Building And Safety Codes For Open And Closed Stairway Risers
Open Risers and Building Codes: What Stair Builders Need to Know
Open riser stairs, with their modern aesthetic and airy feel, can be a striking design element in many homes. However, stair builders must be aware that these stylish stairs may not always meet building code requirements, especially when it comes to safety and fire egress.
What are Open Risers?
Open risers refer to the gaps between stair treads, where the space between the bottom of one step and the top of the step below is left open instead of being filled with a traditional riser. This design creates a visually lighter staircase and can enhance the sense of spaciousness in a room.
Building Code Considerations
Safety Concerns: Open risers can pose a tripping hazard, especially for young children or individuals with mobility impairments. Small objects can also fall through the gaps, potentially causing accidents.
Fire Egress: In the event of a fire, open risers can allow smoke and flames to spread more quickly between floors, hindering escape and potentially compromising the integrity of the staircase.
The 4-Inch Sphere Rule
Many building codes, including those based on the International Building Code (IBC), employ the "4-inch sphere rule" to assess stair safety. This rule states that a 4-inch diameter sphere should not be able to pass through any opening in the stair construction, including open risers. This is to prevent small children from getting their heads or limbs stuck in the gaps.
Open Risers and Fire Egress Stairs
Open risers are generally not permitted in fire egress stairways. These stairways are designed to provide a safe escape route during a fire, and any openings that could compromise their fire resistance are typically prohibited.
Local Building Code Variations
It's crucial to remember that building codes can vary significantly from one jurisdiction to another. While some areas may allow open risers under certain conditions, others may have strict prohibitions.
Design Considerations and Alternatives
Partial Open Risers: Consider using smaller openings or incorporating decorative elements within the riser space to maintain visual interest while enhancing safety.
Safety Glass Risers: Glass risers can create a sense of openness while still providing a barrier and meeting safety requirements.
Cable Railing Systems: These systems can provide a modern look while maintaining the necessary safety features for stairways.
Open and clear communication with your local building inspector is crucial when incorporating open risers into your stair designs. Discuss your plans early in the process to ensure your design complies with all applicable codes and regulations.
