Fire rating UL94
Flammability UL94 grade is the most widely used plastic material flammability standards. It is used to evaluate the ability of the material to extinguish when it is ignited. There are many ways of judging depending on the burning rate, the burning time, the anti-drip ability, and whether or not the dripping bead is burned. Each test material can have many values based on color or thickness. When selecting the material of a product, its UL rating shall meet the thickness requirements of the wall portion of the plastic part. The UL rating should be reported with the thickness value, and reporting the UL rating without thickness is not enough.
Plastic flame-retardant grade from HB, V-2, V-1 to V-0 step by step:
HB: The lowest flammability rating of UL94. For samples 3 to 13 mm thick, the burn rate is less than 40 millimeters per minute; for samples less than 3 millimeters thick, the burn rate is less than 70 millimeters per minute; or extinguished before the 100 millimeter mark.
V-2: After two 10 second combustion tests on the sample, the flame extinguishes within 30 seconds. Cotton can be ignited under 30cm.
V-1: After two 10 second combustion tests on the sample, the flame extinguished within 30 seconds. Can not ignite cotton wool below 30cm.
V-0: After two 10 second combustion tests on the sample, the flame extinguished within 10 seconds. Can not have burning things fall.