Smart Manhole Covers Call For Help When Metal Thieves Strike

City managers in Hangzhou, China have turned to a new generation of smart manhole covers in an all-out effort to counter a rash of thefts by metal salvagers. The high-tech covers feature electronic tags that act as both silent alarms and tracking devices should a cover be removed without proper authorization.

Manhole cover theft is a big deal in China: over the past decade in Beijing alone, a quarter of a million of the heavy metal discs have been swiped. Rising replacement costs and detrimental impacts on public safety have grown too high to ignore.

In Hangzhou at least, this worrisome trend is being addressed through a pilot project employing “smart manholes”. The discs are designed to counter metal thieves in a number of ways with the most basic being their composition: ductile iron, a form of the metal that carries a very low value with scrap dealers. Once the word gets around, thieves will be less likely to go to the time and trouble of stealing the heavy covers.

In the meantime, the covers themselves will assist authorities in their recovery thanks to integral electronic sensor tags. “When a cover is moved and the tilt angle is greater than 15 degrees,” explains Tao Xiaomin of the Hangzhou urban management office, “the tag will send an alarm signal to us.” In addition, a digital position system utilizing the sensors discloses the cover's location and will allow authorities to intercept the thieves before they can "flip" the stolen cover. By the end of April city managers expect to have installed 100 of the smart manhole covers on Hangzhou's streets. (via Hangzhou Weekly, ECNS and Zhongguowangshi)