What is the purpose of stair shafts in a building’s design?

Stair shafts primarily serve as safe zones during emergencies, particularly during a fire or other evacuation scenarios. These shafts are designed to provide vertical access and are often built to contain smoke and heat, allowing occupants to safely exit the building while minimizing exposure to hazardous conditions. The design typically includes fire-rated materials and may also feature pressurization systems to keep smoke out of the stairway, ensuring that it remains a viable escape route.

While stair shafts may also contribute to aesthetic appeal, accommodate elevators, or allow some natural light through design features like windows, their primary function is to ensure safety and effective evacuation during critical situations. This focus on safety is a fundamental principle in architectural design, particularly in high-rise and large commercial buildings where quick evacuation is a critical concern.