Early Forest Fire Detection and Verification using Optical Smoke, Gas and Microwave Sensors

AbstractThe research project “International Forest Fire Fighting” (iWBB) was funded by the Minister for Economic Affairs and Energy of the State of North Rhine-Westphalia, Germany. A group of companies, research institutes and universities have been working together to develop an integrated, but modular system. An integrated approach for early forest fire detection and suppression is based on an adequate combination of different detection systems depending on wildfire risk, the size of the area and human presence affiliated with an adequate logistical infrastructure, training by simulation, and innovative extinguishing technology. As in the case of wildfires large areas have to be monitored only remote sensing technologies (e.g. video based systems) are able to perform early detection adequately. To reduce false alarms a remote controlled unmanned aerial vehicle (UAV) equipped with gas sensors and a thermal camera flies to a potential fire to specify the origin of the reported cloud. The UAV can also be used as a scout for fire fighters. After successful fire extinction an unmanned blimp can be used as a fireguard to reduce the risk of re-ignition of the fire. As monitoring tools, a microwave radiometer detecting hot spots also at insufficient vision (due to smoke clouds and below the ground surface), gas and smoke sensors and a thermal camera are mounted on the blimp. The benefit of a blimp is a higher payload. This paper presents an investigation of an early forest fire detection system on the basis of indoor (performed in the fire lab of the University of Duisburg-Essen) and outdoor tests. A commercial highly sensitive aspirating smoke detector, two gas sensors (H2 and CXHX), a microwave radiometer and the detection algorithms are described. A general overview about the project and the carrier platforms is presented

Analysis of Dust Properties to Solve the Complex Problem of Non-fire Sensitivity Testing of Optical Smoke Detectors

AbstractThe purpose of an automatic fire detection system is the fast and reliable detection of arising fires in order to keep damage as low as possible. The European Standard EN54 defines a series of tests to prove and certify the functionality of smoke detectors, i.e. to prove that the detector is able to detect a fire in a prescribed period of time. Unfortunately the complex task of avoiding false alarms is not completely addressed. In contrast to the well standardized methods for the evaluation of the detection capability of a smoke detector, there is a lack of a reproducible and representative test method concerning the false alarm susceptibility with regard to nuisance aerosols. The consequences of false alarms should not be underestimated, as they may cause costs to serve the operator, especially in airborne applications. Many false alarms are caused by construction works in the surrounding of smoke detectors. For that reason several dust sources have been analyzed. Several approaches are possible and have been implemented to reduce the false alarm susceptibility of optical smoke detectors caused by dust and steam, e.g. different wavelengths and scattering angles. Unfortunately the developer has no representative test methods to quantify improvements and to point out the false-alarm resistance with e.g. a seal of quality due to new developments. Important is the knowledge of dust and steam properties such as the particle size distribution in comparison to particle size distribution of smoke of a fire. This paper presents a new approach for the test of smoke detectors regarding their susceptibility to false alarms due to nuisance aerosols, like steam and dust. The presented test apparatus is a very helpful and important tool for developers as well as for test houses during the developing and certification process. System designer will have a quantitative decision criterion to find the optimal detector for a specific place of installation. The paper compares the analysis of dust properties caused by construction works with standardized test dusts and shows how to solve the problem