Breathe Easier: The ABC’s of HEPA Filters

HEPA (for you trivia enthusiasts stands for High Efficiency Particulate Air) filters can eliminate at least 99.96% of particles, as small as 0.3 micrometers, in the air. Particles this small are complicated, but not impossible, to filter.

HEPA filters, made of fibers arranged in a random fashion into a type of mat, can filter the air with great effectiveness. Of course, the thickness and the diameter and density of the fibers will affect its functionality. The HEPA filters are made to capture contaminants in one of the following ways:

• Interception: smaller contaminants flow along the airflow coming within radius of the fiber and get stuck to the fiber.
• Impaction: larger contaminents are not able to avoid the fibers and get stuck to the fibers by the force of the air flow.
• Diffusion: the smallest particles collide with gas molecules and are slowed down in their air flow path through the filter.

First created in the 1940’s and commercialized in the 1950’s, the original term HEPA became the commonly used name for any highly effective filter. Over the last 5 decades, these HEPA filters have progressed to meet higher expectations for air quality in various industries including HVAC.