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This paper describes the further development of the evacuation software 'Simulex'. The aim of the research project is to develop a computer model for evacuation which has a strong scientific basis for the simulated movement of escaping people, and can be readily used as a research and design tool. The software has been written by researchers at Edinburgh, in collaboration with staff at Lund University. The project has been funded by The Swedish Fire Research (Brandforsk) board and The Engineering and Physical Sciences Research Council. The software is capable of modelling large, geometrically complex buildings, with multiple floors and staircases, and accepts CAD generated files to define individual floor plans. Thousands of individual people can be accommodated, and the user can view the movement of each individual at any point in the building at any time during the evacuation. A text file which contains detailed information about the evacuation vrocess is vroduced at the end of a simulation. These capabilities represent significant advancements in the software described previously by Thompson & Marchant [8].

Computational heat transfer became one of the major tools for engineering system design in 1970’s. It has been introduced into Chinese society since 1980’s, especially after Brian Spalding’s first lecture in 1984 in China. As one of Brian’s a few early visiting scholars from China, Professor W. C. Fan has begun his endeavor to expand computational heat transfer to fire research. This paper will first briefly introduce the history of the development of computational modeling with particular applications in fire research — a state funded large project, and then present some representative research work in fire research including recent works on high altitude fire and performance based design.Copyright © 2013 by ASME

Available data show that future changes in global change drivers may lead to an increasing impact of fires on terrestrial ecosystems worldwide. Yet, fire regime changes in highly humanised fire-prone regions are difficult to predict because fire effects may be heavily mediated by human activities We investigated the role of fire suppression strategies in synergy with climate change on the resulting fire regimes in Catalonia (north-eastern Spain). We used a spatially-explicit fire-succession model at the landscape level to test whether the use of different firefighting opportunities related to observed reductions in fire spread rates and effective fire sizes, and hence changes in the fire regime. We calibrated this model with data from a period with weak firefighting and later assess the potential for suppression strategies to modify fire regimes expected under different levels of climate change. When comparing simulations with observed fire statistics from an eleven-year period with firefighting strategies in place, our results showed that, at least in two of the three sub-regions analysed, the observed fire regime could not be reproduced unless taking into account the effects of fire suppression. Fire regime descriptors were highly dependent on climate change scenarios, with a general trend, under baseline scenarios without fire suppression, to large-scale increases in area burnt. Fire suppression strategies had a strong capacity to compensate for climate change effects. However, strong active fire suppression was necessary to accomplish such compensation, while more opportunistic fire suppression strategies derived from recent fire history only had a variable, but generally weak, potential for compensation of enhanced fire impacts under climate change. The concept of fire regime in the Mediterranean is probably better interpreted as a highly dynamic process in which the main determinants of fire are rapidly modified by changes in landscape, climate and socioeconomic factors such as fire suppression strategies. This study has received financial support from the projects CGL2008-05506-C02-01/BOS, CGL2011-29539/BOS and Consolider Montes CSD2008-00040 granted by the Spanish Ministry of Education and Science (MEC). Additional funding to LB and MC was received from the Catalan government through projects 2010 BE 272 and the ‘Beatriu de Pinós’ Programme (2009 BP-B 00342).

In fire research and forest firefighting, there is a need of robust metrological systems able to estimate the geometrical characteristics of outdoor spreading fires. In recent years, we assist to an increased interest in wildfire research to develop non destructive techniques based on computer vision. This paper presents a new approach for the estimation of fire geometrical characteristics using near infrared stereovision. Spreading fire information like position, rate of spread, height and surface, are estimated from the computed 3D fire points. The proposed system permits to track fire spreading on a ground area of 5mx10m. Keywords: near infrared, stereovision, spreading fire, geometrical characteristics

Wildlife response to natural disturbances such as fire is of conservation concern to managers, policy makers, and scientists, yet information is scant beyond a few well-studied groups (e.g., birds, small mammals). We examined the effects of wildfire severity on bats, a taxon of high conservation concern, at both the stand (

