Mobile crane wire hoist rope failure
In May 2022, a worker suffered facial injuries when a steel beam fell from a mini-crawler crane at a construction site.
Early investigations indicate the mini-crawler crane was lifting the beams while the worker was using a tag line when the crane’s wire rope failed.
As a result, the steel beam fell approximately 5m hitting several precast props before striking the man’s face.
Investigations are continuing.
These findings are not yet confirmed, and investigations are continuing into the exact cause.
Cranes and mechanical lifting gear are used to handle heavy loads and, as such, create the potential for serious injury or death.
Lifting of loads may present a risk to the health and safety of people near the mobile crane from:
- damaged lifting gear
- mechanical or structural failure of the crane
- crane instability from overload or soft ground
- unsecured and dropped loads (falling objects).
Ways to manage health and safety
Taking steps to manage risks is a condition of doing business in Queensland. Effective risk management starts with a commitment to health and safety from those who manage the business. If an incident occurs, you'll need to show the regulator that you’ve used an effective risk management process. This responsibility is covered by your primary duty of care in the Work Health and Safety Act 2011.
Use the hierarchy of controls to help decide how to eliminate and reduce risks in your place of work. The hierarchy of controls ranks types of control methods from the highest level of protection and reliability to the lowest. It’s a step-by-step approach to eliminating or reducing risks. You must work through the hierarchy of controls when managing risks, with the aim of eliminating the hazard, which is the most effective control.
Possible control measures to prevent similar incidents
A principal contractor has a duty to ensure the overall coordination of the lifting operations at a workplace where construction is being performed. This includes ensuring systems are in place for communication between all PCBUs and workers at the workplace.
Failure to carry out appropriate planned inspections and preventative maintenance programs may lead to structural or mechanical failure and collapse of a mobile crane. The Work Health and Safety Act 2011 includes duties for persons conducting a business or undertaking, owners and suppliers of plant.
A crane owner’s responsibilities include, but are not limited to ensuring:
- there’s a thorough equipment maintenance and inspection program
- equipment is maintained and inspected is in accordance with the crane manufacturer’s requirements and the requirements of the Mobile Crane Code of Practice 2006 (PDF, 1.34 MB) and other relevant technical standards
- that only people with the appropriate mobile crane licence class operate the mobile crane (additionally, the crane owner who employs crane operators should also ensure the operators have undergone familiarisation and refresher training as required under the requirements of the Mobile Crane Code of Practice 2006 (PDF, 1.34 MB).
Planning and coordinating mobile crane operations
Planning for mobile crane operations should start as early as possible. This involves:
- consultation with people engaged such as the principal contractor or crane hirer, crane supplier, engineer and crane operator
- ensuring the type and number of mobile cranes selected suit the particulars of the lift
- determining the size of the crane crew via a risk assessment and implementing appropriate controls, especially in relation to minimising the risk of collision between the crane and other plant, and loads contacting other structures, overhead powerlines or workers
- not siting a mobile crane until carefully considering if it:
- has adequate capacity to lift the load at the maximum radius
- could collide with other plant and structures at the workplace.
- using a reliable method of signalling between the crane operator and dogger
- using documented lifting procedures to help to define responsibilities and approach the crane lift in a logical, systematic way (Safe work method statements must be prepared for a range of high risk construction work associated with cranes)
- implementing effective exclusion zones around mobile cranes 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 if it requires closure of a public footpath or roadway, approval must be obtained from the relevant authority).
Inspecting and maintenance
Routine inspection and maintenance should be carried out in accordance with the crane manufacturer’s instructions. These inspections may consist of a program of weekly, monthly and quarterly inspections, and should include:
- all functions and their controls for speed, smoothness of operation and limits of motion
- all emergency and safety switches and interlocks, including limiting and indicating devices
- lubrication of all moving parts
- inspection of filter elements and fluid levels
- visual inspection and measurements as necessary of structural members and other critical components such as brakes, gears, fasteners, pins, shafts, wire ropes, sheaves, locking devices and electrical contactors
- signage, including warning signs and control markings
- wear on wheels
- additional items nominated in the crane manufacturer’s instructions
- ensuring lifting hooks have operable safety latches.
All replacement parts should be identical or equivalent to the original parts or components. A written report should be supplied upon completion of the inspection. Inspecting and testing of mobile cranes should also include annual inspections and 10-year major inspections.
Steel wire ropes
All hoist, luff, pendant, trolley and counterweight ropes must be inspected for wear to ensure they do not exceed the discard criteria specified in AS 2759: Steel wire rope – Use application and maintenance.
If the competent person considers a wire rope requires replacing within the next three months, the rope should be replaced with one that passes the inspection criteria of AS 2759: Steel wire rope – Use, application and maintenance. Ropes must only be replaced with the type of rope specified by the crane manufacturer unless a professional engineer specifies otherwise and can fully justify the use of an alternative rope specification.
All rope sheaves must be removed and inspected for cracking, alignment and damage. The sheave groove size must be checked and the sheave replaced if it is outside of the manufacturer’s specification. Bearings must be replaced if necessary. Synthetic sheaves should be replaced if recommended to do so by the sheave manufacturer.
Crane motion limits
The crane is to be fitted with motion limiting devices on crane functions where damage to, or failure of, the crane could occur. The device that prevents the hook block from contacting the boom head (“anti-two block”) is to be of the type that stops operation of the hoist, luff and telescope functions of the crane before contact with the boom head (i.e. two blocking) occurs. Anti-two block switches, which provide a visual and/or audible warning only, are unacceptable and should be replaced as soon as possible with motion cut devices.
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 for the type of crane being operated, and completed refresher training as required
- know any workplace conditions that may affect crane operation, including ground conditions, the presence of overhead powerlines, nearby structures, cranes and concrete placement boom
- 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 functional test before the commencement of each work shift, including inspecting and testing the following:
- all relevant items indicated in the operations manual
- operating and emergency controls
- safety switches and interlocks, including motion limiting and indicating devices
- visual inspection of the structure
- wire ropes to ensure they are sitting correctly on the drum and correctly reeved on the sheave.
The results of the inspection must be entered into a logbook and kept with the crane.
A reliable method of signalling between the crane operator and dogger and any other assisting workers is essential for safe crane operation. Failure to implement a reliable method of communication may lead to unsafe crane operation resulting in dropped loads or collisions.
You must minimise any remaining risk with suitable personal protective equipment. For example: hard hats, protective footwear, eye protection, safety vest.
The control measures put in place should be reviewed regularly to make sure they work as planned.
- Mobile crane code of practice 2006 (PDF, 1.34 MB)
- How to manage work health and safety risks code of practice 2021 (PDF, 0.65 MB)
- Guidance - Cranes
- Safety Alert - Tower crane hoist rope and brake failures
- Safety Alert - Crane rope sheave failures
- AS 2759: Steel wire rope – Use application and maintenance
Support for people affected by a serious workplace incident
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