For TruckTalk visitor's convenience here is a copy of standard 223 directly
from the GPO site.
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WAIS Document Retrieval[Code of Federal Regulations]
[Title 49, Volume 5, Parts 400 to 999]
[Revised as of October 1, 1998]
From the U.S. Government Printing Office via GPO Access
[CITE: 49CFR571.223]
[Page 672-677]
TITLE 49--TRANSPORTATION
CHAPTER V--NATIONAL HIGHWAY TRAFFIC
SAFETY ADMINISTRATION, DEPARTMENT
OF TRANSPORTATION
PART 571--FEDERAL MOTOR VEHICLE SAFETY STANDARDS--Table of Contents
Subpart B--Federal Motor Vehicle Safety Standards
Sec. 571.223 Standard No. 223; Rear impact guards.
S1. Scope. This standard specifies requirements for rear impact
guards for trailers and semitrailers.
S2. Purpose. The purpose of this standard is to reduce the number of
deaths and serious injuries that occur when light duty vehicles collide
with the rear end of trailers and semitrailers.
S3. Application. This standard applies to rear impact guards for
trailers and semitrailers subject to Federal Motor Safety Standard No.
224, Rear Impact Protection (Sec. 571.224).
S4. Definitions.
In this standard, directional terms such as bottom, center, height,
horizontal, longitudinal, transverse, and rear refer to directions
relative to the vehicle orientation when the guard is oriented as if it
were installed on a vehicle according to the installation instructions
in S5.5 of this section.
Chassis means the load supporting frame structure of a motor
vehicle.
Guard width means the maximum horizontal guard dimension that is
perpendicular to the longitudinal vertical plane passing through the
longitudinal centerline of the vehicle when the guard is installed on
the vehicle according to the installation instructions in S5.5 of this
section.
Horizontal member means the structural member of the guard that
meets the configuration requirements of S5.1.1 through 5.1.3 of
Sec. 571.224, Rear Impact Protection, when the guard is installed on a
vehicle according to the guard manufacturer's installation instructions.
Hydraulic guard means a guard designed to use fluid properties to
provide resistance force to deformation.
Rear impact guard means a device installed on or near the rear of a
vehicle so that when the vehicle is struck from the rear, the device
limits the distance that the striking vehicle's front end slides under
the rear end of the impacted vehicle.
Rigid test fixture means a supporting structure on which a rear
impact guard can be mounted in the same manner it is mounted to a
vehicle. The rigid text fixture is designed to resist the forces applied
to the rear impact guard without significant deformation, such that a
performance requirement of this standard must be met no matter how small
an amount of energy is absorbed by the rigid test fixture.
S5. Requirements.
S5.1 Projected Vertical Height. The horizontal member of each
guard, when viewed from the rear as it would be installed on a trailer
pursuant to the installation instructions or procedures required by S5.5
of this standard, shall have a vertical height of at least 100 mm at
each point across the guard width, when projected horizontally on a
transverse vertical plane. Those installation instructions or procedures
shall specify that the guard is to be mounted so that all portions of
the horizontal member necessary to achieve a 100 mm high projected
vertical height are located not more than 305 mm forward of the
vehicle's rear extremity, as defined in S4 of 49 CFR 571.224, Rear
Impact Protection. See Figure 1 of this section.
S5.2 Strength and Energy Absorption. When tested under the
procedures of S6 of this section, each guard shall comply with the
strength requirements of S5.2.1 of this section at each test location
and the energy absorption requirements of S5.2.2 of this section at test
location P3, as specified in S6.4 of this section. However, a particular
guard (i.e., test specimen) need not be tested at more than one
location.
S5.2.1 Guard Strength. The guard must resist the force levels
specified in S5.2.1 (a) through (c) of this section without deflecting
by more than 125 mm.
(a) A force of 50,000 N at test location P1 on either the left or
the right side of the guard as defined in S6.4(a) of this section.
(b) A force of 50,000 N at test location P2 as defined in S6.4(b) of
this section.
