USA — Brush fires occur all too often in Southern California. Dry brush and high winds from the desert can quickly escalate a spark from a campfire into a deadly inferno that sweeps across coastal rolling hills and inland towns covered in dry, brittle brush. So it makes perfect sense that the U.S. Forest Service, the agency’s San Dimas Technology Development Center, and the Los Angeles County Fire Department wanted to test an RFID-supported platform that could provide early-warning signals in the event of a fire. To that end, the group conducted a controlled early-detection burn test last month, focused on bulldozers and shrubs on site in Castaic, a community in California’s Los Angeles County.
The U.S. Forest Service and the Technology Development Center set out to mimic a high-intensity wildfire engulfing bulldozers in flames, on land owned by the L.A. County Sheriff’s Department. The group wanted to test a burn-overthat is, when an object becomes engulfed in flamesin order to determine the best scenario for this critical situation. The project tested two types of bulldozersenclosed and open cabmonitoring both inside and outside temperatures, along with gasses omitted from burning plastics, to determine the best place for survival in the event that firefighters get caught in a blaze. When fighting a conflagration, bulldozer operators clear a section of forest to create what is called a fire line. When the wind shifts, it can put an operator in danger. The Los Angeles County Fire Department helped to conduct the test, allowing the fire to burn for 30 minutes to an hour before cleaning up the burn site.
ProximaRF provided the ProxFire Detection System (PFDS), an integrated solution aimed at detecting wildfires, and worked with IT logistics firm Naniq Systems to implement a platform that monitors fires as they occur. RTSync Corp., which develops advanced modeling and simulation methodology and software/hardware environments, identified the placement of sensors for the test. The company is a commercial spin-off of the Arizona Center for Integrative Modeling and Simulation, operated by the University of Arizona and Arizona State University.
The PFDS solution is designed to support early and rapid response protocols, to save lives and reduce environmental and property damage. The system operates on a sensor-gateway network consisting of RFID-based 433 MHz sensors from Sensible Solutions Sweden AB, as well as a gateway to receive the RF signals transmitted by the sensors.
In the absence of a fire, the sensor remains dormant and functions as a passive RFID tag. But if the temperature reaches 170 degrees Fahrenheit (77 degrees Celsius) from a developing fire, the sensor activates and uses its battery power to transmit a signal encoded with a unique identification number to a PFDS wireless gateway in range of the signal, which relays the alarm to the ProximaRF software, which can then be accessed via the Internet at a central location, such as an operations center for forest-fire response and management. The gateway transmits its location (thanks to a built-in GPS receiver), as well as a timestamp and the sensor’s ID number. The RFID sensors support a 3,000-meter (9,843-foot) transmission read range to the gateway. If not burned, a sensor’s battery will operate for approximately three years.
“My concern is that it can be several years before a fire occurs in a particular area, so if we put the sensors in that area, will they still work if the sensors need batteries?” says Ralph Gonzales, the San Dimas Technology Development Center’s fire program leader. “Science Tomorrow has a similar system they claim is passive and sends a signal once it reaches a certain temperature.”
For the burn test, located on land used by Los Angeles County’s Pitchess Detention Center, the Southern California team employed 14 sensors covering a total of approximately 1.5 acres (about two sensors per acre). Two unburned sensors were recovered. The preliminary analysis, Gonzales says, suggests the trio achieved positive results, measured by the ability to achieve specific temperatures and collect data.
While there are several ways in which to distribute the sensorslaid on the ground, or tossed from a low-flying plane or helicopter into heavily wooded areasfor the Castaic test, each sensor was hung from a tree, according to Kimberly Gray, Naniq Systems’ director of RFID-IT logistics. Gray helped implement the system for the site’s test burn.
The gateway, which is powered by a battery and coated with a special resin to protect it against the elements, supports WAN connections through multiple interfaces, including GSM data, GPRS, 3G and Wi-Fi. The device performs a self-diagnostic test to establish communications protocols.
“It took four minutes after the fire was set during the Castaic site test before the first sensor transmitted a signal to the gateway,” says Brent Chapel, ProximaRF’s CEO, who estimates that a fire burning for six hours costs about $2 million. “If we’re able to get the firefighters to the scene within half an hour, we can hold the size of the fire to seven acres.” Chapel estimates that the PFDS platform would cost $14,000 per square mile to deploy. Based on information received from the Western Forestry Leadership Coalition, Chapel believes the return on investment far outweighs the expense. Statistics from the Western Forestry Leadership Coalition, he says, reveal that the total cost of fire damage reached $2,082 per acre in 2007, or about $1,332,000 per square mile. That total takes into account the length of time gateways and sensors either remain dormant or are used under normal conditions.
Most wildfires are already out of control by the time firefighters can detect them. For that reason, the threat of fire has been a major safety issue for years, especially on the 18,000 acres of land surrounding Malibu, Calif., and for the homeowners who live in that area. The current method of predicting possible threats in that neighborhood, Gray says, consists of firefighters stationed at watch sites, looking through binoculars to monitor what is taking place in and around the coastal community.