Which of the following is NOT a correct step when isolating a fire to prevent smoke spread?

• A. Close the affected compartment door
• B. Close air vents
• C. Open the compartment door to ventilate
• D. Follow isolation steps per procedure

Answer: (C)

When isolating a fire, the main goal is to limit airflow and keep smoke confined to the affected area. Keeping the compartment door closed helps seal off the space, making it harder for heat and smoke to move to other areas. Closing air vents further reduces fresh air feeding the fire and slows smoke spread. Opening the compartment door to ventilate would introduce more air, potentially feeding the fire and pushing smoke into adjacent compartments—this undermines containment. Following the established isolation steps per procedure ensures the actions taken are coordinated and safe, so the correct approach is not to open the door for ventilation.