Final answer:
Positive-pressure ventilation in firefighting involves introducing a flow of air at a higher pressure into a building to push the smoke and heat out. This technique allows firefighters to rescue victims and reduces the risk of flashover.
Step-by-step explanation:
Positive-pressure ventilation in firefighting is a technique used to control and extinguish fires by introducing a flow of air into the building at a pressure higher than that of the surrounding atmosphere. This creates a positive pressure gradient that pushes the smoke and heat out of the building, allowing firefighters to access and rescue victims while also reducing the risk of flashover. The increased airflow can also help to suppress the fire by decreasing the oxygen concentration, making it more difficult for the fire to sustain itself.