Tracking Construction Cranes in Real-Time

By Claire Swedberg

Stafford Tower Crane is using an active RFID system from AssetPulse to track the location of cranes and components at construction sites.

Construction crane leasing company Stafford Tower Crane of America is using a radio frequency identification system to track its cranes and their large components throughout the United States. The crane leasing company, the U.S. division of Dublin, Ireland's Stafford Tower Crane Ltd., has tagged its 15 cranes and numerous individual pieces on those cranes with active RFID tags. At present, the company is gathering data about the locations of those cranes and parts. The system was developed by AssetPulse, a San Jose, Calif., company offering customizable asset-tracking software.

Stafford Tower rents cranes to construction sites throughout the United States and needed a system that would assist in locating crane parts quickly. Until six months ago, when it began piloting this system, Stafford tracked its cranes and their many 20-foot-long components using paper and pencil, says Patrick Stafford, president and owner of Stafford Tower Crane of America. "It was really a nightmare," he recalls.

Vijay Sarathy

The trouble occurs when construction projects require first a crane, then additional tower components to make the crane taller as construction progresses. On many construction jobs, components can be ordered and shipped to a site three to five times or more. Many towers, in fact, have as many as 16 added components by the time construction is completed.

Components are often transported directly from one construction site to another, while others return to one of Stafford's holding and maintenance yards. When a crane needs to be erected, the proper crew needs to be in place and the construction site needs to be readied. Crane components are occasionally missing, putting the entire project on hold.

"We have to be able to keep track of the components," Stafford says, "so that such an event doesn't happen."

Crane parts themselves are expensive, and so is their use. Cranes can cost up to $700,000 apiece, with individual components valued at about $17,000 each. Rentals can cost a construction company $25,000 per month for the crane and its components. For all these reasons, it's imperative that Stafford track the precise locations of all its cranes and parts at all times so it can quickly know if a piece is missing, as well as where to obtain the piece it needs.

Stafford is deploying the AssetPulse system in two phases, says Vijay Sarathy, AssetPulse's cofounder and vice president of marketing. Initially, he explains, the ID numbers of tags affixed to crane components are being captured with an RFID reader in a backpack carried by Stafford personnel.

The company is using active 433.92 MHz RFID tags from RF Code on its cranes and parts. The tags use a proprietary air-interface protocol and have a read range of 300 to 2,500 feet, depending on the size of the reader antenna. Their unique ID numbers are captured by the RF Code reader, loaded in a seven-pound backpack that Stafford personnel can wear at a job site.

Using the reader, employees can immediately determine if all components are present and verify which construction site they are in. The interrogator connects wirelessly to a laptop at the site, which then transmits via a GPRS connection to the server running the AssetPulse software and hosted by AssetPulse. Stafford, or its customers, can log on to the software via the Internet and locate a specific crane or its components.

For the second phase, scheduled to begin in the next quarter of this year, each crane will have its own RFID reader installed in its cab, to identify the components used for that crane. Data will be transmitted via a GPRS connection. The cranes will also have GPS units installed so Stafford can pinpoint the location of the crane or its various components at a large construction site.

The AssetPulse asset-tracking software can operate with any RFID or bar-code readers, Sarathy says. The server, where data about the parts and their locations resides, can be hosted either by the customer or by AssetPulse. "It's a completely agnostic system," he says.

Stafford Tower Crane intends to make the system available to its customers as well, by encouraging them to purchase their own RFID readers and tags for such high-value items as the generators frequently located at construction sites. "We're happy with the way things are progressing," Stafford says, adding that the larger division of Stafford Tower Cranes, located in Ireland, may follow the lead of the U.S. division with RFID tracking.

Using the backpack reader, Sarathy says he can now go to a job site, turn on his reader and immediately know if a component has been left behind with a new shipment. "When I arrive at a staging area," he says, "I know what inventory we have out there."

For the second phase, the interrogator in the cab will replace the need for a backpack reader.