UL94 is a fire rating test standard formulated by Underwriters Laboratories in the United States, which is used to evaluate the combustion performance of plastic materials under flames. According to the UL94 standard, the fire rating of plastic materials is divided into the following six levels:
1. V0 level: It will not continue to burn after the flame is extinguished, and the burning time does not exceed 10 seconds, which meets the strict fire protection requirements.
2. V1 level: It will not continue to burn after the flame is extinguished, and the burning time does not exceed 30 seconds.
3. V2 level: It will not continue to burn after the flame is extinguished, and the burning time does not exceed 60 seconds.
4. VTM-0 level: It will not continue to burn after the flame is extinguished, meeting the requirements of the vertical burning test.
5. VTM-1 level: It will not continue to burn after the flame is extinguished, meeting the requirements of the vertical burning test.
6. VTM-2 level: It will not continue to burn after the flame is extinguished, meeting the requirements of the vertical burning test.
These ratings are evaluated based on how well the material will burn under fire, with V0 being the highest rating, indicating the material has the best fire performance.