UL94 is a plastics flammability standard released by Underwriters Laboratories in the United States. The standard determines whether a material will extinguish or spread a flame once it has been ignited. V-0 is a classification of this standard outlined as:
V-0: Burning stops within 10 seconds on a vertical specimen; drips of particles allowed as long as they are not inflamed.
How is material tested to UL94 V-0?
The test is conducted on five specimens of the material which measure 13mm x 125mm x 13mm thick (maximum thickness). Each material specimen is then clamped in a vertical position. A Bunsen burner with a flame height of 20mm is then positioned so that the top of the burner is 10mm lower than the material specimen. The flame is then applied to the material for 10 seconds. The Bunsen burner can be moved to ensure that the flame remains directly below the material. After 10 seconds the flame is removed, the time that the specimen continues to burn for is recorded. Once the flame is extinguished the burner is applied for another 10 seconds and the process is repeated.
Criteria to pass UL94 V-0
- The specimens should not have a flame for more than 10 seconds after either application of the Bunsen burner.
- The total flame time must not exceed 50 seconds for the set of 5 material specimens
- The material must not drip flaming particles that ignite the cotton indicator.
- The material must not have glowing combustion for more than 30 seconds after the removal of the Bunsen burner.
- The material must not burn with flame or glowing combustion up to the clamp
What are The Applications of UL94 V-0 Silicone?
UL standards are used as a safety rating for a range of produces when there are concerns about the product burning. From LED lighting to electronics and ovens.
In automotive, rail and aerospace industries where safety is of critical importance UL94 V-0 and other tests such as EN45545 and FAR/JAR 25.823 are essential safety standards. In the event of a fire, the silicone rubber would help resist the flames and prevent the spread of fire.