First NYC is different from rest of US generally, and I don't know those codes like I do the major national model codes.
The
smoke control
system that the International Building Code and Life
Safety Code permit as an option to a Fire
Safety Curtain is different than the powered ventilation in place of roof vents you describe. What you describe is basically a big range hood. The
smoke control that the
IBC and
LSC permits is a much more extensive
system and for most intents and purposes, not
practical, or at least not for under 5000 seats and even then, it has some
practical problems. It requires significant make up air - think many many doors that open to the outside automatically upon detection of a fire - and sophisticated controls.
All of these systems - compartmentalization between
stage and
auditorium by curtain, deluge, or
smoke control AND venting
smoke from the
stage - are all to provide adequate time for occupants to
egress. Sprinklers slow growth of a fire and may put it out, but are primarily relied upon for property protection, not a major priority of the building and fire codes. In practically all of the large loss of life fires in assembly occupancies, asphixiation from
smoke - or occasionally crowd crush - is the cause of death and if you look at theaters, almost always in the highest seats. So, keep
smoke out of the audience. It seems where these systems have worked, the vents over the
stage get the credit, and I can find very little justification for the US style fire
safety curtain, because it does not stop
smoke from getting through if the
stage is positive pressure or - in other words - if the
neutral pressure plane is below the top of the
proscenium.
