[Code of Federal Regulations]
[Title 49, Volume 5]
[Revised as of October 1, 2002]
From the U.S. Government Printing Office via GPO Access
[CITE: 49CFR571.222]
[Page 681-693]
TITLE 49--TRANSPORTATION
OF TRANSPORTATION
PART 571--FEDERAL MOTOR VEHICLE SAFETY STANDARDS--Table of Contents
Subpart B--Federal Motor Vehicle Safety Standards
Sec. 571.222 Standard No. 222; School bus passenger seating and crash protection.
S1. Scope. This standard establishes occupant protection
requirements for school bus passenger seating and restraining barriers.
S2. Purpose. The purpose of this standard is to reduce the number of
deaths and the severity of injuries that result from the impact of
school bus occupants against structures within the vehicle during
crashes and sudden driving maneuvers.
S3. Application. This standard applies to school buses.
S4. Definitions. Contactable surface means any surface within the
zone specified in S5.3.1.1 that is contactable from any direction by the
test device described in S6.6, except any surface on the front of a seat
back or restraining barrier 76 mm or more below the top of the seat back
or restraining barrier.
School bus passenger seat means a seat in a school bus, other than
the driver's seat.
Wheelchair means a wheeled seat frame for the support and conveyance
of a physically disabled person, comprised of at least a frame, seat,
and wheels.
Wheelchair occupant restraint anchorage means the provision for
transferring wheelchair occupant restraint system loads to the vehicle
structure.
Wheelchair securement anchorage means the provision for transferring
wheelchair securement device loads to the vehicle structure.
Wheelchair securement device means a strap, webbing or other device
used for securing a wheelchair to the school bus, including allnecessary
buckles and other fasteners.
S4.1 The number of seating positions considered to be in a bench
seat is expressed by the symbol W, and calculated as the bench width in
millimeters divided by 381 and rounded to the nearest whole number.
S5. Requirements. (a) Each vehicle with a gross vehicle weight
rating of more than 4,536 kg shall be capable of meeting any of the
requirements set forth under this heading when tested under the
conditions of S6. However, a particular school bus passenger seat (i.e.,
test specimen) in that weight class need not meet further requirements
after having met S5.1.2 and S5.1.5, or having been subjected to either
S5.1.3, S5.1.4, or S5.3.
(b) Each vehicle with a gross vehicle weight rating of 4,536 kg or
less shall be capable of meeting the following requirements at all
seating positions other than the driver's seat:
(1)(A) In the case of vehicles manufactured before September 1,
1991, the requirements of Secs. 571.208, 571.209, and 571.210 as they
apply to multipurpose passenger vehicles; or
(B) In the case of vehicles manufactured on or after September 1,
1991, the requirements of S4.4.3.3 of Sec. 571.208 and the requirements
of Secs. 571.209 and 571.210 as they apply to school buses with a gross
vehicle weight rating of 4,536 kg or less; and
(2) The requirements of S5.1.2, S5.1.3, S5.1.4, S5.1.5, S5.3, and
S5.4 of this standard. However, the requirements of Secs. 571.208 and
571.210 shall be met at W seating positions in a bench seat using a body
block as specified in Figure 2 of this standard, and a particular school
bus passenger seat (i.e., a test specimen) in that weight class need not
meet further requirements after having met S5.1.2 and S5.1.5, or after
having been subjected to either S5.1.3, S5.1.4, or S5.3 of this standard
or Sec. 571.210.
S5.1 Seating requirements. School bus passenger seats shall be
forward facing.
S5.1.1 [Reserved]
S5.1.2 Seat back height and surface area. Each school bus passenger
seat shall be equipped with a seat back that, in the front projected
view, has a front surface area above the horizontal plane that passes
through the seating reference point, and below the horizontal plane 508
mm above the seating
[[Page 682]]
reference point, of not less than 90 percent of the seat bench width in
millimeters multiplied by 508.
S5.1.3 Seat performance forward. When a school bus passenger seat
that has another seat behind it is subjected to the application of force
as specified in S5.1.3.1 and S5.1.3.2, and subsequently, the application
of additional force to the seat back as specified in S5.1.3.3 and
S5.1.3.4:
(a) The seat back force/deflection curve shall fall within the zone
specified in Figure 1;
(b) Seat back deflection shall not exceed 356 mm; (for determination
of (a) and (b) the force/deflection curve describes only the force
applied through the upper loading bar, and only the forward travel of
the pivot attachment point of the upper loading bar, measured from the
point at which the initial application of 44 N of force is attained.)
