UL 94 flammability test using LISUN Glow wire tester

There are multiple methods for the evaluation of flammability and fire resistance of the material. They are usually direct flame and indirect flame methods. ”Direct Flame Method” applies a flame to a vertically or horizontally placed specimen under specific orientations. On the other hand, the ”Indirect Flame Method” uses a non-flaming heat source and then applies it to the mounted specimen. ”Glow wire testing” is a type of indirect flame test method. Test results make us able to make a comparison of materials’ ability to resist ignitions and flames.

What is a Glow Wire Test?

The Glow wire test is one of the most crucial tests for various electronic applications. It is a physical, thermal test method for testing plastics. It is designed to evaluate the flame-resistant properties of all the plastic materials used in electronic equipment.

Apart from that, this test is done for the protection of equipment from the risk of fire from overheating. It also provides protection to the electrically generalized parts, due to which the plastic material can ignite.

This might happen in normal or abnormal use, malfunction, or product failure. This test helps in the simulation of an overheated part that comes in contact with the plastic material.

Series of Standards

The glow wire test is carried out in accordance with multiple series like IEC 60695-2-10, IEC 60695-2-11, IEC 60695-2-12, and IEC 60695-2-13. All these series have different methods of test and purposes. These are

• IEC 60695-2-10: Glow wire test apparatus and standard procedure
• IEC 60695-2-11: Glow wire test for checking the flammability of the end products
• IEC 60695-2-12: Glow wire flammability index (GWFI) test for various plastic materials
• EC 60695-2-13: Glow wire ignition temperature (GWIT) test for various materials

Glow Wire Tester

The glow wire test apparatus is best suitable for producing and inspecting the quality of low-voltage electrical instruments and other electrical appliances. It is considered a simulation test item of IEC 60695-2-10, UL746A, IEC 60695-2-11, IEC 60695-2-12 and IEC 60695-2-13. All these standards use non-flame ignition methods.

The apparatus is made from a specific material (Ni80/Cr20), and heating wire is like resistance heating alloys. The temperature for conduction of the test is 550 ? ~ 960 ?. Test conditions are as below

• Temperature tolerance: ±5°C at 500°C~750°C|±15°C at 750°C~1000°C
• Time required for heating: 0-999 Seconds Adjustable
• Lightning time: 0 -998 Seconds, Automatic Timing, Manual Recording
• Extinguishing time: 0-999 Seconds, Automatic Timing, Manual Recording
• Test Speed: 10-20mm/s
• Volume of the shape: W:1000mm*D:675mm*H:1250*mm
• Machine Weight: Glow Wire Test Apparatus: 50 KG
• Hot penetration depth: 7mm ± 0.5mm (Maintaining Pressure of 1N ± 0.2N into the Sample)

The glow wire test apparatus is suitable for all the electrical and electronic equipment and insulation or combustible materials.

UL 94 Flammability Test

UL 94 is considered one of the most widely used flammability tests for determining the relative flammability of plastic materials. Several factors can influence flammability, including ease of the ignition flame, spread fire endurance rate of heat release, and ease of extinction.

The UL 94 flammability tester is used for the determination of performance of plastic materials, rubber or film under fire to check its resistance level.

A. Horizontal flammability test
B. Vertical flammability test

Conformity Criteria

Criteria Conditions
V-0
After flame time for each specimen t1 or t2
<10s
Total after flame time for any condition set
< the 50s
Cotton indicator ignited by flaming particles or drops
No
After Flame or afterglow of any specimen up to the holding clamp
No
After Flame plus afterglow time for each specimen after the second flame application
< the 30s

Rating of the test

Based on the performance during the test, a material will be given a rating of V0, V1, V2, or no rating at all. This rating is critical as the electrical utility industry looks to minimize the potential spread of fire originating from electrical overload, component failure, insulation breakdown, or loose connection. The apparatus employs a ul bar, a piece of cotton, and a burner. The plastic must pass the following tests.

• First, the plastic is given 10 seconds to ignite. Then, the remaining burning time is measured. If the plastic is self-extinguishing, the second ignition of 10 seconds follows.
• The time is measured again. In addition, the burning up to the clamp was checked. If the burning drops ignite, the cotton is monitored.
• As fire is a complex reaction, this procedure is repeated five times.
• All t1 durations are added up to produce the total burning time t2.
• The UTC and DITC are all documented five times as well. The lowest performance decides the classification.

Frequently Asked Questions

What is meant by the ”flammability test”?

Flammability Testing determines to which extent the material or finished product can resist ignition when exposed to fire or heat.

What is meant by ”UL 94 rating”?

Underwriters laboratories (USA) have set a plastic flammability standard known as UL 94. This standard is used to classify plastics according to how they burn or ignite in various conditions.

Lisun Instruments Limited was found by LISUN GROUP in 2003. LISUN quality system has been strictly certified by ISO9001:2015. As a CIE Membership, LISUN products are designed based on CIE, IEC and other international or national standards. All products passed CE certificate and authenticated by the third party lab.

Our main products are Goniophotometer, Integrating Sphere, Spectroradiometer, Surge Generator, ESD Simulator Guns, EMI Receiver, EMC Test Equipment, Electrical Safety Tester, Environmental Chamber, Temperature Chamber, Climate Chamber, Thermal Chamber, Salt Spray Test, Dust Test Chamber, Waterproof Test, RoHS Test (EDXRF), Glow Wire Test and Needle Flame Test.

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