In stairway design, except for which of the following should handrails be provided on both sides?

In stairway design, handrails are typically essential for safety and accessibility. The requirement for providing handrails on both sides is primarily to ensure that users can safely navigate stairs, especially in public spaces. Spiral staircases present a unique situation; due to their design, it is often impractical or impossible to install handrails on both sides while still maintaining proper function and aesthetics.

Unlike spiral staircases, exterior stairs, wide corridors, and stairs within dwelling units can accommodate handrails on both sides. Exterior stairs are generally designed for public use and safety, requiring handrails to assist users, especially in outdoor settings where conditions like rain or snow may create hazards. Wide corridors can also benefit from handrails on both sides, providing support and stability for individuals while navigating through the space. Similarly, stairs within dwelling units can enhance accessibility and safety by providing handrails on both sides, allowing residents to move comfortably through their homes.

In summary, the unique design challenges associated with spiral staircases justify the allowance for handrails only on one side, making it the exception in this case.