How far back should a fan be positioned for positive pressure ventilation (PPV)?

The ideal positioning of a fan for positive pressure ventilation (PPV) is typically suggested to be 12-15 feet from the designated opening. This distance allows for optimal airflow to create a sufficient pressure differential that effectively pushes the smoke or contaminants out of the structure while also reducing the possibility of the air column becoming turbulent or ineffective. Being too close may result in inadequate air distribution and could disrupt the intended flow pattern needed for successful ventilation. Positioning the fan within this range allows for the best balance between airflow and control, ensuring that the ventilation process is efficient and safe.