Flammability of Automotive Materials (FMVSS 302)

Test Sample Requirements

Test samples must meet the following requirements:

• The standard sample size is 102-mm x 356-mm (approximately 4-in. x 14-in.).
• If the available width is less than 102 mm, the maximum available width should be used.
• If the available length is less than 356 mm, multiple pieces should be provided so when laid back-to-back they reach 356 mm.
• The thickness is that of the single or composite material used in the vehicle, unless the material's thickness exceeds 13 mm, in which case the sample is cut down to 13 mm total, measured from the surface of the sample which would be closest to the occupant compartment air space.
• 5 samples must be tested.
• If the material could react differently depending which direction it is cut, it must be tested in two directions. For example, woven materials (e.g. carpet, fabric, etc.) must be tested with 5 samples cut up the roll and 5 samples cut across the roll.
• If the material does adhere to other materials at every point of contact, it must be tested as a composite build-up with those other materials.
• If the material does not adhere to other materials at every point of contact, it must be tested separately.
• When it is not possible to obtain a flat sample because of surface curvature, the sample is cut to not more than 13 mm in thickness at any point.

History of the Horizontal Bunsen Burner Test

In 1969, the National Highway Traffic Safety Administration (NHTSA) determined the need to address fire safety in vehicle interiors. A new test method was created based on the 1951 Federal Specification CCC-T-191b, Method 5906* "Flame Resistance of Cloth, Horizontal". The new test method, known as FMVSS No. 302, was adopted in 1971 to establish a maximum burn rate for interior materials. The goal was to reduce the severity and frequency of burn injuries during vehicle fires by increasing the occupant evacuation time, especially fires caused from discarded cigarettes and matches.

The FMVSS 302 regulation is located in the Code of Federal Regulations, Title 49 - Transportation, Subtitle B - Other Regulations Relating to Transportation, Chapter V - National Highway Traffic Safety Administration, Department of Transportation, Part 571 - Federal Motor Vehicle Safety Standards.

*The CCT-T-191b, Method 5906 test method was superseded by FED-STD-191, Method 5906, and is still in use.

Additional Resources