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Interpretation ID: nht94-2.39

TYPE: Interpretation-NHTSA

DATE: April 14, 1994

FROM: John Womack -- Acting Chief Counsel, NHTSA

TO: Thomas D. Turner -- Manager, Engineering Services, Blue Bird Body Company

TITLE: None

ATTACHMT: Attached to letter dated 1/6/94 from Thomas D. Turner to John Womack (OCC 9549); Also attached to letter dated 3/9/77 from Frank A. Berndt to W.G. Milby (Std. 217)

TEXT:

This responds to your letter of January 6, 1994, asking several questions concerning a recent amendment to Standard No. 217, Bus Emergency Exits and Window Retention and Release (57 FR 49413; November 2, 1992). Our response to each of your questions fol lows.

1. Your first question requested confirmation that a left side emergency exit door required by S5.2.3.1(a)(2)(i) would meet the location requirements of S5.2.3.1(a)(2)(i) if it is located in the center one-half of the passenger compartment.

Your question concerns the first required additional emergency exit installed on a bus with a rear emergency exit door. Section S5.2.3.2(a)(2) requires this exit to be a side emergency exit door "located on the left side of the bus and as near as practi cable to the midpoint of the passenger compartment." Locating the door or the 12-inch required aisle opening for the door in the center one-half of the passenger compartment would not ensure compliance with this requirement. This is because it may be p ossible to locate a door in the center one-half without locating the exit "as near as practicable to the midpoint of the passenger compartment." In determining the permissible location for this exit, you should determine where the exit would be located if it was located at the midpoint of the passenger compartment. If it is not practicable to locate the exit there, you should move the door only as far as necessary for a practicable location.

2. Your second question requested confirmation that there are no fore and aft location requirements for side emergency exit doors other than the requirements for a left side emergency exit door required by S5.2.3.1(a)(2) (i).

You are correct. Except for a left side emergency exit door installed as the first additional emergency exit on a bus with a rear emergency door, the only location requirements for side emergency exit doors concern the side of the bus on which the exit must be located. I have attached for your information an appendix which lists all the location requirements for additional emergency exits.

3. Your third question requested confirmation that all side emergency exit doors, including any voluntarily installed, are required to comply with the requirements of the new final rule, including the seat placement requirements in S5.4.2.1( b).

You are correct. Your letter referred to a March 9, 1977 interpretation that voluntarily installed side emergency exit doors were not required to meet the school bus requirements, but were required to meet the non-school bus requirements. Previously, t he school bus emergency exit door requirements in Standard No. 217 referred to "the emergency door." At that time school buses were required to have either one rear emergency exit door or one side emergency exit door and one rear push-out window. Thus, any school bus was required to have only one emergency exit door. The reference to "the emergency door" was to the required door.

In the recent amendments to Standard No. 217, some of the performance requirements for emergency exits apply to "each" emergency exit. See, for example, S5.4.2.1(b). This change in the language extends these requirements to any emergency exit door in a school bus. Other requirements apply to "required" emergency exits. See, for example, S5.5.3(c). These requirements do not apply to voluntarily installed emergency exits.

I hope you find this information helpful. If you have any other questions, please contact Walter Myers of my staff at this address or by phone at (202) 366-2992.

APPENDIX Emergency Exit Location Requirements In the March 15, 1991, notice of proposed rulemaking to amend Standard No. 217, Bus Emergency Exits and Window Retention and Release, NHTSA proposed very specific location requirements for emergency exits in school buses (56 FR 11153). The agency receiv ed comments that many of these locations were not possible or practicable. In response to these comments, the agency concluded that the final rule should include only general requirements for the required exits (57 FR 49413; November 2, 1992). Therefor e, the only location requirements for additional emergency exits (1) included in the final rule were:

o For a bus with a rear emergency exit door, the first additional emergency exit must be an emergency exit door on the left side of the bus and as near as practicable to the midpoint of the passenger compartment (S5.2.3.2(a)(2)).

o For a bus with a side emergency exit door and a rear push-out window, the first additional emergency exit must be an emergency exit door on the right side of the bus (S5.2.3.2(a)(3)).

o If additional emergency exit doors are installed, they must be alternated between the right and left sides of the bus (S5.2.3.2(a)(2) and (3)).

o No two emergency exit doors may be located in the same post and roof bow panel space (S5.2.3.2(a)(4)).

o If one emergency roof exit is installed, it must be located as near as practicable to the mid-point of the passenger compartment (S5.2.3.2(b)(2)).

o If two emergency roof exits are installed, they must be located as near as practicable to a point equidistant from the midpoints of the passenger compartment and either the front or rear of the passenger compartment (S5.2.3.2(b)(3)).

o If three or more emergency roof exits are installed, the space between each exit shall, to the extent possible, be the same or equal to the space between the front (or rear) limit of the passenger compartment and the front (or rear) ro of exit (S5.2.3.2(b)(4)).

o Emergency roof exits must be installed so that their longitudinal centerline coincides with the longitudinal centerline of the bus, except that a roof exit may be offset a distance equal to the distance another roof exit is offset in the opposite direction (S5.2.3.2(b)(5) and (6)).

o Emergency window exits must be evenly divided between the right and left sides of the bus (S5.2.3.2(c)).

(1) The November 2 final rule requires all school buses to have either a rear emergency exit door or a side emergency exit door and a rear push-out window. The rule also requires "additional" emergency exits on buses of specified passenger capacities. " Additional" emergency exits, as the term is used in this appendix, refers to emergency exits other than the rear emergency exit door and side emergency exit door/rear push-out window which Standard No. 217 requires of all school buses.