Abstract: There is indicated a method of generating smoke aerosols for proper planning and testing and for demonstration of the effectiveness of fire alarm systems, and pyrolysis apparatus for carrying out the method. In the method a test piece, for example, an electrical cable or the like, is heated over a specific period of time, according to a first alternative, along a predeterminable temperature curve, or, according to a second alternative, is held at a constant or a well-nigh constant temperature. By means of the method according to the invention it is possible to simulate a reproducible progress of a real electrical fire in a compressed period of time.