[F1ANNEX VIII U.K. Conditions governing the testing of vehicles with inertia (overrun) braking systems
Textual Amendments
9. COMPATIBILITY OF THE CONTROL DEVICE AND THE BRAKES OF A VEHICLE U.K.
9.1. A check shall be made on the vehicle, taking into account the characteristics of the control device (Appendix 2) and of the brakes (Appendix 3) as well as the trailer characteristics mentioned in point 4 of Appendix 4, as to whether the inertia braking system of the trailer complies with the requirements laid down. U.K.
9.2. General tests for all types of brakes U.K.
9.2.1. Those parts of the transmission which have not been tested at the same time as the brake control device or the brakes shall be tested on the vehicle. The results of the test shall be entered in Appendix 4 (for example i H1 and η H1 ). U.K.
9.2.2. Mass U.K.
9.2.2.1. The maximum mass of the trailer G A shall not exceed the maximum mass G′ A for which the control device is authorised. U.K.
9.2.2.2. The maximum mass of the trailer G A shall not exceed the maximum mass G B which can be braked by the joint operation of all the trailer brakes. U.K.
9.2.3. Forces U.K.
9.2.3.1. The threshold force K A shall not be less than 0,02 × g × G A nor greater than 0,04 × g × G A . U.K.
9.2.3.2. The maximum damping force D 1 shall not exceed 0,10 × g × G A in the case of trailers with rigid drawbars, nor 0,067 × g × G A in the case of multi-axled trailers with pivoted drawbars. U.K.
9.2.3.3. The maximum towing force D 2 shall be between 0,1 × g × G A and 0,5 × g × G A . U.K.
9.3. Test of braking efficiency U.K.
9.3.1. The sum of the braking forces exerted on the circumference of the trailer wheels shall be at least B* = 0,5 × g × G A including a rolling resistance of 0,01 × g × G A . This represents a braking force of B = 0,49 × g × G A . In this case, the maximum permitted thrust on the coupling is: U.K.
D*
=
0,067 × g × G A in the case of multi-axled trailers with pivoting drawbars, and
D*
=
0,10 × g × G A in the case of trailers with rigid drawbars.
In order to check whether these conditions are observed, the following inequalities shall be applied:
9.3.1.1. In the case of inertia braking systems with mechanical transmission U.K.
9.3.1.2. In the case of inertia braking systems with hydraulic transmission U.K.
9.4. Control travel test U.K.
9.4.1. In the case of control devices for multi-axle trailers with pivoted drawbars, of which the brake rod system is dependent upon the position of the towing device, the travel of the control s shall be greater than the effective travel of the control s′; the difference in length shall be at least equivalent to the loss of travel s o . The travel s o shall not exceed 10 % of the effective travel s′. U.K.
9.4.2. The effective travel of the control s′ shall be determined in the following way: U.K.
9.4.2.1. If the brake rod system is affected by the relative position of the towing device, then U.K.
9.4.2.2. If there is no loss of travel, then U.K.
9.4.2.3. In the case of hydraulic braking systems U.K.
9.4.3. The following inequalities shall be applied in order to check whether the travel of the control is adequate: U.K.
9.4.3.1. In the case of inertia braking systems with mechanical transmission: U.K.
9.4.3.2. In the case of inertia braking systems with hydraulic transmission: U.K.
9.5. Additional tests U.K.
9.5.1. In the case of inertia braking systems with mechanical transmission, a check shall be made as to whether the rod system by which the forces are transmitted from the control device is correctly fitted. U.K.
9.5.2. In the case of inertia braking systems with hydraulic transmission, a check shall be made as to whether the travel of the master cylinder actuator reaches a minimum level of s/i h . U.K.
A lower level shall not be permitted.