Wildfire management in the United States and elsewhere is challenged by substantial uncertainty regarding the location and timing of fire events, the socioeconomic and ecological consequences of these events, and the costs of suppression. Escalating U.S. Forest Service suppression expenditures is of particular concern at a time of fiscal austerity as swelling fire management budgets lead to decreases for non-fire programs, and as the likelihood of disruptive within-season borrowing potentially increases. Thus there is a strong interest in better understanding factors influencing suppression decisions and in turn their influence on suppression costs. As a step in that direction, this paper presents a probabilistic analysis of geographic and temporal variation in incident management team response to wildfires. The specific focus is incident complexity dynamics through time for fires managed by the U.S. Forest Service. The modeling framework is based on the recognition that large wildfire management entails recurrent decisions across time in response to changing conditions, which can be represented as a stochastic dynamic system. Daily incident complexity dynamics are modeled according to a first-order Markov chain, with containment represented as an absorbing state. A statistically significant difference in complexity dynamics between Forest Service Regions is demonstrated. Incident complexity probability transition matrices and expected times until containment are presented at national and regional levels. Results of this analysis can help improve understanding of geographic variation in incident management and associated cost structures, and can be incorporated into future analyses examining the economic efficiency of wildfire management.

BACKGROUND: Widespread invasion by non-native plants has resulted in substantial change in fire-fuel characteristics and fire-behaviour in many of the world's ecosystems, with a subsequent increase in the risk of fire damage to human life, property and the environment. Models used by fire management agencies to assess fire risk are dependent on accurate assessments of fuel characteristics but there is little evidence that they have been modified to reflect landscape-scale invasions. There is also a paucity of information documenting other changes in fire management activities that have occurred to mitigate changed fire regimes. This represents an important limitation in information for both fire and weed risk management. METHODOLOGYPRINCIPAL FINDINGS: We undertook an aerial survey to estimate changes to landscape fuel loads in northern Australia resulting from invasion by Andropogon gayanus (gamba grass). Fuel load within the most densely invaded area had increased from 6 to 10 t ha(-1) in the past two decades. Assessment of the effect of calculating the Grassland Fire Danger Index (GFDI) for the 2008 and 2009 fire seasons demonstrated that an increase from 6 to 10 t ha(-1) resulted in an increase from five to 38 days with fire risk in the 'severe' category in 2008 and from 11 to 67 days in 2009. The season of severe fire weather increased by six weeks. Our assessment of the effect of increased fuel load on fire management practices showed that fire management costs in the region have increased markedly (∼9 times) in the past decade due primarily to A. gayanus invasion. CONCLUSIONSSIGNIFICANCE: This study demonstrated the high economic cost of mitigating fire impacts of an invasive grass. This study demonstrates the need to quantify direct and indirect invasion costs to assess the risk of further invasion and to appropriately fund fire and weed management strategies. Language: en

Understanding concrete behavior under transient high temperature is an important aspect of structural fire research. Consequently, many investigations have been performed under uniaxial loading conditions, but, only a few under biaxial states of stress. This report has two primary goals. The mechanical behavior of unsealed concrete and mortar was studied under biaxial stresses and transient temperature. Furthermore, the influence of the concrete composition was investigated for quartzitic concrete and mortar in thermal expansion tests and biaxial transient creep tests. Based on the test results a model of the transient creep of concrete under multiaxial loading is proposed. In combination with a suitable high temperature failure model, this model is applicable for concretes with different compositions.

The indoor carbon monoxide concentration in 10 car parks with volumes varying from 1,000 m 3 to 35,000 m 3 and ceiling height of 3 m was simulated using the multi-zone network model CONTAM93/94 developed at the Building and Fire Research Laboratory of the National Institute of Standards and Testing (NIST) in the U.S.A. Use of the model in designing the ventilation system in a car park is illustrated. Experimental measurements on the carbon monoxide level in that car park were performed to verify the results.

A series of experiments were conducted to examine potential vulnerabilities of wood decks to continuous, wind-driven firebrand showers. Sections of wood decks (1.2 m by 1.2 m) were constructed and attached to a reentrant corner assembly. The deck/reentrant corner assembly was then exposed to continuous, winddriven firebrand bombardment generated by the newly developed NIST full-scale Continuous Feed Firebrand Generator (NIST full-scale Continuous Feed Dragon) installed in the Building Research Institute’s (BRI) Fire Research Wind Tunnel Facility (FRWTF). Three different wood deck types were exposed to wind-driven firebrand showers at wind speed of 6 m/s; Western Red Cedar, Douglas-Fir, and Redwood. For each wood deck tested (exposed to a total firebrand mass flux of 17.1 g/m 2 s), firebrands accumulated on the deck surface, and each wood deck type was observed to ignite by flaming ignition. The average time to flaming ignition was 437 s for Cedar, 934 s for Douglas-Fir, and 756 s for Redwood. Therefore, wood decks were observed to be vulnerable to ignition from continuous, wind-driven firebrand showers. Results of these experiments are discussed in detail.

