- SPECIAL REPORTS
- THE MAGAZINE
He continues: “I saw laser scanning as a growth industry. Engineering companies have begun to recognize the value in laser scanning efficiency, productivity and survey data detail and now specifically request laser scanning surveys. … With laser scanning, I am able to collect an entire field or facility survey in one setting--nothing is missed--giving clients a complete and accurate data set the first time. That kind of accuracy and efficiency saves clients significant time and money. And that’s a plus difficult to debate.”
Ross McDonald, a project leader with Husky Energy Inc., a Point Geomatics client, agrees. “Laser scanning allows us to execute our work much more cost effectively and with a higher degree of accuracy,” he says. “We’ve discovered, over time, that the traditional ways of creating as-built drawings and documents manually is unreliable and very costly. The accuracy and efficiency of laser scanning provides for a comprehensive data capture of the facilities and infrastructure within our existing assets, and the integration of the data point clouds with 3D modeling technology provides a higher level of confidence through the phase development of our projects. The real money is saved in the construction of the facilities because this technology allows us to shop-prefabricate with a high degree of accuracy, minimizing or eliminating field rework.”
Already equipped with three Leica Geosystems ( www.leica-geosystems.us ) laser scanners, Tucker recently acquired what he calls the “Lamborghini of scanners”: the Leica HDS6000 phased-based system. “The HDS6000 can acquire half a million points a second and runs up to 250-times faster than my previous Leica scanner,” Tucker says. “That’s a significant selling point to customers.”
The first to acquire the Leica HDS6000 instrumentation in Canada, Tucker says he now has the “pole position” to serve his varied clients, build a larger base of laser-scanning converts and continue to drive laser scanning into the mainstream.
Scanning the FutureAccording to Tucker, Husky Energy’s McDonald has already converted. McDonald has been using scan data since 2000 when endorsement of the technology was still in its infancy. Now that it’s moved past the crawling stage, many project managers consider laser scanning a “given” for their varied survey needs. So when McDonald needed a crude oil storage tank surveyed last November at Husky’s pipeline terminal complex in Hardisty, Alberta, he called Tucker.
Serving as the major hub for oil in western Canada, the Hardisty Terminal handles approximately 25 percent of the total volume of crude oil exported from the region. Major stakeholders, including Husky, Gibson Energy Ltd. and Enbridge Inc., all have significant facilities at the complex where they store millions of barrels of oil; Husky alone maintains 12 storage tanks, the largest of which can store 300,000 barrels of oil. Many stakeholders, including Husky, are also actively planning or already constructing new facilities at Hardisty to meet increasing capacity demands.
Though the Hardisty Terminal is one of Husky’s key facilities, it did not have an effective spatial data management system--a necessary element for the company’s project team to properly plan for and execute the facility’s high-priority expansion. McDonald says the extensive plan for Hardisty Terminal cannot be efficiently developed with methodologies such as total stations or manual as-built drawings, so he made laser scanning the survey tool of choice at the oil storage site.
“Laser scanning and 3D modeling provide us with an accurate, holistic view of the facilities at any given time, which gives us the intelligence to plan, execute and monitor the overall program, not just one individual project,” he says. “That’s the most cost-effective way to execute these projects.”
The Holistic ApproachHusky’s laser scanning initiative first began with surveying the entire “tank farm,” which is scattered across three separate campuses, to develop an accurate 3D model of the facility that could be used to evaluate various alternatives for expansion. In addition to collecting topographical laser scan data on undeveloped Husky land, Tucker also scanned Husky’s existing facilities, including its 48-foot-high, 210-foot-diameter tanks and associated booster pumps, manifolds and interconnected piping, all of which was tied to the same survey control. The point cloud data was then sectionalized corresponding to Husky’s “design area indices” to make it easier to manage the data volumes. Included with the raw point cloud data were still photographs of all scanned features and a short video with commentary relative to the conditions at the time each area was scanned.
“By scanning the entire tank farm at the outset, engineering contractors have an accurate and complete data set to work from no matter where they are onsite,” Tucker says. “So, if an engineering company needs to work in an area where there is no available as-built model, they can bring in the laser data and use that as the as-built for their new design work.”
Since the initial survey completed in March 2007, Tucker has been systematically updating the master data set each time infrastructure is added or changed or upgrades are planned. His most recent assignment was to re-scan an existing tank. Using the HDS6000, Tucker was able to scan the position of the entire tank, complete with valves, 24-inch to 30-inch nozzles and piping, in four hours--a job that previously took Tucker two days to complete with total stations and other scanners. He then provided the laser scan data to McDonald to update the master data set.
