New RFID Tags Help ‘Call Before You Dig’

By Admin

3M introduced new RFID tags designed to be buried for identifying underground assets. The new tags use the same frequencies as traditional marker detection systems, but allow users to identify, rather than detect, underground objects and to update data on the tag.

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This article was originally published by RFID Update.

July 13, 2007—3M expanded its family of RFID tags for locating and identifying buried pipes, cables, and other underground assets. The new products work at different depths and provide identification and data about the buried asset, in addition to signaling its location.

Underground marker tags have been used for about 35 years to help utilities, public works departments, and construction firms locate cables, pipes, valves, and other underground assets, 3M's Corey Willson told RFID Update. There are millions of such markers throughout the world, and 3M sells a new one approximately every 25 seconds. Markers operate at a set range of frequencies between 65 KHz and 135 KHz, with different frequencies used for different types of assets according to American Public Works Association standards.

The markers are used to locate items for service and to provide guidance for safe excavation. Willson said traditional marker tags were used only for detection and did not store or transmit any identification data. Similar to anti-theft tags used in retail, they merely emanated RF to signal their presence; no actual data was transmitted by marker tags until 3M introduced intelligent RFID tags in 2002 that could communicate a unique ID number and other information.

The new products 3M introduced this week expand its intelligent product portfolio. The new markers are part of 3M's Dynatel Locator System, which also includes a handheld computer used to find and read the underground markers.

"What we really have now is an asset tag," said Willson. "Users can not only detect an object, they can get a unique serial number so they know exactly what it is. They can also write new information to the tag. Customers are excited about being able to update when the last time the asset was accessed and serviced."

The new products are a "finger marker" and a "full range marker." The finger marker is approximately two-thirds of an inch in diameter. It is for near-surface applications, such as identifying manhole covers that will be paved over. Finger markers can be buried under concrete and extracted by drilling, rather than having to use a jackhammer or other equipment for a larger excavation.

"There is a lot of interest in this product because it's small. Traditional ball markers are about four inches in diameter," said Willson. "There is an organization in Europe that's interested in the finger marker to identify trees, because they can throw dozens of these into a backpack and easily hike out with them into the forest."

The full-range marker can be read from up to nine feet below ground. It is intended for identifying more deeply buried asset like electric lines, wastewater pipes, and related components.

"GPS and GIS [geographical information systems] are exploding, and that's driving more use of underground RFID markers," said Willson. "That technology offers huge productivity improvements over manual recording, so utilities are mapping many more points of interest. RFID gives them a way to add the unique asset ID number right to the location record."

Read the announcement from 3M