Apr 07, 2009When Structural Metal Decks Ltd. (SMD), one of the United Kingdom's largest providers of composite concrete flooring, faced the prospect of laying off workers due to the current economic downturn, the company discovered a way to keep them employed by providing its own safety nets in house, and by tracking them with radio frequency identification. The RFID system, provided by British firm Core RFID, enables the structural floor company to track the location and condition of its own 500 safety nets, previously leased from outside sources.
The company has provided flooring in such locations as London's Heathrow Airport and 02 Arena, as well as at Dubai's Ski Dubai resort and Burj Dubai hotel, installing 1 million square meters (10.8 million square feet) of flooring each year, with approximately 500 projects in the same timeframe.
About six months ago, faced with declining revenue due to the recession, SMD chose to begin managing its own safety nets, in order to reduce the cost of leasing them. U.K. law requires that nylon safety nets be installed for construction workers in elevated work sites, and that the condition of those nets be closely monitored and tracked. Ultraviolet rays from the sun can weaken the nets, says Craig Galway, SMD's contracts director. Therefore, the firm needs to track not only the results of net inspections on a regular basis, but also where the nets have been, and the types of conditions to which they may have been exposed.
Initially, Galway says, the company tried a tracking method that utilized bar-coded labels attached to the nets, but found that the labels could not withstand the rigors of the job site without becoming unreadable due to dirt or damage. Tracking the nets manually by means of a label printed with a human-readable seven-digit serial number, he says, was out of the question since the nets are stored in a warehouse where blowing wind and rain can make it very difficult for employees to handwrite the serial numbers on a piece of paper to be stored in the office.
In mid-March 2009, SMD launched an RFID system, provided by systems integrator CoreRFID, that includes tags for the nets themselves, as well as two Motorola MC35 handheld computers with built-in RFID interrogators and CoreRFID's Portable Data Collector software to manage the data related to those reads. This information includes when the nets are inspected, where they are sent and when they return. HID Global HF 13.56 MHz tags, compliant with the ISO 15693 standard, are applied to the corner of each safety net. These tags store a unique ID number linked to data regarding that net in SMD's back-end system, such as its manufacturer, date of manufacture and seven-digit serial number, as well as where it has been used. CoreRFID can host the server that stores such data, says John Williams, CoreRFID's marketing manager. In this case, however, SMD opted to host its own server, and worked with CoreRFID to locate the best point for attaching the tags.
As the nets are used and their tags repeatedly read, additional information about them accumulates, including the projects for which they were deployed, the time at what the nets were used, who booked a particular net for a specific job, and details regarding all repairs, tests and inspections.
There are several scenarios in which records of the nets would be required. Governing agencies might request the records, as could the company itself when determining whether a specific net is safe to be sent onto a work site. In addition, customers at a site might ask to view records of the safety nets in use at that location.
With the new system, staff members utilize the handheld interrogator to read a net's tag ID number when a net is first used, inputting data related to that net in the back-end system. Then, every time the net's status changes—when it is sent to a job site, for instance—an employee interrogates the tag and inputs that work site's location. A worker again reads the tag when the net returns, when it is inspected, and when it is sent to a repair area, or to a stock area to remain in storage until the next time it is used.
Safety nets typically have a three- to five-year life span, Galway says. By tracking the nets' usage and repair history, he explains, the company will have better control of how the nets are used, and be better able to maximize their usage before the lifetime expires. What's more, the system tracks how long it takes to repair a net, as well as what led to its breakage or damage.
"We can also run a report to see which nets are due for an annual test," Galway notes. Whenever the firm attempts to send a net to a work site, it receives an alert notification if that net is due for inspection within the next 45 days.
"Training the users was easier than expected," Williams says. "Mainly, we think, because the system is much less cumbersome than the previous manual one, and the point-and-click approach we use seems to be liked by the site staff. The only unexpected item was that mobile network coverage at one site was less than anticipated." That, he says, was because the readers were using a GPRS connection with a SIM card to transmit data to the back-end system. According to Galway, SMD is now switching to a Wi-Fi connection to achieve more reliable data transfer. "Since the software supports that, too," Williams states, "it wasn't really a problem."
