FireLess II

System components

Gateway: Gathers the sensor signals and transmits them to the control center by means of cell phone network. Solar powered.

Sensors: Detect temperature and humidity of litter as well as humidity of humus. Battery powered.

A weather station can be combined with the gateway to measure air temperature and humidity, wind speed and direction as well as precipitations (mm/h)

Dynamic forecasting of the risk of forest fires

A new system for dynamic forecasting of the risk of forest fires allows authorities to plan their standby services more effectively.

Today, in order to forecast forest fires, it is usually the case that the moisture of the combustible material is indirectly derived from the area’s meteorological data. However, as different soil types and forest types react differently to changes in humidity, the calculations do not always correspond to the local conditions. For this reason, WSL researchers from Bellinzona and the company Enveve, a remote measurement specialist, have developed the system Fireless2, which determines the moisture of forest litter and humus locally. A set of sensors on and in the forest floor is wirelessly connected to a solar-powered mini control centre which continually transmits the measurement data to the monitoring authority’s computers. Taking the current meteorological data into account, these can then provide a precise picture of the risk situation.

WSL has put the system through extensive field testing over the course of two years. Interest was mainly focused on whether the data obtained with sensors delivers reliable indications of the actual risk of forest fires. The assessment of forest fire risk from Fireless2 was regularly compared with an assessment based on the customary measuring method, in relation to actual fire outbreaks. In addition, samples of combustible material were regularly taken in the field, so as to determine how moist they actually were. The field tests showed the correlation between the system’s estimate and the actual moisture of the combustible material to be, in some respects, considerably stronger with Fireless2 than with the conventional method. In particular, the measurements in humus and in needle litter delivered highly precise results. With regard to leaf litter, the correlation was within normal limits. However, Fireless2 was able to show trends (i. e. decreasing or increasing moisture) more quickly.

(Text originally published on ethrat.ch)

Technical Details

Communication:  433 MHz bewteen sensores and gateway, GSM for the interaction beween gateway and control center. A Collision Detect Algorithmus is used to manage transmission errors.

Power suppy: The gateway can store up to 30 days of data. Its internal battery is constantly recharged by a solar panel, with a backup battery ready for critical situations. The sensors are optmized for minimal power consumption and each have a battery designed to last up to five years.

Security: The whole system ist waterproof and windresistant. Data transmission is

encrypted.

• FireLess II function schema
  

• Gateway  (Section "Sensors on Board" concerns the optional weather station)
  

• Litter Sensor

• Humus Sensor
  

More information

• WSL: Forecasting the risk of forest fires more precisely (ETH Board)
  

Contact

• Marco Conedera

• marco.conedera@wsl.ch