# Lobby occupant loads



## pmarx

1A, non-separated mixed use building under 2009 IBC. Four floors will contain only hotel guestrooms and four floors above that will contain only condominiums or apartments. Access to each from the ground floor is by way of separate lobbies. Would the occupant loads of either (or both) lobby be calculated on one of the assembly functions of Table 1004.1.1 rather than the residential function? Unfortunately I thought to ask this question from home so I don't have the square footage of the areas in question. I can tell you that the condo/apartment lobby (which also includes a vestibule against the weather) is relatively small and won't include furniture. It is possible that the mailboxes will be located there but that hasn't been determined. Otherwise, it's only going to be used for people to stand while they wait for the elevator. Even if it were 800 SF, at 5 SF/occ that would result in an occ load of 160 and would require two exits. That's absurd. The hotel lobby may be another matter. There will likely be sofas and chairs set up for people to "assemble".


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## cda

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, 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, toilet rooms, mechanical rooms and closets.


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## cda

I am not thinking it is assembly area

In all situations are people just coming and going ??

No offices or shops? Or other


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## pmarx

cda said:
			
		

> I am not thinking it is assembly areaIn all situations are people just coming and going ?? I would say that will be the case for the condo/apartment lobby. The hotel lobby could have people lingering for a short while I suppose.
> 
> No offices or shops? Or other No


I guess I need to add at least 10 characters outside the quotes.


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## cda

49----

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.

Should have asked are either of these part of the exit way for upper floors??

Or any living units on first floor?


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## RLGA

For nontransient residential, like apartments and condominiums, I typically include the lobby as part of the residential floor area.  For transient residential, like hotels and motels, I usually consider the lobby as an assembly use, but it kind of depends on how the lobby is designed.  For transient residential, something to keep in mind: how often have you seen a hotel lobby inundated with people when a tour or school team unloads off a bus for checking in?


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## pmarx

I'm comfortable assigning the residential load to the R-2 lobby (200 sf/occ). It's 24'-8" deep (including a vestibule) by 18'-8" wide. Using 5 sf for standing space would give an occupant load of 93 and would require two exits when someone only has to walk less than 30 feet to be out the front door. That's ridiculous. I do agree that the R-1 lobby can potentially have a higher concentration of people even on rare occasions to the extent that a second exit would have to be provided. I was figuring it was similar to a bank lobby.


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## mark handler

pmarx said:
			
		

> I was figuring it was similar to a bank lobby.


Or restaurant waiting room? Since many Hotels have open bars and restaurants in the "lobby" space?







Check- in to left bar to right


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## jar546

So to resurrect this, what would the type occupancy be for the lobby of a high rise with R2 condos?  If there were an area to congregate with seating and a security desk with employee.  Would you consider the lobby R2?


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## north star

*$ ~ $*

An A-3 unless less than 50 Occ. Load, then a B occ. Group.
See Section 303 in the `15 IBC.

*$ ~ $*


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## mtlogcabin

I would agree with RLGA and would have to look at the OL based on the size and use of the lobby. Even though it may be an A-3 I might allow a lower OL than the table requires

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.


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