Interpretation ID: 77-4.9

TYPE: INTERPRETATION-NHTSA

DATE: 09/29/77

FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA

TO: Thomas Built Buses, Inc.

TITLE: FMVSS INTERPRETATION

ATTACHMT: Attached to letter dated 7-5-84 from F. Berndt to R. Marion; Also attached to letter dated 3-23-90 from A.H. Brett to M.B. Mathieson; Also attached to letter dated 12-3-90 from P.J. Rice to M.B. Mathieson (A36; Std. 217); Also attached to letter dated 3-26-90 from M.B. Mathieson to E.Z. Jones (OCC 4598); Also attached to letter dated 3-30-90 from M.B. Mathieson to M.F. Trentacoste; Also attached to letter dated 8-8-89 from M.F. Trentacoste to K. Finkel

TEXT: This responds to your August 25, 1977, letter asking several questions about the applicability of Standard No. 217, Bus Window Retention and Release, to buses other than school buses.

Your first state your conclusion that paragraph S5.2 of the standard applies only to buses other than school buses. Your interpretation of S5.2 is correct. Secondly, you state that S5.2.1 applies to all buses with GVWR's of more than 10,000 pounds. This assertion is incorrect. See S5.2.3. Paragraph S5.2.1 applies only to buses other than school buses that have GVWR's greater than 10,000 pounds.

Your final inquiry pertaining to Standard No. 217 concerns the requirement for unobstructed emergency exits in both school and non-school buses. You first correctly state that paragraphs S5.4 through S5.4.2.1 describe the required size of the unobstructed openings for school buses. You then claim that there is no equivalent description for the size of unobstructed openings required in buses other than school buses. This last statement is not entirely accurate. The amount of unobstructed emergency exit openings required for buses other than school buses is detailed in S5.2. This section establishes requirements for the total area of unobstructed emergency exit openings and for the location of those exits. This section also specifies the extent to which the area of each exit is to be counted in determining compliance with the total unobstructed opening requirement. Therefore, although the standard does not specify minimum size requirements for individual exits in buses other than school buses, the standard does contain other requirements for unobstructed openings in buses other than school buses.

You concluded in your letter that buses other than school buses are not required to use the parallelepiped device in determining whether their rear exits comply with the requirements. This conclusion is accurate. For purposes of clarity, however, you should note that Standard No. 217 does not mandate rear doors in buses other than school buses. Those buses can utilize either rear exits or roof exits. Further, regardless of the fact that you use a rear emergency door in buses other than school buses, you must insure that you also provide the other mandatory exits and the correct area of unobstructed openings as described in paragraphs S5.2 through S5.2.2.

SINCERELY,

Thomas BUILT BUSES, INC.

August 25, 1977

Office of The Chief Counsel U. S. Department of Transportation

Attn: Roger Chilton

The purpose of this letter is to request an interpretation of FMVSS No. 217 regarding the range of it's application, as follows: Para.S.5.2 - Speaks to buses other than schoolbuses and requires "unobstructed" openings for emergency exit . . ." going on to define the area requirements.

Para.S.5.2.1 - Speaks to "Buses with GVWR of more than 10,000 pounds". This presumably covers all buses. It further states that ". . . buses with a GVWR of more than 10,000 lbs. shall meet the unobstructed openings requirement by providing . . . one rear exit that conforms to S.5.3 through S.5.5".

Under paragraph S.5.4 thru S.5.4.2.1.(a) as amended May 25, 1976, the unobstructed opening of a school bus is described as "an opening large enough to permit unobstructed passage of a rectangular parallelepiped 45 inches high, 24 inches wide and 12 inches deep, keeping . . .". There is no description that pertains to the unobstructed opening of a non-school bus.

We have, therefore, decided that the non-school bus needs only a 12 inch wide clear aisle opening at the rear door to meet the requirements of FMVSS 217. Is this interpretation correct?

We would appreciate an early answer to this query.

Malcolm B. Mathieson, Engineering Manager