Every year Mediterranean Europe is severely hit by forest fires. The resulting economic and environmental damage is enormous. The problem of forest fires has cultural, social and economic aspects that cannot be easily addressed. To limit the burned area, it is important that once a fire has started, the firefighting services intervene rapidly, as after a certain point fires become increasingly difficult to control and this requires very early detection.

Currently, detection of forest fires is carried out by observers or by means of passive sensing systems such as near-infrared cameras.  However their range of detection depends excessively on environmental and weather conditions and since they are line-of-sight systems, their detecting capability is drastically reduced in mountainous areas. The aim of the work that has been carried out at Instituto Superior Técnico is to assess alternative active sensing methods for fire detection based on lidar. These systems emit electromagnetic radiation and capture the radiation that is backscattered by the smoke plume.

Appropriate mathematical processing of the signal enables the dimensions, distance, and velocity of the target to be determined. The advantages of active (as opposed to passive) sensing methods are greater sensing distances, constant sensitivity around the clock, relative independence of atmospheric conditions, and accurate determination of the distance to the fire.  Lidar has been used extensively for studying the atmosphere and wind regimes, for military applications and in remote sensing, but currently available lidar equipment is unsuitable in terms of cost, size, and ease of use for the application under consideration. The on-going project aims to apply for the first time a simple, biaxial monostatic lidar to the sensing and study of forest fires.

In field tests carried out within the framework of a joint international project (GESTOSA, see http://www2.ruf.
uni-freiburg.de/fireglobe/iffn/
country/pt/pt_5.htm)

the researchers have successfully detected experimental campfires produced by burning dry grass and olive logs at a rate of just 0.02 kg/s up to distances of 6.5 km. For burning rates of 2 and 10 kg/s, theoretical calculations allowed to estimated ranges of 17 and 23 km, respectively, provided that the weather conditions are good. The smoke plumes manifest themselves in raw lidar signals as narrow peaks. Automatic fire recognition with acceptable low level of false alarms was solved using neural networks. A new instrument provided with scanning ability and based on an eye-safe laser is presently under development.

For additional information, contact Prof. Rui Vilar, Departamento de Engenharia de Materiais, Instituto Superior Técnico, Av. Rovisco Pais 1, Lisbon 1049-001, Portugal, telephone: +351 21 841 8121, email: rui.vilar@ist.utl.pt.

Note the data being collected as soon as the mattress is ignited.  At 2.25 seconds a thermal image is overlaid so that the burning mattress flames can be viewed. 
(Click HERE to run AVI file.)

After a number of prison fires, (in particular, a prison fire which claimed the lives of five inmates in 1987.) the Metropolitan Fire and Emergency Services Board, Melbourne, Victoria, Australia, was asked to conduct fire tests on prison mattresses.  The focus of the study was on the flammability of mattresses that could be or were in use in the Victorian prisons. 

The goal of the fire tests was to identify the best mattresses to be used in a correctional facility. However, before work could begin, a study was made of the standards for testing mattresses and bedding.  Standards from Australia, Britain, New Zealand, and the United States of America analyze the material properties used in mattresses and their resistance to various ignition sources, heat 

flammability and smoke development.  Not all tests used a pass or fail grading system to rate mattresses.  It was learned that no single standard assessed the fire hazard of the mattresses under actual fire conditions.   To gather fire performance data for prison mattresses, test mattresses were ignited in a replica of a prison cell.

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