Figuring Occupant Load for A-2 (restaurant) occupancy

[dan.wilson75]

I'm in the middle of a debate with a client regarding how to calculate the total occupant load for a dining room with unconcentrated tables and chairs in an A-2 Occupancy (restaurant). My interpretation is you take the entire net floor area and divide that area by 15 (per IBC Table 10004.5). This entire floor area INCLUDES the circulation space between the tables and chairs. Doing so, I get an occupancy load factor of around 500 for this particular project I am working on. The Owner's interpretation is that you EXCLUDE the circulation area between the tables and chairs. Their logic is a person is either going to be walking to or from their table or sitting at their table. There will never be a scenario where the entire restaurant is full of people sitting at tables AND standing in the aisles. Under this interpretation the occupant load factor is around 300 for the same project. To me this logic makes sense, however I've encountered some jurisdictions where they have allowed the aisles to be excluded from the calculation, and other locations where they haven't allowed this. I can't find anything in the code that says black and white that the aisles can excluded. What is your interpretation?

 

[classicT]

[BE] 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.

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

I would not allow for the exclusion of the circulation aisles under net floor area. A defined corridor, yes; but a circulation path is an occupied area.

 

[Jay Smith]

This image from the 2015 IBC Commentary shows using the entire floor space divided by 15 to calculate occupant load. No aisles deleted.

 

[steveray]

I can be flexible on some stuff, but not an outright pass to all circulation.......

 

[fatboy]

I can be flexible on some stuff, but not an outright pass to all circulation.......

And I have been flexible to an extent, but the starting point is gross floor area of the seating area.

 

[ICE]

Not my area of expertise but there seems to be wiggle room in the dining room.


[BE] OCCUPANT LOAD. The number of persons for which the means of egress of a building or portion thereof is designed.

[BG] OCCUPIABLE SPACE. A room or enclosed space designed for human occupancy in which individuals congre- gate for amusement, educational or similar purposes or in which occupants are engaged at labor, and which is equipped with means of egress and light and ventilation facilities meeting the requirements of this code.

[BE] 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 thick- ness of interior walls, columns or other features. The floor area of a building, or portion thereof, not provided with sur- rounding exterior walls shall be the usable area under the hor- izontal projection of the roof or floor above. The gross floor area shall not include shafts with no openings or interior courts.

[BE] FLOOR AREA, NET. The actual occupied area not including unoccupied accessory areas such as corridors, stair- ways, ramps, toilet rooms, mechanical rooms and closets.

1004.5 Areas without fixed seating. The number of occu- pants shall be computed at the rate of one occupant per unit of area as prescribed in Table 1004.5. For areas without fixed seating, the occupant load shall be not 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 1004.5. Where an intended function is not listed in Table 1004.5, the building official shall establish a function based on a listed function that most nearly resem- bles 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

 

[Tim Mailloux]

the occupant load calcultion for tables and chairs is 1 per per 15sf. Now a person sitting at a table doesn't actually take up 15sf of space, that 15sf per person in the calculation accounts for the actual space someone takes up along with things like circulation space inside the room.

 

[mtlogcabin]

Not my area of expertise but there seems to be wiggle room in the dining room

There is never any wiggle room for OL when sizing the exits IMHO. Everything else is up for discussion. I have even posted lower OL at the owners request. I found out later it saved him money on his pay-per view licensed events

When it comes to buying UFC for your business, there is no set fee. The cost of pay-per-view UFC events for bars, restaurants, casinos and other commercial establishments can vary depending on their size. Usually, rates are based on a Fire Occupancy Certificate. The cost for a bar or restaurant that holds 50 patrons will differ with one that holds 500.

 

[Sifu]

It is easy to get caught up in the idea that reality doesn't match code. However, I think it is possible (probable?) that in the formation of code for occupant load this was taken into account. Especially in the case of chairs and tables that are not fixed. The worst case has to be considered. If the owner pushes it he could say he only has 10 tables, and the rest is circulation. I vote no, the aisles can't be eliminated. I have never had anybody make that assertion, so I had never considered it before. I might make allowances for actual unoccupied areas, but not a blanket elimination of aisles or aisle accessways.

 

[bill1952]

A good caterer can get to 1 person per 10 sq ft, or just a tad under, at 8 tops or 10 tops. Usually not a concern for egress because the egress for the room - hotel ballroom or similar - is designed for much denser use.

 

[tonto961]

Not my area of expertise but there seems to be wiggle room in the dining room.


[BE] OCCUPANT LOAD. The number of persons for which the means of egress of a building or portion thereof is designed.

[BG] OCCUPIABLE SPACE. A room or enclosed space designed for human occupancy in which individuals congre- gate for amusement, educational or similar purposes or in which occupants are engaged at labor, and which is equipped with means of egress and light and ventilation facilities meeting the requirements of this code.

[BE] 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 thick- ness of interior walls, columns or other features. The floor area of a building, or portion thereof, not provided with sur- rounding exterior walls shall be the usable area under the hor- izontal projection of the roof or floor above. The gross floor area shall not include shafts with no openings or interior courts.