(c) A force of 100,000 N at test location P3 on either the left or
the right side of the guard as defined in S6.4(c) of this section.
S5.2.2 Guard Energy Absorption. A guard, other than a hydraulic
guard, shall absorb by plastic deformation within the first 125 mm of
deflection at least 5,650 J of energy at each test location P3. See
Figure 2 of this section.
[[Page 673]]
S5.3 Labeling. Each guard shall be permanently labeled with the
information specified in S5.3 (a) through (c) of this section. The
information shall be in English and in letters that are at least 2.5 mm
high. The label shall be placed on the forward-facing surface of the
horizontal member of the guard, 305 mm inboard of the right end of the
guard.
(a) The guard manufacturer's name and address.
(b) The statement: ``Manufactured in ________'' (inserting the month
and year of guard manufacture).
(c) The letters ``DOT'', constituting a certification by the guard
manufacturer that the guard conforms to all requirements of this
standard.
S5.4 Guard Attachment Hardware. Each guard, other than a guard that
is to be installed on a vehicle manufactured by the manufacturer of the
guard, shall be accompanied by all attachment hardware necessary for
installation of the guard on the chassis of the motor vehicle for which
it is intended.
S5.5 Installation Instructions. The manufacturer of rear impact
guards for sale to vehicle manufacturers shall include with each guard
printed instructions in English for installing the guard, as well as a
diagram or schematic depicting proper guard installation. The
manufacturer of a rear impact guard for one of its own vehicles shall
prepare and keep a copy of installation procedures applicable to each
vehicle/guard combination for a period of one year from the date of
vehicle manufacture and provide them to NHTSA on request. The
instructions or procedures shall specify:
(a) Vehicles on which the guard can be installed. Vehicles may be
designated by listing the make and model of the vehicles for which the
guard is suitable, or by specifying the design elements that would make
any vehicle an appropriate host for the particular guard (e.g., vehicles
with frame rails of certain spacing and gauge of steel).
(b) A description of the chassis surface to which the guard will be
attached, including frame design types with dimensions, material
thickness, and tire track width. This description shall be detailed
enough to permit the agency to locate and duplicate the chassis surface
during compliance testing.
(c) An explanation of the method of attaching the guard to the
chassis of each vehicle make and model listed or to the design elements
specified in the instructions or procedures. The principal aspects of
vehicle chassis configuration that are necessary to the proper
functioning of the guard shall be specified. If the chassis strength is
inadequate for the guard design, the instructions or procedures shall
specify methods for adequately reinforcing the vehicle chassis.
Procedures for properly installing any guard attachment hardware shall
be provided.
S6. Guard Test Procedures. The procedures for determining compliance
with S5.2 of this section are specified in S6.1 through S6.6 of this
section.
S6.1 Preparation of Hydraulic Guards. For hydraulic guards, the
horizontal member of the guard is deflected in a forward direction until
the hydraulic unit(s) have reached the full extent of their designed
travel or 610 mm, whichever occurs first. The hydraulic units are
compressed before the application of force to the guard in accordance
with S6.6 of this section and maintained in this condition throughout
the testing under S6.6 of this section.
S6.2 Guard Installation for Strength and Energy Absorption Tests.
(a) The rear impact guard is attached to a test device.
(b) The test device for the compliance test will be whichever of the
following devices, if either was used, the manufacturer used as a basis
for its certification of the guard in S5.3(c) of this section. If the
manufacturer did not use one of these devices or does not specify a
device when asked by the agency, the agency may choose either of the
following devices--
(1) A rigid test fixture. In the case of testing on a rigid test
fixture NHTSA will consult the installation instructions or procedures
to determine the surface or structure that the guard is supposed to be
mounted to and mount it to the rigid test fixture in the same way.
(2) A complete trailer for which installation of the guard is
suitable, as
[[Page 674]]
provided in the manufacturer's installation instructions or procedures
required by S5.5 of this section. The trailer chassis is secured so that
it behaves essentially as a fixed object during the test, such that the
test must be passed no matter how little it moves during the test.
