Right, the number 20 would result in a stricter occupant load than what the local/state allows, so being stricter than code shouldn’t present a problem.
That said, I like your idea and would basically be telling the township that we’re posting the maximum occupant load per the building code, and then—if they have jurisdiction—they can impose a lower occupancy limit.
My assumption is that the state or local agencies are providing funding for the daycare, which effectively means they’re saying: “We’ll fund your childcare program, if you comply with our specific requirements.”
In that case, the owner can absolutely use the IBC occupant load calculations to establish the maximum allowed occupancy. However, by doing so, they’re essentially opting out of the program requirements and, in turn, would lose access to the associated funding.
That leads me to the question again of how to treat the common areas in the occupant load calculations. Logically, if I use a consistent count of 35 SF per person across the entire space, the numbers work out uniformly. But if I use 20 SF per person in some rooms, it implies a higher number of occupants overall—some of whom would logically be present in common areas as well (meaning I should then technically account for more occupants utilizing the common areas).
This is where I often get stuck: (general in many projects) Common areas impact the specific room egress (as they definitely can have a combined and higher OL than specific smaller rooms), but they don’t always change the overall occupant load. Yet (in this case) when I include both classroom and common area loads in my calculations, it appears I’m designing for more people than will realistically be present at one time—especially from an egress or plumbing fixture perspective.
(Another time this comes up is when a school has an auditorium- would definitely count that toward the total occupant load, and other assembly areas used only and specifically by the students in the school, where the OL count for those rooms really should not effect the overall egress calculation and plumbing).
