What is a Filter Class?

Filter class is a term used to describe the efficiency of a filter. In the coming years, filter class designations such as G1 to G4, M5, M6, F7 to F9 will slowly be replaced by a new standard in accordance to the new ISO 16890 filter norm. To clarify we have made an overview of the ‘old’ filter classes and with which filter class they will be replaced.

Air filter grades are determined by ISO 16890, which is the current international standard for testing air filters for ventilation systems in the food and beverage industry. It replaced BS EN 779:2012 on 30th June 2018. The test method represents real-life performance much more accurately than previously and the filter classification system (based on particulate matter efficiency or ePM) is much more transparent. Furthermore, for the first time, the same filter classifications are used globally.

The old BS EN 779 air filter grades (G1 to F9) have been replaced with a new filter classification system.

The ISO 16890 classification system reports a simpler percentage efficiency within 1 of 4 particle size ranges:

ePM1 Filter efficiency for particle size range 0.3 – 1 μm

ePM2.5 Filter efficiency for particle size range 0.3 – 2.5 μm

ePM10 Filter efficiency for particle size range 0.3 – 10.0 μm

ISO coarse Gravimetric filter arrestance for filters not able to achieve minimum 50% efficiency at ePM10.

Although EN 779 and ISO 16890 cannot be directly compared, due to their different filter testing methods, you can find a chart giving an indicative comparison for filter replacement purposes here.

Air filter classification

The DIN EN 1822 standard and its filter classes

The DIN EN 1822 standard is a filter standard for HEPA filters and includes the following filter classes:
•    EPA filter (Efficient Particulate Air filter)
•    HEPA filter (High-Efficiency Particulate Air filter)
•    ULPA filter (Ultra-Low Particulate Air filter)

Classification Standard EN1822

Efficient air filters (EPA), high efficiency air filters (HEPA) and ultra low penetration air filters (ULPA-filters) which used in the field of ventilation and air conditioning and for technical processes, e.g. for applications in clean room technology or pharmaceutical industry are classified and tested according to the EN 1822:2009 standard.

These HEPA(ULPA) filters ,which used in the field of ventilation and air conditioning and for technical processes, e.g. for applications in clean room technology or pharmaceutical industry are classified and tested according to the EN 1822:2009 standard.