What is the recommended proximity of the exhaust opening to the fire when using PPV?

The recommended proximity of the exhaust opening to the fire when using Positive Pressure Ventilation (PPV) is for it to be close to the fire. This positioning allows for the most effective removal of smoke and heat from the area, thereby improving visibility and reducing the temperature in the space where firefighters are operating. By placing the exhaust opening in close proximity to the fire, the PPV fans can effectively push clean air into the structure, which helps to displace the hot, smoky air and create a safer environment for both the occupants and the firefighters.

This method maximizes the efficiency of the ventilation system, ensuring that it can rapidly clear the area of harmful gases and smoke, which is critical during firefighting operations. Other options, such as placing the exhaust opening far away or at a specific distance, would not facilitate the optimal airflow required for effective ventilation. Consequently, positioning the exhaust opening close to the fire is essential for the successful application of PPV techniques.