Engineers from UNSW Sydney have created a new fire detection system that uses Wi-Fi signals to identify fires. A scheduled controlled test detonation of a car by the Sydney Harbor Tunnel Company offered additional data to show the technology's effectiveness.

Fire Safety Standpipe Sprinkler
(Photo: F. Muhammad/Pixabay)
Fire Safety Standpipe Sprinkler

Thermal Imaging False Positive Readings

Detection systems currently in use, which are primarily based on thermal imaging, frequently produce false positive readings by picking up levels of smoke or changes in temperature that are not dangerous or brought on by an actual fire, such as from a damaged exhaust pipe on a car or a hot radiator.

Some scientists make an effort to solve such problems. In 2019, KoreaScience published a study that provides a fire detection algorithm with a low false alarm rate suited for a thermal imaging surveillance environment whose characteristics alter based on the time of day or night and environmental changes.

New Wi-Fi Dependent Fire Detection System Technology

Recently, a new device that tracks Wi-Fi signals as they travel through the air has been developed by a team from the School of Electrical Engineering and Telecommunications, led by Professor Aruna Seneviratne and Dr. Deepak Mishra. Additionally, it examines in-depth environmental alterations brought on by things like temperature and smoke.

The researchers have recognized the specific patterns in the data from radio signals during fire incidents, and artificial intelligence within their program aids in real-time environment analysis. This allows the system to more accurately assess whether an actual fire is bringing on any atmospheric changes, and if they are, they can raise the alarm or start an automatic sprinkler system.

Proof that Wi-Fi Dependent Fire Detection System Works

In the middle of the night, within the Sydney Harbor Tunnel, Seneviratne and his colleagues were able to demonstrate their novel technique during a controlled test. During a planned emergency response training exercise, the researchers put up a number of transmitters and receivers to monitor the environment as a test car designed for the purpose was detonated and set on fire. 

The researchers collaborated with the Sydney Harbor Tunnel Company, the owner/operator of the tunnel, and Tantek MST, the tunnel's present mission-critical equipment provider.

According to Seneviratne, it is essentially high school level physics. He said they could track the radio signal moving through the air since they have a transmitter and a receiver. The density of the air varies with temperature and alters the signature of the reading when they receive the signal. In fact, they have experimentally shown that these variations are closely related to the temperature differences between the transmitter and receiver.

The density of the air is also impacted by smoke and other chemicals, such as carbon monoxide, which can be formed in fire scenarios. These substances will leave distinct signatures on the results. These signatures are specifically recorded as wireless channel information.

In order to evaluate whether a real fire is occurring, the researchers also include artificial intelligence into the system to analyze all the data and compare it to baseline measurements.

Wi-Fi Waves Various Transmission Frequencies

The novel method created at UNSW uses subcarriers and different transmission frequencies found in Wi-Fi signals. Similar to how various items have unique effects on various light wavelengths, various Wi-Fi frequencies similarly have a range of effects.

In order to determine the most sensitive frequencies that may be used for the analysis, the Wi-Fi sensing system combines the impact of environmental phenomena on all of the Wi-Fi subcarrier frequencies. The researchers estimate that processing and analyzing up to 1,300 packets of data per second is possible.

The new method, according to Seneviratne, is crucial to boosting confidence in automatic fire detection systems, which at the moment can occasionally struggle even to tell the difference between a fire and a bright, flickering neon light.

The UNSW team is certain that their method can be used in various settings, including industrial sites, commercial high-rise structures, and even homes.

Assembling an array of transmitters and receivers also helps to identify the zonal location of a specific fire which can then aid emergency services in responding quickly and efficiently. As well as improved sensing, the Wi-Fi system promises to be much cheaper than existing thermal imaging camera technology and is easier to maintain.

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Fire Alarms Types and Price Tag

According to RealPars, the existing fire alarm systems include heat detectors, smoke detectors, carbon monoxide detectors, multi-sensor detectors, and manual call points. Most of these systems are expensive.

Seneviratne said that their transmitters and receivers cost no more than $100, compared to the $10,000 price tag of existing specialized fire detection cameras. Existing specialized fire detection cameras can cost around $10,000, whereas our transmitters and receivers are $100 or even less. 

He added that another issue with cameras is that they require constant upkeep. The lenses frequently need to be properly aligned and maintained clean. With the new technology, virtually little maintenance is necessary because the transmitters and receivers are just transmitting a radio signal. As a result, running the system is also substantially less expensive.

 

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