Employees in the immediate vicinity of a raised concrete-placing boom are at risk of death or serious injury in the event of a structural or mechanical failure of the boom or stabilising outriggers.
Inadequate inspection and maintenance of critical components (such as the slew ring assembly, boom pins, bushes, welds, king post) increase the risk of catastrophic structural or mechanical failures.
Recommended ways to control risks
Employers must provide and maintain plant (concrete-placing booms) so that they are, so far as is reasonably practicable, safe and without risks to health.
To reduce the risk of structural or mechanical failure of concrete-placing booms, employers need to ensure:
- concrete-placing booms are subjected to appropriate inspection regimes such as pre-operational, routine and periodic inspections
- the concrete-placing boom manufacturers recommendations are adhered to
- the relevant Australian standard AS 2550.15:2019 'Cranes, hoists and winches – Safe use Part 15: Concrete placing equipment' is adhered to and
- issues or defects, identified during inspections, are addressed
Employers should keep a record of all details of persons engaged to undertake the work, including the competent person undertaking or supervising the assessment for continued safe operation, and any persons or contractors undertaking parts of the work.
Employers need to ensure that employees do not enter the area beneath a raised boom. Where line-hands cannot avoid working under a raised boom, the time spent under the raised boom can often be reduced by manoeuvring the hose from the side to avoid working directly under a raised boom.
Periodic inspections are part of the preventative maintenance program outlined in AS 2550.15:2019 and should be conducted in addition to other inspections (eg pre-operational and routine inspections). Periodic inspections of concrete-placing booms should only be undertaken by competent person(s).
The following factors need to be documented (including for example through the use of photos) by the competent person undertaking the periodic inspection:
- what components were looked at, including the critical components of the concrete-placing boom that were assessed
- what was looked for (eg wear, cracking, damage to components)
- the rejection and acceptance criteria
- how the inspection was conducted (eg by non-destructive testing (NDT), measurement, visual)
- what was found (e.g. measured value, no cracks detected)
- recommendations regarding the inspected component and
- actions that are being taken based on the recommendations
Inspecting critical components
Critical components, including structural welds, need to be inspected.
If a critical component cannot be adequately inspected or tested (for example, by NDT) due to other components or sections of the plant partly or fully obstructing the critical component, then the obstructing item(s) need to be removed to facilitate adequate inspection or testing.
If the competent person determines that removal of the obstructing component(s) to facilitate inspection is not required, the periodic inspection report needs to include identification of the components not inspected and the rationale for the decision. The rationale should include (but is not limited to) the following:
- the age of the concrete-placing boom
- hours of use of the boom
- design issues and
- absence of evident damage or condition which may indicate possible internal deterioration of the boom
The periodic inspection report should also include information regarding when the uninspected components are next scheduled for inspection.
If the competent person is not confident in stating that the concrete-placing boom is safe for continued operation without inspecting or testing certain components, then the concrete-placing boom should not be used and needs to be withdrawn from service.
Records of periodic inspections
All reports provided in regard to the inspection activity should be signed and authorised appropriately.
Inspection and maintenance records should:
- be in a format that allows a third party to readily access and review them
- give the reader a clear understanding of what has taken place in relation to the operation, inspection and maintenance activities and
- be kept for the life of the concrete-placing boom
WorkSafe expects records of all periodic inspections of concrete-placing booms, including documentation of the 'Assessment for continued safe use', to be available for inspection.
Under the Occupational Health and Safety Act 2004, employers must, so far as is reasonably practicable:
- provide and maintain a working environment that is safe and without risks to the health of employees and independent contractors
- provide and maintain plant so that they are safe and without risks to health
- eliminate risks to health and safety. Where the risk cannot be eliminated, it must be reduced so far as is reasonably practicable
- consult with employees and health and safety representatives when identifying or assessing hazards or risks and making decisions about risk control measures
Under the Occupational Health and Safety Regulations 2017, employers must:
- identify all hazards associated with the use of plant at the workplace, so far as is reasonably practicable
- control risks in accordance with the plant hierarchy of control, for further information on the plant hierarchy of control see the WorkSafe Plant Compliance Code
- ensure plant is inspected, to ensure that risks associated with its use are monitored
- keep record of any inspection and maintenance carried out on concrete-placing booms