(c) The seat shall not deflect by an amount such that any part of
the seat moves to within 102 mm of any part of another school bus
passenger seat or restraining barrier in its originally installed
position;
(d) The seat shall not separate from the vehicle at any attachment
point; and
(e) Seat components shall not separate at any attachment point.
S5.1.3.1 Position the loading bar specified in S6.5 so that it is
laterally centered behind the seat back with the bar's longitudinal axis
in a transverse plane of the vehicle and in any horizontal plane between
102 mm above and 102 mm below the seating reference point of the school
bus passenger seat behind the test specimen.
S5.1.3.2 Apply a force of 3,114W newtons horizontally in the
forward direction through the loading bar at the pivot attachment point.
Reach the specified load in not less than 5 nor more than 30 seconds.
S5.1.3.3 No sooner than 1.0 second after attaining the required
force, reduce that force to 1,557W newtons and, while maintaining the
pivot point position of the first loading bar at the position where the
1,557W newtons is attained, position a second loading bar described in
S6.5 so that it is laterally centered behind the seat back with the
bar's longitudinal axis in a transverse plane of the vehicle and in the
horizontal plane 406 mm above the seating reference point of the school
bus passenger seat behind the test specimen, and move the bar forward
against the seat back until a force of 44 N has been applied.
S5.1.3.4 Apply additional force horizontally in the forward
direction through the upper bar until 452W joules of energy have been
absorbed in deflecting the seat back (or restraining barrier). Apply the
additional load in not less than 5 seconds nor more than 30 seconds.
Maintain the pivot attachment point in the maximum forward travel
position for not less than 5 seconds nor more than 10 seconds and
release the load in not less than 5 nor more than 30 seconds. (For the
determination of S5.1.3.4 the force/deflection curve describes only the
force applied through the upper loading bar, and the forward and
rearward travel distance of the upper loading bar pivot attachment point
measured from the position at which the initial application of 44 N of
force is attained.)
S5.1.4 Seat performance rearward. When a school bus passenger seat
that has another seat behind it is subjected to the application of force
as specified in S5.1.4.1 and S5.1.4.2:
(a) Seat back force shall not exceed 9,786 N;
(b) Seat back deflection shall not exceed 254 mm; (for determination
of (a) and (b) the force/deflection curve describes only the force
applied through the loading bar, and only the rearward travel of the
pivot attachment point of the loading bar, measured from the point at
which the initial application of 222 N is attained.
(c) The seat shall not deflect by an amount such that any part of
the seat moves to within 102 mm of any part of another passenger seat in
its originally installed position;
(d) The seat shall not separate from the vehicle at any attachment
point; and
(e) Seat components shall not separate at any attachment point.
S5.1.4.1 Position the loading bar described in S6.5 so that it is
laterally centered forward of the seat back with
[[Page 683]]
the bar's longitudinal axis in a transverse plane of the vehicle and in
the horizontal plane 343 mm above the seating reference point of the
test specimen, and move the loading bar rearward against the seat back
until a force of 222 N has been applied.
S5.1.4.2 Apply additional force horizontally rearward through the
loading bar until 316W joules (J) of energy has been absorbed in
deflecting the seat back. Apply the additional load in not less than 5
seconds nor more than 30 seconds. Maintain the pivot attachment point in
the maximum rearward travel position for not less than 5 seconds nor
more than 10 seconds and release the load in not less than 5 seconds nor
more than 30 seconds. (For determination of S5.1.4.2 the force
deflection curve describes the force applied through the loading bar and
the rearward and forward travel distance of the loading bar pivot
attachment point measured from the position at which the initial
application of 222 N of force is attained.)
S5.1.5 Seat cushion retention. In the case of school bus passenger
seats equipped with seat cushions, with all manual attachment devices
between the seat and the seat cushion in the manufacturer's designated
position for attachment, the seat cushion shall not separate from the
seat at any attachment point when subjected to an upward force in
newtons of 5 times the mass of the seat cushion in kilograms and
multiplied by 9.8 m/s 2, applied in any period of not less
than 1 nor more than 5 seconds, and maintained for 5 seconds.
