In the Dance Studio Case Study

How many occupants can the client expect to have on the proposed additional level? Assume that the proposed additional level will be built with the same footprint as the building below, and round up to the nearest occupant.

84
occupants
Incorrect - the answer is 72

Based on the 2018 IBC, exercise rooms are allotted an occupant factor of 50 (gross). See Table 1004.5.

The case study scenario notes that the proposed additional level will be the same gross square footage as the building below (4,200 sf) and will be 85% efficient. Therefore, the size of the proposed exercise room will be:

4,200 sf x 0.85 = 3,570 sf

To find the number of occupants that are permissable in this space, divide the square footage by the occupancy factor found earlier:

3,570 sf / 50 occupants per gross square foot = 71.4 occupants, which rounds up to 72 occupants. (Note that the question requires rounding up.)

I don’t understand why did we take the net area not the gross?

Thank you

@coachchrishopstock can you please take a look into this question?

Thanks,
-Darion

Hi @ylouka - I can totally understand the confusion here, let me try to explain.
We’re at the schematic design phase in this example, so floor plans are not yet fully developed. It’s common to estimate the efficiency of the floor plate at this stage - by saying it’s 85% efficient, we’re noting that corridors, stairs, elevators, etc. will take up 15% of the floor plate. These spaces do not contribute to occupant load, so we must multiply the gross area of the floor by 85% to estimate the size of the dance studio.
After doing that, we use this number and multiply by the occupant load factor (50) to arrive at the number of occupants.

1 Like

Thanks for explaining.

Hi @coachchrishopstock @coachdarionziegler–asking this here so the dance studio questions can stay together! When I did the calculations for the additional level, I subtracted 3500 SF from the 4200 GSF to account for the double-heighted dance studio listed in the program. Did I miss something in the question that should have led me to use the full 4200 GSF as my starting point?

Thanks!
Desiree

I did the same thing! But I guess they are assuming the entire thing is a single story and the entire footprint is being added onto.

@coachchrishopstock @coachdarionziegler @coachjoeyandrada

My answer was 42. I arrived at it based on the 2018 IBC, exercise rooms are allotted an occupant factor of 50 (gross). See Table 1004.5.

The case study scenario states that the proposed additional level will be “built with the same footprint as the building below”. NOT “will be the same gross square footage as the building below.”

Per the scenario, “The building is 4,200 gross square feet” and is two stories.

Does that not mean that the footprint is 2,100 sf?

Thus the adidtional level would be 2,100 sf and 2,100 sf/50 = 42.

Technically, as others have noted, the FOOTPRINT would likely be
[(4200 sf gross building - 3500 double height space)/2] +3500 sf for the double height space

4200-3500 = 700 (which is the amount of the additional spaces)
700/2 stories = 350 per story for support spaces
350 at the ground level for support spaces + 3,500 sf for the dance studio = 3,850 sf FOOTPRINT
3,850 sf footprint/50 gross occupants per gross sqaure foot per Table 1004.5 = 77 occupants

Can one of the coaches comment please?

6300 N. Northwest Highway P.O. Box 31846, Chicago, IL 60631-9998 / All rights reserved © 2020 Black Spectacles.