Certified Fire Protection Specialist (CFPS)

What happens to the effective ventilation area of an opening as the layer of smoke descends during a flashover?

1. Increases

2. Decreases

3. Remains the same

4. Fluctuates

The correct answer is: Decreases

As a fire progresses and smoke begins to descend during a flashover, the effective ventilation area of an opening decreases. This is primarily due to the way smoke behaves in a fire environment. As the smoke layer descends, it can block or partially obstruct the openings that would typically allow for the upward flow of air. This phenomenon reduces the overall ventilation effectiveness, meaning that the area through which fresh air can enter and smoke can exit is diminished. The accumulation of smoke near the openings not only physically blocks part of the ventilation path but also affects the pressure dynamics within the space, further inhibiting adequate ventilation and leading to a higher concentration of smoke in the area. Understanding these dynamics is crucial for fire protection specialists when designing and implementing strategies for smoke control and ventilation in buildings subjected to fire scenarios.