Forest management under a changing climate requires assessing the effects of climate warming and disturbance on the composition, age structure, and spatial patterns of tree species. We investigated these effects on a boreal forest in northeastern China using a factorial experimental design and simulation modeling. We used a spatially explicit forest landscape model (LANDIS) to evaluate the effects of three independent variables: climate (current and expected future), fire regime (current and increased fire), and timber harvesting (no harvest and legal harvest). Simulations indicate that this forested landscape would be significantly impacted under a changing climate. Climate warming would significantly increase the abundance of most trees, especially broadleaf species (aspen, poplar, and willow). However, climate warming would have less impact on the abundance of conifers, diversity of forest age structure, and variation in spatial landscape structure than burning and harvesting. Burning was the predominant influence in the abundance of conifers except larch and the abundance of trees in mid-stage. Harvesting impacts were greatest for the abundance of larch and birch, and the abundance of trees during establishment stage (1-40 years), early stage (41-80 years) and old- growth stage (>180 years). Disturbance by timber harvesting and burning may significantly alter forest ecosystem dynamics by increasing forest fragmentation and decreasing forest diversity. Results from the simulations provide insight into the long term management of this boreal forest.

Stand-replacing fires influence soil nitrogen availability and microbial community composition, which may in turn mediate post-fire successional dynamics and nutrient cycling. However, fires create patchiness at both local and landscape scales and do not result in consistent patterns of ecological dynamics. The objectives of this study were to (1) quantify the spatial structure of microbial communities in forest stands recently affected by stand-replacing fire and (2) determine whether microbial variables aid predictions of in situ net nitrogen mineralization rates in recently burned stands. The study was conducted in lodgepole pine (Pinus contorta var. latifolia) and Engelmann spruce/subalpine fir (Picea engelmannii/Abies lasiocarpa) forest stands that burned during summer 2000 in Greater Yellowstone (Wyoming, USA). Using a fully probabilistic spatial process model and Bayesian kriging, the spatial structure of microbial lipid abundance and fungi-to-bacteria ratios were found to be spatially structured within plots two years following fire (for most plots, autocorrelation range varied from 1.5 to 10.5 m). Congruence of spatial patterns among microbial variables, in situ net N mineralization, and cover variables was evident. Stepwise regression resulted in significant models of in situ net N mineralization and included variables describing fungal and bacterial abundance, although explained variance was low (R²

Smoke from bushfires is an emerging issue for fire managers because of increasing evidence for its public health effects. Development of forecasting models to predict future pollution levels based on the relationship between bushfire activity and current pollution levels would be a useful management tool. As a first step, we use daily thermal anomalies detected by the MODIS Active Fire Product (referred to as “hotspots”), pollution concentrations, and meteorological data for the years 2002 to 2008, to examine the statistical relationship between fire activity in the landscapes and pollution levels around Perth and Sydney, two large Australian cities. Resultant models were statistically significant, but differed in their goodness of fit and the distance at which the strength of the relationship was strongest. For Sydney, a univariate model for hotspot activity within 100 km explained 24% of variation in pollution levels, and the best model including atmospheric variables explained 56% of variation. For Perth, the best radius was 400 km, explaining only 7% of variation, while the model including atmospheric variables explained 31% of the variation. Pollution was higher when the atmosphere was more stable and in the presence of on-shore winds, whereas there was no effect of wind blowing from the fires toward the pollution monitors. Our analysis shows there is a good prospect for developing region-specific forecasting tools combining hotspot fire activity with meteorological data.

The smoke filling process for the three types of atrium spaces commonly built in Hong Kong are simulated using the two types of deterministic fire model: zone models and field models. The zone models used are the FIRST, CFAST, and CCFM.VENTS models developed at the Building and Fire Research Laboratories, NIST, USA and the NBTC one-room model of FIRECALC developed at CSIRO, Australia. The field model is a self-developed fire field model based on computational fluid dynamics theories. The results predicted by the two approaches are very similar. Simulation using a field model requires much more computing time compared with the use of a zone model, but it can give more detailed information on the fire-induced flow and temperature fields.

