Excavation work generally means work involving the removal of soil or rock from a workplace using tools, machinery or explosives to form a tunnel, an open face, hole, trench or cavity. A person conducting a business or undertaking (PCBU) must manage risks associated with all kinds of excavations (no matter how deep) at the workplace.
A PCBU must manage risks to health and safety associated with a person including a member of the public from:
- falling into an excavation
- being trapped by the collapse of an excavation
- being struck by a falling thing while working in an excavation
- being exposed to an airborne contaminant or a gas while working in an excavation.
A PCBU must also have regard to all relevant matters, including the following:
- the nature of the excavation
- the nature of the excavation work, including the range of possible methods, tools and plant for carrying out the work
- the means of entry into and exit from the excavation.
Any construction work involving an excavation that is carried out in or near a shaft or trench with an excavated depth of greater than 1.5 metres, or a tunnel, is considered to be 'high risk construction work' and a Safe Work Method Statement (SWMS) must be authorised before carrying out the work.
For more information on managing risks associated with excavation work refer to the Excavation work - Code of Practice.
A high risk construction work SWMS is a document that is prepared in consultation with the relevant persons and must account for the workplace-specific circumstances that may affect the way in which the high risk construction work is done. A SWMS must:
- identify the high risk construction work
- specify all hazards relating to the work to be done and risks to health and safety associated with those hazards
- describe how the control measures are to be implemented, monitored and reviewed
- take into account all relevant matters, including circumstances at the workplace that may affect the way in which the work is carried out
- take into account the Work Health and Safety Management Plan that has been prepared for the workplace, if the work is carried out in connection with a construction project.
For more information about Safe Work Method Statements refer to the Excavation work - Code of Practice.
A PCBU who proposes to excavate a trench at least 1.5 metres deep must ensure, so far as is reasonably practicable, that the work area is secured from unauthorised access, including inadvertent entry by members of the public, having regard to risks to health and safety arising from unauthorised access and the likelihood of unauthorised access occurring to the work area.
The PCBU must also minimise the risk to any person arising from the collapse of the trench by ensuring that all sides of the trench are adequately supported at all times by doing one or more of the following:
- shoring by shielding or other comparable means
- receiving written advice from a geotechnical engineer that all sides of the trench are safe from collapse. The advice may be subject to a condition that specified natural occurrences may create a risk of collapse and must state the period of time to which the advice applies.
A PCBU who has management or control of a workplace where excavation work is being carried out must take all reasonable steps to obtain current underground essential services information relating to the part of the workplace where the excavation work is being carried out, and areas adjacent to it, before directing or allowing the excavation to commence. This information must be provided to any person engaged to carry out excavation work.
'Underground essential services information' means the following information about underground essential services that may be affected by the excavation:
- the essential services that may be affected
- the location, including the depth, of any pipes, cables or other plant associated with the affected essential services
- any conditions on the proposed excavation work.
Dial Before You Dig is the national referral service for information on underground infrastructure. It puts those who intend to excavate in touch with underground asset owners who are members of the Dial Before You Dig service.
The asset owners respond by providing information (generally plans) on the location of any underground pipes and cables, along with information on how to work safely and carefully while excavating in the vicinity of underground plant.
You can lodge your free Dial Before You Dig enquiry online at www.1100.com.au or by telephone through the national call centre on 1100.