Chapter 9 — ALTERATIONS—LEVEL 3

Section 903 — BUILDING ELEMENTS AND MATERIALS

2025 California Existing Building Code (Title 24, Part 10) · 2025 edition · ingested 2026-07-07 · California

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903.1 Existing shafts and vertical openings.

903.1 Existing shafts and vertical openings. Existing stairways that are part of the means of egress shall be enclosed in accordance with Section 802.2.1 from the highest work area floor to, and including, the level of exit discharge and all floors below.

903.2 Fire partitions in Group R-3.

903.2 Fire partitions in Group R-3. Fire separation in Group R-3 occupancies shall be in accordance with Section 903.2.1. 903.2.1 Separation required. Where the work area is in any attached dwelling unit in Group R-3 or any multiple single-family dwelling (townhouse), walls separating the dwelling units that are not continuous from the foundation to the underside of the roof sheathing shall be constructed to provide a continuous fire separation using construction materials consistent with the existing wall or complying with the requirements for new structures. Work shall be performed on the…

903.3 Interior finish.

903.3 Interior finish. Interior finish in exits serving the work area shall comply with Section 802.4 between the highest floor on which there is a work area to the floor of exit discharge.

903.4 Enhanced classroom acoustics.

903.4 Enhanced classroom acoustics. In Group E occupancies, where the work area is a Level 3 alteration, enhanced classroom acoustics shall be provided in all classrooms with a volume of 20,000 cubic feet (565 m [3] ) or less. Enhanced classroom acoustics shall comply with the reverberation time in Section 808 of ICC A117.1. on Jul 18, 2025 11:14 AM (CDT) THEREUNDER. � � ALTERATIONS—LEVEL 3