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Occupancy for small conference/break rooms

T

tg947

Member
Joined
Mar 12, 2013
Messages
9
Location
Raleigh
What occupant load to assign to accessory conference rooms or break rooms in a B occupancy less than 750 sq ft? There was a previous discussion which I can't find where the consencus was that the occupancy of these spaces should be at an Assembly rate instead of Business. I am convinced that the statements in 303.1 that such spaces shall be 'Business occupancy' do in fact pertain to the occupancy rate. Understanding that the table in 1004 dictates occupancy density the only way to determine if you are in an assembly or business space is via the definitions in chapter, which explicitly dictate these spaces to be Business. That makes sense with the limit being 750 sq ft since if you did populate the space at an assembly rate this would be the point where two exits are required. It also seems to be a way of the code recognizing such accessory spaces will have some of the occupants come from the main spaces. I'm outnumbered. Can anyone agree with me?
 
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tg947,

1st, ...Welcome to The Building Codes Forum! :cool:

2nd, ...What edition of the codes are you using / referring to,

...type of seating in the space [ fixed, ...non-fixed, ...tables &

chairs, ...etc. ]?

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See Exception 3 to 2009 IBC Section 303.1. A space less than 750sf used for assembly purposes is Group B, or part of the occupancy to which it is accessory.

Table 1004.1 provides occupant load factors, not occupancy classifications.

As far as non-simultaneous occupancy, you can try to apply the exception to 1004.1.1, though the means of egress from each space will still need to be designed for its occupant load, even if the occupant load of the spaces is not summed.
 
2009 IBC

tables and chairs but I'm arguing that the code says these are business (100 gross).

Thanks
 
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Have you reviewed Table 1004.1.1 [ `09 IBC ]?

750 sq. ft. / 15 sq. ft. per occupant net = 50 occs. = 2 MOE

from that space.

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I still haven't seen a reason to call it assembly, and chapter 3 clearly states it is business. Now your gonna tell me occupancy and use are seperate but not so fast. the code doesn't seem to do this (see 1004.1.1 for use of the word occupancy for use)

750/100 = 7.5.

Maybe the code writers should have limited the exception to 735 sq ft.
 
storage space in B? 1 to 300. If chapter 3 said it was to be considered business then it would be 1 to 100.
 
I think Aegis nailed it .....use and occupant loading (not occupancy!) are different......Table 10whatever gives you a breakdown of specific loading that you may find inside any "use" (or occupancy)....The chapter 3 stuff (where you treat it as a B) gets you out of all of the other specifics for A uses...sprinklers, main exit, fire ratings, etc....
 
chapter 5 already lets accessory uses out of seperation ratings. Sprinklers? Small accessory assembly areas aren't likely to kick that in. So is there a real purpose to the chapter 3 exceptions if not for occupancy loading??

Also, Table 10.4.1.1 has entries for business and assembly - why do you assume conference rooms are assembly? How do you get to that without going through chapter 3. Accessory spaces are not exactly public destinations anyway.

I know what everyone was taught but in this case it doesn't jive with the book.
 
Business is a bad example because it is done in gross.....including all areas....not net...If I can explain this right...I would review the whole space (occupancy) at 100 per, but "special" areas would get looked at for specifc requirements by room...
 
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It is a "B"

But you need to use the occupant load factor for the use if the space

So not 100

302.1 General. Structures or portions of structures shall be classified with respect to occupancy in one or more of the groups listed below. A room or space that is intended to be occupied at different times for different purposes shall comply with all of the requirements that are applicable to each of the purposes for which the room or space will be occupied. Structures with multiple occupancies or uses shall comply with Section 508. Where a structure is proposed for a purpose that is not specifically provided for in this code, such structure shall be classified in the group that the occupancy most nearly resembles, according to the fire safety and relative hazard involved.
 
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AegisFPE was on the right track. The conference room is an assembly use but not an assembly occupancy. The space is still classified as B in regard to occupancy, but for determining occupant load, the assembly load factor (usually unconcentrated at 15 sf net/occupant) is used to determine the occupant load. The rest of the office space is calculated at 100 sf gross/occupant.

Now, you could argue that the total occupant load of the building be based on 100 sf gross/occupant if the conference room is used only by employees, especially for determining fixture counts, but for egress, the space will need to be analyzed specifically for it load. If the conference room will refrequently be used by occupants other than the employees, then I would look to add the conference room occupant load added to the occupant loads of the other areas to get a total occupant load for the building.
 
301.1 Scope.

The provisions of this chapter shall control the classification of all buildings and structures as to use and occupancy.

Table 1004.1.1 relates to the "Function" of the space

Are they gathered in the room for a meeting (civic) use? How about food or drink consumption(break room) then the function of the space is assembly at 15 people per sq ft for tables and chairs.

If the code did not have this exception for small rooms then a 9,000 sq ft 2 story V-B building could not have a conference room or break room located on the second floor
 
Using 2009 IBC, I believe the correct loading would be to use an assembly loading from Table 1004.1.1 for a break room or conference room.

In your scenario, what is 750 sq ft - the entire tenant space or the conference room alone?

Assume this type of scenario:

A conference room (for employees only) in a multi-floor office building. People from different floors or areas of the building may use this conference room because their conference room is already in use, and they will temporarily increase the number of occupants in this part of the building. Add some clients, vendor reps, etc. and the number increases further. The egress for this room and surrounding parts of the building must handle the total occupant load.

If you do not agree with everyone is saying, you can try using the exception from 1004.1.1.

Exception: Where approved by the building official, the actual number of occupants for whom each occupied space, floor or building is designed, although less than those determined by calculation, shall be permitted to be used in the determination of the design occupant load.
 
mtlogcabin wouldn't up to 10% accessory areas be allowed without that exception? Thanks for the example.

Yes it's very possible to get additional people in your conference room from another floor or whatever. But sometimes the code puts in items for practicality. Doing conf/break rooms at assembly means if I have a big office bldg and decide to put a coke machine in an office I now have plan reviewers demanding an analysis of plumbing fixtures and exits because the occupancy increased. In reality, the occupancy didn't increase. It may have decreased cause I took away an office.
 
mtlogcabin wouldn't up to 10% accessory areas be allowed without that exception? Thanks for the example.
Click to expand...
Sure but if your second floor was less than 7,500 sq ft then your accessory "A" use would have to be reduced accordingly. With the exception in 303.1 you can have a 3,000 sq ft 2nd floor with 25% of it being an "A" use. It provides flexibilty within the code for smaller buildings.
 
Well, first off, welcome to the forum. As you may have guessed, there are plenty of folks here with opinions.

That being said, I agree with the folks that are telling you that the occupancy load for a space must be based on its use, not the occupancy classification of the space. As you have pointed out, and A use under 50 is a B, but you still need to calculate the OL for the A use, table/chairs, chairs only, standing? JMHO
 
mtlogcabin scored a blow by providing some use of the chapter 3 exceptions if they aren't for occupancy. I'm still winning this debate on points though. Everybody else is saying the small accessory conf/break rooms are assembly occupancy just because they are. The world at large does not associate the word assembly with conference room - the basis has to come from chapter 3.
 
Yea ...........

Need to start somewhere
 
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The reason they use 750 sq. ft. is: 750/15=50, turning it into an A occupancy. Less than that and you have an assembly occupancy of less than 50 making it a B occupancy. The use is still assmbly.
 
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