Floor Area for Flush Out

I'm looking for some help with the area to be used for a flush out calculation. The gross project area included in PI-Form 3 includes electric/janitor closets, core toilets, mechanical room and emergency stairs. From other comments, it seems like I need to include the closets & toilets in the flush out. The mechanical room is a dedicated mechanical floor on which my client is adding some fans. There is no air being supplied for the emergency stairs and mechanical room, by my client since these are base building areas. The closets & toilets are being exhausted only, but there are transfer air louvers. Should I include the emergency stairs and mechanical room in the flush out calculation? Thanks.