Excavations and trenches
Before excavation work is carried out, the relevant person or principal contractor, for construction work, must:
- find out what underground services exist
- obtain relevant information about the service (location, type, depth, restrictions to be followed)
- record the information.
Dial 1100 Before You Dig is a useful service.
A relevant person must:
- consider the information
- follow any reasonable restrictions
- implement necessary control measures.
A relevant person is responsible for managing the risks associated with:
- an excavation collapsing
- objects falling into an excavation
- a person falling into an excavation
- substance exposure in an excavation, for example, carbon monoxide from plant.
A barricade or hoarding at least 900mm must be erected around an excavation unless it is not possible or no members of the public are likely to be in the area of the excavation.
A relevant person must implement any control measures necessary to prevent risk from the collapse of another structure such as an adjoining building or road.
Trenches
A barricade at least 900mm high must be erected around a trench that is 1 metre or more deep unless it is not possible or only workers involved with the trench will be in the area; or another form of barrier exists, for example, excavated materials near the trench.
Relevant people need to ensure that if a person is entering a trench more than 1.5 metres deep it is either:
- shored or shielded
- benched - not higher than it is wide and no vertical face exceeding 1.5 metres
- battered - angle not exceeding 45° and bottom vertical face not exceeding 1.5 metres
- approved in writing by an engineer as safe to work in.
Written approval to vary the benching and battering requirements may be obtained from an engineer. The approval must be kept on site at all times.
Ladders used for access must be no more than 9 metres apart in the area of the trench where work will be carried out.
Last updated March 17, 2006