(c) The guard is attached in accordance with the instructions or
procedures for guard attachment provided by the guard manufacturer for
that guard as required by S5.5 of this section.
S6.3 Force Application Device. The force application device employed
in S6.6 of this section consists of a rectangular solid made of rigid
steel. The steel solid is 203 mm in height, 203 mm in width, and 25 mm
in thickness. The 203 mm by 203 mm face of the block is used as the
contact surface for application of the forces specified in S5.2.1 (a)
through (c) of this section. Each edge of the contact surface of the
block has a radius of curvature of 5 mm plus or minus 1 mm.
S6.4 Test Locations. With the guard mounted to the rigid test
fixture or to a complete trailer, determine the test locations P1, P2,
and P3 in accordance with the procedure set forth in S6.4 (a) through
(c) of this section. See Figure 1 of this section.
(a) Test location P1 is the point on the rearmost surface of the
horizontal member of the guard that:
(1) Is located at a distance of \3/8\ of the guard width from the
vertical longitudinal plane passing through center of the guard;
(2) Lies on either side of the center of the guard's horizontal
member; and
(3) Is 50 mm above the bottom of the guard.
(b) Test location P2 is the point on the rearmost surface of the
horizontal member of the guard that:
(1) Lies in the longitudinal vertical plane passing through the
center of the guard's horizontal member; and
(2) Is 50 mm above the bottom of the guard.
(c) Test location P3 is any point on the rearmost surface of the
horizontal member of the guard that:
(1) Is not less than 355 mm and not more than 635 mm from the
vertical longitudinal plane passing through center of the guard;
(2) Lies on either the right or left side of the horizontal member
of the guard; and
(3) Is 50 mm above the bottom of the guard.
S6.5 Positioning of Force Application Device. Before applying any
force to the guard, locate the force application device such that:
(a) The center point of the contact surface of the force application
device is aligned with and touching the guard test location, as defined
by the specifications of S6.4 of this section.
(b) The longitudinal axis of the force application device passes
through the test location and is perpendicular to the transverse
vertical plane that is tangent to the rearmost surface of the guard's
horizontal member.
S6.6 Force Application. After the force application device has been
positioned according to S6.5 of this section, apply the loads specified
in S5.2.1 of this section. Load application procedures are specified in
the S6.6 (a) through (d) of this section.
(a) Using the force application device, apply force to the guard in
a forward direction such that the displacement rate of the force
application device is the rate, plus or minus 10 percent, designated by
the guard manufacturer within the range of 2.0 cm per minute to 9.0 cm
per minute. If the guard manufacturer does not designate a rate, any
rate within that range may be chosen.
(b) If conducting a strength test to satisfy the requirement of
S5.2.1 of this section, the force is applied until the forces specified
in S5.2.1 of this section have been exceeded, or until the displacement
of the force application device has reached at least 125 mm, whichever
occurs first.
(c) If conducting a test to be used for the calculation of energy
absorption levels to satisfy the requirement of S5.2.2 of this section,
apply the force to the guard until displacement of the force application
device has reached 125 mm. For calculation of guard energy absorption,
the value of force is recorded at least ten times per 25 mm of
displacement of the contact surface of the loading device. Reduce the
force
[[Page 675]]
until the guard no longer offers resistance to the force application
device. Produce a force vs. deflection diagram of the type shown in
Figure 2 of this section using this information. Determine the energy
absorbed by the guard by calculating the shaded area bounded by the
curve in the force vs. deflection diagram and the abscissa (X-axis).
(d) During each force application, the force application device is
guided so that it does not rotate. At all times during the application
of force, the location of the longitudinal axis of the force application
device remains constant.
[GRAPHIC] [TIFF OMITTED] TC01AU91.145
[[Page 676]]
[GRAPHIC] [TIFF OMITTED] TC01AU91.146
[[Page 677]]
[61 FR 2030, Jan. 24, 1996, as amended at 63 FR 3662, Jan. 26, 1998]
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