Recovering buried data21 February 2004
3M has developed a passive sensor based system designed to keep track of buried cables and pipes. It is suitable for any kind of underground system, such as water, power, telecomms, waste, cable tv and even gas or fuel pipework. 3M says that its system, known as the EMS 1400 Series iD Ball Marker, is a unique innovation its field. It consists of a plastic ball containing fluid and a passive sensor; a series of them are buried along the route and when found and interrogated by a radio signal from a hand held detector can provide a wide range of information about the cable or pipe as well as about fault conditions. The data is likely to include details of the facility in question, hazard levels, type of application, date of placement and so on.
The device is available for a range of seven radio frequencies and can be read at depths up to 1.5 m. The markers are highly durable, at least equal to the lifetime of the cable, and the fluid within the ball constitutes a self-levelling feature.