# Occupant Load - Do You or Don't You?



## nealderidder (Apr 29, 2019)

I've done this both ways and had it approved both ways. Do you or don't you include circulation (hallways, corridors, stairs) and spaces like bathrooms? These are spaces that are occupied non-simultaneously, meaning an occupant in a corridor is either coming from or going to another space, he's not camped out in the corridor (unless his desk was moved there and maybe he should take a hint!).

Just curious what your experience is with including or excluding these spaces from an overall occupant load. 

Thanks,
Neal


----------



## steveray (Apr 29, 2019)

In gross you do, in net, you don't have to...

FLOOR AREA, GROSS. The floor area within the inside
perimeter of the exterior walls of the building under consideration,
exclusive of vent shafts and courts, without deduction
for corridors, stairways, ramps, closets, the thickness of interior
walls, columns or other features. The floor area of a
building, or portion thereof, not provided with surrounding
exterior walls shall be the usable area under the horizontal
projection of the roof or floor above. The gross floor area
shall not include shafts with no openings or interior courts.

FLOOR AREA, NET. The actual occupied area not including
unoccupied accessory areas such as corridors, stairways,
ramps, toilet rooms, mechanical rooms and closets.


----------



## RLGA (Apr 29, 2019)

Here's how I approach it:

If the story includes spaces that have occupant loads based on gross and net areas, then I include the restrooms, corridors, etc. within the floor area for the main gross area function since they support that function as well as the other functions. If a restroom, corridor, etc. only support a net area space, then I don't include those accessory areas. For example, if a story is mostly offices, but has conference rooms, then I would include the restrooms and corridors within the gross business area function. Another example, if a story half classrooms with a hallway and restrooms, and the other half is a school administration area with its own corridors and restrooms (but has access to the classroom half), then I would include the corridors and restrooms associated with the administration area within the gross business area of the administration offices, but not include the corridors and restrooms associated within the net area of the classroom half of the story.
If a story has predominately net area functions with some minor gross area functions (e.g., small storage rooms, a small office or two, etc.), then I do not include the corridors and restrooms, but each gross area function is based on the gross area that function occupies including walls and columns.


----------



## nealderidder (May 2, 2019)

I see what you're saying Ron and I'm wondering how receptive a B.O. would be to that approach... 

While we're on the subject. Has anyone had success having large assembly rooms counted as "business areas" for egress sizing when they are non-simultaneous uses? I'm thinking of a large training room in an office building used by employees (those people captured in the 100/SF gross calculation). I get that the room itself must provide exits based on 15/SF but I'm having trouble accepting that my exiting from that floor must be sized for the employees in the training room plus the employees in the office area (they're the same people).

I'm wondering just how often a B.O. actually allows "_the actual number of occupants for whom each occupied space, floor or building is designed, although less that those determined by calculation, shall be permitted to  be used in the determination of the design occupant load"
_
I'm thinking of a particular case where a floor designed to accommodate 126 people winds up with an occupant load of 781 because of large training rooms and break areas. Other than the occasional handful of visitors, the assembly spaces are only used by the employees. There will be no public concerts going on in the break room while the offices are fully occupied (or any other time).


----------



## RLGA (May 2, 2019)

nealderidder said:


> I see what you're saying Ron and I'm wondering how receptive a B.O. would be to that approach...
> 
> While we're on the subject. Has anyone had success having large assembly rooms counted as "business areas" for egress sizing when they are non-simultaneous uses? I'm thinking of a large training room in an office building used by employees (those people captured in the 100/SF gross calculation). I get that the room itself must provide exits based on 15/SF but I'm having trouble accepting that my exiting from that floor must be sized for the employees in the training room plus the employees in the office area (they're the same people).
> 
> ...


If the training room is used by employees only from the same story, I could see how that might be acceptable. However, if the training room is used by employees from other locations or on other stories, then no, that would not be acceptable.


----------



## Rick18071 (May 3, 2019)

Why can't a training room be "B"?

SECTION 304
BUSINESS GROUP B
304.1 Business Group B. Business Group B occupancy
includes, among others, the use of a building or structure, or a
portion thereof, for office, professional or service-type transactions,
including storage of records and accounts. Business
occupancies shall include, but not be limited to, the following:
Airport traffic control towers
Ambulatory care facilities
Animal hospitals, kennels and pounds
Banks
Barber and beauty shops
Car wash
Civic administration
Clinic, outpatient
Dry cleaning and laundries: pick-up and delivery stations
and self-service
Educational occupancies for students above the 12th grade
Electronic data processing
Food processing establishments and commercial kitchens
not associated with restaurants, cafeterias and similar
dining facilities not more than 2,500 square feet (232 m2)
in area.
Laboratories: testing and research
Motor vehicle showrooms
Post offices
Print shops
Professional services (architects, attorneys, dentists,
physicians, engineers, etc.)
Radio and television stations
Telephone exchanges
*Training and skill development not in a school or
academic program (this shall include, but not be limited
to, tutoring centers, martial arts studios, gymnastics and
similar uses regardless of the ages served, and where not
classified as a Group A occupancy).*


----------



## RLGA (May 3, 2019)

It can be, as long as the occupant load does exceed 49. Once the occupant load hits 50, then it becomes a Group A.


