The purpose of this standard is to define a reaction to fire test method applicable to fusible materials of any thickness, in order to contribute to their classification with regard to their behavior against fire as construction materials (see UNE standard 23-727). The materials are called fuses if during the preceding tests (test on the electric burner, see UNE 23-723, or radiation test, see UNE 23-721, depending on their thickness), drops have fallen, whether ignited or not. . The test is not applicable to glued wall coverings or floor coverings.