International fire research activities, priorities, constraints and opportunities are examined from a late 20th century vantage point. Recent accomplishments in computer technology are identified as the single most important phenomenon responsible for the advancement of the science and "shrinking" of the globe. Computer technology and the global research cooperation it has engendered are put within the context of societal demands and research funding limitations impacting on fire research activities in the various research organisations. Society's insistence on fiscal responsibility in the conduct of science is symptomatic of a greater need to balance increased demand for resources by a growing world population with the sustainability imperative. Fire research and its practitioners are well positioned to contribute meaningfully to the debate on ecosystem management, restoration and sustainability currently underway in the global village. Key words: fire research, computer applications, international fire research activities, fire research and science policy, ecosystem management, sustainability

The fire environment in thirty-six car parks of volumes varying from 2,000 m3 to 50,000 m3, ceiling heights of 3 m, 4 m and 5 m are simulated using the fire zone model, CFAST version 2.0 developed at the Building and Fire Research Laboratory, NIST in U.S.A. The concept of using the space volume as a criterion to determine the requirement of smoke extraction system is reviewed. The concept of time constant in an atrium hall is proposed to be used in car parks and underground spaces. The empirical expression fitted by experimental data appearing in NFPA-92B is applied to calculate the time con stant. This is then correlated with the smoke filling time for those thirty-six car parks with and without natural horizontal ceiling vents. Design of the smoke extraction system for underground spaces is also studied.

The fire risk in Chinese restaurants in Hong Kong is studied in this paper. The local regulation, the existing design for fire safety and the past fire record are discussed. Surveys on the fire load in fifteen Chinese restaurants of different sizes are made and reported. The fire equivalent duration period, which is related to the surveyed fire load density is calculated. Since smoke is a key factor in discussions of fire safety, the time required to fill the restaurants with smoke had to be calculated. In this case, fire models have to be used and the zone model CFAST developed at the Building and Fire Research Labora tory, NIST, U.S.A. is used to study the fire environment. Correlations are derived between the equivalent duration period and the predicted maximum hot gas temperature and the corresponding smoke layer interface height.

An intentionally set fire caused the massive ammonium nitrate explosion in April 2013 that killed 15 people and injured hundreds more in West, Texas, federal officials announced last week. “We hypothesized, considered, tested, and eliminated all reasonable accidental and natural causes,” says Rob Elder, special agent for the Bureau of Alcohol, Tobacco, Firearms & Explosives. “This fire was a criminal act.” ATF is offering up to $50,000 for information leading to the arrest of whoever set the blaze at the West Fertilizer Co. storage facility. Elder said investigators determined the fire was started on purpose after they conducted more than 400 interviews and analyzed evidence at the blast site along with witness photos and videos. They also performed extensive testing at an ATF fire research lab in Beltsville, Md. No arrests have been made and authorities would not comment on whether there are any suspects. But, Elder adds, “I think

The fire environment in car parks of volumes varying from 2,000 m3 to 50,000 m3, ceiling heights of 3 m, 4 m and 5 m are simulated using three fire zone models, namely CFAST and CCFM.VENTS developed atthe Building and Fire Research Laboratory, NIST in U.S.A., and the NBTC one-room hot layer model of the fire engineers' calculator FIRECALC developed at the Division of Building and Construction, CSIRO, Australia. The model CFAST is found to be very suitable and the average hot gas temperatures predicted by it are correlated with the volume of the car parks. A time constant taking into account the size geometry and design fire is proposed to assess the fire risks of a car park. Ten local car parks of volume up to 50,000 m3 are surveyed with the fire environment simulated. The derived correlation relation on the average hot temperature fits well with the volume and the time constant. The experimental data on small car park fires are also used to compare with the results predicted by these three zone models.

Historical data are essential for understanding how fire activity responds to different drivers. It is important that the source of data is commensurate with the spatial and temporal scale of the question addressed, but fire history databases are derived from different sources with different restrictions. In California, a frequently used fire history dataset is the State of California Fire and Resource Assessment Program (FRAP) fire history database, which circumscribes fire perimeters at a relatively fine scale. It includes large fires on both state and federal lands but only covers fires that were mapped or had other spatially explicit data. A different database is the state and federal governments’ annual reports of all fires. They are more complete than the FRAP database but are only spatially explicit to the level of county (California Department of Forestry and Fire Protection – Cal Fire) or forest (United States Forest Service – USFS). We found substantial differences between the FRAP database and the annual summaries, with the largest and most consistent discrepancy being in fire frequency. The FRAP database missed the majority of fires and is thus a poor indicator of fire frequency or indicators of ignition sources. The FRAP database is also deficient in area burned, especially before 1950. Even in contemporary records, the huge number of smaller fires not included in the FRAP database account for substantial cumulative differences in area burned. Wildfires in California account for nearly half of the western United States fire suppression budget. Therefore, the conclusions about data discrepancies and the implications for fire research are of broad importance.

