Interpretation ID: nht69-2.6

DATE: 01/16/69

FROM: AUTHOR UNAVAILABLE; William Haddon, Jr., M.D.; NHTSA

TO: Rolls-Royce Limited Motor Car Division

TITLE: FMVSS INTERPRETATION

TEXT: Thank you for your letter of November 8, 1968, requesting a clarification of the 30g horizontal inertia load direction specified in Standard No. 201, as published in the Federal Register on October 25, 1968.

In section S3.3.1(c), "Subject the interior compartment door latch system to a horizontal inertia load of 30g in a longitudinal direction....." means both forward and rearward directions. In addition, the loads specified in S3.3.1(a) are applied in both the inboard and outboard and the up and down directions. This is consistent with similar type requirements in Standard No. 206.

You state that a forward and rearward 30g inertia load requirement is more stringent than the alternative procedure of S3.3.1(b), the barrier test. The Bureau believes, and one large manufacturer so stated in his comments, that the most meaningful test of the ability of an interior compartment door to remain closed is one which considers the distortion and deformation loads that occur in a collision. A barrier or equivalent dynamic test is the best way of realistically evaluating the ability of these doors to remain closed. The Bureau, therefore, believes that the barrier test is as stringent a requirement as S3.3.1(c).