S5.2 Restraining barrier requirements. Each vehicle shall be
equipped with a restraining barrier forward of any designated seating
position that does not have the rear surface of another school bus
passenger seat within 610 mm of its seating reference point, measured
along a horizontal longitudinal line through the seating reference point
in the forward direction.
S5.2.1 Barrier-seat separation. The horizontal distance between the
restraining barrier's rear surface and the seating reference point of
the seat in front of which the barrier is required shall not be more
than 610 mm measured along a horizontal longitudinal line through the
seating reference point in the forward direction.
S5.2.2 Barrier position and rear surface area. The position and
rear surface area of the restraining barrier shall be such that, in a
front projected view of the bus, each point of the barrier's perimeter
coincides with or lies outside of the perimeter of the seat back of the
seat for which it is required.
S5.2.3 Barrier performance forward. When force is applied to the
restraining barrier in the same manner as specified in S5.1.3.1 through
S5.1.3.4 for seating performance tests:
(a) The restraining barrier force/deflection curve shall fall within
the zone specified in Figure 1;
(b) Restraining barrier deflection shall not exceed 356 mm; (for
computation of (a) and (b) the force/deflection curve describes only the
force applied through the upper loading bar, and only the forward travel
of the pivot attachment point of the loading bar, measured from the
point at which the initial application of 44 N of force is attained.)
(c) Restraining barrier deflection shall not interfere with normal
door operation;
(d) The restraining barrier shall not separate from the vehicle at
any attachment point; and
(e) Restraining barrier components shall not separate at any
attachment point.
S5.3 Impact zone requirements.
S5.3.1 Head protection zone. Any contactable surface of the vehicle
within any zone specified in S5.3.1.1 shall meet the requirements of
S5.3.1.2 and S5.3.1.3. However, a surface area that has been contacted
pursuant to an impact test need not meet further requirements contained
in S5.3.
S5.3.1.1 The head protection zones in each vehicle are the spaces
in front of each school bus passenger seat which are not occupied by bus
sidewall, window, or door structure and which, in relation to that seat
and its seating reference point, are enclosed by the following planes;
(a) Horizontal planes 305 mm and 1016 mm above the seating reference
point;
(b) A vertical longitudinal plane tangent to the inboard (aisle
side) edge of the seat; and
[[Page 684]]
(c) A vertical longitudinal plane 83 mm inboard of the outboard edge
of the seat;
(d) Vertical transverse planes through and 762 mm forward of the
reference point.
S5.3.1.2 Head form impact requirement. When any contactable surface
of the vehicle within the zones specified in S5.3.1.1 is impacted from
any direction at 6.7 m/s by the head form described in S6.6, the axial
acceleration at the center of gravity of the head form shall be such
that the expression
[GRAPHIC] [TIFF OMITTED] TR27MY98.016
shall not exceed 1,000 where ``a'' is the axial acceleration expressed
as a multiple of ``g'' (the acceleration due to gravity), and
``t1'' and ``t2'' are any two points in time
during the impact.
S5.3.1.3 Head form force distribution. When any contactable surface
of the vehicle within the zones specified in S5.3.1.1 is impacted from
any direction at 6.7 m/s by the head form described in S6.6, the energy
necessary to deflect the impacted material shall be not less than 4.5
joules before the force level on the head form exceeds 667 N. When any
contactable surface within such zones is impacted by the head form from
any direction at 1.5 m/s the contact area on the head form surface shall
be not less than 1,935 mm 2.
S5.3.2 Leg protection zone. Any part of the seat backs or
restraining barriers in the vehicle within any zone specified in
S5.3.2.1 shall meet the requirements of S5.3.2.2.
S5.3.2.1 The leg protection zones of each vehicle are those parts
of the school bus passenger seat backs and restraining barriers bounded
by horizontal planes 305 mm above and 102 mm below the seating reference
point of the school bus passenger seat immediately behind the seat back
or restraining barrier.
S5.3.2.2 When any point on the rear surface of that part of a seat
back or restraining barrier within any zone specified in S5.3.2.1 is
impacted from any direction at 4.9 m/s by the knee form specified in
S6.7, the resisting force of the impacted material shall not exceed
2,669 N and the contact area on the knee form surface shall not be less
than 1,935 mm 2.
S5.4 Each school bus having one or more locations designed for
carrying a person seated in a wheelchair shall comply with S5.4.1
through S5.4.4 at each such wheelchair location.
