Exterior stairways and ramps in buildings are generally required to be separated from the building’s interior for fire safety. This separation is crucial to ensure that exit routes remain protected in case of a fire within the building. However, building codes recognize certain situations where this separation may not be necessary, providing exceptions based on specific conditions. These exceptions are designed to offer flexibility in building design while maintaining an acceptable level of safety for occupants needing to evacuate. Understanding these exceptions is important for architects, builders, and code officials to ensure compliance and optimize building designs, especially concerning the path people need to take to exit a building.
One common exception relates to building height. For buildings that are not more than two stories above grade plane, and excluding certain high-risk occupancy groups like R-1 and R-2 (hotels and apartments), separation from the interior is not mandated. This exception is applicable when the level of exit discharge is the first story above grade. In simpler terms, for smaller, low-rise buildings, if the exit leads directly to the outside at ground level from the first floor, the strict separation requirement for exterior stairs can be waived.
Another exception addresses situations where an exterior ramp or balcony acts as an intermediary space. If an exterior stairway or ramp is served by an exterior ramp or balcony that connects two separate exterior stairways or other approved exits, separation may not be required. This exception hinges on the balcony or ramp’s perimeter being at least 50 percent open. Furthermore, to qualify as open, these openings must be a minimum of 50 percent of the enclosing wall’s height and at least 7 feet above the balcony level. This design allows for natural ventilation and reduces smoke accumulation in the exit pathway.
A further exception is linked to buildings permitted to have unenclosed exit access stairways as per Section 1009.3 of the building code. If a building design already incorporates unenclosed exit access stairways under those specific allowances, then the exterior stairway or ramp connected to it also need not be separated from the building’s interior. This exception acknowledges designs where open exit pathways are already an accepted feature of the building’s fire safety strategy.
Finally, a significant exception applies to exterior stairways or ramps connected to open-ended corridors, provided a set of stringent conditions are met. Firstly, the entire building, including corridors, stairways, and ramps, must be equipped with a comprehensive automatic sprinkler system complying with Section 903.3.1.1 or 903.3.1.2. Secondly, these open-ended corridors must adhere to the specifications outlined in Section 1018, which likely concerns their design and fire-resistance ratings. Thirdly, each end of the open-ended corridor must connect to an exterior exit stairway or ramp that complies with Section 1026, ensuring proper exit capabilities. Fourthly, the exterior walls and any openings near the exterior exit stairway or ramp must comply with Section 1022.7, likely pertaining to fire-resistance and protection of openings. Lastly, at any point in an open-ended corridor where there is a change in direction exceeding 45 degrees, a clear opening of at least 35 square feet or another exterior stairway or ramp must be provided to prevent smoke traps. These clear openings must be positioned to minimize smoke or toxic gas accumulation, ensuring a safer path to exit.
These exceptions to exterior stairway and ramp separation requirements are carefully crafted to balance safety with practical building design. They allow for certain building configurations without compromising the overall fire safety strategy, particularly by considering factors like building height, open spaces, sprinkler systems, and the design of corridors and exit pathways. Understanding these nuances is crucial for ensuring both code compliance and effective, safe building designs.
