Interpretation ID: 1985-02.40

TYPE: INTERPRETATION-NHTSA

DATE: 06/07/85

FROM: AUTHOR UNAVAILABLE; Jeffrey R. Miller; NHTSA

TO: Mr. M. Mizuguchi

TITLE: FMVSS INTERPRETATION

TEXT:

Mr. M. Mizuguchi Ashimori Industry Co., Ltd. 12, 4-chome Yokobori, Higashi-ku Osaka, Japan

Dear Mr. Mizuguchi:

Your letter of February 28, 1985, was forwarded to my office for reply. You asked whether the webbing attached to a buckle you intend to use must meet the webbing width requirement of S4.2 of Standard No. 209, Seat Belt Assemblies. The webbing is enclosed in a plastic sheath. As explained below, the webbing must meet the width requirement of the standard.

S4.2 of Standard No. 209 provides that the "width of the webbing in a seat belt assembly shall be not less than 1.8 inches, except for portions that do not touch a 95th percentile adult male with the seat in any adjustment position and the seat back in the manufacturer's nominal design riding position when measured under the conditions prescribed in S5.1(a)." The purpose of S4.2 is to ensure that belt webbing which comes into contact with an occupant has a minimum width that spreads the load imposed by the belt in a crash. By requiring webbing to spread rather than concentrate the load, the belt width requirement helps minimize the possibility of webbing-caused injury.

In the case of your design, the webbing is enclosed in a tightly-fitting plastic sheath. You state that the webbing/sheath combination can come into contact with an occupant. The sheath enclosed with your sample is made from an easily deformable plastic. Thus, when the crash loads are imposed by the belt, the sheath will deform and the crucial factor in concentrating the load on an occupant is the width of the belt. Since the webbing/sheath combination can contact and impose crash loads on an occupant, the agency concludes that the webbing must meet the minimum width requirement of S4.2.

If the webbing were encased in a reinforced sheath that did not appreciably deform under loading, the agency would consider both the width of the webbing and its encasing sheath in determining whether the requirement of S4.2 was met.

I have enclosed the sample of your product sent with your letter. If you have any further questions, please let me know.

Sincerely,

Jeffrey R. Miller Chief Counsel

Enclosure

Ref. No M/M02-28 Osaka Feb, 28, 1985

Messrs. Department of Transportation National Highway Traffic Safety Administration Washington, D. C. 20590, U. S. A.

Attn: Mr. Francis Armstrong Director Office of Vehicle Safety Compliance Enforcement

Dear Mr. Francis Armstrong,

We'd like to ask you the following question. Recently, we are trying to make a soft and flexibility seat belt system, and then the enclosed buckle is one of our sample. This sample is composed of narrow webbing and a little solid plastic boot. However, according to FMVSS NO. 209 item 4.2 (a) "webbing width" describing it's width should be not less than 1.8 inches (about 46mm), the problem of elongation and etc, it is very difficult for us to judge whether our sample does conform to regulation N0.209 on the view of interpretation of the Law or not. Of course, this assembly does meet with the requirement of seat belt assembly prescribing in NO. 209. When this sample is located in vehicle, we are afraid that this sample will touch slightly or enough to person's body. Here, we enclosed please find our sample of buckle side of seat belt assembly herewith. So could you pleases inform us of your official comments very soon. Your earliest written answer will be highly appreciated.

Yours faithfully,

Ashimori Industry Co., Ltd.

M. Mizuguchi

encl. sample of bucket seat