Calculating and interpreting forest fire intensities

1982 ◽  
Vol 60 (4) ◽  
pp. 349-357 ◽  
Author(s):  
Martin E. Alexander
Keyword(s):  
Forest Fire ◽  
International System ◽  
Unit Length ◽  
Fire Behavior ◽  
Energy Output ◽  
Fire Intensity ◽  
Linear Rate ◽  
Fire Front ◽  
Quantitative Basis ◽  
The Impact

Frontal fire intensity is a valid measure of forest fire behavior that is solely a physical attribute of the fire itself. It is defined as the energy output rate per unit length of fire front and is directly related to flame size. Numerically, it is equal to the product of net heat of combustion, quantity of fuel consumed in the active combustion zone, and a spreading fire's linear rate of advance. The recommended International System (SI) units are kilowatts per metre. This concept of fire intensity provides a quantitative basis for fire description useful in evaluating the impact of fire on forest ecosystems.

scholarly journals Mathematical modeling of the impact of forest fires on buildings and structures

2018 ◽  
Vol 209 ◽  
pp. 00021
Author(s):  
Valeriy Perminov ◽  
Victoria Marzaeva
Keyword(s):  
Mathematical Modeling ◽  
Forest Fire ◽  
Forest Fires ◽  
Fire Behavior ◽  
Fire Intensity ◽  
Physical Mechanisms ◽  
Important Concern ◽  
Fire Initiation ◽  
The Impact ◽  
Fundamental Physical

The protection of buildings and structures in a community from destruction by forest fires is a very important concern. This paper addresses the development of a mathematical model for fires in the wildland-urban intermix. The forest fire is a very complicated phenomenon. At present, fire services can forecast the danger rating of, or the specific weather elements relating to, forest fire. There is need to understand and predict forest fire initiation, behavior and impact of fire on the buildings and constructions. This paper’s purposes are the improvement of knowledge on the fundamental physical mechanisms that control forest fire behavior. The mathematical modeling of forest fires actions on buildings and structures has been carried out to study the effects of fire intensity and wind speed on possibility of ignition of buildings.

Experimental assessment of the influence of radiant heat transfer on the transition of a crown fire to settlements

2021 ◽  
pp. 19-26
Author(s):  
Николай Петрович Копылов ◽  
Елена Юрьевна Сушкина ◽  
Александр Евгеньевич Кузнецов ◽  
Виктория Ивановна Новикова
Keyword(s):  
Heat Flow ◽  
Forest Fire ◽  
Fire Resistance ◽  
Fire Protection ◽  
Forest Fires ◽  
Radiant Heat ◽  
Radiant Heat Transfer ◽  
Crown Fire ◽  
Fire Front ◽  
The Impact

Проведены экспериментальные исследования влияния лучистого теплообмена на переход верхового лесного пожара на постройки IV и V степеней огнестойкости. Лесной верховой пожар моделировался горением штабеля древесины с интенсивностью тепловыделения, близкой к интенсивности при реальных пожарах. Получена зависимость изменения плотности теплового потока от расстояния до кромки горения. Экспериментально определены температура воздуха с подветренной стороны пожара и плотность выпадения искр в зависимости от расстояния. Проверена эффективность защиты растворами ретардантов деревянных строений от возгорания при лучистом теплообмене между факелом пламени пожара и объектом защиты. Crown fires are the main threat of the combustion transfer from the forest to objects located in it. Fire services dealing with forest fires face the problem how to protect these objects from forest fires. It is proposed to treat the object with retardant solutions before a forest fire approaches. To assess the effectiveness of such tactics for fire protection of objects when exposed to a heat flow from the combustion front there were carried out experiments on large-scale crown fire models. A crown fire is simulated with a pile of wood with a heat release rate of ≈ 13 MW m. The wind is generated by fans, its speed is close to the speed at which a forest fire occurs. Measurements of the heat flux density, medium temperature, and the density of sparks falling downwind of the fire front at different distances and heights were carried out. Calculations were carried out to assess the impact of heat flow on buildings of IV-V degrees of fire resistance. The results obtained are compared with experimental data and they are in good agreement. There have been determined the distances from the fire front at which the fire protection with retardant solutions is effective for structures of IV-V fire resistance degrees at radiant heat exchange.

