In the electronics and electrical industries, the fire resistance of materials has always been a key factor in ensuring product safety and reliability. Especially in the field of cables and wires, the selection and testing of fire resistance ratings are crucial. Today, we will take a deep look at the fire resistance ratings of TPE (thermoplastic elastomer) wires, especially the V0 fire resistance rating and its relationship with the UL VW-1 vertical burning test.

Fire rating classification of TPE wire

The fire rating of TPE wire is classified according to its burning behavior under specific conditions. These levels include HB, V2, V1 and V0, with HB being the lowest level and V0 being the highest level. When the TPE compound itself has V0-level fire resistance, the wire made from it will also maintain the same V0-level fire rating. This is because V0-level materials have excellent flame retardant properties and can quickly self-extinguish even under high temperatures and flames, thus ensuring the safety of the wire in a fire.

Features of V0 fire protection grade

V0 fire rating means that TPE wire has excellent performance in the following aspects:

1.?Flame retardant properties: V0 grade TPE wire can quickly extinguish itself when encountering flames, thus preventing the spread of fire. This flame retardant property is achieved by adding flame retardants or using special processes.

2.?Low smoke and halogen free: V0 grade TPE wire produces less smoke and toxic gases when burning, which helps reduce the harm of fire to people and the environment.

3.?Good electrical properties: V0 grade TPE wire not only has excellent flame retardant properties, but also has good electrical properties such as insulation resistance and voltage resistance, ensuring that the wire will not cause a fire due to electrical failure during normal use.

UL VW-1 vertical burning test

In order to verify the fire resistance of TPE wire, the UL VW-1 vertical combustion test is usually carried out. This test simulates the burning behavior of the cable under the condition of being exposed to flame in the vertical direction. The following are the detailed steps and judgment criteria of the test:

Test steps

1.?Fix the test material vertically on the test frame, ensuring that it maintains an angle of 20° with the flame of the burner.

2.?Burn the test material with a flame for 15 seconds, then extinguish the flame and observe the burning behavior of the test material.

3.?After the first combustion, wait 15 seconds and burn the test material with the flame again. Repeat this process 5 times.

Judgment Criteria

1.?Burning time: During the entire test process, the flame burning time shall not exceed 60 seconds.

2.?Burning degree: After the test material is burned, the unburned part should account for more than 25% of the original length.

3.?Drops: During the test, burning objects falling from the test material shall not ignite the surgical sponge below.

The UL VW-1 vertical burning test can accurately evaluate the fire resistance of TPE wire. When the TPE compound itself is rated V0, the wire made from it can usually easily meet these criteria in the test, thus proving its excellent flame retardant properties.

The fire rating of TPE wire is crucial to the safety and reliability of the product. Selecting TPE wire with V0 fire rating and verifying it through the UL VW-1 vertical burning test is a key measure to ensure the fire resistance of the product.