Maintaining sufficient clearances when lifting or lowering the crane hook or load close to structures
Published: 16 August 2012
Last Updated: 16 August 2012
The purpose of this alert is to highlight the importance of maintaining sufficient clearances between cranes and other plant and structures to avoid contact or collision.
On 21 July 2012, a worker was seriously injured after being hit by a falling scaffolding component on a high-rise construction site. The incident occurred when a tower crane was hoisting up its lifting gear near scaffolding. As the tower crane equalising sheave was being hoisted, it appears the lifting gear may have snagged on the scaffolding, causing a scaffolding component to fall.
The siting of tower cranes should only occur after a competent person(s) in consultation with relevant stakeholders has carefully considered the work environment. Where cranes are required to operate near buildings or structures, crane loadings and access should be considered at the project design stage.
Factors to be considered include:
- personnel movement within the crane working area
- contact or collision between the crane with other plant and structures e.g. scaffold and other cranes.
When lifting or lowering the crane hook or load close to structures make sure that:
- the raise and lower speed is slow enough so that contact with a structure can be avoided
- the dogger has a clear view of the hook and load at all times.
- The number of people in the crane crew should be determined by a risk assessment and be appropriate to ensure the safe operation of the tower crane at the workplace. The size of the crane crew should especially be considered in relation to minimising the risk of collision between cranes and other plant, and loads contacting other structures, overhead powerlines and workers.
- The risk assessment should consider the size and complexity of the work to be undertaken when determining the number of operators and doggers to work together in a crew. The risk assessment should also consider the need for the appointment of a crane coordinator.
- Directions to a crane operator must only be provided by a licensed dogger.
- When the crane is being guided by a dogger in close proximity to other structures, including scaffolding, the dogger should ensure that other people are not exposed to risk of injury from contact or collision between the crane or its load with the structures.
- There must be a reliable method and system of communication between the crane operator and the doggers.
- A safe system of rules for communication should be developed and implemented, including:
- how people communicate over the radio (e.g. terms to use for consistency)
- that people are appropriately trained and examined in relation to their competency in the system
- that records are kept in relation to the system and training.
- When more than one dogger is involved in a lift, each dogger should understand when responsibility for their part of the lifting operation should be handed over to another dogger.
- Work should stop immediately if there is a loss of communication.
- Ensure sufficient clearance between tower cranes and scaffold to limit a risk of injury from a collision between the crane or its load. Contact or collision of the crane and scaffold can potentially affect worker safety and the safe use and structural integrity of scaffolding.
Operators of cranes and other plant are also reminded to maintain safe distances from overhead electric lines. For information about exclusion zones and safe working around these lines refer to the Electrical Safety Code of Practice 2010: Working Near Exposed Live Parts.
For more information, refer to the Tower Crane Code of Practice 2006, the Scaffolding Code of Practice 2009, and the Work Health and Safety, Consultation, Co-operation and Co-ordination Code of Practice 2011.
Visit www.worksafe.qld.gov.au or call the WHS Infoline on 1300 369 915.