Interpretation ID: nht74-2.33

DATE: 08/26/74

FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA

TO: E.I. DuPont de Nemours & Company, Incorporated

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of August 2, 1974, asking for the appropriate method for bending plastic material over the mandrel as specified in Test No. 22 of ANS Z26.1-1966, which is incorporated into Federal Motor Vehicle Safety Standard No. 205 (49 CFR 571.205). You indicate that the test procedure does not specify either the bending force, or whether mechanical means for bending are allowed.

Paragraph 5.22.2 of Test 22 states, in part, as follows:

After conditioning, the test specimens shall be immediately bent over a mandrel so that either the entire length of the specimen shall conform to the surface of the mandrel or that it be bent 130 degrees over the mandrel, with the longitudinal axis of the specimen normal to the axis of the mandrel. (emphasis added)

As the procedure does not specify the bending force, or the method in which it is to be applied, the NHTSA would consider as appropriate any force or method of application that would permit the plastic to be bent immediately after conditioning. There is nothing to prohibit the use of hand or mechanical pressure, but it must be applied in such a way that an immediate bending takes place.

Yours truly,

ATTACH.

I. DU PONT DE NEMOURS & COMPANY

INCORPORATED

PLASTICS DEPARTMENT

August 2, 1974

Office of Chief Counsel -- National Highway Traffic Safety Administration, Department of Transportation

Dear Sir:

We manufacture a transparent acrylic safety glazing material, Lucite (register) AR abrasion-resistant sheet. Many of our markets are in the transportation industry, including public buses, people movers, and recreational vehicles. Safety glazing materials must conform to ANSI Z26.1-1966 code for glazing motor vehicles operated on land highways, as required by FMVSS #205. The ANSI Z26.1-1966 code, Item 6, flexible Plastics category, is defined in part by Test No. 22. This test requires that a sample of the plastic be "bent over a mandrel so that either the entire length of the specimen shall conform to the surface of the mandrel or that it be bent 180 degrees over the mandrel." (The diameter of the mandrel being 80 times the sample thickness.) The stated purpose of the test is to determine "satisfactory flexibility".

No mention is made of the method or technique used in forcing the plastic to conform to the mandrel. The test does not indicate whether mechanical means are allowed; and, if so, what force. It is my understanding that some independent testing laboratories use hand pressure.

Would you please indicate to me what the NHTSA or DOT position is on this test and the test method to be used

Thank you.

Sincerely,

Paul D. Carfagna -- Technical Representative, Lucite (register) AR Marketing