HEPA Air Purifier

HEPA filters are used wherever the room air is to be cleaned of small particles and particulates that may be harmful to the human organism. On the one hand, allergens such as pollen or animal hair are captured, and on the other hand, very small particles such as fine dust or exhaust fumes. In the private sector, HEPA filters are found in commercially available air purifiers, among other things. In the commercial sector and working environment, they are used for air purification in industry, offices, laboratories, or medical facilities, for example.

Why choose HEPA?

HEPA filters are essential for thorough air cleaning and are mainly used in air purifiers and air cleaners. Air purifiers clean the air in a home or office of allergens, fine dust, house dust, animal hair, smoke, or odors, among other things. To check the effectiveness of such a filter, the degree of separation is essential. The higher the degree of separation, the more efficient the air purification. Especially for allergy sufferers, it is crucial that even the smallest allergens are captured to significantly reduce allergy symptoms.

Air purifiers certified with a HEPA designation filter particles between 0.1 and 0.3 microns in size from the air with a separation efficiency of at least 99.95%. A more precise classification is provided by the European filter standardization according to EN 1822-1:2009, which divides the filter classes into 17 different collection efficiencies.

These filters, widely used today, have their origins in the military. They were first developed during the Manhattan Project in the 1940s. There, they were intended to clean the air of small radioactive particles. Later, the technology was introduced to the civilian sector. Medical facilities and research laboratories in particular benefit greatly from the impressive efficiency of modern HEPA air filters.

How it works?

The operation of HEPA air filters is mainly based on the following three physical laws:

  • Barrier effect. The particles entering the air filter follow the airflow generated by the air purifier. Due to the arrangement of the glass fibers, the small particles come so close to the fibers that they stick due to adhesion forces.
  • Inertia effect. This effect utilizes the weight of heavier or larger particles, which cannot follow the airflow simultaneously but continue to fly due to their greater inertia, causing them to stick to filter fibers.
  • Diffusion effect. This effect refers to the heat-induced Brownian motion of particles. These collide randomly with one another and thus repeatedly change their direction of movement, which causes them to hit filter fibers, among other things, to which they adhere – also due to adhesion forces.

HEPA filters usually consist of fine glass fiber mats enclosed in a wooden, plastic or metal frame. Since the glass fibers used have a diameter of only 1-10 micrometers and the fibers are also arranged randomly and chaotically, the filter performance is extremely high. In addition, in order to provide the best purification, HEPA air purifiers also have a charcoal screen that eliminates odors and impurities that might have escaped.