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The speed of attack on forest fires is the key to success in fire suppression. Fire alarm routing has to be as rapid as possible, and the site needs to be located with accuracy. At present in France, 70% of fires are reported by individual people; the relief center switchboard is saturated by the use of mobile phones and information can be incomplete, sometimes false. All of these factors disrupt the relief chain.
The human resources involved on the fire scene are the essential core of the detection operations, while automatic detection systems such as satellites, thermal cameras, laser apparatus and analyses of video images are an additional aid to fire detection.
There are a number of products available on the European market. Artis Fire from T2M of France and Sistema Ciclope from INESC of Portugal are based on smoke plume detection, while Bosque from Faba-Bazan of Spain and BSDS from Teletron of Italy are infrared detection systems.
In Europe, the distribution of dwellings, campsites, rubbish dumps — located either within forest massifs or on the urban/wildland interface — calls firstly for fire prevention. Chemical additives in fire prevention could be very helpful in the wildland-urban interface. In the Mediterranean Basin, many city dwellers live on the city boundaries, more and more houses are being built in the forest massifs, and increasing numbers of people spend leisure time in these areas.
Deforestation due to excessive ground clearance must be avoided to protect vegetation. More importantly, retardants used must not have any harmful effects on the ecosystem; the main objective is to reduce vegetation ignition. Studies dealing with the eco-friendly use of chemical fire retardant additives as forest fire prevention are being carried out through the ERAS European Project, coordinated by the Centre d'Essais et de Recherche de l'Entente, or CEREN.
We need to understand how potential fires behave in the vicinity of structures and their impact on the environment, which is the purpose of a European project initiated by the Spanish company Typsa Tecnica y Protectos. The general objective of this project, called Warm, is to characterize direct and indirect risks from fires in the wildland-urban interface in Europe and to provide a methodology and information system to minimize property losses while reducing social and environmental impact, through rationalized wildfire defense plans.
Fire's spread, intensity and duration are strongly related to fuel loading. At present, fuel management such as shrub removal, tree thinning and prescribed burnings are a good way to reduce fire hazard. In the United States, a specific tool called Farsite, based on the Behave Fire Behaviour model of Rothermel, has been developed to help managers with fuel management plans. The Behave model uses input data to characterize the corresponding American vegetation for fuel models.
Specially designed European fuel Behave models have been used to test some prevention plans, as Mediterranean vegetation characteristics are very different from American ones. In two recent European projects, Inflame and Prometheus, seven fuel models have been developed to represent Mediterranean fuels and Farsite can now be used for fuel treatment in European countries. Two other systems have been created to help forest managers through these projects: FMIS and Firestation.
On a European scale, standardization of firefighting tactics, close cross-border collaboration and standardized equipment, will allow for relief operations to be standardized.
World aviation resources include military aircraft that have been equipped as water tankers, such as Trush Commander, Hercules and Illiouchine 76, with onboard water capacity reaching 1,200 to 40,000 liters. Helicopters such as the Ecureuil, Erickson Air Crane and M26 have an onboard water capacity of between 1,000 and 20,000 liters. Amphibious aircraft have been developed by only one company: Bombardier.
At the French Securite Civile's request, CEREN has made comparison tests of drops released from different types of aircraft, studying the ground distribution pattern to determine correlations with the quantity of water dropped, taking into account the dropping system. The SHAEP, or Systeme Heliporte d'Aspersion d'Eau Pressurise, project's objective is to validate a new dropping system by helicopter that includes an 800-liter tank.
Aerial support is a determining factor in the effective development of fire suppression plans. However, its effectiveness depends on the extinguishing agent used. Doping water to enhance its extinguishing or retardant capabilities against the fire isn't new. There are essentially two types of products: short-term retardants with an efficiency time of no more than 30 minutes and long-term retardants which could last many hours.
Short-term retardants are mainly foaming agents. For aerial or ground application, the foaming agent is diluted from three to six parts to a thousand. From an operational point of view, continued use in a wind higher than 30km/h is a waste of time; the drop drifts away from the target.
The main characteristic of long-term retardants is that they remain efficient even when water has evaporated. The chemical compound (ammonium polyphosphate) is the active agent that dissipates under heat action according to endothermal reactions. Tests by CEREN have shown that its efficiency is three to eight times higher than water, especially when fuel dehydration is total. An economic study has shown that aerial transportation of retardant costs less than water.
Retardant action has been studied in the Acre Project, coordinated by CEREN, showing that the efficiency of fire suppression is increased by the use of retardant. CEREN has also developed a new project, ERAS, which examines how retardants can assist ground resources in fire suppression. At a fire site, nightfall precludes aerial firefighting activities. In this situation, it would be better to improve water-extinguishing capabilities by adding a retardant. In close collaboration with firefighters, an experimental procedure for applying retardant products from the ground is undergoing tests.
Retardant penetration on different types of vegetation is being assessed, followed by experiments during controlled fires to sharpen some parameters such as the best application ratio and viscosity of the product. The whole concept will be validated during real size fires.
In the same way, experimental work on evaluation of the width of a retardant reinforced firebreak needed to stop a forest fire will be examined. The required retardant application rate to reinforce a fuel break can then be established.
The German company Wagner has initiated a system using explosive hoses; that will be developed through the FIMEX European Project.
This project aims to provide a new method for the suppression of forest fire that would improve the efficiency of the firefighting services. Water-filled hoses with inserted blasting cords are exploded in advance of the fire front to generate firebreaks. The water accelerated through the explosion is spread almost simultaneously in the form of small water droplets, causing spontaneous cooling of the burning fuel.
Also firefighters have been invited to join a consortium to investigate modifying fire equipment on forest fire vehicles, especially the main pump and the variable flow cannon, which can form a direct attack on a flame front for rapid extinguishing or to prepare fire lines.
The Direction Departementale d'Incendies et de Secours des Bouches du Rhone uses a model to provide information on the time scale of the flame front position and the number of resources required. The advantage of this semi-empirical model is its activation time, providing operational staff with a rapid response. All the parameters have been evaluated through plottings from real-life fires and experimental fires in the Bouches du Rhone Department.
Automatic detection systems have been developed for unmanned zones, but satellite surveillance is not yet used as activation times do not match the realities of the terrain. Detection time must be less than two minutes with accurate localization. European projects such as Rapsodi have encouraged collaboration between industry, research communities and firefighters.
Fire suppression in inaccessible areas is risky. The first requirement is to make sensitive zones safer for firefighters: prepare the terrain with access routes, provide for water resources, clear the ground, inform the public — all these actions have to be part of a forest massif management plan.
Future projects such as Warm and Spread will help and modeling tools like Farsite can be activated to simulate fire ignitions and fire propagations. Furthermore, the ERAS Project with ground retardants involves firefighters from Greece, Portugal, Spain, Israel and France. These projects will act as a guide and as a validation for research work.
This article first appeared in the April 2002 issue of Fire International and is reprinted with the journal's permission. Contact Fire International at +44 1737 768611.
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