Flame Retardant Grade of Plastics
The flame retardant grade of plastics increases gradually from HB, V-2, V-1 to V-0:
1. The lowest flame retardant grade in the HB:UL94 standard. For 3 to 13 mm thick samples, the burning speed is less than 40 mm per minute; for less than 3 mm thick samples, the burning speed is less than 70 mm per minute; or it is extinguished before the 100 mm mark.
2. V-2: The flame extinguishes within 60 seconds after two 10-second combustion tests. There can be burners falling.
3. V-1: After two 10-second combustion tests, the flame will extinguish in 60 seconds. No burning material can fall.
4. V-0: After two 10-second combustion tests, the flame will be extinguished in 30 seconds. No burning material can fall.
