[ANNEX II U.K. Braking Tests and performance of braking systems
1. BRAKING TESTS U.K.
1.3. Type I test (fade test) U.K.
1.3.1. With repeated braking U.K.
1.3.1.1. The service braking system of all motor vehicles shall be tested by successively applying and releasing the brakes a number of times, the vehicle being laden, in accordance with the conditions shown in the following table: U.K.
| Category of vehicle | Conditions |
|---|
| V 1 km/h | V 2 km/h | Δt (s) | n |
|---|
| M 1 | 80 % V max
≤ 120
| ½ V 1 | 45 | 15 |
| M 2 | 80 % V max
≤ 100
| ½ V 1 | 55 | 15 |
| M 3 | 80 % V max
≤ 60
| ½ V 1 | 60 | 20 |
| N 1 | 80 % V max
≤ 120
| ½ V 1 | 55 | 15 |
| N 2 | 80 % V max
≤ 60
| ½ V 1 | 60 | 20 |
| N 3 | 80 % V max
≤ 60
| ½ V 1 | 60 | 20 |
where:
V 1
=
refer to point 1.1.2
V 2
=
speed at end of braking
V max
=
maximum speed of the vehicle
n
=
number of times brakes applied
Δt
=
duration of a braking cycle (time elapsing between the initiation of one brake application and the initiation of the next).
1.3.1.2. If the characteristics of the vehicle do not allow for the period of time prescribed for Δt, the duration may be increased; in any event, in addition to the time necessary for braking and accelerating the vehicle, a period of 10 seconds shall be allowed in each cycle for stabilising the speed v 1 . U.K.
1.3.1.3. In these tests, the force applied to the control shall be so adjusted as to attain a mean fully developed deceleration of 3 m/s 2 at the first application of the brakes. This force shall remain constant throughout the succeeding brake applications. U.K.
1.3.1.4. During brake applications the highest gear ratio (excluding overdrive, etc.) shall be continuously engaged. U.K.
1.3.1.5. For regaining speed after braking, the gearbox shall be used in such a way as to attain the speed v 1 in the shortest possible time (maximum acceleration allowed by the engine and gearbox). U.K.
1.3.2. With continuous braking U.K.
1.3.2.1. The service braking system of trailers of categories O 2 and O 3 shall be tested in such a manner that, the vehicle being laden, the energy input to the brakes shall be equivalent to that recorded in the same period of time with a laden vehicle driven at a steady speed of 40 km/h on a 7 % down gradient for a distance of 1,7 km. U.K.
1.3.2.2. The test may be carried out on a level road, the trailer being towed by a motor vehicle; during the test, the force applied to the control shall be adjusted so as to keep the resistance of the trailer constant (7 % of the maximum stationary axle load of the trailer). If the power available for hauling is insufficient, the test can be conducted at a lower speed but over a greater distance; as shown in the following table: U.K.
| Speed (km/h) | Distance (metres) |
|---|
| 40 | 1 700 |
| 30 | 1 950 |
| 20 | 2 500 |
| 15 | 3 100 |
1.3.3. Hot performance U.K.
1.3.3.1. At the end of the Type I test (test described in point 1.3.1 or test described in point 1.3.2 of this Annex) the hot performance of the service braking system shall be measured under the same conditions (and in particular at a constant control force no greater than the mean force actually used) as for the Type 0 test with the engine disconnected (the temperature conditions may be different). For motor vehicles, this hot performance shall not be less than 80 % of that prescribed for the category in question nor less than 60 % of the figure recorded in the Type 0 test with the engine disconnected. However in the case of trailers, the hot brake force at the periphery of the wheels when tested at 40 km/h shall not be less than 36 % of the maximum stationary wheel load, or less than 60 % of the figure recorded in the Type 0 test at the same speed. U.K.
1.3.3.2. In the case of a motor vehicle which satisfies the 60 % requirement specified in point 1.3.3.1, but which cannot comply with the 80 % requirement specified in point 1.3.3.1, a further hot performance test may be carried out using a control force not exceeding that specified in point 2.1.1.1 of this Annex. The results of both tests are entered in the report.] U.K.