What Does Hepa Filter Do

You may have come across the term "HEPA Filter" when looking to purchase an air purifier, HVAC arrangement or vacuum cleaner. Knowing what they are and how they work will requite you an understanding of how HEPA filters in products can be beneficial.

What Is A HEPA Filter?

This type of air filter can theoretically remove at least 99.97% of dust, pollen, mold, bacteria, and any airborne particles with a size of 0.3 microns (μm). The diameter specification of 0.3 microns responds to the worst case; the most penetrating particle size (MPPS). Particles that are larger or smaller are trapped with even college efficiency. Using the worst-example particle size results in the worst-example efficiency rating, for example 99.97% or better for all particle sizes.

What Does HEPA Correspond?

According to the Ecology Protection Agency (EPA), "HEPA is a blazon of pleated mechanical air filter. It is an acronym for "loftier efficiency particulate air [filter]" (as officially defined by the U.S. Dept. of Free energy).

Where Did HEPA Filters Come From?

Originally, HEPA filters were secretly adult by the military machine because of their use for chemical, biological, and radiological defense purposes. "Post-obit Globe War II, the Diminutive Energy Commission (AEC) chose the military machine's HEPA filters as their main device for particle removal in all frazzle air systems of nuclear facilities." (Department of Energy,DOE) HEPA filters were starting time used in the Manhattan Project to prevent the spread of airborne radioactive contaminants and later commercialized in the 1950s.

How Do They Work?

Today, about HEPA filters are made from a mixture of glass fibers that are interlaced. Particles are captured in one of four means: straight impacting, interception, diffusion, or sieving.

Direct Impacting:Big particles travel in a straight line, collide, and are trapped.
Interception: Particles collide with fibers and remain attached to the fibers.
Improvidence:Every bit smaller particles travel, they collide with the cobweb and are captured.
Sieving:Occurs when the particle is as well big to fit in between the fiber'southward spaces.

Variations of HEPA Filtration

HEPA Filters can come up in many forms with differentiating factors such every bit grade, course or MERV rating. There are standards ready by the Section of Energy (DOE), but HEPA filter type may vary by manufacturer.

HEPA filters are separated into different HEPA grades based on their filtration efficiency of small particulate matter (PM) 2.5 and PM 10 particles. The standard to make up one's mind this "…is centered on the performance of the filter for the most difficult, or about penetrating particle size (MPPS)." This nomenclature system "… is based on messages and figures in the aforementioned mode as for coarse and fine filters co-ordinate to the EN Classes. The filters are divided into eight classes from H10 to U17, depending on the efficiency of their media at the MPPS (most penetrating particle size) and the size of any weaknesses or leaks introduced by fabrication of the finished detail." (Science Straight)

A Minimum Efficiency Reporting Value (MERV) rating reports a filter's ability to capture larger particles betwixt 0.iii and ten µm (microns). The college the MERV rating, the more particles are captured by the filter.

See the tabular array beneath for more on particulate thing, MERV ratings, and more than.(Section of Free energy, DOE)

*Minimum Efficiency Reporting Value (MERV) Rating*	*Particle Size*	*Typical Pollutants*
17 - 20	<0.xxx µm>	Some airborne viruses
13 – 16	0.3 – 1.0 µm	Bacteria, Tobacco smoke, Cooking oil, Most smoke
ix - 12	ane.0 – 3.0 µm	Diverse dusts
5 - 8	3.0 – 10.0 µm	Mold spores
one - 4	> 10.0 µm	Pollen, Grit mites

TruSens filters capture particulate affair equally small as 0.3 microns.

Where HEPA Filters Are Used

HEPA filters accept evolved over time and are used in many industries. Some of the products that you tin can at present notice them in are listed below. The type of filter used varies based on the company or manufacturer.

Air purifiers
Face masks
Vacuum cleaners
Airplanes
Cars
HVAC systems

HEPA Filters and Air Purifiers: What to Await For

HEPA filters are the nigh commonly used form of filtration in an air purifier. When deciding to purchase an air purifier and filter for your home, consider boosted purification systems as well. Although the HEPA filter is typically the biggest defense force against airborne particulates, when it's paired with additional filtration or sterilization it tin can improve your air quality even more and extend the life of the HEPA filter. According to the Centers for Disease Control and Prevention (CDC) 1 or more depression-efficiency disposable prefilters, installed outside of a HEPA filter, may extend HEPA filter life sometimes at least 25%.

Conclusion

HEPA filters generally capture particulates such as fume, grit, bacteria, pollen, and more. These filters help protect us from breathing in potentially harmful pollutants inside our homes and other indoor environments. Although HEPA filters started as a defense to nuclear particles, the shift to commercialization has made it possible for the filters to be used past everyday consumers in a more diverse manner.