Flame Retardant Soaking Process

For injection molded parts, commonly used flame retardant ratings include HB, V-2, V-1, V-0, 5VB, and 5VA, with the rating increasing progressively from HB, V-2, V-1, V-0, 5VB to 5VA. HB: The lowest flame retardant rating in the UL94 standard. For samples 3 to 13 mm thick, the burning rate must be less than 40 mm/min; for samples less than 3 mm thick, the burning rate must be less than 70 mm/min; or the flame must extinguish before reaching the 100 mm mark. V-2: After two 10-second burning tests, the afterflame and residual flame must extinguish within 60 seconds. Dripping particles can ignite cotton. V-1: After two 10-second burning tests, the afterflame and residual flame must extinguish within 60 seconds. Dripping particles cannot ignite cotton. V-0: After two 10-second burning tests, the afterflame and residual flame must extinguish within 30 seconds. The dripping particles cannot ignite the cotton.