ISO 3450:2011 pdf free download – Earth-moving machinery – Wheeled or high-speed rubber-tracked machines – Performance requirements and test procedures for brake systems.
The instructions are to include a notice to the user that the machine is to be immediately taken out of service until corrected if the service, secondary or parking brakes do not operate within specifications or performance requirements as defined by the daily brake check method, in-service, periodic or post-maintenance brake verification.
Instructions for the periodic verification of braking systems may give test conditions different than those prescribed in this International Standard in order to permit testing or other verification by the user.
4.12.3 Additional instructions for machines designed to tow trailers
If applicable, information on the machine’s allowable trailer towing capacity shall be provided in machine manuals or labels along with any other applicable trailer towing instructions or precautions by the earth-moving machinery manufacturer. The information, if provided, should include the maximum un-braked trailer towing load and the maximum combination of payload and towing load for the earth-moving machinery.
4.13 Estimating brake slope capability
The estimated brake slope capability defines the ability of a braking system to stop and hold a machine on a slope. Other factors, such as ground conditions, side-slopes, speed, payload retention or the need to maintain the machine within the earth-moving machinery manufacturer’s specifications can limit the machine’s operating slope capability to slopes less steep than those where the brakes are actually able to stop and hold the machine.
Annex B gives one method for estimating brake slope capability.
5 Test conditions
5.1 Overall test parameters
The manufacturer’s operational precautions shall be observed when carrying out the performance tests. All machine parameters related to braking systems shall be within the machine manufacturer’s specifications, including tyre size and pressure, brake adjustment, warning actuation points and braking system pressures, which shall be within the machine manufacturer’s specification range. No manual adjustment, such as readjustment to prevent diminished or improved braking performance, shall be made to the braking system during any single performance test.
The instruments used to carry out the measurements shall be of an accuracy and be measured in units in accordance with ISO 9248.
The performance requirements given in Tables 2 and 3 shall be achieved from single-stop and hold testing at the service limit condition for the braking systems. These requirements shall be validated by physical testing or alternative means, including calculation and extrapolation from physical test data. The validation means shall be recorded in the test report in accordance with Clause 7.
See 6.4.3 and 6.6 for alternative braking system performance test methods.
NOTE Hydrostatic brake systems typically are not materially affected by brake wear limits.
5.2 General test conditions
When the machine transmission provides a selection of gear ratios, the stopping tests shall be conducted with the transmission in the gear corresponding to the test speed specified. The power train may be disengaged prior to completing the stop.
Retarders shall not be used during the service brake performance tests, but may be used during the secondary brake performance test. A hydrostatic or similar propel drive system is not considered to be a retarder.
Machines with operator-selectable, multiple-drive axles shall be brake-performance tested with the non-braked selectable axle(s) disengaged.