Growth Of Laser Profiling Technology Enhances CCTV Inspections

By Jeff Griffin, Senior Editor | September 2008 Vol. 63 No. 9

Closed circuit television (CCTV) inspections have become the standard method for inspecting the condition of the inside of underground pipe infrastructure, providing information about their condition and areas where deterioration and damage require pipes be repaired, rehabilitated or replaced. CCTV inspections also verify repairs are properly made and that new pipe has been correctly installed.

Recently, laser profiling technology is adding new dimensions to the inspection process and its potential caused a buzz at the most recent NASSCO (National Association of Sewer Service Companies) convention earlier this year.

Laser technology does not replace conventional CCTV inspections, but complements them, providing valuable data previously unavailable to system owners and project engineers.

"The technology can be used independently or in conjunction with CCTV inspection equipment," says Gerry Muenchmeyer, P.E., Muenchmeyer Associates, and technical director of NASSCO.

Laser profiling usually is done by a separate piece of equipment that is attached to the inspection train as it is pulled through the pipe line.

"Whereas CCTV will provide a picture of the condition of the existing pipe," Muenchmeyer continues, "the laser will provide a profile measurement of the existing pipe. Pipe defects such as partially collapsed or distorted pipe are very difficult to determine through a CCTV inspection, and the laser profile will provide detailed documentation of the pipe profile along the entire length of the pipe. This information can then be viewed in a strip profile format to determine the most badly deteriorated sections of the pipe. The engineer can use this information to design a renewal pipe that meets the exact requirements to restructure the old pipe."

Muenchmeyer says with typical CCTV inspections, the old pipe is visually inspected and a best guess of the pipe distortion then is made by the engineer. For pipe rehabilitation, new liner pipe is designed based on this information. A laser profile will provide more detailed information about the host pipe's circumferential profile allowing for a more accurate pipe liner design by the engineer. After the renewal pipe is installed, the laser profiler will then document the condition of the new pipe as it relates to the existing host pipe.