Interpretation ID: nht88-3.55

TYPE: INTERPRETATION-NHTSA

DATE: 09/21/88

FROM: ERIKA Z. JONES -- CHIEF COUNSEL NHTSA

TO: HIROSHI KATO -- MMC SERVICES INC.

TITLE: NONE

ATTACHMT: LETTER DATED 05/18/88 TO ERIKA Z. JONES FROM HEROSHI KATO, OCC-2048

TEXT: Dear Mr. Kato:

This responds to your letter asking for an interpretation of Safety Standard No. 201, Occupant Protection in Interior Impact, as it applies to so-called "one-piece" instrument panels and console assemblies. Your request for confidential treatment of the photographs and diagrams you enclosed with your letter of vehicle models "A" and "B" was granted by the agency on June 21.

The areas of the vehicle interior to which your question relates are the instrument panel, which generally speaking, is subject to the standard, and the console assembly, which is not. Most of our letters relating to these areas dealt with vehicles whos e console assemblies were separate structures distinguished by "gaps," or indentations. However, you ask about a vehicle interior that has no obvious gaps or separation between the dashboard and the console assembly (hence its "one-piece" appellation). Instead, the longitudinal floor-mounted structure that lies between the front seats of the vehicle rises gradually at an upward slant towards the vehicle's dashboard, and joins with the vehicle's dashboard without any obvious gaps or spaces, as though t he dashboard and center console were of one piece. At the top of the instrument panel is an overhanging surface above a setback area. This overhanging surface protrudes rearward in such a way that a vertical line tangent to the surface strikes the bott om of the one-piece structure at a point near the floor of the vehicle, between the front seats.

Paragraph S3.1 of Standard No. 201 sets the head impact protection requirements for instrument panels. These requirements apply primarily to the upper portions of the instrument panel. Paragraph S3.1 states, "Except as provided in S3.1.1, when that are a of the instrument panel that is within the head impact area is impacted" by a head form, the deceleration of the head form shall be within specified limits. S3.1.1 sets out five exceptions to the instrument panel performance requirements, two of which (S3.1.1(a) and S3.1.1(e)) are relevant to your design. The first of these, S3.1.1(a), provides that the requirements of S3.1 do not apply to console assemblies.

We believe your letter raises two primary issues. The first is whether a console assembly in effect ceases to be a console assembly for the purposes of the head impact protection requirements of Standard No. 201, and as a consequence becomes subject to those requirements, when it is part of a one-piece design and adjoined with the dashboard. While we concur with your assessment that the answer to this question is no, we note that determining the dividing line between a dashboard and an adjoining conso le is difficult where there is no intervening gap or indentation.

That brings us to the second issue, which is how to determine the rearmost surface of the instrument panel in a vehicle using a one-piece design such as yours. S3.1.1(e) of the standard provides that "(a)reas below any point at which a vertical line is tangent to the rearmost surface of the panel" are not subject to the head impact protection requirements of the standard. You suggest that the rearmost surface is the overhanging surface at the top of the instrument panels on your two vehicles and that the console is the area below that overhanging surface. While we are not prepared to pick the dividing line between the instrument panel and the console, we agree that those overhanging surfaces are the rearmost points of the instrument panel. A vertic al line tangent to those overhanging surfaces strikes the one-piece structure at a point that is clearly part of the longitudinal structure running between the seats, i.e., that is clearly part of the console, and therefore excluded by S3.1.1(a) from the head impact protection performance requirements of Standard No. 201.

Notwithstanding the direct reference in S3.1.1(a) to console assemblies, the agency has not defined the term either in Standard No. 201 or elsewhere. In the October 27, 1986 letter to which you refer in your letter, we told your associate, Mr. Shimizu, that we regarded a "low-lying structure mounted on the floor and [lying] primarily between the vehicle seats" to be a console assembly. However, no attempt was made to define what was meant by "low-lying" or "console assembly" or to apply the latter term to structures such as yours that join with the vehicle's dashboard without any obvious gaps or spaces.

Given that console assemblies are excluded from the requirement in S3.1 for instrument panels, it is important to determine the boundaries of the instrument panel. S3.1.1(e) is helpful in this regard. S3.1.1(e) has the effect of limiting the head impac t protection requirements of the standard to the upper portions of the instrument panel.

With respect to the instrument panel for model A, we conclude that the rearmost surface of the instrument panel is the overhanging surface that is above the setback area. Any area that is rearward of a vertical line tangent to the overhanging surface on the one-piece instrument panel and console assembly is located on a "low-lying structure mounted on the floor and lying primarily between the vehicle seats"--i.e., it is located

on a console assembly. Since, for the purposes of S3.1.1(e), the relevant area is the rearmost surface of the instrument panel, areas of the instrument panel on model A that are below this rearmost surface are excluded from the head impact protectio n requirements of the standard.

Similarly, with respect to model B, the rearmost surface of the instrument panel is the overhang at the top of the panel. Any area rearward of this surface would be part of the "console assembly," as we have used that term in our letter to Mr. Shimizu. Accordingly, areas of the panel lying below the point at which a vertical line is tangent to this surface are excluded from S3.1. Generally speaking, the upper portions of the instrument panel of both models A and B are subject to S3.1 and would theref ore have to meet the head impact protection requirements of the standard.

In conclusion, we concur with your belief that there should be a reasonable way to distinguish a console assembly from an instrument panel. Your letter has highlighted a possible need to clearly define either "instrument panel" or "console assembly" in Standard No. 201, and also an issue as to whether there is a continued need for the exemption for console assemblies found in S3.1.1(a) of the standard. We will further consider these issues and may initiate rulemaking to possibly define console assembl y or to remove the current exemption in S3.1.1(a) of the standard.

I hope this information is helpful. Please contact my office if you have further questions.

Sincerely,