Collecting and Sharing Data: The Effect of 3-D Scanning

Construction modeling using 3-d laser scanners is becoming common on large construction sites, such as data centers, and electrical contractors can expect to see more of these devices—and more requests for them—on projects of all sizes. While acquiring a scanner requires an initial expense, they could pay for themselves in competitive edge, error prevention and litigation support.

These 3-D scanners help document what happens on the construction site, enabling ECs or general contractors to prove the work was done right, prevent errors and reduce insurance costs.

The scanner digitally captures the dimensions and the relationship of objects based on their location, with a laser line of light that is invisible to the eye. Users can scan objects at a distance of 80 to 340 meters (260–1,115 feet) or more, depending on the scanner being used. Contractors can compare the resulting data with project drawings and building information modeling (BIM) details.

It starts by using a tripod-based or handheld scanner to collect information about the site before the electrical system installation begins. For electrical contractors, scanning can begin in areas where trenches are being dug, before conduit goes in underground. At any time in a project, if the laser beam is obstructed, the user would have to scan multiple locations until the entire area is covered.

The scanners were initially launched as a tool for architects. More recently, however, electrical and other subcontractors are finding value by tracking their own work or that of their project team members.

 “A lot of electrical contractors are doing 3-D scanning for their own benefits,” said David Burczyk, segment manager—field technology group, Trimble.
Their gain isn’t just from collecting information for the contractor’s own purposes. Some ECs are sharing the data with other subs and general contractors and even selling the service for others to track their own work or create “as-built” model deliverables at the end of a project.

Trimble, initially a GPS-based location technology provider, has brought scanning solutions to the geospatial market since 2003, and introduced its 3-D scanners to ECs in 2012. Over the past five years, more companies saw value in the data they collected and the software to support that data.

“It’s still an educational process,” Burczyk said.

More contractors are becoming aware of the technology, and more customers, such as building owners, are beginning to seek data from such systems.
A scanner itself is just the beginning. Trimble offers its RealWorks scanning software for registering the data and EdgeWise software for automated modeling and analysis. Contractors can collect the data and then do design work accordingly in Revit BIM software from Autodesk.

Thus far, building owners are commonly asking for a capture of as-built scans showing the electrical and other installations before the walls are covered up. Generally, a contractor is scanning the site before installation and the as-built installation after it’s nearly finished, but they are starting to find value in scanning as the work is in progress, as well.

“In that way they can document their progress,” Burczyk said. “[The resulting data is] a valuable way to set yourself apart.”

Using 3-D scanning also helps with the virtual planning. Scanners help contractors capture the real-world conditions and use those conditions to plan in coordination meetings.

“The more information you have, the better,” Burczyk said.

That data helps eliminate the risk of errors when several subcontractors might find that their work is set to clash.

The technology can also be used back in the office or shop. If prefabrication is being done, for instance, 3-D scanners can collect the data needed to ensure the work being done in the shop matches what is needed on the work site.

Data centers may be the first adoption sites due to the sheer complexity of the installations.

“All that conduit running underground—from a facility stand point—just naturally lends itself to 3-D scanning,” Burczyk said.

Cost and benefit

The cost of technology can vary according to the contractor’s needs. The lower-cost solution is the handheld versions that have less accuracy, shorter scanning range, and are typically carried around the site periodically. For very high accuracy—as much as within two millimeters—and longer range, companies such as Trimble provide tripod-mounted scanners. Typically, a tripod-based scanner and software solution has the highest cost, but can pay for itself in the prevention of error and rework.

Which scanning solution is the best? Ultimately, it differs for every contractor.

This image shows the point cloud model overlaid on top of GC BIM model and how accurately they integrate.
This image shows the point cloud model overlaid on top of GC BIM model and how accurately they integrate.

“When you ask [contractors] what’s most important to you, you get a variety of answers,” Burczyk said.

Some, especially smaller ECs, don’t require the highly sensitive and highly accurate equipment. In fact, at the lowest cost, some contractors are doing virtual walkthroughs with the location data available to them on their smartphones or tablets.

Ideally, tripod-based scanners provide a good overview of the whole project, while handhelds can be used for small detailed areas where scanning might otherwise be difficult, such as hard-to-reach areas.

Legal support

S-E-A Ltd. is an international forensic engineering company that offers, among other equipment and solutions, a construction modeling tool using 3-D laser scanning technology.

The firm helps companies in reconstructing accidents to determine cause and, for the past several years, has offered 3-D scanning for companies that want to preserve additional data about their work that could protect them in the event of litigation. The company’s 360-degree tools can scan a site before, during or after a construction project and are often using during multiple phases of construction. The companies employing the technology include building owners, developers, architects, contractors and their insurers, said Ryan Siekmann, group manager for national accounts—imaging sciences, S-E-A.

S-E-A does more than just offer the 3-D tools and digital output. Building on its nearly 50-year history, it also provides reverse engineering support to help contractors or other users determine the best stage of a construction project to scan. The installation and the scanning itself can be done quickly and without delaying construction activity; S-E-A’s 3-D scanners capture up to a million data points every second.

A key financial benefit for all stakeholders in a construction project is data to defend a company during litigation or even prevent a lawsuit entirely. With roots in the legal trade, S-E-A knows just how much litigation actually costs those in the construction industry. Siekmann said that legal fees, settlements and consulting expenses cost U.S. builders and contractors more than $1 billion each year. The scanner, along with the company’s 360-degree Digital Construction Platform, captures and manages data to create records needed to protect a company in the case of legal challenges.

It may also reduce insurance premiums, since those companies insuring a project have better documentation about the work that is being done before, during and at the end of the project.

“Additionally, it provides clash detection when the data can be overlaid with the BIM model for the electrical contractor’s work and that of other subcontractors,” Siekmann said.

By preventing clashes, the solution could pay for itself in a single incident, when the potential for rework to correct mistakes or a costly change order is prevented. It also makes bidding more cost-effective and enables some compression of schedules due to the better organization of the site, the progress on-site, and the assurance that the details are accurate.

Because S-E-A is already in the business of forensics engineering, its products are focused on providing the data that will mitigate errors and serve to reassure that the work was done properly. While contractors scan their sites for a variety of reasons, Siekmann said the company is focused on helping companies reveal the cause of incidents and preventing them, when possible.

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