Innovative solution efficiently captures accurate underground utility as-builts during construction

Most of underground utility damage during construction is attributable to incomplete, inaccurate and out of date records and network documentation. This data is the result of an inefficient, error-prone, and paper-based information flow from engineering, through construction crews, and resulting in “as-builts” of uncertain quality which eventually form the utility’s repository of record, typically in a GIS. Recently a mobile solution has been developed that ensures that centimetre-level accurate as-builts are efficiently captured in the field in real-time. By digitalizing and automating the collection and validation of all construction data, accurate and up-to-date as-builts become the new normal. Already used by over half of the 20 largest energy companies in the US, the Locusview system is being extended to support natural gas utilities, electric power utilities and telecom.

Background

Without accurate maps of underground infrastructure, every construction project has the potential to become an expensive disaster site. In the U.S. there are between 400,000 and 800,000 incidents of underground utility damage every year. Every year there are injuries and fatalities attributable to underground utility damage during construction. According to the Federal Highway Administration (FHWA) missing or inaccurate location information about underground utilities is a major source of highway construction project delays. The drag on the U.S. economy resulting from underground utility damage is estimated to be at least $50 billion annually.

Inefficient, error prone construction information flow

90% of underground utility damage during construction is attributable to incomplete, inaccurate and out of date records maintained by utilities and telecoms as well as data format issues including paper and digital ink (pdf). The reason for unreliable records of network infrastructure can be found in an information flow that is found at every utility and telecom.

The design-build-maintain information flow begins with an engineer and drafter producing a design, typically a CAD drawing, which is printed for construction contractors to use in the field in installing new underground network infrastructure. Typically the design is based solely on above-ground surveys because information about existing underground infrastructure is unreliable or missing. The construction contractor may attempt to follow the paper design drawing, but for a variety of reasons what actually ends up in the ground differs from what was designed. The design drawing, nominally an “as-built” but typically an “as-designed”, is then returned to the records management/network documentation group who enter it into the utility’s GIS where it forms the permanent record of the utility or telecom’s network infrastructure. This process is slow and error-prone and backlogs of as-builts waiting to be entered into the GIS stretch into months. The result is that utility and telecom GIS data is often inaccurate, out-of-date and incomplete.

Accurate as-builts are becoming mandatory

To address the problem of unreliable as-builts and the associated human and economic consequences several governments have enacted legislation and regulations requiring the submission of accurate as-builts. Montana has recently revised its statutes governing the installation of utilities on state highway right-of-ways. An updated Administrative Rule mandates that as part of a new permitting process accurate electronic as-builts must be submitted to the Montana Department of Transportation (MDT) upon completion of construction. To ensure accuracy the regulations require that the as-builts be stamped by a licensed professional engineer (PE) or professional land surveyor (PLS).

In 2017 the Singapore Land Authority (SLA) released a standard and specifications for the procedure and practice of utility surveying in Singapore. The standard specifies that after installing utilities and prior to filling the trenches an as-built survey must be performed by a registered surveyor to capture the location of the utilities with horizontal accuracy of ±100mm and vertical accuracy of ±100mm. In addition the standard specifically identifies the survey equipment to be used; total station, GNSS Real Time Kinematic (RTK), or 3D laser scanning. This standard is not mandated, but provides a baseline to be incorporated in all government construction contracts.

In response to the requirement for accurate as-builts, the challenge for contractors is to capture accurate as-builts without adding to field crew workload and without impact to project schedules.

Digitalizing the construction information flow

Locusview was founded in 2014 as a spin-out of the US Gas Technology Institute (GTI) with industry funding to develop next-generation digital construction technology for the energy and telecom industry

Locusview has adopted a paperless, digital approach based on a mobile app that makes field crews the nexus for efficiently capturing accurate as-built information. The user-friendly mobile application makes it easy and even attractive for crews in the field to move from a manual, paper-based process to one in which all construction data is digitally captured and validated in real-time during construction. In addition to ensuring that as-builts accurately represent what was actually built in the field, this approach reduces time and costs in field data collection, reduces the time required to prepare as-builts for submission, and ensures that data gets into the GIS faster.

