Document ID: chunk:federal_register_of_legislation:F2024C00148:reg:12:p20
Version: federal_register_of_legislation:F2024C00148
Segment Type: reg
Provision Reference: reg 12 (pt 20/24)
Character Range: 283683–286630

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Explanatory figure

Example of device for measuring the reflection factor of spherical mirrors

C = Receiver
D = Diaphragm
E = Window of entry
F = Window of measurement
L = Lens
M = Object window
S = Light source
(S) = Integrating sphere

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Annex 6
Procedure for determining the radius of curvature "r"
of a mirror's reflecting surface
1. Measurements
1.1. Equipment
 The "spherometer" described in figure/1 is used.
1.2. Measuring points
1.2.1. The principal radii of curvature shall be measured at 3 points situated as close as possible to positions at 1/3, 1/2 and 2/3 of the distance along the arc of the reflecting surface contained in a plane parallel to the greatest dimension of the mirror and passing through its centre and of the arc perpendicular to it.
1.2.2. Where, because of mirror size, it is impossible to obtain measurement in the directions defined in item/1.2.1. the technical departments responsible for the tests may take measurements at this point in two perpendicular directions as close as possible to those prescribed above.
2. Calculation of the radius of curvature (r)
 "r" expressed in mm is calculated using the formula:

 where rp1 is the radius of curvature of the first measuring point, rp2 at the second and rp3 at the third.

Figure 1

Annex 7
Control of the conformity of production
1. Definitions
 For the purpose of this annex,
 "Type of deflection system" means a given combination of axes, swivel points and other articulating mechanisms which ensures deflection of the rear‑view mirror in the direction of impact concerned.
2. Tests
 Rear‑view mirrors shall be subjected to the following tests:
2.1. Reflecting surface
2.1.1. Verification of the nominal radius of curvature, pursuant to the requirements of paragraph 2 of annex6 to this Regulation;
2.1.2. Measurement of the differences between radii of curvature pursuant to the requirements of paragraph 7.2.2. of this Regulation.
2.2. Deflection system
 Impact test pursuant to the requirements of paragraph 8.2. of this Regulation.
3. Frequency and results of tests
3.1. Verification of the nominal radius of curvature and measurement of the differences between radii of curvature
3.1.1. Frequency:
 One test every three months, per approval number, per nominal radius of curvature.
3.1.2. Results:
 All measurement results shall be recorded.
 The maximum difference values prescribed in paragraph 7.2.2. of this Regulation shall be complied with.
3.2. Impact test
3.2.1. Frequency:
 One test every three months, per approval number, per type of deflection system, per base configuration.
3.2.2. Results:
 All results shall be recorded.
 The provisions of paragraph 8.4. of this Regulation shall be complied with.
3.3. Selection of samples
 The selection of samples to