S5.4.1 Wheelchair securement anchorages. Each wheelchair location
shall have not less than four wheelchair securement anchorages complying
with S5.4.1.1 through S5.4.1.3.
S5.4.1.1 Each wheelchair securement anchorage shall have a
wheelchair securement device complying with S5.4.2 attached to it.
S5.4.1.2 The wheelchair securement anchorages at each wheelchair
location shall be situated so that--
(a) A wheelchair can be secured in a forward-facing position.
(b) The wheelchair can be secured by wheelchair securement devices
at two locations in the front and two locations in the rear.
(c) The front wheel of a three-wheeled wheelchair can be secured.
S5.4.1.3 Each wheelchair securement anchorage shall be capable of
withstanding a force of 13,344 Newtons applied as specified in
paragraphs (a) through (d) of this section. When more than one
securement device share a common anchorage, the anchorage shall be
capable of withstanding a force of 13,344 Newtons multiplied by the
number of securement devices sharing that anchorage.
(a) The initial application force shall be applied at an angle of
not less than 30 degrees, but not more than 60 degrees, measured from
the horizontal. (See Figure 4.)
(b) The horizontal projection of the force direction shall be within
a horizontal arc of 45 degrees relative to a longitudinal
line which has its origin at the anchorage location and projects
rearward for an anchorage whose wheelchair securement device is intended
to secure the front of the wheelchair and forward for an anchorage whose
wheelchair securement device is intended to secure the rear of the
wheelchair. (See Figure 4.)
(c) The force shall be applied at the onset rate of not more than
133,440 Newtons per second.
[[Page 685]]
(d) The 13,344 Newton force shall be attained in not more than 30
seconds, and shall be maintained for 10 seconds.
S5.4.2 Wheelchair securement devices. Each wheelchair securement
device shall--
(a) If incorporating webbing or a strap--
(1) Comply with the requirements for Type 1 safety belt systems in
S4.2, S4.3, and S4.4(a) of FMVSS No. 209, Seat Belt Assemblies; and
(2) Provide a means of adjustment to remove slack from the device.
(b) If not incorporating webbing or a strap, limit movement of the
wheelchair through either the equipment design or a means of adjustment.
S5.4.3 Wheelchair occupant restraint anchorages.
S5.4.3.1 Each wheelchair location shall have:
(a) Not less than one anchorage for the upper end of the upper torso
restraint; and
(b) Not less than two floor anchorages for wheelchair occupant
pelvic and upper torso restraint.
S5.4.3.2 Each wheelchair occupant restraint floor anchorage shall
be capable of withstanding a force of 13,344 Newtons applied as
specified in paragraphs (a) through (d). When more than one wheelchair
occupant restraint share a common anchorage, the anchorage shall be
capable of withstanding a force of 13,344 Newtons multiplied by the
number of occupant restraints sharing that anchorage.
(a) The initial application force shall be applied at a angle of not
less than 45 degrees, but not more than 80 degrees, measured from the
horizontal. (See Figure 5.)
(b) The horizontal projection of the force direction shall be within
a horizontal arc of 45 degrees relative to a longitudinal
line which has its origin at the anchorage and projects forward. (See
Figure 5.)
(c) The force shall be applied at an onset rate of not more than
133,440 Newtons per second.
(d) The 13,344 Newton force shall be attained in not more than 30
seconds, and shall be maintained for 10 seconds.
(e) When a wheelchair securement device and an occupant restraint
share a common anchorage, including occupant restraint designs that
attach the occupant restraint to the securement device or the
wheelchair, the loads specified by S5.4.1.3 and S5.4.3.2 shall be
applied simultaneously, under the conditions specified in S5.4.3.2 (a)
and (b). (See Figure 6.)
S5.4.3.3 Each anchorage for a wheelchair occupant upper torso
restraint shall be capable of withstanding a force of 6,672 Newtons
applied as specified in paragraphs (a) through (d).
(a) The initial application force shall be applied at a vertical
angle of not less than zero degrees, but not more than 40 degrees, below
a horizontal plane which passes through the anchorage. (See Figure 7.)
(b) The projection of the force direction onto the horizontal plane
shall be within zero degrees and 45 degrees as measured from a
longitudinal line with its origin at the anchorage and projecting
forward. (See Figure 7.)
(c) The force shall be applied at the onset rate of not more than
66,720 Newtons per second.
(d) The 6,672 Newton force shall be attained in not more than 30
seconds, and shall be maintained for 10 seconds.
