What is the method for testing positive pressure on a face piece?

Testing positive pressure on a face piece is critical for ensuring the integrity and safety of breathable air in firefighting and hazardous environments. The appropriate method involves breaking the face piece seal by inserting two fingers under the edge. This action allows for an assessment of the seal's efficacy; if the positive pressure system is functioning correctly, any gaps created by the fingers should result in a rush of air into the face piece, demonstrating that the seal holds effectively during use.

This method clearly indicates whether the face piece is maintaining an optimal pressure to prevent contaminants from entering the mask while also efficiently delivering the necessary airflow to the wearer. Other methods listed do not adequately assess the positive pressure or the integrity of the face piece's seal, making the chosen method the most accurate for ensuring safety and functionality in the field.