From which floor or above must a second alarm be called if smoke or fire is visible from the exterior?

A second alarm must be called if smoke or fire is visible from the exterior starting at the fourth floor. This guideline is based on the increased complexity and risk associated with fires in taller buildings, where smoke and fire can spread more rapidly and create greater challenges for firefighters.

Fires originating on or above the fourth floor typically pose significant challenges for access, ventilation, and suppression efforts due to height and potentially increased wind effects. This risk necessitates additional resources to ensure adequate firefighting capabilities and to ensure the safety of both occupants and firefighters. Therefore, the procedure mandates a second alarm to facilitate a rapid response and mobilization of additional equipment and personnel to manage these more severe situations effectively.