Generator of non-toxic aerosol of solid and gaseous phase simulating combustion smoke products is placed into the tested space, compositions (2) of which are activated, then propagation of the aerosol cloud is monitored and recorded and the functionality of the fire ventilation is evaluated. The aerosol consists of a mixture based on potassium carbonate, potassium hydrogen carbonate, carbon, carbon dioxide, water vapours, nitrous gases, nitrogen, and ammonia generated at temperature 600 to 1300° C in quantity of 3 to 100 m3/s while the tested devices for smoke and heat removal are in operation. The device includes generator with vessels (1) containing composition (2) and firing device (3), placed by 4 to 10 in a bed (5) of stands fixed by 1 to 20 in a tub (11) and covered with perforated covers (9). The tub (11) is preferably mounted on a bearing structure (14) of a vehicle.