Much like other scientific endeavours, most fire research is conducted either within individual disciplines - fuels, physics, chemistry, ecology, modelling, and so forth - or, at best, across only two or three disciplines. This is primarily because fire scientists have particular areas of expertise and most collaborations are between scientists within that expertise. Although this approach often leads to significant discoveries, the lack of co-located, multi-scale measurements of pre-fire fuels, active fire processes and post-fire effects hinders our ability to tackle fundamental questions in fire science.

An assessment of outcomes from research projects funded by the Joint Fire Science Program was conducted to determine whether or not science has been used to inform management and policy decisions and to explore factors that facilitate use of fire science. In a web survey and follow-up phone interviews, I asked boundary spanners and scientists about how findings from a random sample of 48 projects had been applied and factors that acted as barriers or facilitators to science application. In addition, I conducted an investigation of recent planning documents to determine whether products from the sampled projects were cited. All lines of evidence suggest that information from most (44 of 48) of these projects have been used by fire and fuels managers in some capacity. Science has mostly been used during planning efforts, to develop treatment prescriptions, and to evaluate current practices. Lack of manager awareness was commonly identified as a barrier to application of science. Conversely, activities and organisations that foster interaction between scientists and managers were identified as facilitating the application of science. The efforts of the Joint Fire Science Program to communicate science findings and engage managers has likely contributed to the application of fire science.

1University of Corsica Pascal Paoli, Campus Grimaldi, SPE UMR 6134 CNRS, BP 52, 20250 Corte, France 2CSIRO Ecosystem Sciences and CSIRO Climate Adaptation Flagship, GPO Box 1700 Canberra, ACT 2601, Australia 3Aix-Marseille Universite, UNIMECA, 60 Rue Joliot Curie, 13453 Marseille cedex 13, France 4U.S. Forest Service, Pacific Wildland Fire Sciences Lab, 400 N. 34th St., Suite 201, Seattle, WA 98103, USA

Many studies have identified drivers of deforestation throughout the tropics and, in most cases, have recognised differences in the level of threat. However, only a few have also looked at the temporal and spatial dynamics by which those drivers act, which is critical for assessing the conservation of biodiversity as well as for landscape planning. In this study, we analyse land cover change between 2000 and 2009 in north-western Colombian Amazonia to identify the interactions between the use of fire, cultivation of illicit crops and establishment of pastures, and their impacts on the loss of forest in the region. Yearly analyses were undertaken at randomly selected sample areas to quantify the average areas of transition of land cover types under different landscape compositions: forest-dominated mosaics, pasture mosaics, fire mosaics, and illicit crop mosaics. Our results indicate that despite the fact that forest areas were well-preserved, deforestation occurred at a low annual rate (0.06%). Conversion to pasture was the main factor responsible for forest loss (the area of pastures tripled within forest mosaics over 8 years), and this process was independent of the landscape matrix in which the forests were located. In fire mosaics, burning is a common tool for forest clearing and conversion to pasture. Thus, forests in fire mosaics were highly disturbed and frequently transformed from primary to secondary forests. The use of fire for illicit cropping was not detected, partly due to the small size of common illicit crops. Forest regeneration from pastures and secondary vegetation was observed in areas with large amounts of natural forest. Overall, assuming the continuation of the observed pasture conversion trend and the use of forest fire, we suggest that our results should be incorporated into a spatially explicit and integrated decision support tool to target and focus land-planning activities and policies.

Pyrophilous jewel beetles of the genus Melanophila approach forest fires and there is considerable evidence that these beetles can detect fires from great distances of more than 60 km. Because Melanophila beetles are equipped with infrared receptors and are also attracted by hot surfaces it can be concluded that these infrared receptors are used for fire detection.The sensitivity of the IR receptors is still unknown. The lowest threshold published so far is 0.6 W/m(2) which, however, cannot explain the detection of forest fires by IR radiation from distances larger than approximately 10 km. To investigate the possible sensitivity of the IR receptors we assumed that beetles use IR radiation for remote fire detection and we made use of a historic report about a big oil-tank fire in Coalinga, California, in 1924. IR emission of an oil-tank fire can be calculated by "pool fire" simulations which now are used for fire safety and risk analysis. Assuming that beetles were lured to the fire from the nearest forests 25 and 130 km away, our results show that detection from a distance of 25 km requires a threshold of the IR receptors of at least 3×10(-2) W/m(2). According to our investigations most beetles became aware of the fire from a distance of 130 km. In this case the threshold has to be 1.3×10(-4) W/m(2). Because such low IR intensities are buried in thermal noise we suggest that the infrared sensory system of Melanophila beetles utilizes stochastic resonance for the detection of weak IR radiation. Our simulations also suggest that the biological IR receptors might be even more sensitive than uncooled technical IR sensors. Thus a closer look into the mode of operation of the Melanophila IR receptors seems promising for the development of novel IR sensors.

