By Steve Winkel, FAIA, PE, CASp
“When are elevator lobbies required in multi-story buildings?” is a question I am often asked by architects. As with most code questions the answer starts with, “it depends”. The 2013 California Building Code (CBC) discusses elevator lobby requirements in Section 713.14.1. There are specific requirements related to building heights and uses that trigger elevator lobby requirements. We will examine those in detail below, but it is important to understand that elevator lobby requirements are related to smoke management at elevator doors, not to the integrity of the elevator shaft fire resistance requirements. Elevator car and shaft enclosure doors are fire rated; they typically meet fire-resistance criteria for 90-minute doors. The problem is that because of how they operate elevator doors are not smoke tight, even when they are closed. So that while a fire is unlikely to break out from a shaft on a floor above a floor where a fire occurs, smoke from that fire can escape from the elevator shaft and may contaminate other floors than the fire floor. The requirements for lobbies are to provide rooms into which the elevator doors open with additional conventional doors that can be sealed to be smoke tight.
The codes allow instances where two stories are interconnected with open stairs. Elevator lobby requirements consider those. The basic 2012 International Building Code (IBC), on which the CBC is based, allows three stories to have interconnected atmospheres before an elevator lobby is required. The California State Fire Marshal has stricter requirements for certain occupancies and uses: A, E, H, I, L, R-1, R-2 and R-2.1 occupancies, high-rise buildings, that allow only two interconnected floors without an elevator lobby.
Under Section 714.3.2 of the CBC there are several exceptions to the basic requirements for an enclosed room-style elevator lobby that have architectural implications:
■ Exception 1 allows omission of a lobby at the ground floor exit discharge if the building is sprinklered
■ Exception 3 allows the use of doors swinging over the elevator doors to provide the smoke seal
in lieu of an enclosed space.
■ Exception 4 says that in other than the occupancies modified by the State Fire Marshal elevator
lobbies can be omitted in sprinklered buildings [Use with caution in Type B office buildings
where an “A” occupancy could pop up on a floor otherwise containing just B office uses).
■ Exception 8 allows use of a “Smoke Guard” roll down smoke seal in lieu of swing doors or an
enclosed elevator lobby.
Commentary by Kerwin Lee, AIA, CASp
There are two other code Sections that can trigger the requirements for an elevator lobby. The first is Section 1007.4 for Accessible Means of Egress and Section 3007.7 associated with the requirements for a Fire Service Elevator Lobbies. The latter applies to super high-rise buildings. Section 1007.4 Accessible Means of Egress is associated with Elevators that are a part of an accessible means of egress. The scoping requirement state: “in buildings where an accessible floor is four or more stories above or below the level of discharge, a minimum of one elevator is required as part of the accessible means of egress.” This applies to buildings that are five or more stories above or below grade. There are two exceptions; one for sprinklered buildings with a horizontal exit on the floor or a sprinklered building with a ramp to grade.
In buildings that are five or more stories (or four basements) in height, an elevator is required as part of the accessible means of egress.
The elevator is required to be accessed from an area of refuge or lobby. There are four exceptions under Section 1007.4 that eliminate the area of refuge. The biggest item is the requirement for emergency power to operate the elevator. The code references Chapter 27, Electrical and Section 3003, Emergency Operation, which neither provides any technical requirements. Although the ASME A17.1 requires the operation of at least one time/cycle, this has been looked at by the fire department as inadequate. The key is operation of the elevator and what would the power demand be? The biggest question is when is a generator required to meet the requirement for the emergency operation of the elevator? This may depend upon the elevator and this would have to be conferred with the elevator manufacturer or designer. ■