What are the flame retardant grades of FEP heat shrinkable tubes?

The flame retardant grade of the FEP heat shrinkable tube is in the UL standard, and there is a VW-1 test standard.

UL, VW-1 test standard is a relatively common standard. The experiment stipulates that the sample is kept vertical, and the test burner (flame height 125mm, thermal power 500W) burns for 15 seconds, then stops for 15 seconds, and repeats 5 times. .

FEP heat shrinkable tube flame retardant grade VW-1 level qualification standards are 1. The flame spread should not exceed 60 seconds. 2. The sample should not be burnt more than 25%. 3. The surgical cotton pads at the bottom cannot be ignited by falling objects.

There are 12 kinds of UL94****************** in the flame retardant grade: HB, V-0, V-1, V-2, 5VA, 5VB, VTM-0, VTM -1, VTM-2, HBF, HF-1, HF-2.

The flammability UL94 rating is the most widely used standard for the flammability performance of plastic materials. It is used to evaluate the ability of a material to extinguish after being ignited. There are many ways to judge according to the burning speed, burning time, anti-drip ability, and whether the drip bead burns. Numerous values are available for each tested material based on color or thickness. When the material of a product is selected, its UL rating should meet the thickness requirements of the plastic part. The UL rating should be reported along with the thickness value, it is not sufficient to report the UL rating without the thickness.

The flame retardant grade of plastic increases step by step from HB, V-2, V-1, V-0, 5VB to 5VA:

HB: The lowest flame retardant grade in the UL94 standard. It is required that for samples 3 to 13 mm thick, the burning rate is less than 40 mm per minute; for samples, less than 3 mm thick, the burning rate is less than 70 mm per minute; or it is extinguished before the 100 mm mark.

V-2: After two 10-second burn tests on the sample, the afterflame & afterburn were extinguished within 60 seconds. The dripping particles can ignite the cotton.

V-1: After two 10-second burn tests on the sample, the afterflame & afterburn were extinguished within 60 seconds. Drip particles should not ignite the cotton.

V-0: After two 10-second burn tests on the sample, afterflame & afterburn were extinguished within 30 seconds. Drip particles should not ignite the cotton.

5VB: After five 5 sec burn tests on the sample, afterflame & afterburn extinguished within 60 sec. The dripping particles should not ignite the cotton. Burn-through is allowed for bulk samples.

5VA: After five 5-second burn tests on the sample, the afterflame & afterburn is extinguished within 30 seconds. Drip particles should not ignite the cotton. Burn-through is not allowed for bulk samples.

Wire burning method in UL1581:

1. VW-1: Vertical burning test (UL wire burning grade);

2. FT1: vertical combustion test;

3. FT2: Horizontal combustion test;

4. FT4: vertical combustion test;

5. FT6: Horizontal combustion and smoke test (the combustion level of the FT type is the electric wire combustion level of the CSA standard);

Among the above grades:VW-1 is the same grade as FT1. FT2 is the easiest to pass and has the lowest grade.

VW-1 is stricter than FT1, both of which are vertical combustion, the judgment criteria: 1. The burning mark (kraft paper) cannot be carbonized by more than 25%; 2. The after-burning time of 5 times of 15-second burning cannot exceed 60 seconds; 3. Burning Drops cannot ignite cotton; VW-1 requires 1, 2, 3; FT1 only requires 1, 2.

For the wire industry, the V-2, V-1, V-0, 5VA, and 5VB of UL94 assess the materials used for the wires. During the test, a standard sample should be formulated with the test material, which will not be marked on the wire.

VW-1, VW-2, FT-1, and FT-2 assess the wire itself. After passing the test, the corresponding grade can be marked on the wire. The flame retardancy of wires is completely different from that of UL94. For example, an insulating material can pass V-0 of UL94 but not necessarily VW-1;

In addition, UL94 is the flame retardant of insulating materials, and the flame retardant requirements of wires are generally on UL758621581; so the flame retardant in UL94 such as V-0 and V-1 is not the flame retardant of wires at all; there is no print on the AWM wire. VW-1/FT1 and V0 burning test in UL94 are very different in equipment:

1. The height and temperature of the flame are different;

2. The methane flow used in the test is also different;

3. The back pressure of methane is also different;

4. The volume of the combustion box is also different: VW-1 requires more than 4 cubic meters, while V0 only requires more than 0.5 cubic meters;

5. The burning times are also different 0Gr4OG\x06;

6. In the combustion results: V0 requires recording the residual burning time, but VW-1 does not.

However, the test conditions and test methods of 5V-level combustion and VW-1 combustion in UL94 are similar and relatively close. Note: Whether it is VW-1 or UL94 combustion test equipment, it must refer to ASTM5025 and ASTM5027, UL1581 and UL94 are only test methods, and the requirements of test equipment must be in accordance with ASTM standards.

Flame retardant grade of heat shrinkable tube: VW-1/FT1 is very different from the V0 burning test in UL94:

1. The height and temperature of the flame are different;

2. The methane flow used in the test is also different;

3. The back pressure of methane is also different;

4. The volume of the combustion box is also different: VW-1 requires more than 4 cubic meters, while V0 only requires more than 0.5 cubic meters;

5. The number of burnings is also different;

6. In the burning result: V0 requires recording the residual burning time, but VW-1 does not!