Floor Area Net occupant calculation

[Tim Mailloux]

I am starting a basic code study for an elementary school project in our office, 2018 CT Building Code based on the 2015 IBC. In the project there are approximately 64 classrooms, and each classroom will have a rear wall full of built in casework (tall storage cabinets, storage cabbies for students, a counter with a sink, etc). Several members of the project team feel that its acceptable to deduct the footprint of these built ins from the net area of each classroom. The deduction would reduce the net area of each classroom by 30sf to 40sf ( 2 occupants based on education 20sf per person), and overall it would reduce the occupant load of the building by up to 128 people.While this approach seems reasonable to me, there is nothing I can find in the model code or the code commentary that allows this approach.

What are your thoughts?

 

[ADAguy]

It depends, you are not reducing the conditioned space only the occupiable space and the cabinets could later be removed. Is your concern the number of room exits or building exits?

 

[cda]

So why??

Reduce exit doors??

No voice evac?

Less tornado shelter area?

Less potties?

 

[Tim Mailloux]

The definition of Floor Area Net does state its the actual occupied area. But my concern is that they could be removed at a later date increasing the occupant load

 

[Tim Mailloux]

So why??

Reduce exit doors??

No voice evac?

Less tornado shelter area?

Less potties?

They are cutting it very close on egress and cutting those 128 occupants would give some breathing room.

 

[cda]

They are cutting it very close on egress and cutting those 128 occupants would give some breathing room.

Ohhhh

Yep you want to scrimp on exiting from a school.

one door or two?

 

[Tim Mailloux]

Ohhhh

Yep you want to scrimp on exiting from a school.

one door or two?

Stairs are the concern, currently have (4) stairs egressing the second floor and they are all just about maxed out egress wise and it would be challenging to make these stairs larger. Currently the plan is code compliant, but we are also only mid way thru design development and a few simple plan changes could push the occupant load over the top and I would like to have some breathing room.

FWIW, CT requires egress capacity for stairs to be calculated at .3 inches per person with or without sprinklers.

 

[JPohling]

Is your occupant load ratio net or gross? if gross then No, if net then Yes

 

[Tim Mailloux]

Is your occupant load ratio net or gross? if gross then No, if net then Yes

Its education K-12, so NET

 

[JPohling]

Its education K-12, so NET

Then I would not calculate the floor areas that are consumed by built in cabinetry or equipment.

 

[ADAguy]

If you are that close, later removal of cabinets could push you over the top.
Is site constrained or is it a budget issue? Consider separating pairs of classrooms with movable walls?
Who reviews school plans in CT?

 

[steveray]

Who reviews school plans in CT?

I do......Tim, you/ and or should detail that limitation on the plan that the casework keeps the OL down and if there is a change it has large ramifications for CYA factor....You met the minimum code. Congrats! They could do anything with that room down the road, like fill it with dynamite, but we don't regulate what might happen...

 

[ADAguy]

Points made but often overlooked