Fire intensity, fire severity and burn severity: a brief review and suggested usage

2009 ◽  
Vol 18 (1) ◽  
pp. 116 ◽  
Author(s):  
Jon E. Keeley
Keyword(s):  
Fire Severity ◽  
Empirical Studies ◽  
Fire Behavior ◽  
Radiant Energy ◽  
Energy Output ◽  
Burn Severity ◽  
Fire Intensity ◽  
Ecosystem Responses ◽  
Single Measure ◽  
Ecosystem Impacts

Several recent papers have suggested replacing the terminology of fire intensity and fire severity. Part of the problem with fire intensity is that it is sometimes used incorrectly to describe fire effects, when in fact it is justifiably restricted to measures of energy output. Increasingly, the term has created confusion because some authors have restricted its usage to a single measure of energy output referred to as fireline intensity. This metric is most useful in understanding fire behavior in forests, but is too narrow to fully capture the multitude of ways fire energy affects ecosystems. Fire intensity represents the energy released during various phases of a fire, and different metrics such as reaction intensity, fireline intensity, temperature, heating duration and radiant energy are useful for different purposes. Fire severity, and the related term burn severity, have created considerable confusion because of recent changes in their usage. Some authors have justified this by contending that fire severity is defined broadly as ecosystem impacts from fire and thus is open to individual interpretation. However, empirical studies have defined fire severity operationally as the loss of or change in organic matter aboveground and belowground, although the precise metric varies with management needs. Confusion arises because fire or burn severity is sometimes defined so that it also includes ecosystem responses. Ecosystem responses include soil erosion, vegetation regeneration, restoration of community structure, faunal recolonization, and a plethora of related response variables. Although some ecosystem responses are correlated with measures of fire or burn severity, many important ecosystem processes have either not been demonstrated to be predicted by severity indices or have been shown in some vegetation types to be unrelated to severity. This is a critical issue because fire or burn severity are readily measurable parameters, both on the ground and with remote sensing, yet ecosystem responses are of most interest to resource managers.

scholarly journals MATHEMATICAL MODELING OF THE FOREST FIRE IMPACT ON THE BRANCH OF A CONIFEROUS TREE

2021 ◽  
Vol 4 (2) ◽  
pp. 1-15
Author(s):  
N.V. Baranovskiy ◽  
◽  
D. S. Menshikov ◽  
Keyword(s):  
Mathematical Modeling ◽  
Forest Fire ◽  
Quantitative Methods ◽  
Heat Propagation ◽  
Coniferous Tree ◽  
Flame Zone ◽  
Fire Front ◽  
Tree Branch ◽  
The Impact ◽  
The Mathematical Model

It is necessary to develop quantitative methods to assess the formation of thermal burns in the morphological parts of coniferous trees. The purpose of the study can be formulated as follows: mathematical modeling of heat transfer in the layered structure of a coniferous tree branch under the influence of a forest fire front. The heat propagation in the “branch-needles-flame zone” system is described by a system of non-stationary differential equations of heat conduction with the corresponding initial and boundary conditions. As an object of research, a digital model of a branch of a coniferous tree for various species, namely, pine, larch and fir, was used. Temperature distributions are obtained for different variants of the branch structure and conditions of the impact of the forest fire front. Conclusions are made about the need for further modernization of the mathematical model. The developed model is the basis for creating software tools for specialized geographic information systems.

scholarly journals Updated Operational Implementation of the Canadian Forest Fire Weather Index System in Ireland

2021 ◽  
Author(s):  
Padraig Flattery ◽  
Klara Finkele ◽  
Paul Downes ◽  
Ferdia O'Leary ◽  
Ciaran Nugent
Keyword(s):  
Forest Fire ◽  
Index System ◽  
Weather Prediction ◽  
Fire Danger ◽  
Energy Output ◽  
Fire Intensity ◽  
Fire Weather ◽  
Reference Period ◽  
Weather Index ◽  
Fire Weather Index

