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Understanding FMVSS 302: Flammability of Interior Materials

Understanding FMVSS 302: Flammability of Interior Materials


The Federal Motor Vehicle Safety Standards (FMVSS) are regulations issued by the National Highway Traffic Safety Administration (NHTSA) in the United States, aimed at ensuring the safety of vehicles and their occupants. One of the critical standards in this extensive list is FMVSS 302, which specifically addresses the flammability of interior materials used in motor vehicles. This blog post will delve into the significance of FMVSS 302, the test procedure it mandates, and a verbal explanation of the formula used in assessing material flammability.


Importance of FMVSS 302

The primary goal of FMVSS 302 is to reduce the deaths and injuries to occupants caused by vehicle fires, especially those originating from the interior materials of a vehicle. This standard applies to passenger cars, trucks, buses, and multipurpose passenger vehicles, focusing on materials used in occupant compartments. By setting a maximum burn rate for these materials, FMVSS 302 aims to delay the spread of fire, allowing occupants more time to escape in the event of a fire.

Test Procedure Overview

The FMVSS 302 test procedure is designed to measure the horizontal burn rate of materials used in the interior of vehicles. Here’s a simplified overview of the procedure:

  1. Sample Preparation: Materials are cut into specific dimensions (typically 356 mm in length and 100 mm in width) and conditioned at 23°C and 50% relative humidity for 24 hours.

  2. Mounting the Sample: The prepared sample is mounted horizontally in a U-shaped holder designed to prevent flame spread to the specimen’s upper surface.

  3. Ignition: A standardized flame is applied to one end of the sample for 15 seconds to ignite the material.

  4. Measurement: The time is measured for the flame to propagate between two set points marked on the sample, usually 38 mm apart.

  5. Calculation of Burn Rate: The burn rate is calculated based on the distance between the two marks and the time taken for the flame to travel this distance.

The Formula in Words

The formula used in FMVSS 302 to determine the compliance of a material with the safety standard involves calculating the burn rate of the material. In verbal terms, the formula is as follows:

  • The burn rate is calculated by dividing the distance the flame traveled by the time it took for the flame to travel that distance. The result is then converted into millimeters per minute to meet the standard’s requirements.

  • To comply with FMVSS 302, the calculated burn rate must not exceed 100 millimeters per minute. This threshold ensures that materials used within the vehicle’s interior are sufficiently resistant to fire spread, contributing to the overall safety of the vehicle occupants in case of a fire.



Adhering to FMVSS 302 is crucial for vehicle manufacturers to ensure the safety of their products and, most importantly, the lives of the people who use them. This standard highlights the importance of material selection and the need for rigorous testing to prevent the rapid spread of fires in vehicle interiors. Kiyo R&D Center & Laboratory is equipped to conduct comprehensive flammability testing, including FMVSS 302, to support manufacturers in meeting these essential safety standards. By understanding and implementing the requirements of FMVSS 302, we contribute to making vehicles safer for everyone. For further assistance or to schedule a flammability test in compliance with FMVSS 302, please contact Kiyo R&D Center & Laboratory. Our team is dedicated to ensuring your materials meet the highest safety standards through meticulous testing and analysis.

FAQs on FMVSS 302

Q1: What types of materials are tested under FMVSS 302? A1: FMVSS 302 testing applies to materials used in the vehicle’s interior, such as upholstery, foam, textiles, and other composite materials that might be exposed to sources of ignition.

Q2: Why is the FMVSS 302 standard critical for vehicle safety? A2: By limiting the interior materials’ burn rate, FMVSS 302 provides occupants with more time to exit the vehicle in case of a fire, thereby reducing the risk of burn injuries or fatalities.

Q3: How is the FMVSS 302 test conducted? A3: The test involves igniting one end of a material sample and measuring the time it takes for the flame to travel a specified distance, from which the burn rate is calculated.

Q4: What happens if a material fails the FMVSS 302 test? A4: Materials failing to meet the FMVSS 302 criteria cannot be used in areas of the vehicle that are subject to this standard. Manufacturers must select or develop alternative materials that comply with the FMVSS 302 requirements.

Q5: Can Kiyo R&D Center & Laboratory assist with FMVSS 302 testing? A5: Yes, Kiyo R&D Center & Laboratory offers comprehensive flammability testing services, including FMVSS 302 compliance testing. Our expert team is equipped to guide you through the testing process, ensuring your materials meet the necessary safety standards.

Wrapping Up

Compliance with FMVSS 302 is essential for the safety of vehicle occupants by significantly reducing the risks associated with interior fires. Kiyo R&D Center & Laboratory is committed to supporting manufacturers and suppliers in navigating these regulations, offering state-of-the-art testing facilities and expertise. For more information or to schedule a test, please reach out to our team. Together, we can ensure that the vehicles on our roads are safer for everyone.