Utility network structures (electricity, gas, telecommunications, water, etc.) are an important part of the economic health of a country. City developments are integrating multiple communication technologies (ICT) and Internet of things (IoT) to manage their assets.
Smart Cities are growing at a blistering pace, relying on larger and more complex networks of utilities to help stimulate their rapid growth. At the same time, aging cities struggle to maintain existing infrastructure, or find space for new installations.
To keep vital services operating, repair and modernisation programs need to undertake vast amounts of street works, and excavate holes to reach the buried utilities. Undertaking any excavation will inevitably bring site workers in close proximity to underground utilities. Consideration should be given to knowing the exact location of all buried utilities before and during any excavation process.
Safe working practices
Over half of all utility strikes are to electrical cables, with a majority caused by mini diggers, air powered tools and metal hand tools. A large number of utility strikes occur when teams do not follow safe working practices, nor consult with utility plans or even use associated detection equipment.
To improve the quality of utility data and reduce the risk of a utility strike, a number of government standards have been developed:
- Desktop utility records to collate existing utility records
- Site reconnaissance to validate existing records
- Geophysical survey to detect underground utilities
- Verify the location of utilities during excavation
Utility strikes are caused by failing to undertake one or more of these steps.
To avoid this from happening we encourage you to follow these 5 recommendations:
- Undertake a desktop survey
To avoid striking buried utilities, all excavation teams need to undertake a desktop survey collating existing records provided by owners and operators on the utilities. However, you should never rely on utility plans as the only source of information. Always conduct a geophysical site survey to verify the records.
2. Perform a site reconnaissance
A physical site reconnaissance should be undertaken to check the utility records and assess if there are any inconsistencies or conflicts.
3. Do a geophysical survey
Prior to excavation, a geophysical survey should be commissioned to detect, identify and verify the location of all utilities.
A common technique for searching utilities is the utilization of an Eletro Magnetic Locator (EML). Utilizing an EML or cable locator (Leica Digicat 550i), a surveyor can detect and trace the utility using the magnetic fields. This is called passive locating.
Locating electrical cables using a cable locator on its own will only allow the operator to detect utilities with live current. To detect all services, a signal transmitter (Leica Digitex t100) should be operated with the locator. This small portable unit induces a specific artificial signal to a cable or pipe, which can be traced by the cable locator. This is called active locating.
By undertaking this second process, a majority of buried utilities can be located, reducing utility strikes by 45%.
4. Verify the location of buried utilities
When undertaking an excavation, buried utilities may pass along or through the working site. When a utility is located within the excavation area, trial holes could be dug, carefully exposing and clearly making its position.
Commonly, only cable locators are issued to field crews, with signal transmitters being classed as an extra piece of equipment, often left in the back of vans and not used.
Technology built within the Leica Digicat 750i cable locators, can record and log the instruments activity. The instrument records the signal transmitter during the survey. Data can then be analysed through the Leica LOGiCAT VU management software to determine if the best practice has been followed or to evaluate staff training requirements.
5. Train your crew
Lack of training provides an added high risk to excavation teams. A high number of utility strikes are caused by operators who have not received adequate training.
At Leica Geosystems we take training very seriously and we undertake a range of training programs teaching operatives the correct methods to locate underground utilities.
To learn more about utility strikes download our White Paper “Why do utility strikes occur?”
Written by Anabela Ferreira Fernandes