Which of the following must be deenergized when sprinklers actuate in the same area?

• A. HVAC fans
• B. HVLS fans
• C. Lighting
• D. Elevators

Answer: (B)

When sprinklers discharge in a space, the goal is to minimize air movement that could spread water, heat, or smoke and to reduce electrical hazards around the wet environment. Large ceiling fans (HVLS fans) move a lot of air with relatively low speed, so if they stay energized, they can carry sprinkler water droplets or smoky air to other parts of the area. Turning them off helps localize the water to the sprinklered zone and reduces the potential for spreading smoke or delaying evacuation. HVLS fans aren’t essential to life safety in the immediate firefighting scenario, so deenergizing them is the safest, most effective action in this moment. Elevator operations and lighting/other systems have their own fire-response procedures, and HVAC systems are typically controlled by fire-sequence logic, but the large air movers specifically pose the greatest risk if left running when sprinklers actuate.