Document ID: chunk:federal_register_of_legislation:F2007C00493:front:0:p15
Version: federal_register_of_legislation:F2007C00493
Segment Type: other
Provision Reference: 
Character Range: 42058–45250

Where the actuating force is dependent on the stroke, as in the case of spring brakes, the value of A used in the equation above must be that corresponding to the 'Brakes' actuator stroke achieved by the 'Emergency Brake System' This can be determined by plotting on a graph of 'Control Signal' versus stroke as detailed in clauses 19.2.2 and 19.2.3:
19.2.2.                          The input to the emergency brakes actuator in units of 'E' from the data provided for the 'Control System' at various strokes; and
19.2.3.                          The 'Foundation Brake' stroke achieved at various 'Control System' inputs.
19.3.                                The ratio of brake force to static 'Axle Load' at each 'Axle' must not exceed that specified in the data for the suspension as 'Approved' under the provision of clause 22.4.
20.                                      PARKING BRAKE CALCULATION
20.1.                                The gradient, expressed as a percentage, on which the 'Parking Brake System 38/...' can hold the trailer must be determined by computing the total braking force at the wheels (N) to which the 'Parking Brake System 38/...' is fitted and dividing by [98.1 x 'Aggregate Trailer Mass' (tonnes)]
20.2.
The braking force at each 'Axle' must be calculated according to
              where:
              F is the tangential force at the braked wheels on the 'Axle' concerned
              A is the input to the park brake actuator in units of 'E'
              T is the 'Brakes' output torque per 1.0 'E' for the 'Park Brake System'
              R is the rolling radius of the tyre fitted to the wheel.
20.3.                                The provisions of clause 19.2.1, 19.2.2 & 19.2.3. must apply.
20.4.                                When 'Emergency Brake System' performance data is used to demonstrate compliance of the 'Parking Brake System 38/...', the geometry of the 'Brakes' must be such that brake effectiveness will be not less in the reverse direction.
21.                                      TIME RESPONSE
21.1.1.                          The time response of a 'Service Brake System' may be taken as complying with the requirements of this rule if the 'Service Brake System' is installed in a manner identical to that prescribed in the documentation describing the 'Approved' 'Control System' used, except as allowed in clause 21.2.
21.2.                                Actuator volumes at full 'Foundation Brake' stroke and line lengths may be reduced (for actuation response test), and actuator volumes at the point when the 'Foundation Brake' friction materials cease to contact each other may be increased (for release response test) from those specified in the 'Approved' 'Control System' documentation, but other devices, fittings and dimensions may not be changed.
22.                                      SPECIFICATION OF BRAKE SYSTEM COMPONENTS
22.1.                                Sub-assemblies of 'Brake System' components may be 'Approved' by the 'Administrator' as part of the 'Brake System' approval process where information has been supplied in accordance with the requirements of the appropriate sub-paragraphs of clause 22.