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 PCBU must manage risks associated with all kinds of excavations (no matter how deep) at the workplace.
PCBUs, employers and workers are to refer to the Excavation work - Code of Practice.
You 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.
You 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.
High risk construction work
Excavations are considered as high risk construction work when work is:
- carried out in or near a shaft or trench with an excavated depth of greater than 1.5 metres
- a tunnel
- near underground services
- undertaken near mobile powered plant.
A Safe Work Method Statement (SWMS) must be authorised before carrying out high risk construction work.
Underground essential services
A PCBU 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 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
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.
Any trench of at least 1.5 metres deep must be, so far as is reasonably practicable, secured from unauthorised access, including inadvertent entry by members of the public. This is to minimise the 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.