Many of you on this forum have firefighting experience. On rooftop air handlers with direct exhaust who decides what the unit does when the fire alarm goes off? Is it specific to the city or building?

Is it best to have the air handler exhaust smoke until the fire department cuts power? Would it depend on the estimated time to evacuate the building? Say run the exhaust for 45 minutes if it takes 30 minutes to evacuate the building? These are the same questions I am asking our customer but I would like to see the different applications and their effects that people have seen in real world applications.

I also know there are so many variables involved that it becomes complicated. From my Navy firefighting days I remember ventilating the compartment with a hatch, then someone opens a hatch on the other side and it creates a blow torch effect.

I would appreciate hearing your views on this application.