One of the most important aims of forest fire research is how to better controlforest fires. One way to attain this aim is to develop better decision tools forestimating how much water is required for extinguishing a fire with a specific setof conditions. There has in the past generally been little research conducted withrespect to water requirements when suppressing a wildfire. A number ofexperiments were conducted in the early ‘70s where a spray rig with a nozzlearrangement was used in order to apply water uniformly across a fuel bed. Twostudies regarding the required duration of water application related to fires inbuildings were conducted in the past. Both studies were based upon statisticaldata from fire brigades; the duration of water application was determined as afunction of the fire area. This paper encompasses an analysis of more than64,000 wildfires occurring in Sweden between 1996 and 2009. The valuescalculated from the obtained formulations with regression analysis were found tobe in good agreement in the following cases: The amount of water as a functionof the extinguishing time, the extinguishing time as a function of the fire area;and the fire area as a function of the flame height. It was observed that thederived equations from the analysis in the above cases could provide an accuratecomputation. These relationships could be of considerable use when developingdecision tools for wildfire suppression, optimizing the use of resources duringthe suppression activities.

9 páginas, 3 figuras, 2 tablas., Forest ecosystems where periodical tree bark harvesting is a major economic activity may be particularly vulnerable to disturbances such as fire, since debarking usually reduces tree vigour and protection against external agents. In this paper we asked how cork oak Quercus suber trees respond after wildfires and, in particular, how bark harvesting affects post-fire tree survival and resprouting. We gathered data from 22 wildfires (4585 trees) that occurred in three southern European countries (Portugal, Spain and France), covering a wide range of conditions characteristic of Q. suber ecosystems. Post-fire tree responses (tree mortality, stem mortality and crown resprouting) were examined in relation to management and ecological factors using generalized linear mixed-effects models. Results showed that bark thickness and bark harvesting are major factors affecting resistance of Q. suber to fire. Fire vulnerability was higher for trees with thin bark (young or recently debarked individuals) and decreased with increasing bark thickness until cork was 3-4 cm thick. This bark thickness corresponds to the moment when exploited trees are debarked again, meaning that exploited trees are vulnerable to fire during a longer period. Exploited trees were also more likely to be top-killed than unexploited trees, even for the same bark thickness. Additionally, vulnerability to fire increased with burn severity and with tree diameter, and was higher in trees burned in early summer or located in drier south-facing aspects. We provided tree response models useful to help estimating the impact of fire and to support management decisions. The results suggested that an appropriate management of surface fuels and changes in the bark harvesting regime (e.g. debarking coexisting trees in different years or increasing the harvesting cycle) would decrease vulnerability to fire and contribute to the conservation of cork oak ecosystems., We thank all people involved in field work, particularly Inés Duarte, Mireia Casanovas, Raimundo Duarte, Rui Tujeira, Tito Lopes and Vanessa Castro. We also thank Stephen Roxburgh (CSIRO), Miguel Bugalho and Joaquim Silva (ISA) for revising the manuscript, and three anonymous reviewers which contributed to the manuscript improvement.

The time constant which has been previously proposed to characterize the smoke-filling time in an atrium space for design purposes is further evaluated in this paper using the CFAST, FAST and CCFM. VENTS zone models developed at the Building and Fire Research Laboratory, NIST, USA. A design fire of thermal power and area related to the volume of the atrium space is proposed in order to evaluate the time constant. Results of the zone-modelling simulation supported the fact that the time required to fill 80% of the atrium space with smoke is related to its time constant. Full-scale experimental results on smoke-filling processes in atria available in the literature are compared. Use of this quantity to specify the smoke-filling time for an atrium space is recommended for design purposes.

Whether a smoke extraction system has to be installed for an atrium building in Hong Kong is currendy determined by its volume. This is not a satisfactory criterion, since the smoke filling times in atria of the same volume but different shapes are very different. A time constant is proposed as an appropriate parameter to replace the atrium volume. This paper reports an evaluation of this quantity using the zone model FIRST developed at the Building and Fire Research Laboratory, NIST, USA. Simulation by this model of smoke extraction effects in different types of atria is studied, and the results are compared with experimental results on smoke filling from the literature. In addition, a crude analysis without thermal effects was carried out. Closed-form expressions on the time required to fill 80% of the atrium height with smoke were derived. Lastly, a'design fire' is proposed to calculate the time constant of the atrium.

