Things you must know about HEPA Filter

by Amili R. SEO If you are looking to buy a home air purifier, you are more likely to come across a term ‘HEPA filter’. It is one of the most used technologies in the field of air filtration. Its main task is to cleanse the air by making it pass through a ventilation system and then throwing the clean air outside. Let’s get to know everything about HEPA filters in this post.

What is HEPA filter?

HEPA stands for High Efficiency Particulate Air Filter. Its use in an air filtration unit is quite common since it helps in the removal of airborne pollutants from the air and delivery of clean air outside. A HEPA filter traps and prevents tiny, possible harmful particles like dirt, dust, mites, pollen, and dander from entering your lungs. These filters contain an extremely fine, mesh-like film of fibers that collect and remove these pollutants.

The Working of HEPA Filters

There are four ways a HEPA filter captures airborne pollutants when they pass through the filter.

1. Impaction – Small particles get attached to the web when polluted air passes through it

2. Interception – It takes place when a pollutant tries to pass through the air filter but strikes and attaches to a fiber

3. Diffusion – This is when particles bound nearby by gas molecules and finally stick to the fibers

4. Sieving – The pollutants get stuck between fibers while passing through the filter.

Though all commonly available air purifiers claim to have HEPA filters, a good quality HEPA filter is the one that can capture 99.97% of pollutants of a size of 0.3 microns or larger. However, it is important to note that a HEPA filter may be ineffective in treating odors, viruses, and bacteria. While searching for the best air purifier, it is recommended to search for terms like ‘True HEPA’ or ‘Absolute HEPA’.

The HEPA Standard

When it comes to choosing HEPA filters, it is not about a particular brand. Instead, it is about investing in a type of filter that is meant to clean the air as per HEPA standards.

HEPA refers to a formal public and industrial (non-consumer) standard derived by the US Department of Energy (DOE). However, at the same time, there are European standards also in use like H13 or U16.

The formal definition of HEPA was given during the 1940s in a Manhattan Project since there was a requirement of filters that could find out radioactive elements. Do keep in mind that the standard does not dictate how the filter should be created or what material should be used, but it defined that it should be able to trap particles of specific sizes and types.

Unluckily, any kind of air filter with HEPA name does not need to pass through any certification via a regulatory body. The public service contractors must abide by the stringent standards when installing HEPA filters in air purifiers or nuclear units. In such scenarios, it is needed to prove that they have got the right HEPA standard. However, this sanction is not applicable to commercial gadgets like air purifiers.

Particles that can be removed by HEPA filters.

According to the latest HEPA standards, any air filter will be considered HEPA filter if it can trap and remove 99.95% of airborne particles that pass through it. This means that a specific size of particles, precisely the one having a size of 0.3 µm.

The most common particles that can be removed by a HEPA filter are dust, pollen, dirt, virus, bacteria, moisture, and aerosol.

HEPA filters usually cannot trap gaseous elements such as fumes, chemicals, odors, and gases, and volatile organic compounds (VOCs). If you get an air purifier claiming that it can eliminate VOCs and gaseous contaminants, it is much higher than a typical HEPA filter. They can be considered a hybrid filter that can be loaded with an activated carbon filter.
 
In regard to the improvement of air quality, air purifiers balance the airflow, air filtration, and air pressure to cleanse the maximum possible air. A majority of air purifiers consider cleaning an amount of air gauged in cubic feet per minute (CFM; or Q). In simple language, they refer to the use of Clean Air Delivery Rate (CADR), or the rate at which air passes through the filter.

Types of HEPA Filters

There are different types of HEPA filters available to choose from:

• True HEPA: An air filter termed as True HEPA stays true to the prescribed HEPA air filter standard. It would be able to remove 99.97%of airborne particles of 0.3 microns size.

• Absolute HEPA: It is similar to True HEPA, but it comes with a higher filtration.

• UltraHEPA: This means that the said product is “100x more powerful than HEPA air filters.”

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Created on Mar 26th 2024 02:04. Viewed 87 times.

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