RISK – Service strike
Positive location is defined as verifying the precise horizontal and vertical location of services and utilities through the actual exposure at a specific point.
Exposure methods may include water jetting / excavation, vacuum excavation and using insulated hand tools.
Whilst there are other, less physical, methods of identifying the approximate location of services, such as electromagnetic cable locators and ground-penetrating radars, the actual exposure and visual confirmation of the precise depth and condition of the service is required for all services within 5m of the planned excavation.
Vacuum excavating at the QUU Project
Positive location involves potholing to a pre-determined depth to verify if assets exist in the immediate location. This may be conducted using water jetting, vacuum excavation or insulated hand digging tools suitable for the voltage concerned.
Potholing using high pressure water jetting
Concrete slabs may be protecting underground services. If an underground slab is found, extreme care must be taken to ensure the concrete is not broken. If an alternative route cannot be found, the utility owner must be contacted.
Where underground services may be impacted, the location of underground services must be physically marked (for example with signposts or spray paint) in a way that is conspicuous and not easily removed.
All drawings associated with the works should reflect the colour coding requirements. Underground essential services identified or exposed should be clearly marked using the same colour coding system
Underground service colour coding as per AS 1345.