SURVIVABILITY AND RESCUE TRANSCEIVER TECHNOLOGY

BY BRUCE EDGERLY

Research has shown that rapid intervention team (RIT) response times are often too long to save the lives of lost, trapped, or disoriented firefighters. Mobilization time, reluctance to initiate Maydays, and the limitations of existing location technology conspire to limit the window of survivability for distressed firefighters. But radio frequency technology, currently in use in the snow safety industry, promises to open up this window of survivability in the fire service.

Introduced by two manufacturers at the 2004 Fire Department Instructors Conference (FDIC), firefighter rescue transceivers (FRTs) are finding a home in the increasingly dangerous U.S. fire service. With hotter fires, lighter construction, more aggressive tactics, and fewer opportunities for live training, firefighters are twice as likely to die inside structures as they were 30 years ago.1,2 Leading causes of these line-of-duty deaths are getting lost, trapped, and disoriented. Firefighter rescue transceivers are proving effective not only in decreasing search times for RIT teams and buddy rescues but in reversing disorientation in the first place-before it gets ugly and deteriorates into a Mayday.

FIRE AND ICE

At first glance, you might ask, “What do fire and snow rescue have in common?” Asphyxiation. In the fire service, this most often results from carbon dioxide buildup in the face piece after the victim’s SCBA runs out of air. In snow safety, most avalanche victims die from asphyxiation when carbon dioxide builds up in the “ice mask” that forms around the victim’s face in densely settled avalanche debris. In both instances, the victim must be recovered rapidly to prevent brain damage or death.

1) Firefighter rescue transceivers (FRTs) can detect the victim�s signal through walls, floors, and other obstacles. A perimeter search on the building exterior can reduce the firefighter search to a small sector, reducing search times and exposure to rescue personnel. FRTs also open the window of survivability by increasing the chances of buddy and self-rescue. [Photo courtesy of Jasonville (IN) Fire Department/Southwestern Fire & Safety.]

Although avalanche rescue transceivers have been available for more than 30 years, it wasn’t until 1997 that the technology became digital and thus useful to the fire service. In its analog form, transceivers were primarily audible-based and required the use of complex volume controls. New digital technology has made this location technology useful in noisy and low-visibility conditions, operable with one hand, and easy to learn. Avalanche transceiver manufacturers offering firefighter rescue transceivers in 2005 include Exit Technologies of Boulder, Colorado, and Ortovox of Munich, Germany.

RAPID INTERVENTION VS. BUDDY RESCUE

Search and rescue procedures also have parallels between fire safety and snow safety. For decades, avalanche rescue was normally performed by organized rescue parties, usually in the form of “probe lines” staffed by scores of volunteers systematically probing the debris pile with metal rods and perhaps the assistance of rescue dogs. Unfortunately, the survival rate was extremely low. Response times for search and rescue teams almost always exceed an avalanche victim’s 15-minute window of survivability. And probe lines proved to be painfully slow, as they require a methodical and well-coordinated advance through the avalanche debris. When avalanche rescue transceivers were introduced in 1968, this enabled instant “companion rescue,” or the location of victims by a member of their own party. Since then, rescue transceivers have become essential equipment for winter recreationists traveling in avalanche terrain. As a result of this technology, more than half of all completely buried avalanche victims now survive.

(2) The Tracker FRT from Exit Technologies is switched from transmit to search mode by pressing the red search button for at least one second (but no longer than two seconds). It can be switched back to transmit at any time. The Tracker will revert to the transmit mode automatically every five minutes unless the searcher presses the button again. This protects searchers who might become incapacitated while performing a search. (Photo courtesy of Exit Technologies.)

In the fire service, rapid intervention is the equivalent of the mountain search and rescue team: The rescue is performed by an organized team outside the victim’s own party. Searches are initiated from outside the structure and are performed room by room and floor by floor, with no distance or directional aids other than the possible sound of the victim’s activated PASS device. Research by Kreis3 and Brunacini4 confirm that rapid intervention is not highly effective in responding to firefighter Maydays. The average time to mobilize a team and locate a victim is more than 10 minutes. This will normally exceed the remaining air supply in the victim’s SBCA-especially if that victim waited to initiate the Mayday until after the onset of his low-air alarm.

The most effective strategy for rescuing firefighters alive is for the search to be carried out by fellow crew members already operating inside the building. (4) This eliminates the time required to mobilize the RIT and can significantly reduce the search time, as it reduces room-to-room, floor-to-floor searching-especially if the search is carried out with a buddy rescue device such as a rescue transceiver.

Figure 1. Case studies show that disoriented ?re?ghters will issue a Mayday no sooner than activation of their low-air alarm-and most often only ¿on their last dying breath.¿ In the best case, this leaves between four and six minutes to be located by a RIT. However, statistics show that RITs take an average of eight to nine minutes to locate a ?re?ghter. This is not rapid enough to prevent a line-of-duty-death. Figure 2. Using a rescue transceiver, a firefighter can self-rescue by reorienting immediately-and avoid tying up the fireground with a Mayday. (Sources: Endnotes 3 and 5.)

