room good vision over the area outside the room, just in case a fire starts out there.
This room is an inner room and subject to a maximum of 60 people according to guidance but would we object to there being 200 in the room if there were sufficient exits from the room for 200 people and if they could disperse freely though the arena to use any of the multiple exits?
Normally we restrict inner room populations to a maximum of 60 because of the dead end element usually associated with them, i.e. we like there to be no more than 60 in a dead end. But my hypothetical room has no dead ends so is the limit of 60 relevant?
Suppose now that we take the glass walled room and the 200 people and put them in a much smaller low ceilinged function room. The function room has enough exits for more than 200 and people from the inner room can move in different directions to different exits when escaping through the function room. Now we have a situation where, in the event of a fire, due to the low ceiling, lateral spread of fire and smoke through the access room could have much more of an effect on means of escape. Should we limit the inner room to 60 now? No one's in a dead end but perhaps we should examine the possibility that a single fire could affect all escape routes from the inner room through the access room.
However, suppose that the inner room is full of 200 people and the outer room is full of another 300 people, as in the scenario given by Lyle above. If we were to dissolve the walls of the inner room, leaving everyone in the same place as they were before, would the removal of the walls make any difference to the risk the people are exposed to?
In fact, I have come across a few situations where largish inner rooms (population > 60) discharge through a number of separate exits into larger access rooms and each time I have considered the distribution of fire loading in the access room, the height of the ceiling, the distribution of exit routes both from the inner room and from the access room as well as the more usual exit widths, facilities for people with impaired mobility, etc. If I'm not happy, stipulations are imposed, maybe I limit them to 60.
Maybe they don't pay any attention.