§393.61 Window Construction

Question 1: Do school buses used for purposes other than school bus operations (as defined in §390.5), have to meet additional emergency exits requirements under §393.61?

Guidance: Yes. §393.61(b)(2) says that "a bus, including a school bus, manufactured on and after September 1, 1973," must conform with NHTSA's §571.217 (FMVSS 217). At the time this provision was adopted, FMVSS 217 applied only to other buses and it was optional for school buses. The FHWA inserted the language, "including school buses," in §393.61(b)(2) to make clear that school buses used in interstate commerce and, therefore, subject to the FMCSRs, were required to comply with the bus exit standards in Standard FMVSS 217.

§393.61(b)(3) regarding push-out windows provides that older buses must conform with the requirements of §393.61(b) or 571.217. Buses which are subject to §571.217 would follow NHTSA's interpretation on push-out windows. Buses which are subject to §393.61(b)(1) of the FMCSRs are required to have emergency windows that are either push-out windows or that have laminated safety glass that can be pushed out in a manner similar to a push-out window.

Question 2: For emergency exits which consist of laminated safety glass, is the window frame or sash required to move outward from the bus as is the case with push-out windows?

Guidance: No. Laminated safety glass is an alternative to the use of push-out windows for buses manufactured before September 1, 1973. §393.61(c) requires that every glazed opening used to satisfy the emergency exit space requirements, "if not glazed with laminated safety glass, shall have a frame or sash so designed, constructed, and maintained that it will yield outwardly to provide the required free opening. * * *" Laminated safety glass meeting Test No. 25, Egress, American National Standard "Safety Code for Safety Glazing Materials for Glazing Motor Vehicles Operating on Land Highways," Z26.1-1966 as supplemented by Z26.1a-1969 (referenced in §393.61(c) and 393.60(a)) is intended to provide an adequate means of emergency exit on older buses without resorting to push-out windows.

However, buses with a seating capacity of more than 10 people manufactured after September 1, 1973, must have push-out windows that conform to 49 CFR 571.217.

Question 3: When calculating the minimum emergency exit space required on school buses used in non-school bus operations, should two or three passengers per bench seat be used in determining the adult seating capacity?

Guidance: The NHTSA has indicated that "School buses can transport 3 to a seat if the passengers are in grades 1 through 5, and 2 per seat in grades 9 through 12." (May 9, 1995, 60 FR 24562, 24567) Therefore, for vehicles originally manufactured as school buses, the total pupil seating capacity provided by the bus manufacturer should be multiplied by 2/3 to determine the adult seating capacity for the purposes of §393.61. This generally yields the same result as using two adults per bench seat.

Question 4: Do school buses which meet the school bus emergency exit requirements established by the NHTSA's November 2, 1992, final rule on FMVSS No. 217 have to be retrofitted with additional emergency exits when used in interstate commerce for non-school bus operations?

Guidance: No. On May 9, 1995, the NHTSA amended FMVSS No. 217 to permit non-school buses to meet either the current non-school bus emergency exit requirements or the upgraded school bus exit requirements established by the November 2, 1992 (57 FR 49413), final rule which became effective on September 1, 1994. Therefore, school buses which meet the upgraded emergency exit standards meet the requirements of §393.61 without the retrofitting of additional exits.

Question 5: Which edition of FMVSS No. 217 is required to be used in determining the emergency exit space requirements when retrofitting buses?

Guidance: The cross reference to FMVSS No. 217 applies to the requirements in effect at the time of manufacture of the bus. Motor carriers are not, however, prohibited from retrofitting their buses to the most up-to-date requirements in FMVSS No. 217. Therefore, at a minimum, motor carriers must meet the non-school bus emergency exit requirements in effect at the time of manufacture, and have the option of retrofitting their buses to meet the emergency exit requirements established by the November 2, 1992 (57 FR 49413), final rule which became effective on September 1, 1994.