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General Knowledge

HEPA Filter – Basics

HEPA Filter – Basics

The term HEPA Filter is common now, but what is it? What does it do and what are its specialties compared to other filters? Let us look into the basics.

What is HEPA

HEPA is the short form for High-Frequency Particulate Absorbing or High-Efficiency Particulate Arrestance. HEPA is an efficiency standard of Air Filters. Commercialization of HEPA was during 1950’s. It has now become a trademark for high efficient filters. HEPA filters are used in many applications that require contamination control. They are used in Air Conditioners, Vacuum Cleaners, Vehicles and many other applications.

HEPA Standards of efficiency

The common standards of HEPA filters require that it must remove at least 99.95% as per European Standards. The American Society of Mechanical Engineers (ASME), US Department of Energy (USDOE) standards are slightly different. It requires removal of 99.97% of particles whose diameter is equal to 0.3µm. Filtration efficiency increases increases for particle diameters both less than and greater than 0.3µm.

The HEPA filters capture Pollen, Dirt, Dust, Moisture, Bacteria, Virus and submicron liquid Aerosol. It is also able to capture floor dust containing Bacteroidia, Clostridia and Bacilli.

Filter Structure

The HEPA Filters are composed of a mat of randomly arranged polypropylene or fiberglass fibers having diameters between 0.5 and 2.0 micrometers. Mostly these filters are composed of tangled bundles of fine fibers. They create a narrow pathway through which air flows. Larger particles are directly blocked by the filter. When smaller particles pass along with air, they collide with the fibers as the air twists and turns. They are blocked by the fibers.

Source of Information: Wikipedia

Read more about HEPA Filters in detail here

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Born and brought up in Kerala, I did my schooling in Kerala and graduated (B.Sc Physics) from the Calicut University. I have worked with a Swedish Company from 1994 to 2015, as a Senior Project Manager in their Group IT Division in Dubai. This blog is the result of my strong desire to communicate with others, sharing what I know and what I could gather from various sources.


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