<p>Since 2006 the Canadian Forest Fire Weather Index System (FWI) has been used operationally at Met Éireann to predict the risk of forest fires in Ireland (Walsh, S, 2006). Although only around 11% or ca 770,000 ha of the total land area of Ireland is afforested, there are also large areas of open mountain and peatlands that are covered in grasses, dwarfshrub and larger woody shrub type vegetation which can provide ready fuel for spring wildfires, when suitable conditions arise. Following winter, much of this vegetation is either dead or has a very low live moisture content, and the flammability of this vegetation can be readily influenced by prevailing weather, most especially following prolonged dry periods. The Department of Agriculture, Food and Marine is the Forest Protection authority in Ireland and issues Fire Danger Notices as part of this work. These notices permit improved preparedness for fire responses and are based on information provided by Met Éireann on the current status of FWI and FWI components using observation data at synoptic stations and the predicted FWI for the next five days ahead based on numerical weather prediction input data.</p><p>The FWI is based on</p><ul><li>three different types of forest fuel, ie how quickly these dry out/get rewetted. These are the Fine Fuels Moisture Code (FFMC), the Duff Moisture Code (DMC) and the Drought Code (DC).</li> <li>components based on fire behaviour: the Initial Spread Index (ISI), the Build-up Index (BUI), and the Fire Weather Index (FWI) which represents fire intensity as energy output rate per unit length of fire front. It is then used to determine the Daily Severity Rating (DSR) of the fire danger. </li> </ul><p>Of these components, the FFMC and ISI components have been found to provide the most accurate indication of risk under Irish conditions, based on the fuels involved and ignition patterns observed to date.</p><p>The DSR was based on a climatology of 1971 to 2005 at the time of operational implantation of the FWI at Met Éireann. An updated climatology based on the new reference period of 1990 to 2020 will be shown as well as the change of the 98 percentiles of extreme rating using this new reference period.  </p><p><strong>Walsh, S.</strong> “Implementation in Ireland of the Canadian Forest Fire Weather Index System.” In <em>Making Science Work on the Farm. A Workshop on Decision Support Systems for Irish Agriculture</em>, 120–126. Dublin: AGMET, 2007. </p>

Modelling logic and the Canadian Forest Fire Behavior Prediction System

1998 ◽  
Vol 74 (1) ◽  
pp. 50-52 ◽  
Author(s):  
C. E. Van Wagner
Keyword(s):  
Forest Fire ◽  
Fire Behavior ◽  
Fire Spread ◽  
Fire Research ◽  
Fire Intensity ◽  
Prediction System ◽  
Behavior Prediction ◽  
Crown Fire ◽  
Fire Modelling ◽  
Semi Empirical

This article outlines the flexible semi-empirical philosophy used throughout six decades of fire research by the Canadian Forest Service, culminating in the development of the Forest Fire Behavior Prediction System. It then describes the principles involved when spread rate and fuel consumption are estimated separately to yield fire intensity, and the anomaly that has resulted from the omission of a foliar-moisture effect on crown-fire spread. Judged on its results so far, this Canadian approach has held its own against any other, and holds full promise for the future as well. Key words: forest fire behavior, Canadian FBP System, fire modelling, crown-fire theory, fire research philosophy

scholarly journals Canadian Forest Fire Danger Rating System: An Overview

1989 ◽  
Vol 65 (4) ◽  
pp. 258-265 ◽  
Author(s):  
B. J. Stocks ◽  
T. J. Lynham ◽  
B. D Lawson ◽  
M. E. Alexander ◽  
C. E. Van Wagner ◽  
...  
Keyword(s):  
Forest Fire ◽  
Fire Management ◽  
Fire Behavior ◽  
Fire Danger ◽  
Rating System ◽  
Fire Intensity ◽  
Fire Occurrence ◽  
Rating Systems ◽  
Fire Danger Rating System ◽  
Forest Fire Danger

Forest fire danger rating research in Canada was initiated by the federal government in 1925. Five different fire danger rating systems have been developed since that time, each with increasing universal applicability across Canada. The approach has been to build on previous danger rating systems in an evolutionary fashion and to use field experiments and empirical analysis extensively. The current system, the Canadian Forest Fire Danger Rating System (CFFDRS), has been under development by Forestry Canada since 1968. The first major subsystem of the CFFDRS, the Canadian Forest Fire Weather Index (FWI) System, provides numerical ratings of relative fire potential based solely on weather observations, and has been in use throughout Canada since 1970. The second major subsystem, the Canadian Forest Fire Behavior Prediction (FBP) System, accounts for variability in fire behavior among fuel types (predicting rate of spread, fuel consumption, and frontal fire intensity), was issued in interim form in 1984 with final production scheduled for 1990. A third major CFFDRS subsystem, the Canadian Forest Fire Occurrence Prediction (FOP) System, is currently being formulated. This paper briefly outlines the history and philosophy of fire danger rating research in Canada discussing in detail the structure of the current CFFDRS and its application and use by fire management agencies throughout Canada. Key words: fire danger, fire behavior, fire occurrence prediction, fuel moisture, fire danger rating system, fire management.

