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figuring occupancy count

Builder Bob said:
Yes the occupant load is calculated for each space for its intended use, then the sum of all these areas is the occupant load for the structure.

gone are the days of saying it is a business occupancy and using 100 gross for the SF of the building.
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Thanks! I have older architects tell me to use that method of "saying it is a business occupancy and using 100 gross for the SF of the building." Was that how it was done in previous building codes before the IBC? Like in the SBC?

Also, what is your opinion on break rooms and the occupant load factor in table 1004.1.2? I am gravitating towards saying assembly with tables and chairs which would give it a 15 sf net load factor. I am thinking this because the business does not have a conference room and if they were to have some kind event where additional people come into the building that are not employees (but employees are there working in their offices) they may use the break room to gather. What do you think?
 
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erik1618 said:
Thanks! I have older architects tell me to use that method of "saying it is a business occupancy and using 100 gross for the SF of the building." Was that how it was done in previous building codes before the IBC? Like in the SBC?

Also, what is your opinion on break rooms and the occupant load factor in table 1004.1.2? I am gravitating towards saying assembly with tables and chairs which would give it a 15 sf net load factor. I am thinking this because the business does not have a conference room and if they were to have some kind event where additional people come into the building that are not employees (but employees are there working in their offices) they may use the break room to gather. What do you think?
Click to expand...


Just be careful or the ahj will enforce assembly requirements do that room. If you can some how keep the occupant load under 50 do it, unless it is just obvious that it can hold more, such as showing 30 tables for training and 3 chairs per table.
 
Stupid is, as stupid does.

How many exits do most elevators have? How many people can you pack in an elevator? Square footage does not always limit the number of occupants in a given area.

Break rooms when used for birthdays, donuts, etc. can often exceed the intended persons per square foot count (standing room only) yell "fire" and how many can get out in a timely fashion?

Exclusive of code good practice is to consider the total number of occupants within the tenant space vs the likelihood that they will all be in one room at the same time.
Code alone is not always a guarantee of survivability in the event of a mass evacuation from a single room.
 
ADAguy, That's why the IBC allows for an increase in calculated occupant load as long as you don't go below 5 s.f. per person.

Most properly, the spaces are analyzed individually for 'function' of space - so a conference room or break room is usually calculated at 15 s.f. per person to allow for tables and chairs with aisles between. The office areas are a 100 s.f. per person.
 
ALSO, the occupant load factor used in chapter 10 is to ensure that more adequate means of egress are used in the design of the structure......... OL for the structure may be debated... One of the hottest debates that went on for a while was the school gymnasium ---- which was often cited for school assemblies .... Which causes problems when the school is leased by a church for Sunday Services and causes egress problems due to security grates/grills being used to isolate the school from the public use Gymnasium....
 
We run it space by space for egress, but if it comes down to a fixture count issue, I would have no issues lumping some small conference rooms at 100 per in a B as long as the egress works and they are actually doing "gross" correctly..In multi tenant buildings I see designers not assigning the common areas (corridors, bathrooms, mechanicals)to anyone and that is a problem.
 
Corridors, bathrooms and mechanical rooms don't have an occupant load per se as they are not normally occupied within the context of the Code.
For a 'gross' square footage calculation they get lumped in with the primary occupancy.
For a 'net' calculation they are generally ignored (or subtracted out).
The logic being that, for example, in an A2 Occupancy I can't put tables and chairs in the corridors, bathrooms, mechanical rooms and then use them as 'assembly space'.
 
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Interesting, though you "can't"/shouldn't put tables and chairs in corridors it doesn't mean that in after hour raves or during parties they won't.
Some never "get it".
 
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