The Dust Disperser SAG 440 has been especially developed to meet the requirements as defined by the guidelines ASHRAE 52.2 and DIN EN 779 for testing the performance of particulate air filters. Due to the particular physical properties of ASHRAE test dust the instrument was adapted to this material. The SAG 440 is particularly suited for feeding / dosing dusts containing a certain proportion of fibres and provides excellent results when producing test dust to check separation efficiencies.