403.5.2 Additional exit stairway.

For buildings other than Group R-2 that are more than 420 feet (128 m) in building height, one additional exit stairway meeting the requirements of Sections 1011 and 1023 shall be provided in addition to the minimum number of exits required by Section 1006.3. The total width of any combination of remaining exit stairways with one exit stairway removed shall not be less than the total width required by Section 1005.1. Stairs sharing any common wall, floors, ceilings, scissor stair assemblies, or other enclosures shall not be considered the additional exit stairway required by this section.

   Exceptions: An additional exit stairway shall not be required to be installed in any of the following instances:

      1.   In buildings where all passenger elevators for general public use and all other elevators used for occupant self-evacuation comply with Sections 3008.1 through 3008.11;

      2.   In buildings where all of the following conditions are met:

         2.1.   The commissioner has approved a timed egress analysis establishing the egress time it would take for a full building evacuation, utilizing the stairs required by Section 1006 and the additional stair that would have been required pursuant to Section 403.5.2;

         2.2.   The commissioner has approved a timed egress analysis establishing the egress time it would take for a full building evacuation, utilizing the combination of the stairs required by Section 1006 and elevators used for occupant self-evacuation as follows:

            2.2.1.   Such analysis need only utilize a number of designated elevators designed for occupant self-evacuation necessary to demonstrate an evacuation time that is less than the time established in Exception 2.1; and

            2.2.2.   Every bank of passenger elevators for general public use shall be served by at least one such designated elevator;

         2.3.   All elevators in the building that either are passenger elevators for general public use or are used for occupant self-evacuation shall comply with Sections 3008.1 through 3008.11. However, the standby power generating equipment required by Section 3008.9 need only be sized to satisfy the loads required to simultaneously operate those elevators identified in the timed egress analysis described in Exception 2.2.

         The minimum number of exits required by Section 1006 are all at least 25 percent wider than the exit width required by Chapter 10. The increase in the stair width shall not be utilized in the timed egress analyses required by Exceptions 2.1 and 2.2.

403.5.3 Stairway door operation.

Doors opening into interior stair enclosures shall not be locked from either side. However, a door locked from the stair side may be permitted provided that such door is equipped with an automatic fail safe system for opening in the event of the activation of any automatic fire detection system, or when any elevator recall is activated, or when any signal is received from the fire command center. Such door shall be deemed as openable from the stair side. Stair reentry signs shall be posted throughout the stairway indicating that reentry is provided only during fire emergencies. Such signs shall be in accordance with Section 1031.4.2.

   Exception: In schools classified as Group E occupancies that require "lockdown drills" as per Section 807 of the New York State Education Law, stairway egress doors from occupied spaces are permitted to be locked from the side opposite the egress side for the duration of the lockdown drill, provided they are openable from the occupied side for egress and are unlocked upon directions from the school administrative personnel following the completion of the lockdown drill.

403.5.3.1 Stairway communication system.

A telephone or other two-way communications system connected to an approved constantly attended station shall be provided at not less than every fifth floor in each stairway where the doors to the stairway are locked in accordance with Section 403.5.3.

403.5.4 Smokeproof enclosures.

Every required interior exit stairway serving floors more than 75 feet (22 860 mm) above the lowest level of fire department vehicle access shall comply with Sections 909.20 and 1023.11

   Exception: Smokeproof enclosures are not required in occupancy Group R-2 unless provided pursuant to Exception 2 of Section 917.1.

403.5.5 Luminous egress path markings.

Luminous egress path markings shall be provided in accordance with Section 1025 and Appendix S.

   Exception: Egress paths serving Group R-2.