Perfecting as-built surveys for retrofits and expansions

HDS laser scanning data (left) can be used to develop accurate as-built 3D models of industrial facilities (right) for retrofit or expansion projects.

In the past, the conventional, manual surveying of industrial sites for retrofits or facility expansion often required hundreds of hours, sometimes over months, and sometimes involved potentially hazardous locations. When as-built infrastructures were hidden or not precisely detailed in original plans, the resulting survey errors usually led to expensive rework or change orders for retrofit or expansion projects.

Today, high-definition survey (HDS) technology makes it possible to collect data from hundreds of survey points, with densities and accuracies of 1/8 inch, in a matter of hours, instead of days or weeks. Provided by professional specialists, HDS can be used to survey a variety of industrial projects, such as processing plants, refineries, mining operations, and other facilities that plan to make modifications, retrofit, expand, or upgrade key equipment.  

HDS technology is based on an imaging laser that collects as many as 50,000 survey shots per second, making it far easier to provide data that can be used for 2D line work or 3D models. The HDS system also features an external camera that collects photographic images in 360-degree, RGB color values. These image files are later fused to the data points that are assembled as point clouds, which can then be utilized for site mapping, project planning, and civil, structural, and MEP design as data is extracted into formats such as AutoCAD, Revit, and MicroStation.

Efficiencies that lead to savings

Stan Postma is vice president of Utah-based engineering services firm, MWH Americas Inc. (a subsidiary of MWH Global). His organization has recently undertaken renovation of a hydroelectric power plant operated by the City of Logan, in northern Utah. 

“We needed to evaluate some existing structures, including a powerhouse that is about 100 years old,” Postma said. “I knew about HDS type of scanning and thought it would be a good application for the project. So, we engaged McNeil Engineering’s HDS team to do that for us. This service captured all of the information about the building in a very quick and efficient manner, enabling us to plan around the existing structure with very accurate information.”

McNeil Engineering in Sandy, Utah is a multi-faceted firm that has performed HDS scanning for the last five years, as well as other survey-related services, civil engineering, structural engineering, consulting, and landscape architecture.

Postma said that the City of Logan also commissioned MWH to survey an existing dam that is going through some design modifications near the powerhouse site. He said the 3D data the HDS system provided was very helpful in planning that project as well. 

According to Postma, this data enabled his staff to put the dam in a 3D animation so they could view it from any angle. This was a very useful tool because it provided a precise reference, and eliminated the need to send personnel to the site for visual confirmations.

“We’re going to end up with savings on change orders and construction efficiencies all around,” Postma said. “Having all the information available in such great detail is going to save money. HDS scanning is very cost-efficient tool.” 

Eliminating errors

Many design and engineering firms turn to HDS technology because the scans it provides are so accurate that it virtually removes the need to work from records that could be somewhat inaccurate, thereby eliminating the need for rework.

Another McNeil Engineering client, Hubbard Engineering in Mesa, Ariz., used the HDS scanning service for a retrofit project at WestWorld, a large, open-air equestrian center and events arena in Scottsdale, Ariz.

“The extreme summertime heat was limiting WestWorld use, so the owners decided to enclose and air-condition the arena,” said Adrian Burcham, PLS, director of land survey at Hubbard. “This was a large retrofit project. We scanned the interior because there were no plans available. The HDS technology enabled us to precisely pinpoint the as-builts for design purposes, including the new HVAC system.”

Burcham said it took just one day to complete the scanning, which he estimated could have taken several weeks with a conventional survey team. “McNeil was able to accurately measure every bolt and column in the original structure,” he said. “Also, we got better accuracy on the visible objects in the arena. We were able to map them tighter than you could using conventional tools.”

Burcham added that the 360-degree photos that McNeil created from points all around the arena were also quite helpful. Used in conjunction with point clouds, the photos made it much easier to reference the project visually.  

An added measure of safety

Because all scanning is performed from ground level, HDS scanning technology is unobtrusive, making it unnecessary to interrupt production processes.

This convenience also adds a measure of safety, as pointed out by Brian Akers, piping lead at Job Industrial Services, Inc. in Salt Lake City. Job Industrial Services handles retrofit and expansion projects with refineries, mining, and power and gas transmission facilities in Utah and throughout the U.S. Naturally, safety is a priority of the firm.

“HDS technology improves on the safety of our personnel because we spend significantly less field time in potentially dangerous environments,” Akers said. “This is the case particularly in the refinery industry, where you may have thousands of miles of infrastructure. If we’re doing a retrofit, we can have a service provide laser scans, and with the point cloud information we can do a model a lot more accurately than we can do with conventional field measurements.”

Job Industrial Services has had the McNeil Engineering team perform HDS scanning at a recent refinery project because the team possessed the necessary state-required training certification and other safety-related qualifications.

“That removes the need for our organization to invest in HDS equipment, create a scanning team, and then send them out to the job sites,” Akers said. “All that saves us capital and the loss of considerable production time at the office end.”

Information provided by McNeil Engineering

Posted in UAV + Surveying | July 1st, 2014 by