The flame retardant grade of plastics decreases step by step from V-0, V-1, V-2 to HB. HB UL94 and CSA C22 2NO 017 are the lowest flame retardant ratings in the standard. The U.S. American flame retardant material standard is ANSI/UL-94-1985 standard UL94 test has five kinds:1. Horizontal burning test of 94HB class2. 94V-0 94V-1 94V-2 level vertical burning test3.94 5-V level vertical burning test4. Flame spread index test with radiant panels5. Vertical burning test of 94VIM-0 94VIM-1 94VIM-2 level Among them, the horizontal burning test method of plastic grade B: Experimental sample: Use a small strip sample with a length of 127mm, a width, a maximum thickness, and the smallest size. Test conditions: carried out in a non-ventilated test chamber. Evaluation method: For materials rated as 94HB grade, the burning speed on the gauge length is not more than 38lnm/min when the thickness of the sample is 200mm. Or when the thickness of the sample is less than 38 lnm/min, or before reaching the 102mm mark, the burning must be stopped. 94V-1 94V-2 level vertical burning test method: Experimental sample: This test uses a small strip sample with a length of 127mm and a maximum thickness of 127mm. Test conditions: carried out in a non-ventilated test chamber. Evaluation method: For materials rated as 94HB grade, the burning speed on the gauge length is not more than 38lnm/min when the thickness of the sample is 2