Everything you ever wanted to know but were scared to ask about elevator lobbies…

We code consultants can’t help but walk around buildings and notice all the areas of non-compliance and one of the biggest offenders is elevator lobby design. Here is a brief summary of the critical features to make sure your elevator lobbies are compliant:

• Elevator lobbies are only required in non-sprinklered buildings, high-rise buildings, and certain Institutional Occupancies.
• Elevator lobbies require a smoke rating and one-hour fire-rating unless the building is fully-sprinklered, then the one-hour fire-rating is not required.
• If the lobbies are not required, but are provided other purposes, such as security, the requirements for smoke and fire ratings are not applicable.
• Regardless of whether they are required or not, whenever provided, elevator lobbies require at least one mean of egress. This is often violated by security systems that do not allow occupants to freely egress from the lobby (and no, those push to exit buttons usually do not meet code).

Where an elevator lobby is required, there are often issues with how smoke ratings of these elevators are provided. When the building is fully sprinklered, and the requirement for the 1-hour fire-rating goes away, the lobbies still must be designed to resist passage of smoke. Specifically, when your elevator lobby is required to be built of smoke partition walls, this requires:

• Latching, gasketed, UL 1784-Listed doors on closers. Most modern glass doors do not meet this requirement as they often do not latch and have gaps between the leaves.
• Smoke dampers in any air transfer opening. It is common to see air transfer openings in lobbies to provide return air but these openings require a smoke damper at the penetration of the lobby enclosure. The damper is not needed if the penetration is part of a fully-ducted system.

Another issue we commonly see is the prevalence of glass elevator lobby walls and doors with closely spaced sprinklers (6’ of center along the walls and doors) to provide a fire-rating. This does not work for a couple reasons:

• First, it is likely the lobby does not need a rating as outlined above. Where a fire-rated elevator lobby is not required, these sprinklers are not needed.
• Second, where a fire rated elevator lobby is required, closely spaced sprinklers along glass walls is a specific provision that is allowed in atriums only and would require a formal variance in any other application. While Section 703.4 of 780 CMR is clear on this issue, it is commonly missed in design and permitting.
• There are specific sprinklers, such as the Tyco WS window sprinkler, that are tested and listed for this application but there are specific limitations to the use of these sprinklers that require further consideration.

If you are looking for guidance related to your new construction project or tenant fit out, give Jigsaw Life Safety a call or contact us to help make sure your project is compliant.