Navigating Stair Design Codes Without Sacrificing Aesthetics

By Brian Salyers, PE | Managing Principal, Fire Protection Engineering, Bay Area

In office environments where open and collaborative spaces are key objectives, tenants often desire unenclosed communicating stairs connecting multiple floors. These stairs provide attractive architectural design opportunities—but also present unique complications for fire safety code compliance. Open stairs can allow fire and smoke to travel vertically through the building, increasing the risk of fire spreading quickly between floors.  Key questions around the communicating stairway that will determine the fire/life safety approach for regulating the stairway include:

• Is the stair a required means of egress?
• Does the stair pass through a fire-rated floor assembly?
• How many stories are connected by the stair?
• Is the floor opening solely occupied by the stairway, or does the stairway represent just a small portion of a much larger floor opening? If the latter, could this larger opening be considered an atrium due to its size and design?
• What is the architectural design intent beyond the stair’s design?

As an example, the four-story stair below was designed as an architectural element (by Forge Architecture and constructed by Mata Construction) in a high-rise building with a floor-level smoke control system. While the staircase was not required for egress, it posed a risk to the smoke control system’s performance, so a creative solution was needed to maintain the integrity of the system, while achieving the design intent. The stairs were enclosed within a 2-hour rated shaft using a combination of strategies that balanced safety.

To meet the 2-hour fire-resistance requirement, the stair in this example used a combination of strategies that balanced safety, code compliance, and design flexibility.

Tested Wall Assemblies

Traditional fire barrier walls were used in certain areas to provide a straightforward path to compliance. These assemblies met UL listings based on tested performance and satisfied the 2-hour rating requirement as outlined in 2024 IBC Section 703.2.1. This option offers the most direct and prescriptive method for meeting code requirements.

Glass Walls with Water Curtain Sprinklers

To preserve openness and visual connection between floors, non-rated glass walls were used in select areas. Closely spaced sprinklers forming a water curtain were used to achieve fire-resistance comparable to a 2-hour rated wall. Though supported by testing and ICC-ES reports, this approach requires AHJ approval under IBC Section 703.2.3 due to its reliance on active systems. Despite the added complexity, it allows for greater transparency, daylight penetration, and acoustic separation while meeting life safety goals.

Automatic Fire Shutters

To maintain open, visually connected stair landings, automatic fire shutters were installed adjacent to the stairs in lieu of traditional fire-rated doors. These overhead shutters deploy during an emergency and are required to be 90-minute rated per 2024 IBC Table 716.1(2), tested to standards such as NFPA 252 or UL 10B in accordance with Section 716.2.1.2. Because these stairs were not part of the required egress system, the design allowed greater flexibility—permitting use of a shutter in place of a typical swinging door. Although not required for egress, the stairway is treated as an exit access stairway under IBC Section 1019 for enclosure and opening protection, allowing the shutter to exceed the typical 25% wall opening limit under Section 707.6(2). To support occupant safety, a manual push-button was provided at each level to retract the shutter, so anyone already using the stairway during an alarm can exit safely.

There are multiple strategies available to achieve fire safety and design goals for stairs that interconnect multiple floors. Each option varies in cost, code implications, aesthetics, acoustics, and functionality. It’s important to evaluate these factors early in the design process and coordinate with the Authority Having Jurisdiction to ensure code compliance and project success.

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