[BE] FLOOR AREA, NET. The actual occupied area not including unoccupied accessory areas such as corridors, stair- ways, ramps, toilet rooms, mechanical rooms and closets.

1004.5 Areas without fixed seating. The number of occu- pants shall be computed at the rate of one occupant per unit of area as prescribed in Table 1004.5. For areas without fixed seating, the occupant load shall be not 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 1004.5. Where an intended function is not listed in Table 1004.5, the building official shall establish a function based on a listed function that most nearly resem- bles 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

This image from the 2015 IBC Commentary shows using the entire floor space divided by 15 to calculate occupant load. No aisles deleted.

Is there a predetermined sqft for specific table and chair arrangements. By that I mean is there a calculation for what space is taken by an 8-top round table and 8 chairs?

 

[tonto961]

In a wedding venue, A-2, do we count the area of the dance floor in the net figure? It would seem that everyone on the dance floor came from a seated place somewhere else and will return there. I could understand counting the dance space in a setting where you might expect standing room areas like a live event or music venue, but not in a setting where the guests sit at tables for dinner and then get up to dance. Any thoughts?

 

[bill1952]

In a wedding venue, A-2, do we count the area of the dance floor in the net figure? It would seem that everyone on the dance floor came from a seated place somewhere else and will return there. I could understand counting the dance space in a setting where you might expect standing room areas like a live event or music venue, but not in a setting where the guests sit at tables for dinner and then get up to dance. Any thoughts?

Are you sure they'll never fill it with tables? or that they won't remove most furniture and use it for a big cocktail party or rally?

 

[tonto961]

Are you sure they'll never fill it with tables? or that they won't remove most furniture and use it for a big cocktail party or rally?

You have a good point. The venue is 34ft x 72ft with 4 exits. They have a storage room for the tables and chairs (not in the 34x72) and they only own 10 tables and 80 chairs. Doesn't mean they couldn't. But couldn't they clear out the 24ft x 24ft storage room and use it for standing room with open double doors? I know we protect on the building's potential, but I really think we expect the occupants on the dance floor in a wedding party, birthday party, graduation party or family reunion to occupy seats when they are not dancing and the venue does not have a stage or performance area for real live music. Just trying to understand the reason to calculate the dance floor as standing room.

 

[tonto961]

Is there a predetermined sqft for specific table and chair arrangements. By that I mean is there a calculation for what space is taken by an 8-top round table and 8 chairs?

 

[Yankee Chronicler]

Is there a predetermined sqft for specific table and chair arrangements. By that I mean is there a calculation for what space is taken by an 8-top round table and 8 chairs?

No. Not in the code.

For seating at [moveable] tables and chairs, IBC Table 1004.5 calls for a ratio of one person per 15 square feet of net floor area. That's the entire floor area potentially occupiable by table and chairs.

If you want to figure something out, a table seating 8 people is typically 60 inches in diameter. IBC 1030.13.1 then says that aisle accessways are to be measured from a point 19 inches from the edge of the table, so for a 60-inch table the effective radius would be 60+19+19 = 98 inches. That works out to an area of 7,542 square inches, or 52.375 sq. ft. Divide that by 8 and you get 6.547 sq. ft. per person. Then you have to add in aisles and aisle accessways within the space.

The code allows for the code officials to approve an occupant load lower than calculated according to Table 1004.5 when the applicant can demonstrate to the code officials that the reduced occupant load is reasonable. We are more likely to look at that for toilet fixture count than we are for number and capacity of exits.

 

[Mr. Inspector]

In a wedding venue, A-2, do we count the area of the dance floor in the net figure? It would seem that everyone on the dance floor came from a seated place somewhere else and will return there. I could understand counting the dance space in a setting where you might expect standing room areas like a live event or music venue, but not in a setting where the guests sit at tables for dinner and then get up to dance. Any thoughts?

You don't know how the next owner will arrange the seating. You can't forget that this building could go through a few owners or renters without a change of occupancy.

 

[Yankee Chronicler]

And I have been flexible to an extent, but the starting point is gross floor area of the seating area.

It's NET area of the seating area. But that doesn't mean deducting the aisles and aisle accessways.

See post #3

IBC definition, and Commentary:

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

This area is intended to include only the room areas
that are used for specific occupancy purposes and
does not include circulation areas, such as corridors,
ramps or stairways, or service and utility spaces, such
as toilet rooms and mechanical and electrical equipment
rooms. Net floor area is typically measured
between inside faces of walls within a room. Floor
area, net and gross, is utilized in Table 1004.5 to
determine occupant load for a space.

 

[bill1952]

I won't comment on plumbing but for egress, make sure they understand that they can seat 8 tops and 10 tops more densely than 1 per 15 SF. Caterers do routinely. I'd be inclined to design egress for "concentrated" or "standing" 7 or 5 SF rather than "unconcentrated" 15 SF. If you design based on 15 SF that's only 163 occupants. Use the 7 SF - 350 occupants - and with the 4 doors no problem. I have done table layouts when I've worked on these kind of spaces so the owner knows what's possible. I just think a posted OL below what's easy and comfortable will be regretted.