Why is it important to have a minimum of five cleared floors above the fire in a fire attack stairwell?

Having a minimum of five cleared floors above the fire in a fire attack stairwell is crucial for effective evacuation. When a fire occurs in a high-rise building, smoke and heat can rapidly ascend, impacting the upper floors. By ensuring that a sufficient number of floors are cleared above the fire, it is possible to create a safe evacuation route for occupants. This allows individuals to escape away from the immediate threat of smoke and flames, while also providing firefighters with access to a secure egress path for those requiring rescue.

The cleared floors serve as a buffer, enabling a safer passage and reducing the likelihood of smoke inhalation or heat exposure for evacuees. Additionally, having multiple floors cleared above aids in minimizing panic among building occupants and allows for better organization and control of the evacuation process, which is critical in maintaining safety during an emergency situation.