Each mechanical ventilation system is equipped with air filters to protect the entire ductwork, fans, heat exchangers in primary ventilation systems and people in clean room installations. The ventilation system is adapted to the needs of a given building, therefore the set of filters meets the relevant requirements and standards to meet the tasks set before it. More complex ventilation systems consist of pre-air filters operating in the first stage of air filtration. They collect the largest pollutants, then their task is performed by filters called fine in the second stage of filtration, which filter the air from tiny pollutants harmful to health. In clean room installations, the third stage of air filtration uses very fine filters to filter the air with absolute utmost care. Each air filter must meet the appropriate standards for air filtration. Filters differ in their efficiency, but also in appearance, which affects their impurity storage properties and the length of work between changes, and the materials used should ensure the easiest possible air flow in order to obtain the lowest possible air resistance on the filter, allowing for low electricity consumption by fans.