Italian Gas Stations Install Leak-Sensing RFID System

By Claire Swedberg

Wolftank is providing a solution that includes nanotron Technologies active RFID tags to send alerts as soon as fuel seepage is detected.


Wolftank, an Italian petrochemical industry technology firm that manufactures a wide range of products for gas stations and other companies, is providing a gas tank safety solution that includes a radio frequency identification sensor that can detect a potential leak and issue alerts accordingly. The system, which employs RFID technology provided by nanotron Technologies, is currently in use by 50 fuel stations throughout Italy.

Wolftank has 9,000 customers—primarily gas stations—95 percent of which are located in Italy. Most recently, the company has been providing refurbishment services to help gas stations comply with new legislation requiring all gas storage tanks to be double-walled (previous tanks had single walls).

Wolftank provides the cleaning and refurbishment services and equipment necessary to convert single-walled tanks to two walls. In addition, the firm is now offering a solution known as SEF16, with a battery-powered RFID sensor to measure conditions within the underground tank, and to issue an alert in the event that a leak is detected, says Martin Majohr, Wolftank’s director of research and development.

With a traditional cabled sensor system, a trench would need to be dug in order to accommodate a cable installed at the tank and traveling back to the station’s management system. Using a wireless system renders the cable unnecessary; however, the tag battery may need to be periodically replaced—typically, about once every two years, depending on the conditions around the tank and the frequency of transmissions.

The Wolftank system utilizes an active RFID tag from nanotron that transmits sensor data from an underground tank to a reader installed at the ground surface via a 2.4 GHz transmission complying with the IEEE 802.15.4a standard. The SEF16 tag is inserted into the underground chamber in which the tank is located, at the manhole opening. The tag’s sensor measures the pressure between the tank’s two walls. If the pressure changes (reaching approximately 300 millibars), the device determines that a leak may have occurred inside the inner storage wall. The tag then transmits an alert to the reader installed at the surface above the tank, with the device forwarding that alert to the gas station’s control center, usually located near or in the station office or dedicated kiosk. The tag’s typical read range through the ground is 10 meters to 15 meters (33 feet to 49 feet), depending on conditions—some types of soil can be more difficult to transmit through than others.

For stations operating multiple tanks, the distance between a reader and the main station can be large; therefore, repeaters are installed every 200 meters to 300 meters (656 feet to 984 feet). In that case, the reader transmits the tag’s sensor data and unique ID number back to the nearest repeater until it reaches the back-end system, where a gateway has a cabled connection to a PC. There, Wolftank’s management software interprets the read data, including each tank’s unique ID and sensor readings, along with a time and date stamp. That information can then be stored in order to create a record of each tank’s sensor readings. Wolftank software typically resides on a user’s back-end system, and can share its data with the user’s own management software, thereby allowing that company to receive alert messages from its own systems via cell phone, SMS text message or e-mail.

The nanotron tag accomplishes transmission through the ground with its chip spread spectrum (CSS) technology, in which the tag sends a chirp amounting to a brief transmission across all of the 2.4 GHz band. In that way, the most effective point of transmission across that band is used to send data through the ground to the reader at the surface—a function that not only makes transmission more reliable, but also requires the least amount of power from the battery. The repeater utilizes the same chirp technology to transmit information to other repeaters or readers located aboveground.

Majohr says the sensors can be accessed via the manhole, as part of routine maintenance to the system and tanks, so that the batteries can be replaced, if necessary.

One gas station in Lana, Italy, is employing the system to monitor four fuel storage tanks that Wolftank converted to double-walled tanks. “Due to the wireless connection, we avoided the cutting of the forecourt which we rebuilt completed a few years ago to obtain a uniform and good-looking surface for the entire gas station,” the station’s owner reports. By using wireless technology, he adds, “during the reconstruction work and installation of the monitoring technology, we [didn’t need] to close the gas station and so avoided a loss of sales.”

According to Majohr, the solution can also work in other applications in which hazardous materials (either oil and gas or chemicals) are stored in areas that are difficult to access, and where wired sensors can be inconvenient.

Wolftank began installing the solution at 50 of its petroleum tank-owning customers in April 2011.