----------



## Rick18071 (May 3, 2019)

RLGA said:


> It can be, as long as the occupant load does exceed 49. Once the occupant load hits 50, then it becomes a Group A.



Don't agree. It does not say that in section 304 under training and skill development and there is nothing about training rooms under any group A  use.


----------



## RLGA (May 3, 2019)

Rick18071 said:


> Don't agree. It does not say that in section 304 under training and skill development and there is nothing about training rooms under any group A  use.


But it also says “this shall include, *but not be limited to*,...*and where not classified as a Group A occupancy.*”


----------



## JPohling (May 3, 2019)

Absolutely a training room over 49 occupants is an A occupancy


----------



## nealderidder (May 3, 2019)

I had the meeting with the B.O. They were comfortable with our approach of looking at the Training Room and Break Room as "accessory" to the main occupancy and non-simultaneous uses. We'll have to egress every space as if fully occupied but do not have to include occupant loads in these accessory spaces when determining overall egress width from the floor. Our issue was that the existing stairs (this is a big TI) couldn't handle the required egress width if all spaces were fully occupied and the Training Room and Break Room were considered assembly.


----------



## Tim Mailloux (May 6, 2019)

nealderidder said:


> I had the meeting with the B.O. They were comfortable with our approach of looking at the Training Room and Break Room as "accessory" to the main occupancy and non-simultaneous uses. We'll have to egress every space as if fully occupied but do not have to include occupant loads in these accessory spaces when determining overall egress width from the floor. Our issue was that the existing stairs (this is a big TI) couldn't handle the required egress width if all spaces were fully occupied and the Training Room and Break Room were considered assembly.



The ICC would disagree with this approach and I have a formal ICC code interpretation backing this up. Occupant loads are determined by the function of the space or room, and have nothing to do with the occupancy group. A small conference room (in an office building room) under 750sf is technically part of the B occupancy, but the occupant load of that conference room is still 1 person per 15sf of floor space. There is also nothing in the code regarding non-simultaneous use, this whole concept needs to go away.

As an example my office has several larger conference rooms that 95% of the time are only used by employees already accounted for in the gross business occupant load calculation (non-simultaneous use). But at least once a month we host an outside industry work shop of 40 plus people in our office during normal business hours. Do we not need to make sure those people can safely egress our office building? The code commentary also goes onto to say that the calculated occupants loads represent the worst case occupant load scenario which will be much higher than normal day to day use.


----------



## mtlogcabin (May 6, 2019)

It is how you determine the OL of the room that my get you over 49 people.
If it is a classroom setting I use 20 PSF OL out of the table for classroom.
If it is martial arts/gymnastics I use the 50 PSF  OL out of the table for exercise room.
If there are computer work stations set up in the room I count the work stations to determine the OL

1004.1.2 Areas without fixed seating.
The number of occupants shall be computed at the rate of one occupant per unit of area as prescribed in Table 1004.1.2. For areas without fixed seating, the occupant load shall not be less than that number determined by dividing the floor area under consideration by the occupant load factor assigned to the function of the space as set forth in Table 1004.1.2. Where an intended function is not listed in Table 1004.1.2, the building official shall establish a function based on a listed function that most nearly resembles the intended function.
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.
FYI
The OL numbers change in the 2018 for "B" uses. It can be anywhere from 50 to 150 people per square foot depending on the use. The BO is charged with approving the numbers submitted.


----------



## Rick18071 (May 6, 2019)

*Training and skill development not in a school or
academic program is under B but not listed under A.*
*Would make more sense it would E rather than A.*


----------



## Tim Mailloux (May 6, 2019)

mtlogcabin said:


> If there are computer work stations set up in the room I count the work stations to determine the OL



That should only be allowed if those computer workstations were fixed (aka bolted to the floor), or the number or workstations was greater than the calculated occupant load.


