The flammability and smoke density are determined, respectively according to SN 198'898 and VKF. The first determines the burning behavior of a vertically oriented fabric, the latter assesses the smoke development of a fabric that is completely burnt down in a test chamber.
The test specimen is hung in a test cabinet. A flame is applied to the bottom edge of a test sample, for a duration of 3 seconds and 15 seconds. The afterflame and afterglow time, damaged length, and the rate of flame spread are observed.
The test specimen is put in a test cabinet and subjected to a flame until it has been burnt down. The generation of smoke is assessed by means of photometry: the maximum light absorption of the smoke is measured.
The test material passes the test if it shows following characteristics:- Afterflame time maximum 5 srconds - Damaged length maximum 150mm.
Based on the measured light absorption the material is classified: - ‘qualmgrad 1’ for strong smoke generation; - ‘qualmgrad 2’ for medium smoke generation; - ‘qualmgrad 3’ for low smoke generation.