This new European standard is based on particle counting methods that actually cover most needs for different applications. EN 1822:2009 differs from its previous edition (EN 1822:1998) by including the following:
An alternative method for leakage testing of Group H filters with shapes other than panels
An alternative test method for using a solid, instead of a liquid, test aerosol
A method for testing and classifying of filters made out of membrane-type media
A method for testing and classifying filters made out of synthetic fibre media
The main difference is related to the classification for the filter classes H10 - H12, which has now been changed to E10 - E12.
Testing per EN 1822 is normally done with an aerosol probe which can be moved over the entire surface of the filter. This moving of the aerosol probe, or scanning, results in the measurement of many local collection efficiencies. These local efficiencies can be used to calculate the overall efficiency of the filter or the leak rate of a specific area of the filter. The overall efficiency calculation is often termed the integral value, while the leak rate is often termed the local value.
Tests are performed on new filters at specified nominal volumetric air flow. Filters of U15 or above must be scanned with a particle counter probe designed for this purpose. An oil thread test can be utilized on filters of H13 and H14 classification.