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Applications of Rubber in UL94 Horizontal and Vertical Burning Tests

UL 94 is a standard developed by Underwriters Laboratories (UL) to evaluate the flammability of plastic and other materials. Based on different thicknesses and burning conditions, this standard classifies materials into different levels and covers two main types of tests: horizontal burning (HB) and vertical burning (V). These tests are primarily used to assess how materials react when exposed to a fire source, particularly in terms of burning speed and self-extinguishing time, ensuring that the materials meet the safety requirements of various applications. The table below shows the UL 94 Standards: Flammability Ratings for Plastic and Other Materials.

UL94 Horizontal Burning (HB) Test

The horizontal burning test (HB) is one of the lowest fire resistance ratings in UL94. This test evaluates the burning performance of rubber materials when placed horizontally. The specific test method is as follows:

• Sample Orientation: Horizontally placed
• Criteria: (1) The flame extinguishes before reaching the 100mm mark; (2) The burning rate is calculated. For materials with a thickness less than 3mm, the burning rate should be less than 75mm/min; for materials between 3 to 13mm thick, the burning rate should be less than 40mm/min.
• Dripping Particles: Particles allowed to drip may ignite cotton.

The application of rubber materials in horizontal burning tests is mainly focused on products requiring basic fire protection, such as the outer casings and internal parts of some electronic devices.

UL94 Vertical Burning (V) Test

The 50W vertical burning test (V) includes ratings of V-2, V-1, and V-0, with fire resistance performance increasing from low to high. This test evaluates the burning performance of rubber materials when placed vertically. The specific test method is as follows:

• Sample Orientation: Vertically placed
• Burning Speed: After removing the fire source, any remaining flame or afterglow must extinguish within a specified time.
• Criteria: After two 10-second burn tests, V-2 and V-1 ratings require the sample to stop burning within 30 seconds, while V-0 requires the sample to stop burning within 10 seconds.
• Dripping Particles: V-2 rating allows dripping particles to ignite cotton, while V-1 and V-0 ratings do not allow dripping particles to ignite cotton.

Rubber materials are more widely applied in vertical burning tests, particularly in industries that require higher fire protection, such as automotive interiors, construction materials, and high-end electronic equipment components. These test methods and ratings help in evaluating and selecting the appropriate rubber materials for specific applications, ensuring that products meet flame retardant targets under fire risk scenarios.

UL94 Flame Retardant Test Levels and Related Standards

The UL94 test standards correspond with other international standards such as ASTM and ISO, ensuring global compliance for material applications. The table below shows the main ratings and corresponding standards:

Through these tests, suitable flame-retardant materials can be selected based on the product application requirements, ensuring product performance under fire risk scenarios.

GMORS Provides High-Performance Flame-Retardant Materials and Customized Technical Support.

To meet these needs, GMORS not only offers a wide variety of rubber materials but also has a specialized laboratory team that can develop and test material formulations according to specific customer requirements. GMORS provides a range of rubber materials tested according to UL 94 standards, including Neoprene (CR), Ethylene Propylene Diene Monomer (EPDM), Fluoroelastomer (FKM), Silicone, and Nitrile Rubber (NBR). Each of these materials has unique physical and chemical properties, making them suitable for various application scenarios. This professional technical service ensures that GMORS is a reliable partner for customers designing high-performance and high-safety products.

In pursuing flame-retardant materials, attention must also be paid to their environmental impact. GMORS is committed to developing rubber materials that meet environmental requirements, ensuring that product safety is enhanced while reducing negative environmental effects. This includes considerations from material selection, energy usage in the manufacturing process, to final product recycling. Every aspect integrates environmental concepts, ensuring that products are compliant and competitive in the marketplace.