Interpretation ID: nht79-3.49

DATE: 08/21/79

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Thomas Built Buses, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your July 20, 1979, letter asking a question concerning Standard No. 217, Bus Window Retention. You ask whether paragraph S5.4.2.1(a) permits the parallelepiped device to compress the seat cushion when it is inserted in a school bus emergency exit in accordance with the test procedures of the standard. The answer to your question is no.

Paragraph S5.4.2.1(a) states that each rear emergency exit must provide "an opening large enough to permit unobstructed passage of a rectangular parallelepiped device . . ." If the parallelepiped device compresses the seat cushion while being inserted in the bus, its passage is not unobstructed as required by the standard. Accordingly, the National Highway Traffic Safety Administration concludes that the device must enter the vehicle without compressing the seat cushion.

SINCERELY,

Thomas BUILT BUSES, INC.

July 20, 1979

Roger Tilton Office of the Chief Counsel U. S. Department of Transportation

Subject FMVSS #217, Section - S5.4.2.1(a)

Dear Mr. Tilton:

In reference to the above section of the standard, we quote in part: "In the case of a rear emergency door, an opening large enough to permit unobstructed passage of a rectangular parallelepiped . . . . ."

In a case where the parallelepiped is inserted into the opening. The result is that the parallelepiped compresses the seat cushioning foam. Question, does the opening comply with FMVSS 217 (S5.4.2.1(a))?

Thanking you in advance, I remain.

James Tydings, Specifications Engineer