The Pathfinder system is a firefighter locator. The system consists of two parts, a Beacon, which transmits an ultrasonic homing signal, and a Tracker, which indicates the path to the specific Beacon. Beacons can be used to identify firefighters, exit/egress points, and auxiliary/internal waypoints. The Firefighter Beacon funtions similar to a PASS device: there is an automatic activation, a motion sensor detects movement, a pre-alarm goes off after 20 seconds of no movement, the device alarms after 30 seconds of no movement, and lastly there is a "panic" button.
The Tracker listens for the specific signal from a Beacon and displays the strength visually with a bar graph and audibly by a series of beeps. By scanning a room with the Tracker – much like scanning with a flashlight – and by moving in the direction of the strongest signal, a disabled firefighter or exit can be rapidly located. One could think of the Beacon as a lighthouse on a clear night, and the Tracker as your eye.
Think of finding a firefighter as the process of solving a maze. When you sit down and try to figure out your strategy, you first need to identify the start and finish of the maze. These two locations are very useful, but they don't tell you how to navigate in between. To do that, you need to have an understanding of what the PATH is like between the two points.
Now Look at the image to the right. The firefighter in trouble is at the location marked "X" and the Rapid Intervention Team (RIT) is entering at location "A." If the RIT knows that the firefighter is in the middle of the building, they might be tempted to head in the direction of door "D" and then "E." Unfortunately, that is the wrong direction to go.
What the RIT members really need to know is how to get to the firefighter, not just his location. In this example, the RIT needs a tool that would give the PATH to get to the firefighter. The Pathfinder system is designed specifically for this purpose. Ultrasound does NOT go through walls, so it travels through the door opening at "C", down the hallway "B", and to location "A." This creates a distinct path, avoiding blind alleys and obstructions. The Tracker tells the RIT to head inside, go down the hallway to the right, and head to the doorway (shown as "C"). It then tells them where to go within the room, right to the firefighter.
One of the apparent advantages of using a radio frequency (RF) approach is that some radio waves can penetrate walls, allowing a firefighter to "see through walls." A serious problem arises from this. Essentially, RF indicates the shortest path as the crow flies, which is often through walls and other obstructions. When a firefighter is low on air, you don't want to spend time breaching when you could be navigating the clear PATH to him or her. Imagine the time it would take to cut through a concrete wall. Now imagine how much how much crucial time could be saved if you were given a path around that wall. The Pathfinder™ system provides that path.
Consider the above example in question 2. The firefighter is at the point marked "X" and the Rapid Intervention Team (RIT) is entering at location "A." An RF device would tell you to head straight through the wall to the firefighter. From the perspective of the RIT members, they don't know how many walls will have to be breached along that route; it may be several. Even worse, if the RIT does not have the appropriate (and heavy) tools, breaching may not even be an option. Knowing that going through the walls may take more time than the firefighter has air, they might be tempted to head in the direction of door "D" and then, eventually, door "E,” resulting in a longer and less effective search.
No. A thermal imaging camera (TIC) allows a firefighter to see through smoke by sensing very-long-wavelength heat signals. If a firefighter is disabled, a rescue team must search for the firefighter. Since the heat signals are not reflected very well by most surfaces, TICs are essentially line-of-sight; that is, any obstacle between the TIC and the firefighter will block the view of the firefighter. As a result, an area must be completely searched until the firefighter is located. If the firefighter is covered by debris – particularly hot embers – the image of the firefighter may be obscured.
The Pathfinder™ system uses an ultrasonic Beacon to send a homing signal, which can be sensed by a Tracker. This ultrasonic signal travels through smoke unobstructed. However, since walls and other surfaces easily reflect ultrasonic signals, a downed firefighter behind a desk or sofa, or even around a corner, can be easily detected. If a firefighter is covered by debris, the homing signal will escape through the debris and can be detected by the Tracker. The Pathfinder™ system is not limited to being a line-of-sight system.
One of the advantages of the Pathfinder™ system is that it can tell you not only which direction to go, but more importantly, what directions not to go. Thus a rescue team can save valuable time by not looking in places where the firefighter is not located.
No. One of the requirements of a Pathfinder™ Beacon is that it OPERATES like a PASS device. For the safety of the firefighter, the unit has to have an automatic means of turning on. It also needs to be activated automatically if the firefighter falls unconscious. And lastly, there has to be a manual alarm or "Panic Button" for the firefighter to use in an emergency.
The reason the Beacon is not just a PASS device has to do with how the signals are received by the firefighter. Think of your ears and a PASS device as one system, and the Pathfinder™ Tracker and Beacon as another system. The PASS device and Beacon are similar in that they both transmit sound in all directions (the Beacon transmitting both sound AND ultrasound). The Tracker and your ears are different, however. While your ears hear in all directions, the Tracker only listens in the direction pointed.
When you try to locate a PASS device with your ears, you hear sound in all directions. When your vision is very limited, or altogether gone, this can become incredibly confusing. Echoes and non-directional hearing can often lead firefighters in the WRONG direction, wasting large amounts of time. The Tracker, on the other hand, only listens in a very specific direction. The unit will tell you the intensity of the signal in the direction pointed. When the largest signal is found, that is the direction of the SHORTEST path to the firefighter.
No. The system does not interfere with PASS devices, thermal imaging cameras, or radios.