1983-3.19 | NHTSA

TYPE: INTERPRETATION-NHTSA

DATE: 11/07/83

FROM: AUTHOR UNAVAILABLE; Frank Berndt; NHTSA

TO: Ms. Patricia Hill

TITLE: FMVSS INTERPRETATION

TEXT:

Ms. Patricia Hill 2150 Hacker Road Howell, Michigan 48843

Dear Ms. Hill:

This responds to your March 23, 1983, letter asking five specific questions relating to Standard No. 302, Flammability of Interior Materials. Your questions and their answers are listed below:

1. Provide a definitive interpretation of "erratic burning" as used in the subject standard that may be related to a test procedure.

"Erratic burning," as that term is used in the standard, relates to incidents where the material may soften or bend at the flaming end in a way that would not allow for uniform burning. Erratic burning, therefore, includes, but is not limited to, nonuniform burning as indicated in S5.1.3 of the standard where the use of support wires is mentioned.

2. Provide a definitive interpretation of the word "anticipate" as used in TP 302-02. That is, must the expectation of a softening and bending of the flaming end be based upon an actual test of an identical test specimen? A similar test specimen?

In actual practice, a test specimen is observed while burning during a compliance test to FMVSS No. 302. If the specimen is found both to soften and bend at the flaming end during testing and also fails to meet the minimum burn rate requirement, a retest is performed using support wires.

3. Does the agency still plan to issue an interpretive ammendment limiting or clarifying the use of support wires as stated in your 1976 letter? When?

The agency currently has no plans for any modifications of Standard No. 302.

4. How do the procedural requirements of the subject standard apply to a test specimen that bends at the flaming end prior to ignition by a bunsen burner?

We are not certain of the question that you are asking. The material would not have a flaming end to bend prior to ignition of the bunsen burner. If by this question you mean to ask what we would do about non-flat test specimens, the agency always attempts to test flat specimens only.

5. Does the NHTSA plan to revise TP 302-02 to reflect your 1976 interpretation and your response to this letter? When?

The agency currently has no plans for any modifications to TP 302-02.

Sincerely

Frank Berndt Chief Counsel

March 23, 1983

Dear Mr. Berndt:

This letter requests an interpretation of the requirements of FMVSS No. 302, Flammability of Interior Materials.

Section 5.1.3 of the subject standard states that a test specimen "that softens and bends at the flaming end so as to cause erratic (emphasis added) burning" is supported by a series of thin, heat resistant wires during testing.

Paragraph 10.2.2 of the NHTSA Laboratory Procedures for Flammability Compliance Tests, TP 302-02 dated June l973 allows a series of "thin (sic) heat resistant wires . . . to support specimens which tend to soften and bend at the flaming end." Paragraph 10.4.1 allows the use of support wires "If bending or curling of the specimen during test is anticipated (emphasis added)." I note that there is no mention of an "erratic-burning" condition in TP 302-02.

In your May l2, l976 letter to Mr. C.C. Setter you stated that the NHTSA intended to issue an interpretive amendment limiting the use of support wires during testing. You also stated that the NHTSA's experience indicated that use of support wires yielded significantly different burn rates. It is axiomatic that use of support wires will yield a slower burn rate. I interpret the text of your letter to mean that support wires could be used in some instances to influence whether a test specimen meets or fails to meet the burn rate requirements of the subject standard. I interpret the intent of your letter in part to counter a 1971 preamble stating that use of support wires had no significant effect on burn rate.

There is reason to believe that most of the domestic automotive manufacturers routinely use support wires for all testing intended to demonstrate or prove compliance with the requirements of FMVSS No. 302. Rationale to support this practice is apparently based upon a liberal interpretation of "erratic burning" in the subject standard and "anticipated" in the NHTSA test procedure. For instance, it is possible to anticipate bending or curling of the flaming end of a specimen prior to the start of a test without regard for historical data.

I am not aware that the NHTSA has performed any flammability testing for enforcement purposes in recent years.

Following is a list of my specific requests for interpretation.

1. Provide a definitive interpretation of "erratic burning" as used in the subject standard that may be related to a test procedure.

3. Does the agency still plan to issue an interpretive amendment limiting or clarifying the use of support wires as stated in your 1976 letter? When?

4. How do the procedural requirements of the subject standard apply to a test specimen that bends at the flaming end prior to ignition by a bunsen burner?

5. Does the NHTSA plan to revise TP 302-02 to reflect your 1976 interpretation and your response to this letter? When?

I trust that this letter will be viewed in a constructive light.

Sincerely,

Patricia Hill

Interpretation ID: 1983-3.19