Interpretation ID: 1982-1.5

TYPE: INTERPRETATION-NHTSA

DATE: 01/13/82

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Blue Bird Body Company

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your letter of October 26, 1981, requesting several interpretations of the requirements of Standard No. 201, Occupant Protection in Interior Impact. The answer to each of your questions is discussed below.

Your first question concerned section 3.3 of the standard, which among other things, requires that an "interior compartment door assembly located in . . . a side panel adjacent to a designated seating position . . ." must remain closed when tested under certain conditions. You stated your belief that the requirement only applies to interior compartment doors located within the head impact area, defined in Part 571.3 of Title 49. You asked if the area adjacent to a designated seating position is to be determined by projecting laterally from the head impact area for a designated seating position to the side panel next to it.

The impact protection requirement for interior compartment doors was added to the standard on October 25, 1968 (33 FR 15794). As explained in that notice, a copy of which is enclosed, the agency specifically denied requests to limit the interior compartment door requirement to doors located in the head impact area. The requirement is designed to provide protection to the head and other portions of an occupant's body that can be thrown against an interior compartment door opened by inertial forces in a crash. To accomplish the purpose of the standard, any interior compartment door, defined in Part 571.3 of Title 49, that is located in a side panel and is next to a designated seating position is covered by the requirements of section 3.3 of the standard.

You also asked how the term "instrument panel" is defined for the purposes of section 3.3 of the standard. You are correct that the term refers to the panel below the windshield which is used to mount the speedometer, other gauges, etc. For the reasons discussed in response to your first question concerning S3.3, any interior compartment door on the instrument panel is covered by the requirements of section 3.3, not just those located in the head impact area.

You also asked about the requirements of section 3.3.1 of the standard. You state that section 3.3.1 allows the use of either option (b) or (c) to show compliance. Your statement is not correct. Section 3.3 of the standard requires more than compliance with either option (b) or (c) of section 3.3.1. Section 3.3 requires interior compartment doors to remain closed when "tested in accordance with either S3.3.1(a) and S3.3.1(b) or S3.3.1(a) and S3.3.1(c)."

You also state that you interpret option (c) of section 3.3.1 to be a horizontal inertial load of 30g in a longitudinal direction which would simulate a forward 30 mile per hour flat barrier impact. Your interpretation is correct. Section 3.3.1(c) provides that an interior compartment door latch must be subject to "a horizontal inertia load of 30g in a longitudinal direction in accordance with the procedures described in section 5 of SAE Recommended Practice J839b, 'Passenger Car Side Door Latch Systems,' or an approved equivalent." The purpose of the requirement is to impose loads similar to the loads experienced by a door latch tested in the 30 mile per hour forward barrier crash required by section 3.3.1(b) of the standard.

You further state that the loading applied in accordance with section 3.3.1(c) should be a forward deceleration inertia loading. Your interpretation is not correct. To ensure that the requirements of sections 3.3.1(b) and 3.3.1(c) are equivalent in stringency, the agency believes that the 30g inertia load requirement of section 3.3.1(c) must take into account the distortion and deformation that would occur in a 30 mile per hour barrier impact. Therefore, the 30g inertia load must be applied in both the forward and rearward direction. Likewise, the 10g inertia load requirement of section 3.3.1(a) must be applied in both the inboard and outboard direction.

Your final question concerned the requirements of section 3.5.1 of the standard, which specifies that armrests must comply with at least one of three options. Section 3.5.1(c) specifies that one option is providing an armrest which has "Along not less than 2 continuous inches of its length . . . when measured vertically in side elevation. . . at least 2 inches of coverage within the pelvic impact area." You are correct that an armrest complying with section S3.5.1(c) can be made of any material, as long as it meets the dimensional requirements set by that section.

If you have further questions, please let me know.

ENC.

BLUE BIRD

BODY COMPANY

October 26, 1981

Frank Berndt Chief Counsel National Highway Traffic Safety Administration Department of Transportation

Reference: FMVSS 201 Occupant Protection in Interior Impact Passenger Car

FMVSS 201, Section 3.3, Interior Compartment Door, states, "a compartment door located in . . . side panel adjacent to a designated seating position . . . ". Blue Bird Body Company interprets this phrase to be an area projected laterally to the side panel from the Head Impact Area as defined by Part 571 Subpart A - Definitions.

This interpretation is based on the concept that FMVSS 201, Section 3.3 is intended to prevent occupant head contact with an inertia opened compartment door during a crash. The Head Impact Area defines the trajectory of the occupant head during such a crash, and thus would define the area of potential head to compartment door contact. Compartment doors within this projected area should comply with Section 3.3, while those outside of this area should be exempt. This is also consistent with the American Heritage Dictory definition of adjacent as being next to; or adjoining. This definition would exempt panels located above the door or upper window header.

Blue Bird Body Company also defined "instrument panel" as referenced in Section 3.3, to be the panel below the windshield that normally is used to mount gages, speedometers, etc, to monitor vehicle functions and that is within the Head Impact Area as defined in Subpart A - Definitions.

Section 3.3.1, Demonstration Procedures, allows either option (b) or (c) to show compliance. Blue Bird Body Company interprets option (c) to a horizontal inertia load of 30g in a longitudinal direction which would simulate a forward 30 miles per hour flat barrier impact, as required by option (b). This would be a forward deceleration inertia loading applied in accordance to Section 5 of the SAE Recommended Practice J839b.

Under Armrest, Section 3.5.1, General, option (c) specifies "not less than two 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". Blue Bird Body Company interprets this to allow any material, including steel tube, aluminum or steel panel, that fulfills the dimensional requirements.

We respectfully request your confirmation of our interpretation to the above sections of FMVSS 201. An early reply would be apprediated.

Thank you.

Thomas D. Turner Manager Engineering Services