UL 94, the Standard for Safety of Flammability of Plastic Materials for Parts in Devices and Appliances testing, is a plastics flammability standard released by Underwriters Laboratories of the United States. The standard determines the material’s tendency to either extinguish or spread the flame once the specimen has been ignited. UL-94 is now harmonized with IEC 60707, 60695-11-10, and 60695-11-20 and ISO 9772 and 9773.
The following method is used to determine the UL 94 V-0, V-1, and V-2 flammability ratings.
The test evaluates both the burning and afterglow times and dripping of the burning test specimen.
Pre-treatment:
2 days / 23 °C / 50 % relative humidity
7 days / 70 °C / hot air oven
Flame height 20 mm
Flame application time 2 x 10 s
The second flame application time begins as soon as the first burning time ends
| Flammability rating UL 94 V | |||
| Test criteria | V-0 | V-1 | V-2 |
| Burning time of each individual test specimen (s) (after first and second flame applications) | ≤10 | ≤30 | ≤30 |
| Total burning time (s) (10 flame applications) | ≤50 | ≤250 | ≤250 |
| Burning and afterglow times after second flame application (s) | ≤30 | ≤60 | ≤60 |
| Dripping of burning specimens (ignition of cotton batting) | no | no | yes |
| Combustion up to holding clamp (specimens completely burned) | no | no | no |
