Interpretation ID: 11322MLS

Mr. Alfred Kozak
Product Engineer
Acts Testing Labs, Inc.
25 Anderson Road
Buffalo, NY 14225-4928

Dear Mr. Kozak:

This responds to your inquiry about testing procedures in Federal Motor Vehicle Safety Standard No. 302, AFlammability of Interior Materials.@ In particular, you asked how section S5.1.3, which specifies the use of support wires in certain situations, would apply to fabric material used in a car seat. The short answer is that during NHTSA compliance testing, support wires would be used in testing any specimen that "softens and bends at the flaming end so as to cause erratic burning." However, the agency cannot specify, outside of the context of a compliance test, whether a given type of material falls in this category.

By way of background information, NHTSA is authorized to issue Federal motor vehicle safety standards that set performance requirements for new motor vehicles and items of motor vehicle equipment. NHTSA does not, however, approve or certify any vehicles or items of equipment. Instead, the applicable statute (49 U.S.C. Chapter 301) establishes a "self-certification" process under which each manufacturer is responsible for certifying that its products meet all applicable safety standards.

You ask about Standard No. 302, which specifies requirements for the flammability resistance of materials in the occupant compartment of new vehicles. Along with specified performance requirements, Standard No. 302 sets forth conditions and procedures under which NHTSA tests materials for compliance with the standard. Section S5.1.3 of the standard states, in relevant part, that:

The test specimen is inserted between two matching U-shaped frames of metal stock 1-inch wide and 3/8 of an inch high. The interior dimensions of the U-shaped frames are 2 inches wide by 13 inches long. A specimen that softens and bends at the flaming end so as to cause erratic burning is kept horizontal by supports consisting of thin, heat resistant wires, spanning the width of the U-shaped frame under the specimen at 1-inch intervals. A device that may be used for supporting this type of material is an additional U-shaped frame, wider than the U-shaped frame containing the specimen, spanned by 1--mil wires of heat resistant composition at 1-inch intervals, inserted over the bottom U-shaped frame.

Please note that NHTSA uses supplemental wires when there is a reasonable expectation that a test specimen will soften and bend so as to cause erratic burning. The agency bases its determination about the likelihood of this condition on observations made in previously-conducted compliance tests of the specimen, or on the agency's knowledge of or testing experience with components that are highly similar to a test specimen. However, since a decision to use wires is made only in the context of compliance testing, we regret that we cannot tell you at this time whether support wires would be used to test the materials about which you are concerned.

Vehicle manufacturers are not required by Standard No. 302 to test the flammability of their vehicles in the manner specified in the standard. The standard only sets the procedure that the agency will use in its compliance testing. Thus, a vehicle manufacturer is not required to use wires only with specimens that are anticipated to soften and bend so as to cause erratic burning. However, vehicle manufacturers are expected to exercise reasonable care in certifying that their product will meet Standard No. 302's requirements when tested by NHTSA according to the specified procedures of the standard. Whether a vehicle manufacturer has met that reasonable care standard in a particular case involving a noncompliance with the standard is a matter that is determined by the agency only in the context of an enforcement proceeding.

You first ask whether the phrase "softens and bends" applies to plastic materials which sag due to heat and specimen weight or to all materials regardless of composition. Section S5.1.3 specifies the use of a supplemental wire support for "a specimen that softens and bends at the flaming end so as to cause erratic burning." Plastic materials are the most commonly used material that can soften and bend. Nevertheless, the agency emphasizes that the procedure would be used for any material that softens and bends at the flaming end so as to cause erratic burning.

You then ask whether the wire supports are used if the material softens and bends without erratic burning. The test condition noted above should be read as a whole. Therefore, the supplemental supports are only to be used if the specimen (1) softens and bends at the flaming end (2) so as to cause erratic burning.

Your third question asks whether wires are used where the flame front cuts or destroys the specimen in such a way as to allow the specimen to sag similar to the sagging experienced with unsupported specimens. According to the test conditions, supplemental support wires are to be used if the flame front causes the specimen to soften and bend so as to cause erratic burning. Data you provided in your letter showed a wide variation of burn rates between the unsupported and supported specimen tests. The agency would not use support wires in situations of erratic burning alone. The agency would use such support wires only in situations in which the softening and bending occurred prior to erratic burning.

Your fourth question expresses your view that the use of supplemental support wires eliminates Adirectional effects@ and orientation, as discussed in S5.2.2. That provision states that AThe specimen is produced by cutting the material in the direction that provides the most adverse test results. The specimen is oriented so that the surface closest to the occupant compartment air space faces downward on the test frame.@ While it is true that the use of supplemental support wires did reduce the burn rate in your testing of certain material, we interpret the requirements in S5.2.2 as a separate test condition. Thus, the requirements in S5.2.2 are not relevant in determining if a supplemental support wire should be used under S5.1.3.

Your fifth question expresses your view that, by allowing the use of supplemental supports, this test procedure introduces potentially flammable materials into automobile interiors. Specifically, you state that your testing indicated that the burn rate was between 11.5 and 13 inches per minute without supports and 1.8 to 2.1 inches per minute with supports. Please note that the use of support wires is intended to increase the consistency and repeatability of the test procedure, thereby providing a uniform basis for assessing the burn rates of different materials. This is accomplished by reducing sagging which results in erratic burning. Accordingly, we believe that the provision in S5.1.3 relating to the use of support wires provides a reasonable test condition for evaluating the flammability resistance of materials used in motor vehicles.

I hope you find this information helpful. If you have any other questions, please contact Marvin Shaw at this address or by phone at (202) 366-2992.

Sincerely,

Samuel J. Dubbin Chief Counsel

Enclosure

ref: 302 d:4/16/96