MARKING OF GAS FILTERS

Gas filter cartridges are typically marked using a combination of letters and numbers, e.g. “A2B2E1”.

The letters stand for the filter type. The filter type indicates which hazardous substances the gas filter protects against.

The numbers stand for the filter class, which gives information about the filters absorption capacity. In each case, the filter class applies for the filter type indicated by the letter directly preceding it. Filters in higher protection classes can be used to protect against higher concentrations of gas in the workplace.

As you can see from the example A2B2E1, a filter cartridge can be made up of several filter types (A, B and E), with the same or different levels of filter class. The filter in the example offers combined protection against organic gases (boiling point > 65° C), inorganic gases and acid gases.