Questar Gas Creates As-built Gas Delivery Maps With Improved Accuracy and Enterprise Integration

by Tren Giles, Questar Gas

For its entire 87-year history, Questar Gas has focused on building accurate, up-to-date asset maps to serve as the foundation to help ensure the safe and efficient delivery of natural gas. The Salt Lake City-based energy company invests significant resources into maintaining a digital GIS map database that surpasses industry standards and exceeds government regulations.

“Our philosophy with regards to assets has always been install it once, map it once, find it forever,” said Darrin Zesiger, project foreman-inspection for Questar Gas. “We always want to know where an asset is located.”

Questar has further enhanced its as-built mapping capabilities over the past two years by rolling out a GPS-based mobile-mapping and data-collection solution to all inspectors working on gas-delivery installations. The process of mapping and collecting details related to a gas main and service installs and then updating the enterprise GIS used to take as long as eight weeks. Now it takes about one day.

“As a result, our as-built data is more accurate and integrated with asset-management workflows,” said Zesiger, “and our inspectors have more time to spend on their primary duty, which is to make sure the installations are done safely and correctly.”

Traceable, Verifiable and Complete

Questar has pipeline assets in Utah, Wyoming and Idaho. Many of the company’s one million retail gas customers live and work in the rapidly growing Salt Lake City area. Since the rollout of the GPS as-built mapping solution, Questar’s 79 inspectors have mapped features and collected pipeline details for more than 53,000 new services and 8.85 million feet of gas main.

The gas utility worked closely with CartoPac International Inc., a provider of integrated mobile mapping and enterprise asset management technologies, to develop the solution. Based in Colorado, CartoPac began its relationship with Questar Gas designing a GPS technique to locate structures in the utility’s pipeline corridors. At the time, the utility’s operations department was also looking at GPS as a means of improving as-built mapping activities. CartoPac was asked to lend its expertise to that project as well.

The Salt Lake City-based energy company invests significant resources into maintaining a digital GIS map database that surpasses industry standards and exceeds government regulations.

“We offered a high-accuracy mobile mapping and inventory software that we were expanding to integrate with asset management,” said Glenn Vlass, CartoPac Vice President. “Map accuracy and workflow integration were exactly what Questar Gas was looking for so we partnered with them to build a solution that integrated with legacy systems and offered advance workflows.”

Vlass explained that utilities and other organizations with federally regulated infrastructure are now under increased pressure to go beyond simply knowing where all of their assets are located. The ongoing trend is for operators to ensure the installation, maintenance and repair of their distribution system is traceable, verifiable and complete.

To make lifecycle asset management possible, CartoPac upgraded its software to link the field mapping element directly to the GIS as well as back-office systems such as document management, work order management and contractor payment. With continuous input and feedback from Questar, CartoPac customized the GPS as-built mapping solution that gave personnel across the enterprise instant access to the location, status and history of newly installed assets through the GIS.

Accuracy is Key

As-built map accuracy and timeliness were Questar Gas’s primary concerns. The company’s pipeline inspectors traditionally collected gas mains and services as they were installed by contractors. Prior to the GPS-based solution, inspectors used measuring tape and paper to record the diameter and length of the pipes put in the ground. The tape was used to locate the pipe offsets relative to nearby physical features such as building foundations, fences and sidewalks. This information was hand-sketched on paper in the field.

“We would station the main and then measure offsets every 100 feet as tie points to physical features,” said Zesiger.

Next, the inspector returned to the service truck to access a computer and digitally re-draw the paper sketch into a simple mapping application. The data was later uploaded back to Questar Gas’s engineering department. There, GIS specialists recreated each service map with associated attributes into the enterprise GIS.

“It took an inspector 25-30 minutes to map each service install with the two-step process in the field,” said Zesiger, pointing out that it required more scheduling of inspectors to ensure correct installation practices. Under the best of circumstances, the accuracy of these maps was about one foot, but problems arose when the features used as tie points were altered. Moved fences and widened roadways introduced errors in the mapped locations of main and service pipes.

The other problem was timeliness, Zesiger explained, “During the busy construction season, replacements and large projects could take up to two months for the as-built information to get into the GIS.”

Until the data was officially added to the GIS several weeks later, Questar Gas was unable to provide line location information to other utilities working in the area or even residents planting trees around their new houses. Lack of timely as-built data in a widely accessible database contributed to tear outs, which are expensive and dangerous problems for everyone.

GPS As-built Mapping

The Questar Gas GPS as-built mapping system is developed on the CartoPac Technology Platform. After evaluating several mobile hardware options, the utility opted to standardize on integrated GPS data collection equipment from Trimble Navigation, currently the Trimble Geo Explorer 6000 and Geo 7X handhelds. Each is linked to an external antenna for higher accuracy GPS signal acquisition around buildings, and a laser range finder for measuring distances in difficult-to-access places.

