Interpretation ID: nht76-3.16

DATE: 05/12/76

FROM: STEPHEN P. WOOD FOR FRANK BERNDT -- NHTSA

TO: INDEPENDENT TEXTILE TESTING SERVICE, INC.

TITLE: FMVSS INTERPRETATION

TEXT: This is in response to your letter of February 18, 1976, concerning testing procedures pursuant to Federal Motor Vehicle Safety Standard No. 302, Flammability of Interior Materials.

As you point out, S5.1.3 of the standard provides that thin, heat resistant wires are used to support a "specimen that softens and bends at the flaming end so as to cause erratic burning." One of your customers asserted that support wires should be used in testing his materials, and you have asked when the use of support wires is appropriate.

Your interpretation of the standard in this case is commendable, and your test practices are calculated to demonstrate clearly the exercise of due care that a particular product complies with Federal motor vehicle safety standards. However, an NHTSA July 19, 1971, interpretation of Standard No. 302 (copy enclosed) permits use of support wires when any bending of the tested material occurs. At the time of that interpretation, it was believed that the support wires would not influence the test results.

More recent testing by the agency demonstrates that the support wires do significantly affect burn rates, and the agency intends to issue an interpretative amendment of the standard that will limit use of support wires.

Thank you for your responsible approach to testing products that are required to conform to Federal motor vehicle safety standards.

SINCERELY,

INDEPENDENT TEXTILE TESTING SERVICE, INC.

February 18, 1976

Office of Chief Counsel National Highway Traffic Safety Administration

We are an independent testing laboratory, whose services include conducting the tests for flammability, including the Motor Vehicle Safety Standard No. 302. A question concerning the test procedure and method has been brought to our attention and we need an official interpretation.

The test method states, "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". We have always interpreted this statement to mean that if the material would have a tendency to become almost vertical upon ignition you would support the material with the wires, otherwise the wires would not be needed; as an example, a specimen of plastic or a headlining material would be supported by the wires. A large percentage of our testing is on materials related to carpeting, either woven or tufted, and we do not use the wires for support since the material does not have a tendency to become vertical during the test.

A manufacturer has sent us some material which is to be used as an upholstery fabric and asked us to conduct the test No. 302. We conducted the test according to the procedure; however, we did not use the support wires on this material as we felt the material was not covered under the above statement. The material was cut into four specimens, two specimens in the machine direction and two specimens in the "cross-machine" direction. Two specimens are tested with the "face up" in both directions and two specimens are tested with "face-down" in both directions, as we cannot determine prior to the test which will give us the most adverse results (para. S5.2.2). The material failed the test. We are enclosing a copy of the test results with the manufacturers name blotted out.

When the manufacturer received the report, he was quite upset, as a copy of his letter to us shows. The material, according to him, should be tested using the support wires which in this case allows the material to pass the test; however, if the support wires are not used, the material will almost always fail the test. We have told him that we do not conduct the test so that the results would always be beneficial to the manufacturer, but that we conduct the test in accordance with the standard and our interpretation of the test method which in some cases is not beneficial to the manufacturer. It is our opinion that flammability tests are not conducted in such a way as to suit a manufacturer because he wants a passing report, but that the test should be conducted under the most adverse conditions so as to give a true look at the material being tested.

I am enclosing a piece of the material in question and hope to have a ruling as soon as possible as to whether or not support wires should be used with this material. We have other tests to perform which we are holding until we hear from you.

Cornelius C. Setter

INDEPENDENT TEXTILE TESTING SERVICE, INC.

TEST NUMBER

-REPORT-

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