Speed is indeed a notable asset of the scanner, but equally important, says McDonald, is its accuracy. “With the accuracy of laser scanning, we are able to create accurate-enough designs to produce construction and fabrication drawings that allow us to shop-fabricate nearly 80 percent of the infrastructure we need on our projects. Without the six-millimeter accuracy of the laser scanner, the project would be forced to field-fabricate a significantly higher percentage of the work. Our No. 1 mandate is safety, and when we can remove a large percentage of the total man-hours from the field into a more controlled environment, we end up with a safer worksite, and significantly reduce the cost of the project and improve the overall schedule.”
That level of data detail also enables McDonald to minimize the expense and effort of modeling assets in 3D. Rather than having to create a new model every time infrastructure is scanned, design engineers can use the laser scan data as an as-built model, which requires them only to create new 3D design models for new infrastructure, such as piping or vessels. That is a significant savings in time and money, Tucker says.
From Field to FactoryThe ability to shop-fabricate based on laser scan data is helping to ease budgetary and deadline pressures for other energy companies, as well. Tucker provides an example of one client that commissioned a company in Italy to manufacture a replacement vessel approximately 3 meters in diameter and 15 meters high for one of its facilities. With the infrastructure being constructed on another continent, there was clearly no room for error. Using scanning technology, the company was able to design the vessel, build it and fit it perfectly in place.
Tucker says the high-density data produced by the Leica HDS6000 is particularly beneficial on projects where as-built drawings are unavailable or out of date. “I recently completed a project on a 1950s plant where no as-built drawings were available,” he explains. “And even if they had been, they would have been wrong. So we went in and scanned every square inch of the plant. The engineering contractor is now using our laser data as the as-built. And they’re only designing new piping and vessels to work around what existing facilities the laser scan data shows.”
Another example of the scan-to-construction viability of laser scanning is a gas plant in British Columbia where a client needed to construct a replacement vessel. Instead of looking to the original 3D design drawings of the existing vessel as a design base for the replacement vessel, the client wanted Tucker to scan the existing vessel to ensure it was congruent with the manufacturer’s drawings. This would allow them to move directly to the bolt-up phase when the vessel arrived. In a matter of hours, Tucker scanned the entire vessel with the Leica HDS6000 and, based on collaboration with the engineering firm, found inconsistencies between the existing vessel and the as-built drawing.
“The centerline of nozzle-to-nozzle differences between the as-built drawing and what was determined by laser scanning differed by a little more than five centimeters,” Tucker says. “Had the in-kind replacement vessel been fabricated to the as-built drawing dimension, the existing piping would not fit and the vessel would not [have been able to] go straight to bolt-up. This would require rework to the existing piping and pressure testing of the re-fabricated pipe spools. Down time for the vessel would have been days instead of hours by reusing existing piping.”
Clear CorroborationShortly after acquiring his Leica HDS6000, Tucker delivered time-critical, accurate data of a deforming pipe at a gas plant near a large Albertan community. At issue was a 40-inch piece of pipe that was sitting on an elevated pipe rack and was vulnerable to subsidence. Though the deformation was visible prior to conducting the laser survey because the rack had started to lean, managers needed to know exactly how much subsidence was occurring in order to decide whether further support measures were needed. Because Tucker had provided scanning data on this vessel previously, the company commissioned him again to perform a deformation survey of the piping and structural steel. Tucker was previously in the field for four days to scan the existing vessel. On his return trip with the new scanner, Tucker needed only one day.
To clearly show the deformation of the pipe, Tucker color-coded the point clouds and overlaid the newer data set on the previous one. This enabled users to recognize any movement in the structural steel in order to model that movement. The data showed that the deformation was much less than anticipated, and no immediate action was required.
Pulsing Into New ApplicationsThough deformation surveys are probably not the most common application for laser scanners, the technology clearly shows that it can pack enough data-detail punch to rival the traditional subsidence measurement tools of inclinometers and string gauges. It also demonstrates its viability for expanding its more common uses within the surveyor’s domain.
Husky’s McDonald explains: “Whenever we add new tanks, and because we are dealing with large-sized nozzles and piping, we scan those nozzles and then scan the tie point for the other end of the piping. We can then update our drawings dimensionally so that we can shop-fabricate those big pipe spools and they drop right into place. So in addition to having laser scan data at the outset and at the end of a project, we also involve the technology in the middle of the project for specialized scanning.”
Clearly, the speed, accuracy and versatility of laser scanning can attract a lot of converts, but Tucker points out that the technology requires skill.
“There is no doubt in my mind that laser scanning is an extremely powerful tool that allows other engineers to achieve great results,” he says. “However, the technology is an acquired skill that I believe needs to remain in the surveyor’s domain. Laser scanning isn’t as simple as turning it on and letting it collect data. You need to understand the geomatics of laser scanning and the subtleties of land surveying to produce accurate laser scan survey data.”