It is a common sight to have means of egress through a lobby. Question is which section of code allows the use of a lobby, for better word say vestibule, as part of Means of Egress?
As we know several parts of means of egress namely, egress path, exits, and exit discharge. The answer to our question lies in the last part of the means of egress which is exit discharge. So let us go to SECTION BC 1027 EXIT DISCHARGE and locate the relevant section under Exception 2, which stipulates
A maximum of 50 percent of the number and capacity of the exit enclosures is permitted to egress through a vestibule provided all of the following are met:
Building code 2014 NYC
2.1. The entire area of the vestibule is separated from areas below by construction conforming to the fire-resistance rating for the exit enclosure.
2.2. The depth from the exterior of the building is not greater than 10 feet (3048 mm) and the length is not greater than 30 feet (9144 mm).
2.3. The area is separated from the remainder of the level of exit discharge by construction providing protection at least the equivalent of approved wired glass in steel frames.
2.4. The area is used only for means of egress and exits directly to the outside.
This answers our earlier question. Since this code defines “a maximum of 50 percent of the number and capacity of the exit enclosures …” It raises one more question. What if you have only one exit? We will answer that question shortly.
ArchitectNYC 