S5.4.4 Wheelchair occupant restraints.
(a) Each wheelchair location shall have wheelchair occupant pelvic
and upper torso restraints attached to the anchorages required by
S5.4.3.
(b) Each wheelchair occupant restraint shall comply with the
requirements for Type 2 safety belt systems in S4.2, S4.3, and S4.4(b)
of FMVSS No. 209, Seat Belt Assemblies.
S6. Test conditions. The following conditions apply to the
requirements specified in S5.
S6.1 Test surface. The bus is at rest on a level surface.
S6.2 Tires. Tires are inflated to the pressure specified by the
manufacturer for the gross vehicle weight rating.
S6.3 Temperature. The ambient temperature is any level between 0
degrees C and 32 degrees C.
S6.4 Seat back position. If adjustable, a seat back is adjusted to
its most upright position.
S6.5 Loading bar. The loading bar is a rigid cylinder with an
outside diameter of 152 mm that has hemispherical ends with radii of 76
mm and with a surface roughness that does not exceed
[[Page 686]]
1.6 [mu]m, root mean square. The length of the loading bar is 102 mm
less than the width of the seat back in each test. The stroking
mechanism applies force through a pivot attachment at the center point
of the loading bar which allows the loading bar to rotate in a
horizontal plane 30 degrees in either direction from the transverse
position.
S6.5.1 A vertical or lateral force of 17,792 N applied externally
through the pivot attachment point of the loading bar at any position
reached during a test specified in this standard shall not deflect that
point more than 25 mm.
S6.6 Head form. The head form for the measurement of acceleration
is a rigid surface comprised of two hemispherical shapes, with total
equivalent mass of 5.2 kg. The first of the two hemispherical shapes has
a diameter of 166 mm. The second of the two hemispherical shapes has a
50 mm diameter and is centered as shown in Figure 3 to protrude from the
outer surface of the first hemispherical shape. The surface roughness of
the hemispherical shapes does not exceed 1.6 [mu]m, root mean square.
S6.6.1 The direction of travel of the head form is coincidental
with the straight line connecting the centerpoints of the two spherical
outer surfaces which constitute the head form shape.
S6.6.2 The head form is instrumented with an acceleration sensing
device whose output is recorded in a data channel that conforms to the
requirements for a 1,000 Hz channel class as specified in SAE
Recommended Practice J211a, December 1971. The head form exhibits no
resonant frequency below three times the frequency of the channel class.
The axis of the acceleration sensing device coincides with the straight
line connecting the centerpoints of the two hemispherical outer surfaces
which constitute the head form shape.
S6.6.3 The head form is guided by a stroking device so that the
direction of travel of the head form is not affected by impact with the
surface being tested at the levels called for in the standard.
S6.7 Knee form. The knee form for measurement of force is a rigid
76 millimeter-diameter cylinder, with an equivalent weight of 44 N that
has one hemispherical end with a 38 mm radius forming a contact surface
of the knee form. The hemispherical surface roughness does not exceed
1.6 [mu]m, root mean square.
S6.7.1 The direction of travel of the knee form is coincidental
with the centerline of the rigid cylinder.
S6.7.2 The knee form is instrumented with an acceleration sensing
device whose output is recorded in a data channel that conforms to the
requirements of a 600 Hz channel class as specified in the SAE
Recommended Practice J211a, December 1971. The knee form exhibits no
resonant frequency below three times the frequency of the channel class.
The axis of the acceleration sensing device is aligned to measure
acceleration along the centerline of the cylindrical knee form.
S6.7.3 The knee form is guided by a stroking device so that the
direction of travel of the knee form is not affected by impact with the
surface being tested at the levels called for in the standard.
S6.8 The head form, knee form, and contactable surfaces are clean
and dry during impact testing.
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[41 FR 4018, Jan. 28, 1976, as amended at 41 FR 28528, July 12, 1976; 41
FR 36027, Aug. 26, 1976; 41 FR 54945, Dec. 16, 1976; 42 FR 64120, Dec.
22, 1977; 43 FR 9150, Mar. 6, 1978; 44 FR 18675, Mar. 29, 1979; 48 FR
12386, Mar. 24, 1983; 54 FR 46268, Nov. 2, 1989; 58 FR 4593, Jan. 15,
1993; 58 FR 46876, Sept. 3, 1993; 63 FR 28948, 28950, May 27, 1998]