ARCHIVED – Urban Infrastructure Rehabilitation v8n3-10

Non-destructive method to assess pipe wall thickness patented by IRC

Water utilities know too well that they face major costs in maintaining and replacing their transmission and distribution pipe networks. And as more and more networks decline each year, these costs are increasing and will peak when water pipes installed during the post-war boom begin to reach the end of their service lives.

The new method relies on measuring how quickly an acoustical signal is transmitted along a section of pipe, using easy-to-access measurement locations such as fire hydrants and control valves.

Gaining access to these pipes to inspect them can be difficult and disruptive-until now. Researchers in IRC's Urban Infrastructure Rehabilitation Program have developed and patented a new non-destructive test method for water utilities to use in evaluating pipe wall thickness without taking the pipe out of service and, even better, without digging, thus minimizing disruption.

WITH IRC'S PATENTED NON-DESTRUCTIVE TEST METHOD, MUNICIPALITIES CAN AVOID THE TYPICAL DISRUPTION SHOWN HERE, WHICH OCCURS WHEN PIPES HAVE TO BE ACCESSED FOR INSPECTION

The new method relies on measuring how quickly an acoustical signal is transmitted along a section of pipe, using easy-to-access measurement locations such as fire hydrants and control valves. Changes to the signal-specifically changes to its transmission or propagation velocity-can be related to changes in the pipe wall thickness.

The testing methodology is simple. Operators place a pair of vibration sensors or underwater microphones in direct contact with a pipe at a known distance apart. They then send an acoustical signal, either by opening a fire hydrant or service connection or using an existing leak at a known location, and measure the time it takes the signal to travel between the two sensors.

The distance from sensor to sensor divided by the time lag gives the operators the propagation velocity. From this value, they can then determine the pipe wall thickness, based on known parameters of the pipe, such as its diameter, and the theoretical relationship with propagation velocity. The value determined for pipe wall thickness using this method is an average for the section between the two measurement points, which is typically 100 metres.

This method can be used on all types of pipes, including cast and ductile iron, steel, PVC, asbestos cement and concrete, and can be carried out as part of routine leak-detection surveys. It can also be used for other pressurized fluid-carrying pipelines, such as those used for oil or gas. In addition, the required measurements and calculations for the method can be made without a high level of operator skill using IRC's LeakfinderRT system, details of which can be found online at http://irc.nrc-cnrc.gc.ca/leak/leakfinder.,

Specific questions about the new pipeline assessment tool can be directed to Dr. Osama Hunaidi at (613) 993-9720, fax (613) 952-8102, or e-mail osama.hunaidi@nrc-cnrc.gc.ca.

IRC looking for partners to commercialize new pipe assessment method
IRC has developed and patented a new test method for use in evaluating pipe wall thickness. The method doesn't take the pipe out of service, doesn't require digging, and works on all kinds of pipes. The required measurements can even be carried out as part of routine leak-detection surveys from easy-to-access locations such as fire hydrants and control valves.

Interested? IRC is looking for a company capable of commercializing this technology and marketing it to water utilities and private water services companies worldwide. In addition, IRC is willing to work with large utilities and service companies on a site-specific basis. Letters of interest are currently being accepted. For more information, Marketing, at (613) 991-2987, fax (613) 993-3142, or e-mail marketing.irc@nrc-cnrc.gc.ca.