Filters and Test Methods

EUROVENT has always led the field in measuring and characterizing air filters. Since 1979 EUROVENT 4/5 has set the standard in Europe and provided the basis for European Standard EN 779 1993, Specifications for Particulate Air Filters for General Ventilation. 

EN 779 1993 in principle contains two different test methods. The filter is tested both with untreated outdoor air and with the addition of synthetic dust. In the first case, the filter s dust spot efficiency is determined, i.e., its capacity to clean normal outdoor air. In the second case, the filter s arrestance is measured, i.e., its capacity to separate synthetic dust. The average value for dust spot efficiency or arrestance during the course of the test is used for classification of the filter. 

Modern measuring techniques, an increased requirement for the indoor environment, and the efficiency of filters in separating particles led to EUROVENT 4/9 1992 Method of Testing Air Filters Used In General Ventilation for the Determination of Fractional Efficiency. This method also provides the basis for the next revision or upgrade of European Standard EN 779 1999. 

In EUROVENT 4/9 the dust spot efficiency has been replaced by measurement of the degree of separation of particles within the 0.2-3 pm range, with a particle size of 0.4 pm used for classification of the filter. 

The increased need to control the indoor environment and filter efficiency in the actual environment has led to EUROVENT 4/10 1996, Recommendations for In Situ Fractional Determination of General Ventilating Filters.  

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