A high-performance HEPA filter differs from similar devices in that it is capable of retaining fine particles of less than 2.5 microns. The effectiveness of these filters is confirmed by the standards GOST R EN 1822-1-2010 and EN 1822-1:2009.
What does HEPA filter mean?
The HEPA filter first appeared in the 40s in the United States, it was invented as part of a nuclear project to trap radioactive particles. In the same years, a similar filter was developed in another nuclear power – the USSR. To answer the question of whether a HEPA filter is needed, you need to ask if a person has a vacuum cleaner, air conditioner or other ventilation system. If these devices are, most likely they use fine HEPA air filters. The abbreviation HEPA fully sounds like High Efficiency Particulate Air and means “highly efficient air purification.”
The main material for HEPA filters consists of randomly arranged glass paper or fluoroplastic fibers of various thicknesses (0.5-5 microns). In the finished product, this material is folded like an accordion. The life of the filter depends on how often it has to work with large particles – they get stuck in the gaps between the fibers and clog the filter, so additional filters should be placed in front of it to catch larger particles.
Although the distance between the fibers of a HEPA filter can be 5-50 microns, which practically eliminates the sieve effect, it is able to trap very small particles, for example, allergens, pollen, dust mites, microorganisms, this result is achieved through several other effects:
- adhesion effect. If a dust particle touches the hair, it sticks to it, and then other particles stick to it. The peculiarity of the HEPA filter is that these particles stick so strongly that it is almost impossible to clean them, but at the same time, the cleaning ability of the product only increases, and the volume of filtered air decreases.
- diffusion effect. The smallest particles (less than 0.1 microns) in the air flow are in chaotic motion, so they sooner or later fall on the filter fibers and settle on them.
- effect of inertia. Particles larger than 0.3 microns settle on the filter fibers due to inertia – air flows around the fibers, and dust collides with them.
- Engagement effect. This mechanism works with particles that are large for diffusion and small for inertia. The essence of the effect is that they can approach the fiber at a distance of their diameter and then they “catch” on it and stick.
Characteristics of HEPA filters
One of the main characteristics of HEPA filters is the percentage of particles caught, according to this parameter they are divided into classes. International classification – HEPA filter, classes:
- HEPA H10 – 85%;
- HEPA H11 – 95%;
- HEPA H12 – 99.5%;
- HEPA H13 – 99.95%;
- HEPA H14 – 99.995%.
Which HEPA filter is best?
What you need to pay attention to when buying universal HEPA filters:
- Product class. The higher the filter class, the better it cleans the air.
- Dimensions. A large filter area will trap more harmful particles, a model with a small area will clog faster.
- Filter folds. The fibrous filter material must be folded evenly and neatly so that air can pass through it freely.
- Additional filters available. If only small particles enter the HEPA filter, it will last longer. To do this, the product must have additional filters that trap large particles.
- The presence of processing. Coating the filter with antibacterial compounds helps to avoid the development of pathogens in the fibers.
HEPA filter for allergy sufferers
It is possible to use a hygienic HEPA filter for people prone to allergies if the product class is higher than H12. Such filters, if used correctly, effectively remove most of the allergens from the air (but not tobacco smoke, formaldehyde fumes and other similar contaminants). Replace the HEPA filter for the home, if it works for an allergy sufferer, should be replaced more often than recommended. During replacement, it is advisable to take the device with the filter out of the house so that allergen particles do not get into the air.
HEPA filter for ventilation
Supply and exhaust systems for indoor air purification are equipped with several filters:
- pre-cleaning for catching insects, dust, wool:
- rough cleaning;
- medium cleaning;
- fine cleaning, for which a HEPA air filter is often used.
High and ultra-high air purification with HEPA H13 and H14 filters is required in the food, aerospace, nuclear power, microelectronics, and medicine industries. High requirements for air purification are also in medicine, especially in maternity wards, neonatal wards, operating rooms, infectious diseases hospitals, and various laboratories.
