This alert provides guidance to owners of hydraulic equipment, operators, and service technicians, as well as designers, manufacturers, suppliers and installers on the hazards and safe practices around the operation and maintenance of hydraulic equipment, or items of plant with a hydraulic system.

Detail of hydraulic bulldozer piston excavator arm

Background

Most persons conducting a business or undertaking (PCBUs) and workers involved with hydraulic circuits are conscious of the hazards surrounding high pressure hydraulics including whipping hoses and fluid injection. However, a number of recent incidents have been caused by less obvious hazards, such as inadequate fluid levels in the system, and unplanned movements of system components:

  • a worker conducting maintenance on a tip-tray truck   narrowly avoided serious injury when the hydraulic system failed lowering the tray unexpectedly
  • a worker was killed when the hydraulics failed to support the tailgate on a truck used to transport horses striking the worker
  • a worker was struck by a component of a brake press when the hydraulic system failed during operation

Key points

  • where practicable, all inspections and maintenance/servicing work should be conducted by a person competent in hydraulics systems and maintenance, including testing and commissioning
  • special care should be taken to ensure the appropriate hydraulic fluid is in use, as recommended by the manufacturer, to ensure the system functions within design parameters
  • maintenance and routine checks should be conducted to ensure adequate hydraulic fluid levels are maintained in the system. Manufacturer’s recommendations should be adhered to as excessive or inadequate fluid levels can cause system failure and present serious risk.
  • foreign particles and inadequate filtration can lead to stuck valves and unplanned movement of components connected to the hydraulic system, presenting serious risk to operator and employees working near the plant.
  • if provided, relief valves fitted to hydraulic systems should be checked by a competent person to ensure appropriate function, as determined by the manufacturer. Bypassing or altering the settings of a relief valve could be subject the hydraulic system to unplanned movements, or unexpected functions.
  • hydraulic system in use in close proximity to workers, operators or others should be conscious and familiar with the risks of high pressure injection (HPI). The use of guarding and hose sheathing should be considered where practicable.
  • most hydraulic fluids have the potential to ignite or sustain ignition sources and appropriate controls should be considered when the hydraulic system is designed, manufactured and serviced. Numerous incidents have occurred due to a leak in a hydraulic fluid circuit spraying on to an operating engine block.
  • while working in proximity to potentially dangerous components of machinery, personnel should not rely on hydraulic systems to maintain those components in a safe position. There should be positive protection from gravitational hazards.

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