1 Purpose
This bulletin outlines the requirements and application procedures for proposing a single exit, single stairway in multifamily residential buildings exceeding three stories in the City of Santa Monica. While 2022 & 2025 California Building Code (CBC) Section 1006.3.4 limits such buildings to three stories and four units per story, the CBC permits applicants to submit an Alternate Materials and Methods Request (AMMR) to propose a design exceeding three stories limit per Section 104.2.3. 2025 CBC Section 104.2.3, and 2025 California Fire Code Section 104.2.3 state:
104.2.3 Alternative materials, design and methods of construction and equipment.
The provisions of this code are not intended to prevent the installation of any material or to prohibit any design or method of construction not specifically prescribed by this code, provided that any such alternative has been approved.
104.2.3.3 Compliance with the code intent.
An alternative material, design or method of construction shall comply with the intent of the provisions of this code.
104.2.3.4. Equivalency Criteria.
An alternative material, design or method of construction shall, for the purpose intended, be not less than the equivalent of that prescribed in this code with respect to all of the following, as applicable:
1. Quality
2. Strength
3. Effectiveness
4. Durability
5. Safety, other than fire safety
6. Fire Safety
The submitted AMMRs are subject to evaluation / approval by both the Building and Safety Division, as well as Fire Department, and each submitted application will be evaluated to ensure an equivalency of proposed life safety measures.
The CBC allows multifamily buildings more than three stories above grade plane provided there are two exit stairways which can be either interior exit stairway (Section 1023) or exterior exit stairway (Section 1028).
The minimum requirements outlined in this Information Bulletin may be updated upon amendments to the 2025 California Building Code and 2025 California Fire Code.
INFORMATION BULLETIN
Single Exit Stairway Provisions for Multifamily Residential Buildings Over Three Stories
Eligibility and Application Process
The licensed architect for the proposed multifamily project greater than three stories in height with the proposed single stair exit must:
• Submit an Alternate Materials and Methods Request per CBC Section 104.2.3. • Provide justification that life safety, fire protection, and egress performance meet or exceed the intent of the CBC.
• Incorporate enhanced design features as described below.
Minimum Required Design Features for Consideration
Multifamily dwelling (R-2 Occupancy) not more than four stories in height:
In addition to compliance with existing California building and fire code requirements, additional minimum required design features required include:
• The building must be sprinklered throughout with NFPA 13 standards. • The building must have not more than four dwelling units per floor. • The maximum floor area shall be limited to 4,000 sq. ft. per story. • Exit from the building must be discharged directly to a public street or to an alley which is 20 feet in width.
• The stairway exit from the R-2 occupancy shall not pass through any other occupancies. • No electrical outlets are permitted in exit stairways. • Emergency escape and rescue openings are required in all bedrooms.
Multifamily dwelling (R-2 Occupancy) more than four stories in height and up to six stories in height:
In addition to compliance with existing California building and fire code requirements, additional minimum required design features required include:
• The building must have not more than four dwelling units per floor. • The maximum floor area shall be limited to 4,000 sq. ft. per story. • Exit must be discharged directly to a public street or an alley which is 20 feet in width. • The stairway enclosure shall be pressurized.
• The travel distance from a dwelling unit door to the exit enclosure door shall be limited to 20 feet.
• The exit from the R-2 occupancy shall not pass through any other occupancies. • Required fire protection and life safety enhancements:
o Emergency escape and rescue openings are required in all bedrooms. o Increased minimum stair width from 44” to 48”.
• No occupied roofs above the highest floor are permitted. • Any occupancies other than R-2 occupancy must not communicate with the R-2 occupancy stairwell.
• No electrical outlets in exit stairways or corridors. • A Peer Review report is required per Section 104.2.3.7 of 2025 California Fire Code and California Building Code.
Review and Determination
Approval is subject to compliance with the design provision identified in this Informational Bulletin, and dependent on the equivalency of proposed life safety measures.
Statewide Code Development
Changes have already been proposed and may be reflected in future editions of the CBC (e.g., 2028 CBC anticipated to allow four-story single-exit buildings statewide).
Per AB 835, the Office of the State Fire Marshal is researching code updates to permit taller single-exit buildings (up to the high rise limit). A first draft of their report is expected in September 2025. The final document will be presented to the State Fire Marshal in November / December of 2025, and this Informational Bulletin will be updated accordingly to remain consistent with any future State adopted code changes.