“During the implementation of the system we decided to coincide its rollout with initiation of company-wide standards for data collection,” said Zesiger. “We bring our inspectors in for a week of training and education on our efforts to standardize asset inventories across the organization to ensure everyone maps assets in the exact same way.”

A typical gas service installation occurs in a subdivision that is still under construction and begins with a call to Questar Gas’ pre-construction representative from the general contractor. A preconstruction representative enters the details into a custom-built work order management system called the HUB where it is routed to engineering for initial design approval. Utility engineers determine the size and location of gas mains and services that will run through the new neighborhoods and to individual houses. Technicians enter the mains and services into the GIS as proposed lines so that they are visible prior to and during construction. They design redlines in ESRI ArcGIS software.

“The installation contractors and our inspectors are assigned to zones within our service territory,” said Zesiger. “Once redlines are completed, the work order management system releases the information to the appropriate contractors and inspectors.”

Using the proposed redline as a guide, the contractor’s job is to install gas mains in the new subdivisions and then run service lines in the property to the service hookup on the side of the house. The contractors are paid based on linear feet of installed pipe trenches with additional pay for cutting asphalt, directional drilling and other special circumstances.

At each job site, the inspector uses the touchscreen on a Trimble data collector to enter a project number for the installation into the GPS as-built mapping software. Once the pipe is laid in the ground, the inspector climbs into the trench with the GPS data collector to map the location of the pipe.

“The Trimble device communicates with the Utah Virtual Reference Station (VRS) network, which provides real-time GPS correction,” said Zesiger. “This gives them an accuracy of plus or minus four inches, and the software lets the inspector know he’s getting the configured accuracy for location data as he walks.”

Where VRS is not available, data can be collected using SBAS. The post processing of this data has been automated and does not require any additional work to be done by the inspector.

The inspector typically stops at critical features, such as valves and pipe joints, and uses the digital camera built into the GPS device to snap a georeferenced photo of these individual features. He also takes pictures of the project site from several perspectives. These photos are geo-tagged with coordinate points and automatically attached as attributes by the software to that job site and its assets.

To enhance the asset management capabilities of the mapping solution and speed data collection, CartoPac extended the software to utilize a barcode reader that communicates with the Trimble GPS receiver via Bluetooth. Once the manufactures have barcodes on all pipe and fittings, the inspector will have the ability to use the barcode instead of manually entering the pipe and fitting attributes. Loaded into the software is a complete database of all assets-polyethylene pipe, valves, fittings, etc.-used for Questar gas delivery. Each asset has an ASTM 2897 barcode that corresponds to information in the database.

“The inspector just scans the barcode on each feature, and the software populates the attribute table with 16 details contained in the bar code about it, including composition and manufacturer,” said Vlass. “This eliminates time-consuming data entry by the inspector.”

This is the first step in building a cradle-to-grave inventory and history of every gas distribution asset.

For the average new home service install, the Questar inspector takes about 10 minutes to map the service, connection with the main, scan barcodes and collect relevant photos. The software in the device uses the sub-foot GPS points to create a very accurate map of the mains and service lines along with other notable features, all with relevant attributes attached.

After mapping one or more installs, the inspector need only return to his truck, which has been equipped with WiFi capability. He wirelessly uploads the collected data to the Questar Gas GIS in Salt Lake City where it is immediately accessible to all other crews and departments. Within a few days, a GIS technician in the engineering department checks the GPS feature locations and attributes for completeness. If all is approved, the job status is completed.

“From the GPS GIS, details of the job will notify various departments the project is completed,” said Zesiger.

The work order management system, for example, receives details of the installation including any additional tasks completed by the field crews to calculate payment for the contractor. It notifies accounting to cut the check and additional data is sent to other departments for their use. More importantly, details of maintenance and repairs will be permanently linked to every asset in the GIS database.

“As regulations tighten, this is the kind of information every gas utility must be able to access,” said Vlass.

Benefits of Integrated Mapping

A benefit is that the entire GPS as-built is one mapping system; a user no longer has to open up individual documents to look at mains and services.

Giles believes the solution will pay off in two significant ways as the assets age. First, integration with back-office applications will enable Questar to provide government regulators with complete details on the installation, maintenance and repair history of every asset in the ground. Secondly, the improved spatial accuracy of the maps will enable repair crews to find buried assets quickly when seconds count.

“The bottom line is that with mains and services, we have to be able to find that buried asset day or night for as long as that pipe in the ground regardless of whether it has a 10-year or 100-year lifespan,” said Zesiger. “This system lets us do that.”

The inspection department has begun introducing the as-built mapping system to other personnel and other departments. The utility is developing techniques to use it in mapping retirement of assets and bore hole workflows. The Questar team is exploring capabilities of the core system to expand into high pressure pipeline inspection.


Tren Giles is operations supervisor for Questar Gas.


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