Interpretation ID: nht87-2.75

TYPE: INTERPRETATION-NHTSA

DATE: 08/21/87

FROM: AUTHOR UNAVAILABLE; Erika Z. Jones; NHTSA

TO: Mr. Hisashi Tsujishita

TITLE: FMVSS INTERPRETATION

TEXT:

AIR MAIL

Mr. Hisashi Tsujishita Chief Co-ordinator Technical Administration Department Daihatsu Motor Co., Ltd. l.Daihatsu-cho, Ikeda City Osaka Prefecture JAPAN

Dear Mr. Tsujishita:

Thank you for your letter requesting an interpretation of the requirements of three of our safety standards. This letter responds to your questions concerning Standard No. 201, Occupant Protection in Interior Impact. I have previously responded to your r equests for interpretations of the other two standards. I regret the delay in this response.

Your questions concern the requirements of S3.5.1(b) of the standard, which provides that "Along not less than 2 continuous inches of its length, the armrest shall, when measured vertically in side elevation, provide at least 2 inches of coverage within the pelvic impact area." You expressed concern about determining whether several different armrest designs comply with that requirement. Specifically, you provided three examples and asked how the requirement would apply to each example. Your example I11 .1 is an armrest that, when viewed in side elevation (i.e., a view in which a person is looking from in front or behind an armrest to determine how the armrest projects from the door surface) has a flat surface. Example I11.2 is an armrest that has a sli ghtly curved surface. Example I11.3 is an armrest with a surface that is steeply angled inward toward the door. Because of the angling of the armrest, it has a sharp projection at its top.

You believe that examples I11.1 and I11.2 comply with the requirement of S3.5.1(c). You also believe that example I11.3 would not comply because of its sharp projection. However, you expressed concern about what criteria should be used to distinguish example I11.2 from example I11.3.

S3.5.1(c) of Standard No. 201 does not set any radius of curvature requirements for armrest surfaces. Thus, a manufacturer is not required to provide an armrest with a flat surface. The only requirement is that the armrest provides at least two inches o f coverage within the pelvic impact area. The purpose of the requirement is to reduce potential injuries to an occupant by ensuring that the armrest has a minimum surface area that will spread the force resulting from an occupant impacting the armrest in a crash. Thus, for this requirement to have a meaningful effect, an armrest should be designed to ensure that there is at least two inches of contact between the surface of the armrest and the pelvic impact area of an occupant. If your examples I11.1 an d I11.2 provide two inches of coverage within the pelvic impact area, they would appear to comply, since they present an essentially flat surface. Based on your drawing, it appears that the steep inwardly sloping angle of the armrest shown in example I11 .3 may not contact a minimum of two inches of the pelvic impact area. One method of determining the degree of occupant contact would be to measure the amount of contact between a test dummy and the armrest in a static push test or in a dynamic side impac t test. We share your concern that an armrest not have sharp projections which could concentrate potentially harmful forces on an occupant striking the armrest.

Finally, you provide a drawing of an additional armrest. Briefly described, the armrest has a slightly curved surface with a decreasing radius within the pelvic impact area. At the top of the portion of the armrest within the pelvic impact area there is a small indentation. The agency has previously said, in an interpretation letter of July 1, 1983 to MMC Services, Inc., that bezels and other indentations are not precluded by the standard. However, the area of the indentation will not be measured in det ermining whether the armrest provides two inches of coverage if the indentation is so deep that it cannot be contacted. Based on your drawing, the indentations shown in your proposed armrest is shallow and would be contactable by an occupant. Thus, the s urface area of the indentation would be counted in determining whether the vehicle complied.

Finally, I would point out that S3.5.1(c) is one of three optional means of compliance that manufacturers may choose. A manufacturer may also meet the requirements of Standard No. 201 by complying with either S3.5.1(a) or S3.5.1(b), in which case it is n ot necessary to provide two inches of coverage with the pelvic impact area.

If you have any further questions, please let me know.

