Risk factors for fatal residential fires

Residential fires are the most important cause of fire-related mortality in the United States. Previous research has concentrated on fatal fires in urban areas; considerably less is known about fatal fires in rural areas.We studied fatal and nonfatal residential fires in predominantly rural areas. Using a casecontrol design, we compared all 151 fatal fires (cases) in single-family dwellings in North Carolina during a 13-month period with a sample of nonfatal fires (controls). Case fires were identified through the medical-examiner system, and control fires that occurred within a few weeks of the case fires were chosen from the records of randomly selected fire departments statewide. For each fire, fire officials were interviewed about the dwelling, the fire, the people involved, and the fire-response system.Although heating incidents were the leading cause of fires, fatal fires were more likely to have been caused by smoking (31% of fatal fires vs. 6% of nonfatal fires). Mobile homes posed a higher risk of death if a fire occurred (odds ratio, 1.7; 95% confidence interval, 1.1 to 2.6), as did the absence of a smoke detector (odds ratio, 3.4; 95% confidence interval, 2.1 to 5.6). Smoke detectors were more protective against death in fires involving young children and when no one present was impaired by alcohol or drugs or had a physical or mental disability. The presence of an alcohol-impaired person was the strongest independent risk factor for death in the case of a fire (odds ratio, 7.5; 95% confidence interval, 4.4 to 12.7).In conclusion, residential fires are most likely to be caused by heating equipment or smoking materials. The risk of death is greatest in fires in mobile homes, in those involving alcoholimpaired persons, and in those in houses without smoke detectors. Reprinted with permission from The New England Journal of Medicine, 1992 Sep 17, 327 (12), pp. 859–863.     

Fire Risk Assessment of Residential Buildings Based on Fire Statistics from China

Fire statistics provide valuable information for the assessment of future fire risks. The paper analyses the fire situation in China from 1991 to 2010. The temporal, spatial, and causal fire incident data for the last 6 years have been analyzed to gain an understanding of fire characteristics and the elements affecting fire risks. It is found that the number of fires was observed to be higher during cold winter months, and fires were more frequent during the weekend. The number of fires was lower during nighttime, whereas the number of fire deaths between midnight and 4 a.m. was much higher than at other times of the day. Most fire incidents occurred in residential buildings. In economically developed East China, the fire situation is much more serious. Electrical failures and improperly fire use in daily life were major causes of fire incidents. Based on the statistical data from China’s fire services and the China Statistical Yearbook, the risk of occupant deaths and the risk of direct property loss are calculated to express the risk level in residential buildings. It is found that the risk of occupant deaths had a declining trend over the years. Statistics is considered a useful tool for learning from the actual events, and it helps decision makers develop proactive fire protection measures to reduce fatalities and financial losses caused by fires.     

The timing of vegetation fire occurrence in a human landscape

Vegetation fires in urban and peri-urban (human) landscapes damage property and infrastructure, threaten lives and incur considerable suppression costs. This study investigated the timing of fires burning in vegetation within and around the city of Perth, Western Australia. The timing of fires from 16 different cause types were investigated at hourly, daily, monthly and annual scales, and using fire danger indices and fuel moisture. Ignitions from most causes were shown to have hourly and monthly profiles that reflect fire danger and fuel availability. Some causes with low heat outputs, such as cigarettes and sparks from cutting and welding, were more sensitive to fire danger and fuel availability than others. Causes related to arson and recreational activities, such as camp fires, were more likely to occur on weekends and public holidays. Arson prevention measures appear to have reduced the incidence of deliberately lit fires, and may have reduced the number of fires occurring on days of total fire ban, although these days have much higher rates of ignition than other days. High profile fire events also increase public awareness and reduce ignition rates. Lessons learned from analyses of fire occurrence can help fire agencies more effectively apply prevention and mitigation programs.     

The Influence of Tunnel Geometry and Ventilation on the Heat Release Rate of a Fire

It has occasionally been observed that fires in tunnels appear to be significantly more severe than fires in the open air. A literature review has been carried out, comparing heat release data from fires in tunnels with heat release data from similar fires in the open air. A Bayesian methodology has been used to investigate the geometrical factors that have the greatest influence on heat release rate. It is shown that the heat release rate of a fire in a tunnel is influenced primarily by the width of a tunnel; a fire will tend to have a higher heat release rate in a narrow tunnel rather than in a wide tunnel. The observed relationship between heat release rate and tunnel width is presented. Results from a study investigating the variation of heat release rate with ventilation velocity for fires in tunnels are also presented. A method for making realistic estimates of the heat release rates of fires in tunnels, based on these results, is presented.     

