In the nick of time
Losing track firefighters on scene happens more than anyone would like to admit. For example, in the 1999 Cold Storage warehouse fire, six Worcester (Mass.) firefighters were only a few feet from an exit when they died. The tragedy led to researchers at the Worcester Polytechnic Institute to tackle the problem by building a prototype model that uses myriad wireless technologies to track firefighters, said WPI’s Jim Duckworth, co-principle investigator on the project.
The institute was awarded nearly $3 million by the Department of Justice and National Institute of Justice to develop a firefighter tracking system. WPI’s goal was to develop a commercial system that can pinpoint a person’s location in three dimensions to within about a foot, have a range of 2,000 feet and track up to 100 people simultaneously — displaying the position and path of each individual on a laptop at an incident command center, Duckworth said.
Researchers led by Duckworth and co-principal David Cyganski determined that they needed a locator system that included transmitters worn by firefighters and receiver units placed outside the building to pick up those signals. They first looked at existing technologies, including GPS, which works great outdoors but is not suitable for indoor use because “it doesn’t have the correct signal strength and suffers from multi-path, where the radio signals bounce off all the metal surfaces,” Duckworth said.
“There was nothing out there we could currently use so we went back to basics to develop our own radio system,” he said. “We knew our ideas would probably have to be modified, so we built it on a software-defined radio where there’s flexibility on how you modify your signals. If we encounter stumbling blocks, we didn’t have to trash the existing prototypes; we just re-programmed it with a combination of software and firmware.”
Duckworth said the prototype system consists of hardware and software components. Each firefighter wears a small cell phone-sized radio transmitter inside his turnout gear that transmits a special set of tones. Tones are transmitted from the firefighter through the building’s walls and floors to the receiver unit outside the building. The receiver units have antennas that pick up the signals being transmitted by the firefighters and are designed to be embedded eventually in fire trucks. The third component is the base station that picks up all the signals from the receiver antennas.
“Then through signal processing algorithms it determines, in three dimensions, where exactly the firefighters are in the building and, in real-time, data are sent to the command’s computer screen so they can see exactly where all of the staff are at any given time,” Duckworth said.
Mapping software loaded on the laptop lets commanders track firefighters, Duckworth said. In addition, WPI received in 2006 an additional $1 million from FEMA to expand the software system. FEMA wanted the institute to combine location tracking with physiological monitoring because the number-one cause of firefighter fatalities is stress-related heart attacks, he said. So the WPI tracking system has been integrated with a physiological monitoring shirt that Foster-Miller developed. The shirt has embedded sensors that determine heart rate.
“We then added that information to our location tracking, and then on the incident commander screen we developed this GUI map that shows location tracking as well as the vital signs of each firefighter,” Duckworth said.
The fire service needs to track personnel in an emergency, said Jose Vazquez, director of first-responder technologies for the Department of Homeland Security’s Science and Technology Directorate. For example, tracking systems let commanders send search-and-rescue teams directly to the lost firefighters to get them out of a building safely, he said.
“You need a precise measurement of where firefighters are located in a structure so commanders can reduce the time to find them,” he said.
Yet current technologies fail to deliver needed data because of interference issues, Vazquez noted.
“In any large structure you have a lot of different components, like studs, cement, brick, metal objects — all these things create problems as far as interference,” he said.
WPI’s system tries to minimize the problem by using multi-path transmissions, where a radio transmission transmits in several directions, Vazquez said. But he admitted it still needs work.
“Because you’ll have echoing from many different objects, you need to find ways that will reduce the noise and allow the signal to come through so you can get the correct ranging,” he said. “WPI still needs additional development and testing to meet first-responder requirements.”
Also researchers still are working on ruggedizing the transmitters worn by firefighters, Duckworth said.
“Our prototypes are fragile … we couldn’t drop them from a great height and they wouldn’t survive high-pressure water in an incident,” he said.
Duckworth said receivers worn by firefighters may cost $500 to $800. Receivers embedded on fire apparatus would be between $1,000 and $2,000, he said.
Some tracking systems have already hit the market. ERT Systems offers OnSite ERT, a rapidly deployable system for tracking emergency personnel and equipment at a scene, said company president Dennis Carmichael.
OnSite ERT consists of sensors and transmitters, as well as software pieces. Each person or piece of equipment is tagged with a small, lightweight ID badge powered by a AAA battery. For example, the tag is placed in sewn pockets on firefighters’ turnout gear or strapped to the side of equipment. The tags then are read by drop readers, which are lunchbox-sized, hardened units manually placed around the fireground. When the unit is activated, it seeks out a GPS lock and looks around for “any other drop units it can see,” Carmichael said.
Carmichael added that the drop readers create an ad hoc network. If additional boxes show up — regardless of which public-safety agencies deploy them — they’ll join the network already in progress and relay information point to point.
Boxes are dropped around the fire zone — determined by command — and are assigned to a predestinated zone, such as for decontamination or live fireground. Data are sent to a command laptop. The command laptop gets the signal strength readings off the tags and the GPS coordinates for boxes. Then, the GUI displays zone and firefighter locations.
“It keeps a running log of everybody, such as where they are located in the building, how long they’ve been there, their movement and so forth,” Carmichael said.
A status page lists firefighters and equipment, as well as in which zone each is located. Zones can be color-coded per a department’s preference, said John Ellis, the company’s vice president of product design. “But typically a hot zone is red, staging is green and rehab might be blue. The inside box changes when the firefighter moves from staging to a hot zone,” he said. “Keep in mind the application is customized, so departments can name zones based on their specific terminology.”
Carmichael said any departments in a region that purchase the equipment can interact with other departments at a large-scale event, if their PC has an Internet connection. “If there is a large-scale event and personnel from another department provide mutual aid, they can be added to the network,” he said. “If they have the system, then the tag is read by the command software, [which] searches the Internet for photo identification and provides verification as they arrive on scene. [The software] adds the scene commander zone on the GUI, same with vehicles and apparatus.”
The Englewood (N.J.) Fire Department recently deployed the system. Englewood is a career fire department with technical-rescue, hazmat, structural and basic life support response with an annual call volume of approximately 2,200. The department purchased the system with funds from an Assistance to Firefighters Grant, spending about $44,000 for four readers, 55 tags and three software licenses, and also to modify the turnout gear, according to Deputy Chief Gerald Marion. “It has been used for only one fire structure call so far,” he said.
But he added that fire is a dynamic and fluid environment where firefighters move through different roles quickly. “And we’ve been in situations where we’ve lost track of personnel or they weren’t where we expected them to be,” he said. “So when we saw this technology, it intrigued us.”
Other tracking systems didn’t have the flexibility the department needed, Marion said. Most were tied to specific devices that had to be on the person at all times, such as SCBA. Instead, ERT’s system was mobile. The department had special pockets sewn onto their turnout gear for the ID badges, which though removable usually are left in pockets.
“If we are in a technical rescue where we are not wearing an SCBA we can still get a count of personnel on scene,” he said of the tags.
Marion said the GUI shows a two-dimensional representation of color-coded zones that can be customized. He said adding additional boxes helps command more finely tune the tracking of personnel.
“The more lunchboxes you have — because that’s what they look like — the more you are able to finely tune where your people are at,” he said
Marion said public-safety agencies interested in tracking personnel have plenty of homework to do. He said leadership needs to examine all the accountability systems available, the way each operates and determine what the department hopes to get out of such systems before committing.
So far, ERT’s system has performed to expectations.
“I was able to see every single firefighter that was on scene,” he said. “It also gave me the tools I needed to account for my personnel, take a roll call and provided alarms to when they might be running low on air.”