----------



## mtlogcabin (May 6, 2019)

Let me clarify
If it is a training room that consist of individual computer work stations that the employees are training on that is how 
I determine the OL fixed or not. 
Now if it is a room the employees bring in their laptops to train on then no the laptops are not part of the furniture and fixtures that remain in the room


----------



## steveray (May 7, 2019)

nealderidder said:


> Our issue was that the existing stairs (this is a big TI) couldn't handle the required egress width if all spaces were fully occupied and the Training Room and Break Room were considered assembly.



What level alteration is it? You may not need to even address egress.....

805.1 Scope. The requirements of this section shall be limited
to work areas that include exits or corridors shared by more
than one tenant within the work area in which Level 2 alterations
are being performed, and where specified they shall
apply throughout the floor on which the work areas are
located or otherwise beyond the work area.

Too many designers do not go to the IEBC to work their way out of a problem IMO...


----------



## JPohling (May 7, 2019)

In my jurisdiction the occupant load for a training room is 1/20sf but the training room furniture needs to be fixed


----------



## Sifu (May 8, 2019)

Tim Mailloux said:


> The ICC would disagree with this approach and I have a formal ICC code interpretation backing this up. Occupant loads are determined by the function of the space or room, and have nothing to do with the occupancy group. A small conference room (in an office building room) under 750sf is technically part of the B occupancy, but the occupant load of that conference room is still 1 person per 15sf of floor space. There is also nothing in the code regarding non-simultaneous use, this whole concept needs to go away.
> 
> As an example my office has several larger conference rooms that 95% of the time are only used by employees already accounted for in the gross business occupant load calculation (non-simultaneous use). But at least once a month we host an outside industry work shop of 40 plus people in our office during normal business hours. Do we not need to make sure those people can safely egress our office building? The code commentary also goes onto to say that the calculated occupants loads represent the worst case occupant load scenario which will be much higher than normal day to day use.


I also have a technical opinion from ICC that says the same thing.


----------



## Rick18071 (May 8, 2019)

JPohling said:


> Absolutely a training room over 49 occupants is an A occupancy



I want to understand how this is determined. Please where does this say that? Would it be A-1,2, 3, 4 or 5?


----------



## Tim Mailloux (May 8, 2019)

Rick18071 said:


> I want to understand how this is determined. Please where does this say that? Would it be A-1,2, 3, 4 or 5?



The 2015 IBC section 303.1.2 states that small assembly type spaces (say conference room or training rooms) with less than 50 occupants or smaller than 750SF can be classified as group B or the same as the primary occupancy which those spaces serve. Logic would derive that small assembly spaces with 50 or more people or larger than 750SF would not be classified as group B or the primary occupancy, and would have to be assigned to one of the assembly occupancy use groups.

I would typically consider a large conference or training room with 50 or more people in a B occupancy an accessory A-3 occupancy.


----------



## JPohling (May 8, 2019)

Rick18071 said:


> I want to understand how this is determined. Please where does this say that? Would it be A-1,2, 3, 4 or 5?



2016 CBC  303.1.2 Small assembly spaces.  The following rooms and spaces shall not be classified as Assembly occupancies:
1.  A room or space used for assembly purposes with an occupant load of less than 50 persons and accessory to another occupancy shall be classified as a Group B occupancy or as part of that occupancy.

2.A room or space used for assembly purposes that is less than 750 sf in area and accessory to another occupancy shall be classified as a group b occupancy or as part of that occupancy.

Therefore any B assembly space over 750 sf or 49 occupants will be considered an A occupancy.
A1, A4 and A5 are out of the equation by nature of their use.  So typically A3 unless your serving alcohol or food as a primary use, then A2


----------



## Rick18071 (May 8, 2019)

Tim Mailloux said:


> The 2015 IBC section 303.1.2 states that small assembly type spaces (say conference room or training rooms) with less than 50 occupants or smaller than 750SF can be classified as group B or the same as the primary occupancy which those spaces serve. Logic would derive that small assembly spaces with 50 or more people or larger than 750SF would not be classified as group B or the primary occupancy, and would have to be assigned to one of the assembly occupancy use groups.
> 
> I would typically consider a large conference or training room with 50 or more people in a B occupancy an accessory A-3 occupancy.



I would agree if "training room" was listed under A-3 but it is not. It is listed under B.


----------



## JPohling (May 8, 2019)

Yes a training room under 49 is a B.  Training over 50 is an A.  It really isn't that difficult.


----------



## steveray (May 8, 2019)

JPohling said:


> Yes a training room under 49 is a B.  Training over 50 is an A.  It really isn't that difficult.



Or is it a classroom....?


----------



## classicT (May 8, 2019)

Per the 2015 IBC Commentary...