Estimating the Flashover Probability of Residential Fires Using Monte Carlo Simulations of the MQH Correlation

An important indicator of fire hazard in residential fires is the occurrence of flashover in the room of fire origin. Since the variability of residential fire scenarios is large, many different cases must be considered to evaluate the hazard of a given flammable product. Efficiently predicting the occurrence of flashover of a naturally ventilated compartment is possible using the correlation of McCaffrey, Quintiere, and Harkleroad (MQH). The large variability in United States (U.S.) living room fire scenarios is characterized from available data and propagated through the MQH correlation using Monte Carlo (MC) simulation. For the parameters, for which no relevant data was found, uniform probability distributions were assumed. The scenarios sampled in the MC simulations generally fell within the range of scenarios for which the MQH correlation has been validated. Flashover probabilities were estimated for fires up to 5 MW in heat release rate (HRR) and up to 8 min in duration. It was found that fires with HRRs less than 400 kW have a flashover probability of less than 0.01% regardless of their duration. Typical furniture fires were used as example cases, and it was predicted that a three seat upholstered sofa with a peak HRR of 2.15 MW has a 90% chance of flashing over a randomly chosen U.S. living room. The results of a global sensitivity analysis indicates that the fire location parameter and the vent opening width are the most important parameters affecting the prediction of the occurrence of flashover in U.S. living rooms. The methodology presented is generalizable, and the results can be readily improved by the collection of more data and the use of higher fidelity fire models.     

Statistical Characterization of Heat Release Rates from Electrical Enclosure Fires for Nuclear Power Plant Applications

Since the publication of NUREG/CR-6850/EPRI 1011989 in 2005, the US nuclear industry has sought to re-evaluate the default peak heat release rates (HRRs) for electrical enclosure fires typically used as fire modeling inputs to support fire probabilistic risk assessments (PRAs), considering them too conservative. HRRs are an integral part of the fire phenomenological modeling phase of a fire PRA, which consists of identifying fire scenarios which can damage equipment or hinder human actions necessary to prevent core damage. Fire ignition frequency, fire growth and propagation, fire detection and suppression, and mitigating equipment and actions to prevent core damage in the event fire damage still occurred are all parts of a fire PRA. The fire growth and propagation phase incorporates fire phenomenological modeling where HRRs have a key effect. A major effort by the Electric Power Research Institute and Science Applications International Corporation in 2012 was not endorsed by the US Nuclear Regulatory Commission (NRC) for use in risk-informed, regulatory applications. Subsequently the NRC, in conjunction with the National Institute of Standards and Technology, conducted a series of tests for representative nuclear power plant electrical enclosure fires designed to definitively establish more realistic peak HRRs for these often important contributors to fire risk. The results from these tests are statistically analyzed to develop two probabilistic distributions for peak HRR per unit mass of fuel that refine the values from NUREG/CR-6850, thereby providing a fairly simple means by which to estimate peak HRRs from electrical enclosure fires for fire modeling in support of fire PRA. Unlike NUREG/CR-6850, where five different distributions are provided, or NUREG-2178, which now provides 31, the peak HRRs for electrical enclosure fires can be characterized by only two distributions. These distributions depend only on the type of cable, namely qualified versus unqualified, for which the mean peak HRR per unit mass is 11.3 and 23.2 kW/kg, respectively, essentially a factor of two difference. Two-sided, 90th percentile confidence bounds are 0.0915 to 41.2 kW/kg for qualified cables, and 0.0272 to 95.9 kW/kg for unqualified cables. From the mean (~70th percentile) upward, the peak HRR/kg for unqualified cables is roughly twice that for qualified, increasing slightly with higher percentile, an expected phenomenological trend. Simulations using variable fuel loadings are performed to demonstrate how the results from this analysis may be used for nuclear power plant applications.     

Gentrification or social renewal? Effects of public supported housing renewal in Denmark

This paper analyses social change, particularly the processes of social decay, in obsolete and deteriorated housing in the older housing stock in Denmark between 1986 and 1996. These changes are compared with the development which has occurred in similar kinds of housing that have been physically upgraded through a government program for housing renewal.

The study shows that this kind of housing attracts a quick turnover of residents and a tendency towards more unemployed or lower income occupants. It is also used by young people as their first home when moving away from their parents.

