HEPA Filtration: What is it and How Important is it?
The High Efficiency Particulate Air filter was designed, interestingly enough, during World War II, as a means of protecting the men and women working on the Manhattan Project. This project, as you may well know, brought us the atomic bomb before Nazi Germany was able to do it, as they were working on similar projects.
The dangerous product of the bomb was radioactive particles, and the military was trying to “filter” these out of the air. In this, the HEPA filters failed, but not for lack of trying.
They were formulated to intercept up to 99% of standard dirt particles as small as 0.3 microns in size. With their invention, the first use of the term HEPA filters occurred.
These filters, as their name indicates, were very efficient. However, they were also extremely expensive and quite bulky. They were practical only in manufacturing plants, specifically electronics and pharmaceutical clean rooms, research facilities, military applications and, of course, hospitals, again primarily in contamination and germ control.
Only later, while experimenting with the construction of these filters, were they made smaller and more affordable, so the average home owner could use them in their air purifying systems. People with breathing problems, such as asthma and many other allergies, along with MCS or Multiple Chemical Sensitivity use this filtering medium to help keep their home and office environments cleaner than they ordinarily would be. Some of these HEPA filtration systems also use mechanical filtration along with an electrostatic process to trap 99.97% of microscopic particles and many odors and gasses that other filter systems simply cannot handle.
Some of the most modern examples of HEPA filters, augmented by this electrostatic system, intercept things such as allergens, mold spores, tobacco, cigarette smoke, pet dander, paint fumes, perfumes, dust, dirt, pollen, insecticides and pesticides. Other substances, such as paint fumes, air fresheners, perfumes and even laundry detergent particles, can be controlled in this way.
Some of the more dangerous toxins in modern living and manufacturing can be filtered out of the air through the use of purifying chemicals, such as potassium permanent, in addition to the activated charcoal found to be very effective in filtration systems.
How do HEPA filters Work?
Contrary to popular belief, HEPA filters do not work like other filters do. They do not simply keep certain particle sizes out of the flow of air by performing as a sieve does. The filtering media is folded or stacked upon itself in a complicated way that acts more like a magnet than a sieve. The air flows around this media, and the particles are attracted to it and become caught in the many folds due to the very exacting laws of particle motion physics. The three principles being depended on by the manufacturers are impaction, diffusion and interception. Again, it’s a magnet, not a sieve.
The HEPA filters began a productive life in 1940 as a trademarked brand. This is now a generic term for any highly efficient filter used in many applications, such as vacuums, air cleaning and purifying systems and other air handling methods.
In the fight against such airborne illnesses as the flu, tuberculosis and other respiratory infections, like asthma and allergies, HEPA filters stand as one of the most effective frontline defenses. This is a great reason for their use in medical facilities. This is also why they are used in pharmaceutical research and manufacturing. The use in homes for keeping the air clean has already been mentioned.
Advantages of a HEPA filtered System
Since indoor air can be as much as 70 times dirtier than outside air, due to many variables, a short list of the advantages of a HEPA filtered system will include:
1. Many commercially available filters can be washed, ensuring a long lifespan, but the function will be decreased.
2. The removal of very small particles of contamination as well as gasses is possible.
3. Any electric or electronic device can be fitted with one of these effective filters as they are continuing to develop new designs and uses.
4. The HEPA filter technology can be used as a stand-alone system or combined with many other technologies.
5. The devices using HEPA filters are usually quieter than other units.
6. They effectively reduce air pollutants and contaminants and assist in preventing dusty surfaces.
The number of companies making equipment, devices and units that need this technology is increasing, so development will continue to improve this system, and the price, due to competition, will get cheaper and cheaper.