3M Systems Locates Plastic Pipes

By Jeff Griffin, Senior Editor | June 2014, Vol. 69, No. 6

A practical and cost-efficient method to accurately locate buried plastic pipe has been developed by 3M, addressing the inability of conventional locating equipment to detect HDPE, MDPE and PVC pipe and conduit that does not contain tracer wire.

The 3M technology uses passive electronic markers packaged with a carrier similar to caution tape or a rope which is placed near or above the pipe. An operator on the ground above the pipe uses a handheld locator to generate a radio signal which is received by the marker and reflected back to the transmitter, identifying the marker’s exact location, type of utility, depth and path.

Positioned at intervals along the pipe, a crew member can quickly identify and mark the path of the pipe.

Locating plastic pipe is a continuing challenge because the primary utility locating tool – a two-component electromagnetic system – can locate plastic pipe only if tracer wire is attached. For years, utility owners and operators have used tracer wires to make plastic facilities locatable, but there thousands of miles of plastic pipe in the ground without tracer wire that is considered un-locatable by electromagnetic equipment because the wire was incorrectly installed or it has been cut or corroded.

Ground penetrating radar is an option for pipe location, but the present technology’s inability to penetrate dense soils limits its effectiveness.

“The use of passive radio frequency identification (RFID) markers to locate buried pipe and facilities is not new – indeed, 3M has offered electronic marker balls for more than 29 years,” said Corey Willson, national sales manager of the 3M Electrical Markets Division. “Markers are attached at various points to pipe during installation or during maintenance. The marker is easily and accurately located using a handheld locator which identifies the marker’s exact position. Most of the major locator manufacturers make radio frequency (RF) locators. Unique to 3M is the ability to read/write to RFID markers.”

Willson said as RF marking evolved with the addition of read/write capability, facility owners began using them to mark the path of pipelines. Typically when ID ball markers are used for path marking, they are placed between 40 to 150 feet apart.

“Using our knowledge and experience with RF marking systems,” said Willson, “we developed a product package with marker spacing of less than 10 feet, addressing unmet needs for locating non-metallic facilities.”

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