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Issued: December 2003
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2.
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Definitions
Chassis means the load supporting frame structure of a trailer. (Châssis)
Note: Directional terms such as bottom,
centre, height, horizontal, longitudinal, transverse, and rear refer to
directions relative to the vehicle’s orientation when the guard
is installed.
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3.
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General Requirements
3.1 Test Conditions and Measurements
3.1.1 Where a range of conditions is specified, a rear impact guard
must be capable of meeting the requirements at all points within the
range.
3.1.2 Each sample rear impact guard shall be subject to testing only once.
3.1.3 All measurements are to be taken with the trailer unloaded,
resting on level ground, with its full capacity of fuel, its tires
inflated, and its air suspension, if so equipped, pressurized in accordance
with the manufacturer’s recommendations..
3.2 Hydraulic Guards
For hydraulic guards, prior to completing the tests specified in
subsections 223(9) to (12) of Schedule IV to the MVSR, the horizontal
member of the guard must be 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.
3.3 Testing Alternatives
The strength and energy absorption tests may, at the option of the
manufacturer, be conducted using either:
(a) A rigid test fixture: The rear impact guard
may be tested by mounting it on a rigid test fixture in the same
manner as it would be attached to the trailer and using the same
mounting hardware, or
(b) A complete trailer: A guard and trailer may be
tested as a complete assembly, if the trailer chassis is rigidly secured
so that it behaves essentially as a fixed object during the test.
If using a rigid test fixture, it must be designed to resist the forces
applied to the rear impact guard without significant deformation,
and it shall absorb no significant amount of energy during these tests.
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4.
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Point Test Procedure
4.1 Point Test Locations
With the guard mounted on the rigid test fixture or attached to a
complete trailer, determine the test locations as follows (see Figure
1).
4.1.1 Test location P1 is the point on the rearmost
surface of the horizontal member of the guard that:
(a) is located at a distance of 3/8 the width of the guard from
the longitudinal vertical plane passing through the centre of the
horizontal member,
(b) lies on either side of the centre of the horizontal member,
and
(c) is 50 mm above the bottom of the horizontal member.
4.1.2 Test location P2 is the point on the rearmost
surface of the horizontal member of the guard that:
(a) lies in the longitudinal vertical plane passing through the
centre of the horizontal member, and
(b) is 50 mm above the bottom of the horizontal member.
4.1.3 Test location P3 is the point on the rearmost
surface of the horizontal member of the guard that:
(a) in the case of a guard that has only two attachment points
to the horizontal member, lies at the junction of the support and
the tested portion of the horizontal member, or
(b) in the case of a guard that has more than two attachment points
to the horizontal member, is located not less than 355 mm and not
more than 635 mm from the longitudinal vertical plane passing through
the centre of the horizontal member, and
(c) is 50 mm above the bottom of the horizontal member.
4.2
Force Application Device to be Used for the Point Load Tests
The force application device to be employed for the point tests consists
of a rectangular solid block of steel that:
(a) is 203 mm in height, 203 mm in width, and 25 mm in thickness,
with each edge of the contact surface of the block having a radius
of curvature of 5 mm ± 1 mm, and
(b) whose 203 mm by 203 mm face is used as the contact surface for application
of the specified forces.
4.3
Positioning of the Force Application Device for the Point Load Tests
Before applying a force to the guard, position the force application
device so that:
(a) the centre point of the contact surface is aligned with and
touching the guard test location, as defined in subsection
4.1,
(b) its longitudinal axis passes through the test location and
is perpendicular to the transverse vertical plane that is tangent
to the rearmost surface of the horizontal member, and
(c) it is guided to prevent rotation and so that the location of its longitudinal
axis remains constant at all times during the application of force.
4.4 Application
of the Forces for the Point Load Tests
After the force application device has been positioned, apply the
necessary force in the following manner:
(a) to the guard in a forward direction, at a rate such that the
test is completed within five minutes from the application of the
force, but without the average displacement rate of the force application
device exceeding 90 mm per minute, and
(b) until the force requirements have been exceeded or until the displacement
of the force application device has reached at least 125 mm, whichever
occurs first.
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5.
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Uniform Load Test Procedure
5.1
Uniform Load Test Force Application Device
The force application device to be employed in applying the uniform
test load is to be unyielding, have a height of 203 mm, and have a
width that exceeds the distance between the outside edges of the outermost
supports to which the tested portion of the horizontal member is attached,
as shown in figure 2.
5.2
Positioning of the Force Application Device for the Uniform Load Test
Before applying a force to the guard, position the force application
device so that:
(a) when applying the uniform test load, the centre of the contact
surface is aligned with the longitudinal vertical plane passing
through the centre of the horizontal member,
(b) the uniform load is applied in a direction that is perpendicular to the
transverse vertical plane that is tangent to the rearmost surface
of the horizontal member, and
(c) it is guided to prevent rotation.
5.3
Application of the Uniform Test Load
5.3.1 At the option of the manufacturer, apply the load in a forward
direction, at a rate such that the test is completed within five minutes
from the application of the load, but without the average displacement
rate of the force application device exceeding 90 mm per minute.
5.3.2 The load is to be applied until the load requirements have been exceeded
or until the displacement of the force application device has reached
at least 125 mm, whichever occurs first.
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6.
| Energy Absorption Test Procedure
The calculation of energy absorption that is required by section
223 of Schedule IV to the MVSR must be based on measurements taken
during the uniform load test specified in section 5 or the P3 point
load test specified in section 4 of this Test Method, at the option
of the manufacturer, and must be carried out in accordance with the
following.
6.1 The force is to be applied to the guard until displacement of the force
application device has reached 125 mm.
6.2 The value of the force is to be recorded at least ten times per 25 mm
of displacement of the contact surface of the force application device.
6.3 The force is to be reduced until the guard no longer offers resistance
to the force application device.
6.4 A force-vs.-deflection diagram of the type shown in Figure
3 is to be generated using the above information.
6.5 The energy absorbed by the guard is to be determined by calculating
the shaded area bounded by the curve and the abscissa (X axis) in
the force-vs.-deflection diagram.
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Figure 1 — Rear View of the Rear Impact Guard
Figure 2 — Typical Application of the Uniform Test Load
Figure 3 — Typical Force-Deflection Diagram
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