Sincerely,

Erika Z. Jones Chief Counsel

Ms. Erika Z. Jones Chief Counsel Office of the Chief Counsel National Highway Traffic Safety Administration 400 Seventh Street, S.W.

Washington, D.C. 20590 U.S.A.

Dear MS. Jones:

The purpose of this letter is to respectfully inquire NHTSA's interpretations with regard to the Federal Motor Vehicle Safety Standards (FMVSS) Nos. 101, 201, and 219.

We wish we could have your early and kind response to the questions on the following pages.

We thank you in advance for your kind attention to this matter.

Sincerely yours,

H. Tsujishita Chief Co-ordinator of Technical Administration Dept. Head Office

Enclosure : QUESTIONNAIRE (1),(2),(3)

cc: Mr. R. Busick, Olson Engineering Inc.

QUESTIONNAIRE (1)

FMVSS No. 101 ; Controls and Displays

Paragraph S5.3.3 of FMVSS No. 101 provides that; "Light intensities for informational readout systems shall have at least two values, a higher one for day, and a lower one for night time conditions. The intensity of any illumination that is provided in the passenger compartment when and only when the h eadlights are activated shall also be variable in a manner that complies with this paragraph." However the applicable items (illuminations) of the above provision are not necessarily definitely for us. we believe that these provisions are applied only to the illuminations for the controls or gauges which are somehow regulated otherwise in FMVSS No. 101, and are,not applied to the illuminations which are optionally equipped and are not otherwise mentioned in the standard, such as following illuminations in Concrete; (1) Digital clock using liquid crystals (2) Radio employed digital frequency indicator using liquid crystals (3) Miscellaneous illuminations for conventional analog clock, cigar lighter, ashtray, and radio control switches, etc. which are lightened only when the headlights (parking lights) are activated.

We would like to confirm that the above items are not applied the variable illumination requirements. Please advise us in detail in this matter.

QUESTIONNAIRE (2)

FMVSS No. 201 ; Occupant Protection in Interior Impact Paragraph S3.5.1(c) of FMVSS No. 201 provides the dimensional requirements for armrests as follows;

"Along not less than 2 continuous inches of its length, the armrest shall, when measured vertically inside elevation, provide at least 2 inches of coverage with the pelvic impact area."

Our concern, however, centers on how to measure the armrest vertically in side elevation.

We believe that this provision does not necessarily require completely plain area of 2 in. x 2 in. on the armrests such as I11.1 below, and that the armrests which have, to some extent, rounded inside surface, such as I11.2, shall be deemed in compliance with this provision.

INSERT GRAPHICS HERE

And we also believe that, no matter how the armrests have more than 2 in. side elevation, considerably sharply projected armrests such as 111.3 shall be deemed in noncompliance with the provision.

However, we can not be sure the criteria for distinguish 111.2 from 111.3. Though we think the most important point to be concerned is its contactability by the occupant, we can not necessary surely know the procedures to prove the contactability. Theref ore we would like to ask your kind favor of showing us the guideline to how to measure armrests to decide the compliancy to S3.5.1(c).

And further, as we are designing a little more complicated shape such as shown on the next page, we wish you would advise us about the compliancy of the armrest. INSERT GRAPHICS HERE

QUESTIONNAIRE (3)

FMVSS No. 219 ; Windshield Zone Intrusion Paragraph S5 of FMVSS No. 219 provides; "When the vehicle ......, no part of the vehicle outside the occupant compartment, except windshield molding and other components designed to be normally in contact with the windshield, shall penetrate the protected zone template, ...." In the case that the windshield wiper penetrate the protected zone template (by some reason such as pushed by the deformed cowl, or accidentally turned-on of wiper switch as a result of contact with test dummy), we would like to confirm whether the vehic le is deemed in compliance or not. (Refer to the illustration below)

We believe the penetration of wiper blades shall be deemed in compliance because the wiper blades are designed to be normally contact with the windshield. The wiper arms, however, only contact with the windshield though the wiper blade. Please advise us about the exemption of wiper arms from this intrusion provision.

INSERT GRAPHICS HERE