Document ID: chunk:federal_register_of_legislation:F2006L03061:body:0:p18
Version: federal_register_of_legislation:F2006L03061
Segment Type: other
Provision Reference: 
Character Range: 49728–52726

storage reservoir and the control valve, initially drops to when the pressure in the least favoured brake actuator reaches 0.65 'E' (420 kPa).

38.3.11.3.5.          With an initial service brake application level of 1.0 'E' (650 kPa) the brake release time shall be taken from when the pressure level, measured between the control valve and the orifice, initially drops to when the pressure in the least favoured brake actuator reaches 0.05 'E' (35.0kPa).

38.3.11.3.6.          The brake control valve shall be of a configuration that permits energy to flow from the storage reservoir to the orifice (O) when in the "on" position and from the orifice to waste when in the "off" position. It shall not allow additional energy to flow into the test rig 'Control Line' by way of its own 'Control Signal'. The brake control valve control shall be designed so that the manner of its operation shall have no effect on the output response of the test rig. The brake control valve may be arranged to provide a modulated test rig output signal for other brake development purposes but which for the purpose of measuring trailer 'Brake System' response in accordance with clause 38.3.11.3 will be rendered inoperative.

38.4.                                Performance Calculation Requirements

38.4.1.                          Service Brake Effectiveness Calculation

38.4.1.1.                    Service Brake Effectiveness will be considered satisfactory if it complies with all the requirements of clause 38.4.1.

38.4.1.2.                    The distribution of braking effort amongst the 'Axles' in an 'Axle Group' shall be a value, or be in the range of values, referred to in clause 38.4.6.3.4 (suspension behaviour).

38.4.1.3.                    In the case of 'Dog Trailers' at least one front 'Axle' shall have a higher friction utilisation than that of at least one rear 'Axle' at decelerations greater than:

           (a)  0.3 g in the case of 2 'Axle' 'Dog Trailers',

           (b)  0.15 g in the case of 'Dog Trailers' with 3 or more 'Axles'.

38.4.1.3.1.              In the case of two-'Axle' 'Dog Trailers' the friction utilization factors may be calculated according to

         Friction Utilisation Factor =  Tangential Force at Wheel
             Dynamic Load at Wheel

so:

F  Friction utilization factor.

P1  front 'Axle' static load

P2  rear 'Axle' static load

P  total static 'Axle Load'

h  height of trailer and load centre of mass

L  'Wheel Base'

z  deceleration, as a proportion of acceleration due to gravity.

38.4.1.3.2.              No friction utilisation factor (F) shall exceed 0.7 at z = 0.45.

This is taken as to mean that wheel lock would have occurred in the physical test otherwise required by clause 38.3.3.2.2 (service brake effectiveness).

38.4.1.3.3.              For 'Dog Trailers' with more than two 'Axles' where it is not practical to calculate the friction utilization factors, a skid test on a loose surface at 'LTM' to