Interpretation ID: nht76-5.13

DATE: 04/27/76

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Blue Bird Body Company

TITLE: FMVSS INTERPRETATION

TEXT: This responds to Blue Bird Body Company's March 22, 1976, request for interpretation of the provision of Standard No. 217, Emergency Exits, that requires unobstructed passage of a described parallelepiped through the opening provided by an open rear emergency door in the case of a school bus with a gross vehicle weight rating of more than 10,000 pounds (S5.4.2(a)). The dimensions of the parallelepiped are 45 inches by 24 inches by 12 inches, and it is oriented so that the 45-inch dimension is vertical, the 24-inch dimension is parallel to the opening, and the lower surface is in contact with the bus floor.

You point out that "unobstructed passage" through the opening could be considered to occur when the rearmost surface of the parallelpiped coincides with a vertical transverse plane that intersects the outer surface of the bus body at either the top or the bottom of the opening, or intersects the inner surface of the bus body at either the top or the bottom of the opening.

The NHTSA considers unobstructed passage of the parallelepiped to occur when its rearmost surface coincides with the vertical transverse plane that intersects the outer surface of the bus body at the bottom of the opening in question. Thus, your intention to assure compliance by measuring unobstructed passage at the point when the rearmost surface is flush with the bus body outer surface appears justified. The agency does not consider the bus body outer surface to include rub rails or trim materials for purposes of this measurement.

YOURS TRULY,

BLUE BIRD BODY COMPANY

March 22, 1976

Richard B. Dyson Assistant Chief Counsel National Highway Traffic Safety Administration

SUBJECT: FMVSS 217, PARAGRAPH S5.4.2a, EFFECTIVE OCTOBER 26, 1976

This paragraph specifies a rectangular parallelepiped 45 inches high, 24 inches wide, and 12 inches deep. We need an interpretation as to the reference point from which the 12" dimension should be measured. The four alternatives are:

1. From outside body at floor level.

2. From inside body at floor level.

3. From outside body at top of parallelepiped.

4. From inside body at top of parallelepiped.

As you can see from the enclosed photograph, the measuring point can make several inches difference depending on where it is located.

Because time is so important to us in complying with this standard and several others, we have made a decision to proceed based on measuring the 12" at the floor level with the rear surface of the parallelepiped flush with the outside surface of the body as shown in the enclosed photos. If this interpretation is not valid, please call us immediately. We shall look forward to your early written confirmation of this interpretation.

Thanks for your attention to this matter.

W. G. Milby Staff Engineer

(Graphics omitted)