Serious injuries: overhead travelling cranes

Possible control measures to prevent similar incidents

The Work Health and Safety Act 2011 includes duties for persons conducting a business or undertaking (PCBU), owners and suppliers of plant. In addition, the Work Health and Safety Regulation 2011 includes specific duties for a PCBU with management or control of plant, including plant that lifts or suspends loads.

Planning and coordinating crane operations

Planning for bridge and gantry crane operations should start as early as possible. This includes but is not limited to:

• consultation with everyone engaged in the work within the working area of the crane
• implementing effective exclusion zones around the crane and adjoining areas to prevent people from entering the area (the size of the exclusion zone should be based on a written risk assessment) and ensuring those involved in the lift do not get under a suspended or partially lifted load.

High-risk work licensing

A CB class high-risk work licence includes bridge and gantry cranes that are controlled from a permanent cabin or control station on the crane or remotely controlled with more than three powered operations. Powered operations include:

• north/south
• east/west
• up/down
• rotating attachment.

The CB high-risk work licence includes the application of load estimation and slinging techniques to move a load. In most situations, a dogging (DG) high-risk work licence will be required for persons who select lifting slings and sling the load. A worker with a CB high risk work licence can carry out limited slinging of loads without holding a DG high-risk work licence.

Crane operator

Bridge and gantry crane operators must have a comprehensive knowledge of the operating capabilities of the crane and be competent to carry out the lifting operation. It is a must for crane operators to:

• know the particular model of crane to be operated, its characteristics, functions and limitations
• know the information in the crane’s operating manual
• ensure loads are evenly balanced and well secured
• hold the appropriate high risk work licence (if applicable) for the type of crane being operated, and complete refresher training as required
• know proper inspection and maintenance procedures to be followed in accordance with the guidelines of the manufacturer and owner
• complete a pre-operational visual inspection and operational check of the crane’s structure and components before each work shift, including inspecting and testing:
  • all relevant items indicated in the operations manual
  • operating and emergency controls
  • brakes.

Lifting materials

Crane-lifted loads should be slung and secured so the load (or any part of it) cannot fall. To ensure the safe lifting of loads:

• General lifting:
  • use lifting hooks with operable safety latches.
  • strap bundled loads (e.g. joists, purlins, scaffold tubes, reinforcement steel) together before lifting.
  • use tag lines required to control loads.
  • only use basket hitches where there is no risk of people being struck if the basket hitch inadvertently comes off the load (otherwise the lifting sling should be wrapped and choked around the lifted load).
• Maintaining the integrity of lifting gear by checking:
  • the lifting gear is tagged and all relevant information listed (e.g. relevant information for a chain sling includes grade of chain, WLL, manufacturer, chain size and Australian Standard marking)
  • lifting hooks are provided with operable safety latches
  • permanently fixed shackles are prevented from unscrewing
  • lifting slings are not damaged (e.g. excessive wear, damaged strands, cracks, deformation or severe corrosion)
  • the sling is appropriate for loads being lifted, including adequate capacity and protection from sharp edges.

The crane operator should ensure the load is always under control when lowering loads, or when the load is suspended. Except in an emergency, the crane operator should not leave the cabin or control station on the crane or the remote control while a load is suspended from the crane.

Crane controls

Crane controls should:

• have fail-safe control buttons (e.g. constant pressure type)
• have function buttons appropriately labelled
• be fitted with a manually reset emergency stop button.

Source: Bridge and Gantry Cranes Information Sheet - Safe Work Australia

Safety devices

Safety devices that can be fitted to bridge and gantry cranes include:

• audible alarms and flashing lights that warn when the crane is moving
• anti-collision devices to prevent:
  • a bridge or gantry crane colliding with the end of the runway
  • two or more bridge or gantry cranes that operate on the same runway from colliding with each other.
• deceleration devices to slow the bridge or gantry crane down—regardless of what control is being pressed when a travelling crane is approaching the end of the runway—to prevent end stop collision or over run (e.g. limit switches and two-stage decelerators)
• load-limiting and movement controlling devices to assess the load and prevent lifting should the rating capacity of the crane be exceeded
• upper and lower limit devices to prevent the hoist from winding the hook into the hoist drum or winding the hoist rope off the hoist drum
• anti-fall devices, such as anti-drop plates, to prevent any part of the structure falling if a travel-wheel fails.

Source: Bridge and Gantry Cranes Information Sheet - Safe Work Australia

Inspection and maintenance

Routine inspection and maintenance should be carried out in accordance with the manufacturer’s instructions. Bridge crane inspection and testing must include:

• a major inspection
• regular inspection and testing required for the crane
• inspection and testing for plant item re-registration.

Source: Bridge and Gantry Cranes Information Sheet - Safe Work Australia

A written report should be supplied upon completion of the inspection.

Work sequence and crane tag out

Sometimes building maintenance requires mobile plant to be positioned in the path of a bridge or gantry crane. This can be especially hazardous when the mobile plant is operating at a height where the mobile plant could be struck by the crane structure (i.e. the bridge beam) such as the case for an EWP being used to change ceiling lights.

Wherever, the crane, hook or load could strike the mobile plant the safest alternative is to tag out and remove power from the crane until the maintenance activity is complete and the mobile plant has been removed from the crane’s travel path.

Storage of materials

The storage system should be properly designed by a competent person. Where there is any question about the stability of the stacked material, an assessment should be made by a suitably qualified professional engineer.

If materials of any type are to be stacked, the storage system should ensure:

• Adequate means of lateral restraint is provided to prevent individual items or the whole stack falling over. The lateral restraint method used needs to be able to withstand any inadvertent impact loads arising from handling of the stacked materials.
• The supporting surface is level and has adequate bearing capacity and:
  • stored materials and any packing cannot sink, irrespective of the effects of the weather
  • suitable packing material is used between stacked elements and on the ground to support the stack
  • any damaged packing material is discarded and replaced.
• Materials that are bent, damaged or geometrically incompatible for stacking are isolated and not stored in stacks.
• All items in the stack are within the dimensional tolerances specified by the manufacturer. Where this information is not readily available, a competent person such as a suitably qualified professional engineer, should be engaged.
• All vehicles and pedestrians, except those involved in stacking the materials, are excluded from the area.
• The storage system allows for foreseeable collision from vehicles or other mobile plant (e.g. trucks, forklifts or cranes), if applicable. This is particularly important when workers are working within the stacked area and where mobile plant regularly enters the area.

You must minimise any remaining risk with suitable personal protective equipment (PPE), such as hard hats, protective footwear, eye protection, safety vests. The control measures put in place should be reviewed regularly to make sure they work as planned.