Even more effective than buddy rescue, of course, is reversing disorientation in the first place. If the firefighter becomes disoriented and separated from the hoseline and crew, he can use the transceiver to locate the nearest crew member (or egress transmitter). This prevents the situation from deteriorating further, enabling the firefighter to silently continue with his duties rather than tying up the fireground with a Mayday.

TRANSCEIVER TECHNOLOGY

The 457 kHz (kilohertz) frequency is used in firefighter rescue transceivers for the same reason that it is used in snow safety: The signal penetrates dense objects including snow, ice, concrete, steel, and wood. Unlike PASS or ultrasonic devices, the signal is not deflected or absorbed but can be detected through walls, floors, and the victim’s body. The transceiver is worn on the firefighter’s SCBA belt and transmits the 457 kHz signal during the entire firefighting operation. It is easily switched from transmit to search mode.

In search mode, these devices can be used for Mayday and self-rescue scenarios. After search mode is activated, the unit will show a distance (in yards or meters) and direction to the nearest FRT of the same type. In a Mayday situation, the search is performed by the victim’s nearest buddy (from inside the structure) or by the RIT (from outside the structure). If performed from within the structure, the searcher will normally detect the victim’s signal immediately. If the searcher is out of range (approximately 100 feet) of the victim, the search would be initiated at the last seen point, the point of dispatch, or along the hoseline the victim was staffing.

Figure 3. In the primary search, the searcher is out of range of the victim and follows the building exterior, hoseline, or point of dispatch in search of the victim�s signal. In the secondary/bracket search, after the FRT signal is picked up, the searcher follows the distance and directional lights toward the victim. In tight quarters, the directional lights are ignored and the rescuer performs a �bracket search,� keeping in contact with walls and other handrails. Rescuers do not need to deviate from established search protocols.

If performed from outside the structure, the RIT can perform a quick perimeter search to determine the area where the signal is strongest, on the horizontal and vertical axis. By narrowing the search to a small sector and a specific floor, room-to-room and floor-to-floor searching can be minimized, as can the risk to personnel involved in the rescue operation. Once this strongest signal is located, the RIT team can enter through the nearest door or window or breach the wall.

When used in conjunction with a thermal imaging camera (TIC), rescue transceivers have proven to be even more effective: The transceiver will show the distance and direction to the victim and the TIC will reveal obstacles to avoid. Without a TIC, in complex areas with numerous obstacles, the directional lights can be ignored. Instead, transceiver manufacturers suggest a “bracket search,” using only the distance readings.

Figure 4. The Tracker is now in service at more than 10 fire departments in the United States. Timed tests indicate significantly faster search times using FRTs, especially by trained users. Tests were performed January-February 2004 at the Wallingford (CT) and Carrollton (TX) Fire Departments.

For self-rescue, the disoriented firefighter can use the transceiver to locate the nearest buddy on his crew. This is done simply by activating search mode and following the distance and direction displays, making sure the distance readings are decreasing. If several crew members are within range, the transceiver will isolate the strongest signal. Some models also feature a separate egress search channel that can locate egress transmitters that have been placed strategically at exits and other points of safety.

FIELD TESTING RESULTS

Field testing has shown these devices to be extremely effective in reducing search times. In tests conducted by fire departments in Wallingford, Connecticut, and Carrollton, Texas, times were reduced by 72 percent or more, depending on the skill level of the user. In both test locations, firefighters were often able to identify the location of the victim without even entering the building. In cases in which they entered the building, search times were on the order of 4:15 minutes for skilled users with the Tracker FRT vs. an average of 14:52 minutes using standard search protocols without a transceiver.

• • •

The application of transceiver rescue technology to firefighting has great potential for reducing fatalities on the fireground. Although the technology is new to the fire service, it has proven to be effective for avalanche victims, with which firefighters share a similar window of survivability. Field tests to date show that the technology can significantly reduce search times for both buddy rescue and rapid intervention. But the greatest potential for the technology could be in preventing Maydays in the first place-enabling the disoriented firefighter to reorient himself and return to a known location while there is still an adequate air supply. ■

Endnotes

1. “Fire Service Fatalities in Structure Fires,” Fire Analysis and Research, National Fire Protection Association, July 2002.

2. “Rapid Intervention Teams and How to Avoid Needing Them.” USFA Technical Reports, United States Fire Administration; May 19, 2004.

3. Kreis, Steve, “Rapid Intervention Isn’t Rapid.” Fire Times, Phoenix, (AZ) Fire Department, Nov. 17, 2003.

4. Brunacini, Nick, “Resource Intervention Crews: Research and Experience Give RICs New Meaning.” FireRescue, April 2004.

5. Bernzweig, David; “Expanding ‘Time to Exit’ for Firefighters.” Fire Engineering, June 2004.

■ BRUCE EDGERLY is vice president of Exit Techologies in Boulder, Colorado.