What factor is known to decrease the chances of flashover during a fire?

Limited ventilation is known to decrease the chances of flashover during a fire for several reasons. Flashover is a rapid spread of fire that can occur when all combustible materials in a room reach their ignition temperature simultaneously. By restricting ventilation, the amount of oxygen that fuels the fire is limited. This limitation slows down the combustion process and reduces the temperature buildup within the room, making it less likely to reach the critical conditions necessary for flashover to occur.

In environments with limited ventilation, the fire may smolder or burn at a lower intensity, consuming available oxygen without the risk of creating conditions conducive to the sudden and explosive growth characteristic of flashover. By controlling the airflow and minimizing the introduction of additional oxygen, firefighters can effectively manage fire behavior, retaining better control over the situation.

In contrast, increased ventilation and strategies like open window ventilation can inadvertently introduce fresh oxygen, possibly leading to a rapid increase in fire development and increasing the risk of flashover. High humidity levels can also play a complex role in fire dynamics but are not typically a direct factor in flashover prevention in the same way limited ventilation is.