HEPA filter for vacuum cleaner
Several types of filters are used in modern vacuum cleaners, and a HEPA filter is used for final air purification, which can be disposable – made of glass paper fibers, or reusable – made of fluoroplastic. Filter manufacturers use products of different classes, often cheaper H10, H11, but in expensive models you can also see H12 and H13 filters. The question of how to clean the HEPA filter of a vacuum cleaner is relevant only for fluoroplastic products. The reusable HEPA filter can be washed under running water and dried.
HEPA filter for air purifier
Indoor air purification systems are very demanding on the quality of filter elements, so they use a HEPA filter for air cleaner classes H12, H13, H14. Filters in air purifiers can be impregnated with bactericidal compounds so that their surface does not become a breeding ground for infection. It is possible to understand that the filter is dirty by the appearance of an unpleasant foreign smell, a decrease in air flow. In this case, the HEPA filter should be washed or replaced.
Washable HEPA filter
Many are wondering if it is possible to wash a HEPA filter, the answer to which is positive, if it is a product made of fluoroplastic fibers. To wash the filter, follow the instructions:
- Turn off the device;
- Open the protective cover and remove the HEPA filter.
- Clean the surface of the material with a brush or brush to remove dust and debris.
- Rinse the filter with running water without detergents.
- Dry the item at room temperature.
- Place the filter in the device.
Carbon HEPA filter
Recently, more and more varieties of filters with improved performance have appeared. For example, a HEPA filter, the classification of which can be very different, is supplemented with an activated carbon coating. Such a model cleans the air not only from polluting particles, but also from smoke and unpleasant odors. In some cases, not the filter itself is coated with carbon, but an additional filter sheet placed behind the HEPA filter.
HEPA fine filter
Well-known global manufacturers of equipment are increasingly using only HEPA 13 or HEPA 14 fine filters in their products, which trap 99.95-99.99% of particles. This technique is expensive, but it is justified if the family has a small child or someone suffers from allergies. Manufacturers do not stop there, and in the future, HEPA filters H15 and H16 will appear on sale, which are already being developed, and, according to estimates, will achieve almost 100% air purification.
How to clean the HEPA filter?
One of the serious drawbacks of the HEPA filter is that it does not destroy, but accumulates all the dirt that it has collected. And if the filter gets into favorable conditions for microorganisms, they will develop. At the same time, cleaning the HEPA filter is almost impossible – the particles firmly settle on the fibers, and they cannot be cleaned (washed off with water only for washable models). It is especially dangerous if mold begins to develop in the filter. The only recommendation to protect yourself is to replace the HEPA filter with a new one. The timing of filter replacement should be indicated in the instructions for the product.
Service life of HEPA filters
It is more often recommended to replace the replacement HEPA filter after 3-6 months of service. But at the same time, one should also take into account how actively the device was operated. For example, the filter life of an air purifier can be calculated for 8 hours daily for 3 months, but if the device actually works much longer every day, the HEPA filter should be changed more often. It is also not necessary to extend the operation longer if the device is used irregularly – the filter can become a breeding ground for infection.
How to replace the HEPA filter?
In domestic conditions, it is impossible to find an adequate replacement for HEPA filters – any homemade product will be inferior in quality. In industry, as a replacement, manufacturers offer the following HEPA filter analogues:
- folded cell filters FyaS, which are used, including in pharmacological production, in laboratories;
- folded cell filters FyaS-MP, cleaning not only from dust, but also from radioactive particles.
How to make a HEPA filter with your own hands?
The need to make a filter on your own may arise if a similar model is not on sale. It is impossible to create a HEPA filter with your own hands, completely identical to the one made in production, but you can still find a replacement. This will require a car cabin filter, similar in its characteristics to HEPA. Vacuum cleaner filter replacement production technology:
- Remove the pleated material from the plastic base of the filter.
- Clean the base from adhesive residue and dirt.
- Cut a piece of the required size from the cabin filter.
- Glue the new filter element into the filter base.
- Dry the filter and place it in the device.
The main problem with a self-made HEPA filter may be that it will begin to let air in at the points of gluing with the plastic base. If this happens, to solve such a problem, it is recommended to use a sealant that needs to be treated with all the seams. Then the product must dry completely and after that it can be used.