scholarly journals A Coupled Atmosphere-Fire Model: Role of the Convective Froude Number and Dynamic Fingering at the Fireline

1996 ◽  
Vol 6 (4) ◽  
pp. 177 ◽  
Author(s):  
TL Clark ◽  
MA Jenkins ◽  
JL Coen ◽  
DR Packham
Keyword(s):  
Forest Fire ◽  
Fire Behavior ◽  
Atmospheric Model ◽  
Fire Spread ◽  
Atmospheric Conditions ◽  
Fire Model ◽  
Eucalyptus Forest ◽  
Fire Front ◽  
Forest Fire Model ◽  
Wildfire Simulation

A numerical atmospheric model is coupled with a simple dry eucalyptus forest fire model to create a wildfire simulation model. This is used to show how certain atmospheric conditions can lead to commonly observed forest fire behavior. Using short line fires, simulations show that with moderate winds, the fire line interacts with the updraft ahead of it causing the fire line to curve forward into a conical shape. Other experiments show that when ambient winds change with height, a pair of rotating updrafts at the curved fire front can touch down within the fire and break up the fire line. We also demonstrate 'dynamic fingering', in which the rotating columns near the fire front intensify to tornado strength and can result in rapid and strong increases in the fire spread rate.

The Canadian Forest Fire Danger Rating System: An Overview

1989 ◽  
Vol 65 (6) ◽  
pp. 450-457 ◽  
Author(s):  
B. J. Stocks ◽  
T. J. Lynham ◽  
B. D. Lawson ◽  
M. E. Alexander ◽  
C. E. Van Wagner ◽  
...  
Keyword(s):  
Forest Fire ◽  
Fire Management ◽  
Fire Behavior ◽  
Fire Danger ◽  
Rating System ◽  
Fire Intensity ◽  
Fire Occurrence ◽  
Rating Systems ◽  
Fire Danger Rating System ◽  
Forest Fire Danger

Forest fire danger rating research in Canada was initiated by the federal government in 1925. Five different fire danger rating systems have been developed since that time, each with increasing universal applicability across Canada. The approach has been to build on previous danger rating systems in an evolutionary fashion and to use field experiments and empirical analysis extensively. The current system, the Canadian Forest Fire Danger Rating System (CFFDRS), has been under development by Forestry Canada since 1968. The first major subsystem of the CFFDRS, the Canadian Forest Fire Weather Index (FWI) System, provides numerical ratings of relative fire potential based solely on weather observations, and has been in use throughout Canada since 1970. The second major subsystem, the Canadian Forest Fire Behavior Prediction (FBP) System, accounts for variability in fire behavior among fuel types (predicting rate of spread, fuel consumption, and frontal fire intensity), was issued in interim form in 1984 with final production scheduled for 1990. A third major CFFDRS subsystem, the Canadian Forest Fire Occurrence Prediction (FOP) System, is currectly being formulated. This paper briefly outline the history and philosophy of fire danger rating research in Canada discussing in detail the structure of the current CFFDRS and its application and use by fire management agencies throughout Canada. Key words: fire danger, fire behavior, fire occurrence prediction, fuel moisture, fire danger rating system, fire management.

Fire behavior in immature jack pine

1987 ◽  
Vol 17 (1) ◽  
pp. 80-86 ◽  
Author(s):  
B.J. Stocks
Keyword(s):  
Forest Fire ◽  
Fire Behavior ◽  
Jack Pine ◽  
Quantitative Prediction ◽  
Fire Intensity ◽  
Fire Weather ◽  
Strongly Correlated ◽  
Fire Weather Index ◽  
Rate Of Spread ◽  
Forest Fire Management

A series of experimental fires, each 0.4 ha in size, was conducted between 1975 and 1981 in an unthinned stand of immature jack pine (1948 origin) in central Ontario to gather quantitative fire behavior data for forest fire management purposes. Twelve fires were conducted over a broad range of burning conditions. Fire behavior and impact characteristics (i.e., rate of spread, fuel consumption, and frontal fire intensity) were found to be strongly correlated with fire weather severity as expressed through various component codes and indices of the Canadian Forest Fire Weather Index (FWI) System. This type of experimental fire information, along with wildfire data, is being used in the development of guidelines for quantitative prediction of fire behavior in major Canadian forest fuel types.

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