Interpretation ID: nht76-2.15

DATE: 11/10/76

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Thomas Built Buses, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This is in response to your letter of September 2, 1976, in which you ask whether the definition of "Contactable surface" in Standard No. 222, School Bus Passenger Seating and Crash Protection, includes areas on the front of the seatback located more than three inches from the top of the seat.

Your interpretation of "contactable surface" is correct. The standard states in paragraph S4 that only the uppermost three inches of area on the front of the seatback is considered part of the "contactable surface." The remainder of the front of the seatback is not considered part of the "contactable surface" and need not meet the head impact requirements of S5.3.

SINCERELY,

Thomas BUILT BUSES, INC.

September 2, 1976

Tim Hoyt National Highway Traffic Safety Administration U. S. Department of Transportation

Enclosed are two (2) prints that show our interpretation of the MVSS #222 seat impact regions. In a previous letter, we were informed that the head impact region (marked "H") extends downward to the "12 inch level" above the S R P on the aisle of the seat. The front of the seat was not mentioned.

Our interpretation of S 4. definitions.

"Contactable Surface" is that we do not need to meet the head impace requirements on the front of the seatback below the "H" region. This region is shaded and dimensioned 3" on the print. Is this interpretation correct?

Thanking you in advance for your services, we remain,

L. T. Mitchell, Jr. Engineering Department

H - HEAD IMPACT REGION

K - KNEE IMPACT REGION

(Graphics omitted)

H - HEAD IMPACT REGION

K - KNEE IMPACT REGION (Graphics omitted)