During construction field crews use the Locusview Mobile app with high accuracy GPS and barcode scanners to capture as-builts, track material usage, capture photos and support other field operations such as joints, splices and welds. But the app doesn’t just capture the asset information, it also validates that the information is complete and accurate according to the company’s data requirements and construction standards. Locusview captures material data faster and more accurately with automated feature creation and attribute generation using barcode scanning. In the case of gas utilities information on all welds and joints needs to be recorded because if done incorrectly welds and joints can lead to leaks and other problems. Locusview helps ensure that these processes are carried out correctly by capturing real-time pictures and by validating welder qualifications (OQ).

High accuracy GPS is implemented in several ways. RTK base stations can be used for real-time high accuracy GPS. In GPS denied areas a laser range finder can be deployed. Alternatively control points can be used to ensure accurate georeferencing.

Back in the office the Locusview Web application enables visibility into the real-time status of projects, making it easier to assess progress and to project revenue streams. It also provides for data validation with automated warnings and notifications of violations; review and approve pre-configured check lists; exporting data to GIS, ERP and asset management applications; reports generation and project closeout.

Benefits

There are several critically important benefits that Locusview provides. Most critically it provides for real-time reality capture, ensuring construction quality by enabling survey-grade accurate location, attributes and material data to be recorded by construction crews as new infrastructure is installed. This ensures that as-builts are accurate and material usage is verified and traceable. It reduces the time to prepare as-builts for submission and speeds up the process of getting the as-built information into the utility’s GIS by up to 70%, which is also crucial for emergency repairs. Having full visibility over the project’s status information in real-time using Locusview’s web tool makes it easier to track project progress and to project revenue streams. The field visibility also enables supervising the work remotely, which is helpful during Covid-19 times. In addition, time and costs are reduced for capturing and managing construction data by eliminating manual paper-based processes.

Just as importantly Locusview ensures that field construction information is captured efficiently. Maintaining a survey team on site to survey newly installed pipes and cables can be prohibitively expensive especially for smaller projects. In actual projects it has been found that Locusview can reduce surveying costs by 50%.

In summary, utilities and telecoms use the technology to build a high-quality digital twin, to support asset management strategies and to ensure regulatory compliance.

Electric power case study

VPI, a Charge company, specializes in the construction of utility-grade electric power distribution infrastructure. During a recent major project involving 35,000 feet of open trenches and 35 construction sites for a large electric power utility in California the as-built requirements changed for both above and below-ground distribution infrastructure. Among the new requirements: as-built locations had to be accurate to ± 0.2 feet (± 6 cm). One of VPI’s major concerns was the cost of keeping a professional survey crew on-site at all times to capture the location of infrastructure to survey accuracy.

VPI looked for an alternative that would lower costs and provide the flexibility of not having to coordinate with outside survey crews. VPI’s main concerns were how to efficiently meet the high accuracy requirements, how to optimize the training and education of field staff, and avoiding adding to the work load of their field crews.

Locusview implemented their solution for VPI to meet the new high-accuracy GPS as-builting requirement that included the mobile app, web app and additional RTK base station coverage. The mobile app was found to be easy-to-use after only four hours of training for field crews. Most importantly using the mobile app instead of a traditional survey crew did not add to field crew workload and was able to be implemented without impact to schedule. Remarkably for this type of project the process only required 10 days from first contact to beginning data collection.

It enabled 16,362 feet of linear electric power assets to be mapped with a median accuracy ± 0.14 feet (4 cm). Nearly 5,000 photos were captured for future reference. With the web application crew foremen were able to monitor construction progress in real-time to ensure data collection was complete and met their requirements before back filling trenches. Avoiding the need to coordinate with outside survey crews resulted in a time savings of ~20% in project management for closeouts and reduced time in the field. Overall VPI realized cost savings of ~50% from reduced man-hours.

Conclusion

This remarkable application provides a solution to the decade-old challenge of efficiently capturing high accuracy as-builts in real-time and eliminating the problem of as-built backlogs. Gas is the most dangerous underground utility and it is not surprising that the development of the Locusview solution was fostered and heavily adopted by the gas distribution industry. Jurisdictions are beginning to require high accuracy as-builts from energy companies, electric power utilities, water utilities and telecom as a basis for a digital twin. To capture accurate as-builts efficiently is the challenge that Locusview addresses. The VPI case study shows that Locusview is able to provide efficient solutions for capturing accurate as-builts without adding to field crew workload and without impact to project schedules. This solution offers important benefits for any field constructed linear asset.

This information was first published on https://geospatial.blogs.com/geospatial/2020/08/innovative-solution-efficiently-captures-accurate-underground-utility-as-builts-during-construction.html