A construction site is not a place to take safety risks, but safety is what you risk when you indiscriminately cut or drill into a maze of rebar. When blades or bits hit metal, they can shatter into flying fragments or grab and bind in the material, causing kickback that can result in severe hand and wrist injuries. Damaged concrete, drill bits, or saw blades additionally lead to downtime and unnecessary replacement costs.
Fortunately, handheld metal detectors have been around for decades and are very easy to use. Zircon, a leading manufacturer of sensor technologies, offers models such as the MetalliScanner® MT 7 and the MetalliScanner® MT X metal locators that can detect rebar in concrete at different depths.
The MetalliScanner MT 7 metal detector can be used to locate rebar, pipes, and other metal before sawing or drilling. The scanner can locate metal, including half-inch rebar, up to six inches deep, and can differentiate between ferrous and non-ferrous metal. It offers users two scanning modes – Standard and DeepScan® modes.
The MetalliScanner MT X metal detector is designed to address the difficult task of locating the spaces between rebar in tight grid patterns. In DeepScan mode, the MT X can locate rebar or metal pipes up to four inches deep.
A Zircon metal scanner was put to the test during the construction of northbound and southbound tunnels for a project along California’s highly trafficked Highway 1. The area is known as Devil’s Slide due to mudslides from the steep terrain above. The two tunnels are each approximately 4,200 feet long and are connected by ten mechanical rooms.
In one of the first phases of the project, the construction crew was tasked with installing a ventilation system in one of the mechanical rooms. However, due to the extensive amount of rebar, the company’s MetalliScanner® MT 6 metal detector, the precursor to its new MT 7, was indicating metal “everywhere” due to its location in earthquake country. One observer described the Devil’s Slide Tunnel as, “less like concrete with steel reinforcement and more like a steel wall with concrete filler.”
The team proceeded to use the Zircon MT 6 to scan for weak signals to find the gaps in the rebar. The team was successful in drilling to install ventilation without hitting rebar 99% of the time − a vast improvement.
For more information about Zircon and its wide range of products, call them at (408) 963-4550, e-mail: info@zircon.com, or visit the company’s website at www.zircon.com.