What is the goal of positive-pressure ventilation?
Select one:
a. Increase pressure to higher than the exterior of the structure and also higher than the fire can produce
b. Increase pressure to higher than the exterior of the structure, not higher than the fire can produce
c. Maintain the same interior and exterior pressure
d. Decrease pressure to lower than the exterior of the structure
The Correct Answer and Explanation is :
The correct answer is b. Increase pressure to higher than the exterior of the structure, not higher than the fire can produce.
Explanation:
Positive-pressure ventilation (PPV) is a firefighting technique that is used to improve visibility, decrease the spread of fire, and create a safer environment for firefighters. The goal of PPV is to control the flow of smoke and heat out of a burning building, which in turn helps to clear the environment for both firefighting efforts and any potential rescues.
In positive-pressure ventilation, firefighters use high-powered fans to force fresh air into the building. This process creates a higher air pressure inside the building compared to the outside, effectively pushing smoke and hot gases out of designated vent openings. The increased pressure inside the structure forces the smoke and heat to escape through these openings, which helps to reduce the buildup of toxic smoke and heat within the building. This is particularly useful in situations where the fire has spread to multiple areas of the building and the smoke has become thick.
However, it’s crucial to note that the pressure inside the building should not exceed the pressure that the fire is producing, as this could potentially push the fire into areas that are otherwise unaffected, causing the fire to spread more rapidly. Therefore, PPV works by creating a differential pressure where the pressure inside the structure is greater than the outside air pressure but controlled in such a way that it does not exacerbate the fire’s growth.
The use of PPV is not only important for firefighting but also for improving the safety of individuals inside the building. By clearing smoke and hot gases quickly, PPV provides a safer atmosphere, reducing the risk of injury and improving the chances for successful rescues.