One of the challenges in subsurface utility engineering (SUE) is a lack of reliable positional intelligence about underground assets. Where are they, and once located, what information do we have about them. Better positional intelligence leads to safer and more effective working practises which in turn improve the bottom line.
“Daylighting”, defined in CI/ASCE 38-02, is the highest level of accuracy, providing information on the vertical and horizontal positions of underground utilities and attributes such as type, size, condition and material.
Daylighting is an apt term as it implies bringing greater clarity to underground asset data. While we cannot physically raise assets above ground to bring them into the daylight we can take steps to ensure data is visible, accessible and current thus improving the positional intelligence available to us.
A life cycle approach to improving positional intelligence requires data from site plans and surveys (e.g. from CAD), on site (as built / as maintained) data, asset and maintenance management systems and Geographical Information Systems (GIS). A key dependency is asset location.
Locating Underground Assets
Missing or inaccurate location records result in issues such as increased service strikes; heightened risks to health and safety and increased works costs. The location of underground assets can be recorded using a single method or several to reflect the degree of accuracy required; level of risk; budget and time available. For example:-
- Passive Remote Frequency Identification (RFiD ) – with or without GPS
- Geo-tagged photographs
- Engineering survey methods such as GPR.
- Textual descriptions including attributes facilitating integration into other systems e.g. datum and node points and section details along a pipe.
PAS 128 “Specification for underground utility detection verification and location” references the potential use of RFiD for tagging underground assets. RFiD tags can cost effectively and accurately mark potential areas of failure such as joints or valves. Data associated with a tagged asset can be stored in the cloud. This is vital to ensure data is accessible; there’s little point in burying a tag and its vital asset information.
Accessibility is enhanced in an intuitive, visual context. For example, AltoSUE™ uses a geospatial cloud based database and maps and / or site survey plans provide locational context. Overlaying data on site plans is invaluable as the map detail may not be accurate nor up to date for construction use. An output from a PAS128 survey will be a CAD plan of the utility services. Making these plans available on mobile devices overlaid with tagged asset data as well as the ability to use background maps enhances on site working.
Integrating on site and cloud based technologies improves the efficiency of data recording and sharing. Collect using tablets or smartphones; upload to the cloud and make it available to on and offsite users immediately or with minimal delay.
The positional intelligence of underground assets is enhanced by enabling other records to be easily accessible on and offsite such as:
- project information
- engineering records
- health and safety
- risk assessments
- 3D data
3D models add value to the repository of underground asset data. However, treat these with caution as they often represent ‘as designed’ states; not the ‘as built’ nor later ‘as maintained’ states. The industry is still working towards practical and cost-effective solutions to the challenge of using 3D models with a variety of innovations under development and coming to the market. Keeping asset life cycle data current has always been a challenge and will become more so as Building Information Modelling (BIM) becomes widely adopted.
Better positional intelligence is fundamental to improving SUE. A holistic approach to managing underground assets requires a number of discrete but integrated processes:-
- Identification of underground asset location via RFiD, geo-tagging etc
- Capturing data on site
- Managing and facilitating access to it on and off site
- Supplementing on site data with other records e.g. site survey plans as well as maps and engineering data to aid with the quick and safe relocation of underground assets
- Integrating SUE data into corporate systems for asset and maintenance management purposes
Daylighting our SUE data provides a safer working environment for on site workers; less disruption and more efficient and profitable works activities.
The themes in this blog are explored in more detail in our white paper – “Daylighting Underground Assets’