UL 94 V0 flame-rated rubber meets Underwriters Laboratories’ (UL) most stringent requirements for resistance to vertical burning. This flammability rating is part of the larger UL 94 standard and is harder to achieve than UL 94 V1 or UL 94 V2, which also apply to vertically-oriented samples. UL 94 V0 rubber also meets tougher flammability criteria than UL 94 HB, which applies to horizontal instead of vertical burning.
Elasto Proxy distributes flame rated rubber and fabricates finished products like UL 94 V0 gaskets and edge trim. We source fire resistant rubber from trusted suppliers and offer sheets, coils, cut lengths, and ready-to-install solutions. Whether you need sponge rubber or solid rubber, we can help you meet tough flammability requirements while achieving sealing and insulation success.
Keep reading to learn more and contact Elasto Proxy for a quote.
What is UL 94?
UL 94 is a standard from Underwriters Laboratories (UL) that defines fire tests for polymers, a category of materials that includes rubber and plastic. UL 94 contains different flame classifications or ratings, each of which has its own test procedure. The vertical and horizontal burn ratings apply to materials that are used in electrical and electronic enclosures, structural parts and insulators.
Certification or compliance with UL 94 is important for fire safety, but it’s also voluntary. In other words, UL 94 is not a regulatory requirement. UL 94 is used mainly in North America, but it’s harmonized with IEC 60707, 60695-11-10, and 60695-11-20 from the International Electrotechnical Commission (IEC) and with ISO 9772 and 9773 from the International Standards Organization (ISO).
What is UL 94 V0 Rubber?
UL 94 V0 is one of three vertical ratings within the UL 94 standard. These ratings (V0, V1, and V2) indicate that a sample of the material was tested in a vertical position and self-extinguished within a specific time after the ignition source was removed. UL 94 vertical ratings also indicate whether the test specimen dripped flaming particles on a cotton indicator.
UL 94 V0 rubber meets the following flammability requirements.
- Burning Time: The material stops burning within 10 seconds after each flame application.
- Dripping: The material does not drip flaming particles that could ignite a cotton indicator placed below the sample.
- Afterglow: After the flame is removed, the material has minimal afterglow (less than 30 seconds)
- Sample Behavior: There is no visible burning or scorching of the cotton indicator.
Among the three UL 94 vertical flame ratings, V0 is the most stringent.
- Burning Time: UL 94 V1 and UL 94 V2 rubber stop burning within 30 seconds, a duration that’s 3x longer than in UL 94 V0.
- Dripping: Although UL 94 V1 rubber does not produce flaming drips, UL 94 V2 rubber may do so.
Sponge Rubber vs. Solid Rubber
Elasto Proxy supplies UL94 V0 flame-rated rubber as ready-to-fabricate materials and finished products. Depending on your application requirements, you can choose sponge or solid rubber in compounds like EPDM or silicone. All UL 94 V0 rubber is fire resistant, but applications such as enclosure sealing or vibration isolation have other requirements.
- UL 94 V0 sponge rubber has a cellular structure that provides compressibility, flexibility, and cushioning. Applications include flame-retardant sealing for consumer and automotive electronics, batteries, and industrial equipment. The type of compound determines performance properties such as environmental or chemical resistance.
- UL 94 V0 solid rubber is less compressible and less flexible, but it’s better at resisting impact. Applications include under-the-hood components, vibration dampening pads, and structural elements in aircraft cabins. Harder rubber provides greater wear and abrasion resistance, but the compound you select also determines performance properties.
Specialized UL 94 V0 rubber is also available. For example, Elasto Proxy can source a UL 94 V0 solid silicone material that also provides shielding against electromagnetic interference (EMI).
Do You Need Flame Rated Rubber?
UL 94 V0 flame rated rubber costs more than commodity elastomers. When fire safety is critical, however, your application may require it. Examples range from household appliances and automotive parts to electric vehicle (EV) charging stations and battery energy storage systems (BESS). Solar panels and wind turbines use flame-retardant rubber, too.
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