The plug circulating air filter box ensures a safe technical ventilation of the safety cabinets in work areas according to the requirements of TRbF 20 attachment L point 4.1. The air filter box type UFA-2030 is able to hold back, solvent-vapours (hydrocarbons) until a filter saturation up to more than 99,999%, under normal conditions as well as, at a simulated solvent-leakage in the safety cabinet. Direct emission of the cleaned exhaust air from the safety cabinet into the work areas. The box is ideal for the usage in working areas because of its low loudness of 39 dB (A).