What does HEPA filter testing measure?

HEPA filter testing primarily measures the penetration of particles through the filter media and converts this value into overall efficiency. This testing is designed to determine how effective the filter is at capturing particles of a specific size, which is essential for understanding its performance in air filtration applications.

In HEPA filters, efficiency is often defined by the percentage of particles that are retained compared to those that pass through; thus, measuring penetration is critical. A filter that has a very low penetration rate indicates high efficiency, as it effectively captures a larger proportion of airborne particles.

Understanding this concept is vital for anyone working with air filtration systems, as it relates directly to a filter's ability to create clean, safe air in indoor environments, such as hospitals, laboratories, and HVAC systems.