Interpretation ID: nht76-5.50
DATE: 07/01/76
FROM: AUTHOR UNAVAILABLE; John Womack for F. Berndt; NHTSA
TO: ROHR Industries, Inc.
TITLE: FMVSS INTERPRETATION
TEXT: This responds to Rohr Industries' April 27, 1976, letter asking how to test an emergency exit that contains no glazing in conformity with the provision of Standard No. 217, Bus Window Retention and Release, that specifies testing before and after a window retention test (S5.3.2.). You also ask whether the emergency exit identification requirements of S5.5.1 specify the placement of operating instructions at a designated seating position which does not qualify as an "adjacent seat" under the definition found in S4 of the standard.
The window retention requirement is not required in the case of an emergency exit that contains no glazing. Because this requirement is clearly inapplicable to such an exit, the emergency exit release requirements of S5.3.2 must be met, but without the need to conduct a window retention test.
In answer to your second question, S5.5.1 requires that a label indicating the location of the nearest exit release mechanism be placed at "adjacent seats" to any exit whose release mechanism is not located within the occupant space of that adjacent seat. There are no labeling requirements in S5.5.1 for seating that is not "adjacent" to the exit. As you note, some interior configurations result in seating whose "occupant space" is not within 10 inches of any emergency exit (measured as set forth in S4). Such seating would not have to be labeled with the location of the nearest release mechanism, although some manufacturers do provide this information voluntarily. The agency has evaluated a requirement for this labeling but considers present labelling practices adequate at this time.
SINCERELY,
April 27, 1976
Robert Williams Office of Crashworthiness National Highway Traffic Safety Administration U.S. Department of Transportation
Reference: FMVSS No. 217, Bus Window Retention and Release
This letter is forwarded in response to your suggestion made during our telephone conversation of April 15, 1976, during which we discussed the interpretation of certain requirements contained in the referenced FMVSS. Our discussion concerned an emergency roof exit installed in an urban transit bus in accordance with paragraph S5.2.1, since the bus configuration precludes installation of an accessible rear emergency exit.
The roof exit under discussion is not a push-out window. No window glazing is involved. It is of a metal-foam-sandwich construction comparable to the surrounding roof. Paragraph S5.3.2 requires each emergency exit allow manual release of the exit "both before and after the window retention test required by S5.1". Clarification of the application of these window retention tests to the non-glazed roof hatch is requested.
a. Is it required that a non-glazed roof emergency exit be subjected to the window retention test specified by paragraphs S5.1?
b. If testing is required, which of the terminating events in S5.1 are applicable when testing a non-window type exit?
c. If testing is required, must the test be accomplished with the vehicle resting on it's side per Figure 3B, Roof Emergency Exit?
During our phone conversation referenced above, you expressed your unofficial interpretations as being that a non-glazed roof emergency exit would be subject to the release force requirements of the standard but not the retention force requirements or testing under S5.1.
Clarification with respect to emergency exit identification is also requested. Paragraph S5.1 states in part -
". . .When a release mechanism is not located within the occupant space of an adjacent seat, a label meeting the requirements of S5.5.2 that indicates the location of the nearest release mechanism shall be placed within that occupant space."
Paragraph S4 defines an "adjacent seat" and "occupant space" in a manner which indicates that a designated seating position is not to be identified as an "adjacent seat" unless some portion of it's occupant space is not more than ten inches from an emergency exit, for a distance of at least fifteen inches measured horizontally and parallel to the exit. As you know, certain bus seating configurations are such that some designated seating positions are directly adjoining fixed windows/piar panels (non-glazed areas between windows). These fixed (non-push-out) windows and pier panels are not designed as, nor marked as emergency exits. The occupant space of the adjoining designated seating position is not within ten inches of an emergency exit for a distance of at least fifteen inches measured horizontally and parallel to that exit. Therefore, it is our understanding that these seating positions are not, by definition, adjacent seats.
a. Do these non-adjacent seats adjoining a fixed window or a pier panel require emergency exit location referral labelling under the current edition of FMVSS No. 217?
b. If so, which paragraph specifies such a requirement?
c. If not, has such a requirement been considered?
Here also during our phone conversation previously referenced, you expressed an unofficial opinion that these particular seating positions were not covered by labelling requirements. Please confirm.
Your review of and assistance with above will be greatly appreciated.
R. L. Ratz Safety Engineering Specialist