----------



## Tim Mailloux (May 8, 2019)

This thread was about occupant load, what does that occupancy classification have to do with occupant load calculations? Whether the training room is group B or A-3 it does not change the fact that the calculated occupant load for the space should either be 1 per 20 (classroom) or 1 per 15 (Tables and Chairs). If the furniture is fixed (aka bolted to the floor) than you should be able to count desks / chairs


----------



## nealderidder (May 8, 2019)

steveray said:


> Too many designers do not go to the IEBC to work their way out of a problem IMO...



And so few jurisdictions actually adopt it. The chapter you're referring to is specifically NOT adopted by California.


----------



## steveray (May 9, 2019)

Does Cali use anything for existing and alterations? 101?


----------



## nealderidder (May 9, 2019)

steveray said:


> Does Cali use anything for existing and alterations? 101?




As you know, each local jurisdiction is supposed to adopt the EBC if they want to use it. But they rarely do. I have had B.O.s refer to it even though they haven't adopted it.

The state has adopted the IEBC (masquerading as the California EBC) but the adopted version specifically excludes chapters 5-14. So we get chapters 1-4 to work things out.


----------



## Michael Schirmer (May 16, 2019)

Tim Mailloux said:


> The 2015 IBC section 303.1.2 states that small assembly type spaces (say conference room or training rooms) with less than 50 occupants or smaller than 750SF can be classified as group B or the same as the primary occupancy which those spaces serve. Logic would derive that small assembly spaces with 50 or more people or larger than 750SF would not be classified as group B or the primary occupancy, and would have to be assigned to one of the assembly occupancy use groups.
> 
> I think I'm tracking you.  Here is our office we understand there is a difference between the life safety occupant load which is for the egress of the greatest number of people possible and the occupancy type for construction.


----------



## Michael Schirmer (May 16, 2019)

is there not an edit button in here?  I messed up the last post again.


----------



## Beguelin (Nov 17, 2019)

Scenario:

In an Office TI you have a training room used for training call center new hires. The room is 1,671 SF. It is set up with tables and chairs for 50 students and one instructor. There are four (4) of these training rooms on a floor and this exceeds 10% of the floor area.


1.       Is the Occupancy Load factor is 15 for Assembly unconcentrated with tables and chairs? 1,671/15=112 occupants.

2.       Is the Occupancy Load factor is 20 for classroom? 1,671/20=84 occupants.

3.       Is the Occupancy for B Concentrated is 51 actual seats? =51 occupants.

4.       Is the space Occupancy Type considered A-3 (lecture Hall) and need to be separated from the rest of the B occupancy?

5.       Is the space Occupancy Type considered B (training or concentrated) and not need to be separated from the rest of the B occupancy?

6.       The space requires 2 exits from the room. When figuring out the total occupancy of the floor for exit width required from the floor do you use 112, 84, or 52 for this space? Does it matter that the people using the training room actually sit at a workstation on the same floor?

7.       When figuring out the total occupancy of the floor for plumbing fixture count do you use 112, 84, or 52 for this space? Does it matter that the people using the training room actually sit at a workstation on the same floor?


----------



## RLGA (Nov 17, 2019)

Beguelin said:


> Scenario:
> 
> In an Office TI you have a training room used for training call center new hires. The room is 1,671 SF. It is set up with tables and chairs for 50 students and one instructor. There are four (4) of these training rooms on a floor and this exceeds 10% of the floor area.
> 
> ...


Here’s how I would do it:

For occupant load use “Classroom” at 20 sf net per occupant.
If occupant load is over 49, then the space is classified as Group A-3.
If owner can prove to the building official’s satisfaction that the training rooms will only be used by other occupants of the building on the same story, then the occupant load could be based on the occupant load of the office areas only. If there’s a chance that employees from other stories or other buildings will use those rooms, too, then you’d have to include all of the occupant loads.
For fixture counts, a similar condition as above would apply. If the training rooms are used only by building occupants, then, with the building official’s approval you may determine fixtures solely on the occupant loads for the office areas.
For allowable area, if all of the rooms together exceed 10% of the floor area for the story, then they cannot be considered accessory occupancies; however, you can for some of the spaces if the aggregate area is less than 10% of the floor area. The area would then be determined using the separated occupancies method. You could also use the nonseparated occupancies method, but then everything would be based on the Group A-3 occupancy group since that would likely be the most restrictive.


----------



## cda (Nov 17, 2019)

Beguelin said:


> Scenario:
> 
> In an Office TI you have a training room used for training call center new hires. The room is 1,671 SF. It is set up with tables and chairs for 50 students and one instructor. There are four (4) of these training rooms on a floor and this exceeds 10% of the floor area.
> 
> ...






Welcome


----------



## cda (Nov 17, 2019)

Maybe B training

and use a factor of 50?


----------