As a result of the powerfully increased international fire research during the last decades, more and more components and systems within fire safety engineering are becoming amenable to analytical and computer modelling. The most manifest verification of this development probably holds for the fire engineering design of load bearing and separating structures. The paper begins with a general survey on the characteristics of a reliability based structural fire engineering design. Then, the physical model, describing the simulated real fire exposure and the thermal and mechanical behaviour of the structure, is commented on with regard to the present state of knowledge and the need of further research. Finally, the different uncertainty sources in the design process and the principles of a cost-benefit optimization are dealt with and exemplified.

Fire losses are continuously increasing in China, there is an urgent need to enhance fire research so as to mitigate fire damage with moderate costs. A system of fire research consisting of basic research, applied research and development of new technology for fire prevention and protection is being formed in China. A general structure of organizations related to fire research is outlined, and several main institutions of fire research are introduced. Typical research work in the State Key Lab of Fire Science is given as an example of fire research in China. INTRODUCTION Rapid Increase of Fire Losses. Fire losses in China have increased rapidly in resent years. A fire statistics with exclusive of forest fire is given in Table 1 , and direct fire losses are shown in Fig. 1. It should be pointed out that the fire loss refers only the direct property loss (DPL). Neither indirect losses such as fees for suppression by fire brigates and the losses as a result of breaking production and supply of electricity, gas, water and so on , nor the fees paid in relation to death and injury of people in fires are included in the calculation of fire losses. In China the forest coverage rate is 13 percent with around 0. 13 hectars per person, which is much lower than the averages in the world. However, China is one of the countries with frequent forest fires. On average over 100 people died, 600 injured and 900,000 hectars of forest are demaged annually by fire, which is about FIRE SAFETY SCIENCE-PROCEEDINGS OF THE FOURTH INTERNATIONAL SYMPOSIUM, pp. 27-45 27 Copyright © International Association for Fire Safety Science 0. 8 persent of the total forest coverage. Accordring to the survey made by the national expert group to the fireslash in the big fire of the Great Xingan mountain in 1987 the fire covered the area of 1. 33 million hectars, among them 0. 89 million hectars were damaged, and 23 thousands hectars became woodless. This forest conflagration burnt and distroyed large amount of forest resources as well as houses, electricity transmission grid system, bridges, tunnels, railways, various machines and equipments ,which made 65 thousands people homeless. The t o ~ a l osses of the forest fire was about 500 million YuanC1]. TABLE 1. Fire Statistics in China (1988-1993) Number Year Death Injury DPL DPL/GNP of Fires (Million Yuan) (%o) * GNP : Gross National Product

The IRSN and AREVA NC are currently conducting a fire research programme to improve knowledge of the clogging of industrial pleated high efficiency particulate air (HEPA) filters in order to develop an empirical model for clogging of such filters by combustion aerosols. The model must insofar as possible be independent of the nature of the fuel. This paper discusses the influence of various 'direct' factors such as the filtration velocity, mass of deposited aerosols per filter area, diameter and morphology of the combustion particles, condensate content of the aerosols, and 'indirect' factors such as the air flow feeding the fire and its oxygen content, which influence evolution in the aeraulics of a clogged filter.

Monitoring stability loss in burning structures can provide firefighters with valuable information during operations. A fireinduced vibration based monitoring technique, developed under previously funded research and development efforts and in collaboration with the Building Fire Research Laboratory (BFRL) and the National Institute of Standards and Technology (NIST), has been field demonstrated in over 30 full-scale burn tests. The technique relies on the interpretation of characteristic response behavior induced in a burning structure that can be associated with changing structural conditions and stability loss. An overview of the important aspects necessary for a practical implementation in the field is presented.

Whether a smoke extraction system has to be installed for an atrium building in Hong Kong is determined by its volume. This article reports an evaluation of this regulation using the zone model FIRST developed at the Building and Fire Research Laboratory, NIST, U.S.A. A survey of the geometri cal configurations of the local atria is made. The general shapes of the atria are classified into three types: 1, 2 and 3, with types 2 and 3 further divided into three sub-types: A, B and C. Smoke filling in those atria is simulated by the model FIRST with the volumes of the atrium space varied from 2500 m3 to 35,000 m 3. It is illustrated that specifying only the volume of the atrium space is not good enough to determine whether a smoke extraction system has to be installed. The geometrical configuration is recommended to be included as well. A time constant is defined for the atrium with a certain design fire.

