In which phase of a compartmentalized fire do conditions exist where open flaming decreases because smoke production displaces and limits available combustion air?

The correct answer is the ventilation-limited phase. During this phase of a compartment fire, the available oxygen for combustion is significantly reduced due to an increase in smoke production. As the fire progresses, combustion consumes the available oxygen; when this occurs, the flames are no longer able to grow effectively, leading to a decrease in open flaming. Smoke, a byproduct of combustion, fills the space and restricts the amount of oxygen available for the fire, thereby hindering further burning.

Understanding this phase is crucial for incident safety officers, as these conditions can lead to the potential for backdrafts or flashovers if not managed properly. Recognizing that the fire is oxygen-limited allows responders to adjust their tactics accordingly, especially in terms of ventilation and suppression strategies. The ventilation-limited phase highlights the delicate balance of fire dynamics in compartment fires and emphasizes the importance of monitoring air supply to manage fire behavior effectively.