UL94 flame retardant rating test

UL94 flame retardant rating is the most widely used material flame retardant performance evaluation standard. It is used to evaluate the ability of materials to extinguish after being ignited and is a commonly used standard for daily testing of material flame retardancy. There are multiple evaluation methods for UL94 based on the combustion rate, combustion time, droplet resistance, and whether the droplets burn after ignition of the material.

UL94 has a total of 12 levels:

HB, V-0, V-1, V-2, 5VA, 5VB, VTM-0, VTM-1, VTM-2, HBF, HF1, HF2。

Among them, VTM-0, VTM-1, and VTM-2 are suitable for plastic film, while HBF, HF1, and HF2 are suitable for foam materials

The level testing plan is as follows:

1) HB level: Horizontal Burning Test

2) V0-V2 level: Vertical Burning Test

3) 5VA/5VB: 5V level fire test 500w (125 mm) vertical burning test

4) RP Class: Radiant Panel Flame Spread Test

5) VTM0-VTM2: Thin Material Vertical Burning Test

6) HF1-HF2: Horizontal Burning Foam Material Test

The specific testing requirements for UL94 are as follows:

HB: Flame retardant rating in UL94 standard. Require a combustion rate of less than 40 millimeters per minute for samples with a thickness of 3 to 13 millimeters; Samples less than 3 millimeters thick have a combustion rate of less than 70 millimeters per minute; Or extinguish before the 100mm mark.

V-0: After conducting two 10 second combustion tests on the sample, the residual flame and residual flame will extinguish within 30 seconds. Dropping particles cannot ignite cotton.

V-1: After conducting two 10 second combustion tests on the sample, the residual flame and residual flame will extinguish within 60 seconds. Dropping particles cannot ignite cotton.

V-2: After two 10 second combustion tests on the sample, the residual flame and residual flame will extinguish within 60 seconds. Dripping particles can ignite cotton.

5VB: After conducting five 5-second combustion tests on the sample, the residual flame and residual flame will extinguish within 60 seconds. Dropping particles cannot ignite cotton. For block samples, it is allowed to be burned through.

5VA: After conducting five 5-second combustion tests on the sample, the residual flame and residual flame will extinguish within 30 seconds. Dropping particles cannot ignite cotton. It is not allowed to burn through block samples.

Common UL94 testing methods

1. Horizontal Combustion Test (HB)

2. 50W vertical combustion test

3.500W vertical combustion test

UL 94 Flame Retardant Rating Criteria

1. UL94 horizontal combustion judgment conditions

2. UL94 vertical combustion judgment conditions

3. UL94 500w vertical combustion judgment conditions

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