This article is a report studying the potential fire risk in atrium buildings in Hong Kong. The general shapes of the atrium buildings are sur veyed and classified into three types. Fire environments in those three types of atria are simulated using three mathematical fire zone models, the FIRST, the ASET and the FAST, developed at the Building and Fire Research Laboratory, NIST, U.S.A. In addition, simulations on four actual atria are also performed. All the results show that smoke will bring many problems, and controlling smoke is essential to providing safety in the atrium spaces.

Performance of the smoke exhaust system in two atria will be studied by fire models in this paper. A two-layer zone model and a Computational Fluid Dynamics field model developed by the Building and Fire Research Laboratory, National Institute of Standards and Technology, USA are used. Numerical results are compared with experiments by hot smoke test in the two atria. Both fire models can give good predictions and so are suitable for evaluating the performance of the smoke exhaust system.

A key requirement for the assessment of toxic hazard in fire is a knowledge of the range, nature and concentrations of toxic/irritant species and smoke particulates present in the fire effluent. Owing to the often extremely hostile conditions present in a fire, it is necessary to adopt specialised methods for sampling and analysis if the results are to be meaningful. This chapter provides both a detailed summary of methodologies which have proved to be successful over a wide range of fire research/testing regimes, and offers guidance for setting up practical sampling and analysis systems.

Python along with various numerical and scientific libraries was used to create tools that enable fire protection engineers to perform various calculations and tasks including educational instruction, experimental work, and data visualization. Examples of web calculators and tools for creating 3D geometry for fire models using Python are presented. The use of Python in the fire research field will foster many new ideas, tools, and innovation in the field of fire protection research and engineering.

Wildland fires are a significant and growing problem for many communities. Simultaneously, fire is increasingly seen as an important component of natural ecosystems. As human development continues to encroach on wildland areas we will see more conflicts between allowing fire in ecosystems and human development. Geotechnologies such as remote sensing, GIS, and Dendrochronology are increasingly important in improving our understanding of the complex processes involved and the complicated social issues that accompany human interaction with wildland fire. Pyrogeography is an emerging approach that brings together many disciplines and techniques to help elucidate the spatial and temporal patterns that can help us better understand wildland fire. This chapter explores the key concepts necessary to understand current spatial research in fire ecology, spatial computer fire models, and some of the spatial data sets that are used in wildland fire research in the United States.

Increased levels of burning in the past 40 years are raising public and scientific concern about the relative importance of rising temperatures, climate variability, and human actions including management practices in initiating and supporting recent conflagrations. Enormous fires in Australia, North America, Europe, and Russia since 2000 have resulted in billions of dollars in property damage, loss of life, and threats to human and ecological health. Levels of fire activity are expected to increase in the coming decades in many regions as temperatures continue to rise and droughts intensify [Moritz et al., 2012]. Linked disturbances such as bark beetle infestations, nonnative plant invasions, and mass-wasting events have also exacerbated the effects of fire in many ecosystems.

At the request of the Forum for International Cooperation on Fire Research, a worldwide survey was conducted of operational computer programs relevant to fire protection. A total of 62 programs, from 10 countries, were identified, and include compartment fire models, fire-sprinkler interaction models, and submodels for fire endurance, building evacuation, thermal detector actuation, fire spread on a wall, and smoke movement. These are listed, plus 12 additional models, including models from three additional coun tries. Then a general discussion is provided of the difficulties in achieving an accurate model of a growing fire in an enclosure, and of assessing the accuracy of a given model.

The California Bulletin (CB) 133 upholstery ignition source is based on the use of crumpled newsprint. The present work examined the reproducibility of several aspects of this source when placed on an inert chair mock-up. The tendency of this source to heat the side arms of a chair, the area of the seat back subjected to high heat fluxes, the peak flux there and the flux duration all showed substantial variability. For inherently lesser variability a gas burner is preferred. A gas burner, derived from that developed at the British Fire Research Station, was shaped so as to deposit a similar pattern of heat to that of the CB 133 source. The two sources were tested for comparability both on chair mock-ups and on full-scale chairs made from a wide variety of materials. The results indicate that the gas burner, as used here, is a somewhat less severe ignition source than is the CB 133 igniter.