In the flammability test of plastics materials in the UL, there is a heat ray ignitability test to see the ignitability by ignition (ignition due to electric energy) and a burner flame ignition test to see the burning rate of the burner flame on the sample There is. This unit tests the ignitability by heat rays, measuring the time from energization to ignition by winding a nichrome wire around the specimen and energizing specified power.