Is it level? Is it flat?
For concrete construction contractors, finishing foremen, superintendents, flooring inspectors, and structural engineers, they are the central questions to any large concrete pour.
Extreme concrete floor flatness (FF) and floor levelness (FL) are requirements for any environment housing sensitive, finely calibrated equipment. Modern warehouse and distribution centers also require concrete floors of exceptional levelness and flatness. Flat, smooth surfaces support safe lift truck operation. Level concrete floors ensure vertical storage shelving of up to 40 feet and higher can support electronic picking systems. There has never been more demand on general contractors and their subcontractors to deliver extremely level, flat concrete floors.
In the 1970s electronic floor profilers were introduced, providing builders with a dramatically more reliable and comprehensive way to meet concrete floor flatness and, finally, levelness requirements. These operator-guided wheeled devices generated measurement values that required a new way to understand the results. This new floor measurement language, called F-Numbers, grew in time as the basis for industry standards. Today the American Society for Testing and Materials (ASTM) recognizes F-Numbers as the basis for Floor Flatness (FF) and Floor Levelness (FL) standards with ASTM E1155 Test Method for Determining Floor Flatness and Floor Levelness Numbers.
With the F-Number system, concrete construction professionals finally had a common, standardized way to understand floor flatness and levelness. Even so, wide industry acceptance was not immediate. Other pour concrete floor finishing enhancements, such as the laser screed and ride-on power trowel, also contributed to rapidly evolving concrete floor flatness and levelness standards.
Running concurrent to that revolution was another: laser scanning. Laser scanning includes a vast array of everyday applications, from bar code readers and DVD players to 3D printers. Laser scanning at the construction jobsite can also serve varied purposes, including reality capture, the science of digitally capturing the precise shape of an object—say the surface topography of fresh concrete pour—by creating point clouds of data that present the object in a highly accurate 3D digital form.
This point cloud representation is analyzed by software that can visualize deviations, say with a colored heat map. These deviations can include floor flatness and levelness.
Today a growing number of general contractors (GCs), concrete contractors, and inspection services perform a highly detailed analysis of just-poured concrete floors for levelness and flatness with a laser scanner.
What advantages do laser scanners and supporting software offer? How does the new measurement technology transform workflows, improve pour outcomes, and simplify measurement.
This case study briefly examines the opportunities and challenges now before construction professionals.
Floor profiling devices have served as the gold standard for FF/FL measurement for more than 40 years. For a fast-growing group of GCs, concrete construction contractors, and floor inspectors, that hold is giving way to the accuracy, speed, convenience, versatility, and payback of laser scanning measurement. Wet-Pour Quality Control Compressing Workflow in Concrete Slab Pour Flatness and Levelness Measurement
Standards-setting bodies have taken note as well, with laser scanning applications now recognized as compliant with ASTM, AISC, ADA, and ACI guidelines.
Key to growing industry acceptance is side-by-side testing of the competing measuring systems. Laser scanning has demonstrated time after time it “delivers the goods” at F-Number levels that meet or exceed traditional floor profile analysis.
Philip Lorenzo, a software developer for Rithm, a maker of FARO laser scanning Apps for construction workflow management, is an active observer. For example, his firm now serves a growing constellation of mid- and large-size GCs nationwide, including:
• Largo Concrete, Inc.
• Morley Builders
What intrigues many GCs is the idea that FF/ FL measurement can be transformed beyond a “gotcha” process where floor issues are discovered far too late in the finishing process. “With laser scanning, problems can be detected while the concrete is still workable. There’s no need for a floor profiler operator to walk on the concrete, or even touch it,” explains Josh DeStefano, DPR Technology Innovation Manager. DPR is a California-based general contractor and the nation’s number-one builder of health care centers.
Thomas Rogers, VDC field Manager of McCarthy Construction, a self-performing general contractor, says their California teams have made this QC step part of their pour workflow. “At first there was some skepticism about wetscanning the pour. I would bring our finishers over to show them all of the defects highlighted live on the computer screen, when they were in a position to fix them,” Rogers says. “Fortunately, I’ve saved them enough floors by using this method that they now trust the process.”
Minimum Viable Workflow
That’s just one of the many attributes that is leading trade pros to reconsider traditional measurement methods. Other workflow friendly benefits of laser scanning include:
Single Registration: There’s no need to laser scan from multiple positions to capture an authoritative point cloud data set. Single position scanning for wet concrete analysis eliminates the need for stitching together multiple scans to render a full view.
Speed: A single operator can capture up to a 70-foot by 70-foot area usually within 3 minutes, and 4 minutes for the computer to calculate a thorough analysis of the floor. Faster verification means the finishing team has time to address potential issues before curing, minimizing the need to grind, cut, float, or perform other costly corrective measures.
Tablet-friendly: Trips back and forth to the trailer to analyze F-Numbers can be reduced or eliminated. Finishing foremen and superintendents can use handheld tablets right at the jobsite to quickly observe results and rapidly direct next steps.
F-Number Familiarity. Software presents laser scanned results in conventional ASTM E1155 values, speeding on-site interpretation and understanding.
One big reason: A new generation of easy-to-use software that vastly simplifies laser-scanned FF/FL measurement and analysis.
FARO with Rithm Inspector
Leading the software breakthrough is Rithm. Their Rithm Inspector software application offers GCs, concrete contractors, and inspection companies the ability to:
• Perform FF/FL according to ASTM E1155, simulating a device that measures elevations at every one-foot interval
• Create reports and generate overall FF/FL based on multiple test runs (Repeatability)
• Automate routines for inspecting stair riser heights to check compliance with International Building Codes (IBC)
• Automate routines for inspecting ramp slopes and cross slopes for compliance with the Americans with Disabilities Act (ADA) requirements
Lorenzo says Rithm Inspector is designed to be easy-to-use, very field-and-tablet-friendly. “There isn’t a lot of background knowledge you need to use it for wet concrete scanning,” observes Lorenzo. Rithm Inspector is built on top of robust, highly versatile SCENE Software from FARO Technologies. The SCENE platform is a comprehensive 3D point cloud processing and managing software platform specially designed to view, administer, and work with 3D scanned data from the FARO Focus3D X and S series Laser Scanners. The FARO Focus3D Laser Scanners offer operators industry-leading portability, capability, and battery life.
“Superintendents and project engineers without highly technical backgrounds in building information modeling (BIM) can quickly become productive with the Inspector App being relatively simple,” Lorenzo says.
User experience verifies that. “People hear ‘laser scanning’ and they think that it’s a big, complicated thing. Collecting data isn’t complicated,” DeStefano observes, an Inspector user.
Laser scanning supported by next-gen applications
Proven laser scanning technology supported by next-gen software applications is helping empower GCs, concrete construction contractors, and floor inspectors with unprecedented real-time build environment insight and analysis.
As user experience shows, the new insight will help compress workflow with minimal floor inspection disruptions and costly remedial action after issues are discovered “too late.” Also, the risks associated with litigation for not meeting FF/FL standards will gradually dissolve, as pour outcomes are promptly verified with repeatable certainty and irrefutable confidence.