This method of test for flammability characteristics is applicable to certain low density insulating materials that do not melt or drip during exposure to fire (see Appendix A). It is used in establishing the Flame Spread Classification for those foamed plastics whose flammability assessment by CAN/ULC-S102 requires the use of the rate formula FSV = 92.5 d/t but where the necessary parameters ('d' & 't') for use in the formula are difficult to define. The purpose of this test is to determine the comparative burning characteristics of the material under test by exposing the material in a corner wall configuration to a test fire.