It is also shown that public supported housing renewal stops this type of housing pattern and increases the share of households that have high incomes. The changes, however, are not considerable and there are also many unemployed people among the newcomers. These changes depend to a large degree on the size and tenure of the renewed dwellings. In private renting, particularly co‐operatives and in larger dwellings the socio‐economic composition of residents undergo greater changes than in smaller dwellings in non‐profit or public housing. Extensive renewal often results in high rent compared with rent from the regulated housing market in Denmark. As a result the renewed dwellings have difficulties in competing with other kind of dwellings. For that reason residents of this type of housing primarily consist of welfare or pension recipients or others who receive high housing benefits. A minority of people with higher income also use these dwellings but mostly as temporary housing as after a few years they often move to owner‐occupied housing.     

Search and mobility in a housing market with limited supply

In this paper, a non-linear dynamic model is presented for a housing market in which various types of households and dwellings are distinguished. The model is based on a stock-flow framework, in which households have to cope with incomplete information when searching for dwellings. The model includes life-cycle patterns (social mobility, ageing) as well as stochastic dwelling preferences. Simulations are carried out with the model to investigate its properties (existence of stationary states, etc.) under various conditions of housing supply. Special attention is paid to vacancy rates, duration of residence, and length of vacancy chains.     

Challenges in Comparing Radon Data Sets from the Same Swedish Houses: 1955–1990

We compare data sets from two different Swedish studies which included measuremem of the indoor radon concentration both in 1955 and in 1990 in 178 of the same houses. The purpose is to learn more about how the indoor radon concentration changes over a time scale of years in the same houses. Many sources of both systematic and random errors exist when comparing these types of data sets. Specific types of errors are due to uncertainties in the calibration of the epuipment, the influence of the weather, the time lengths of sampling, airing of some of the dwellings, and changes in ventilation rates. The data indicate a general increase of the radon concentration in the dwellings between 1955 and 1990, with a 1990/1955 ratio of the averages of 1.3. The average radon concentration in all alum shale houses, (where the building material is a source of radon) in 1990 versus 1955 is 204 ± 22 and 163 ± 23 Bq/m³ and in non-alum shale houses is 62 ± 8 and 42 ± 7 Bq/m³, respectively.     

Socioeconomic deprivation and fatal unintentional domestic fire incidents in New Zealand 1993–1998

A cross-sectional study was undertaken in Aotearoa New Zealand to investigate the relationship between socioeconomic deprivation and risk of an unintentional fatal domestic fire incident. Addresses of unintentional fatal domestic fire incidents were geocoded to small area (census meshblock) level and analysed with the New Zealand index of socioeconomic deprivation. Fatal unintentional domestic fire incidents occurred disproportionately in dwellings in the most socioeconomically deprived meshblocks. Annual rates of fatal unintentional fire incidents per 100,000 households in the most deprived decile were significantly higher than rates in the least deprived decile (RR 5.6, 95%CI 1.9–16). Strategies to prevent fire related deaths must overcome barriers to household fire safety in population groups experiencing increased risk, including the socioeconomically deprived, seniors, and ethnic minorities. Specific intervention strategies relevant to risks associated with socioeconomic deprivation include improving quality and affordability of housing; increasing prevalence of installed and functioning smoke detectors; and regulation of specific characteristics of cigarettes to reduce risk of ignition from abandoned heat sources. Substantial progress awaits reduction of the underlying socioeconomic determinants of disadvantage.     

电动船三元锂电池舱与磷酸铁锂电池舱灭火对比试验研究

为研究三元锂电池电动船的消防安全,搭建了一个船舶锂电池舱火灾试验平台,通过模拟舱室火灾场景,开展了一系列大尺寸灭火试验,从灭火现象、冷却效果及复燃间隔时间等方面对比分析了4种船用固定式灭火系统对三元锂电池和磷酸铁锂电池初期火灾的抑制效果.试验表明,压力水雾灭火系统对两种电池火体现出较好的抑制和冷却效果,5、10 L/(...     

The Housing Careers of Turkish Households in Middle-sized Swedish Municipalities

This paper examines how Turkish households adjust their housing consumption to their needs by making a housing career. The study was conducted in three middle-sized municipalities in the central part of Sweden: Gävle, Västerås and Jönköping. The longitudinal analysis is based on specially processed census data, and is limited to the period 1975-90. The study focuses on the housing choice by Turkish immigrants put into the conceptual framework of the life course. The supply of dwellings and their accessibility as well as the households' resources as constraining factors are explicitly recognised. This study reports a strong impact of higher income and increased household size on the households' moves to larger dwellings, and, in some cases, a move from rented into owner-occupied dwellings. This is in accordance with results from earlier residential mobility studies. Therefore, it would be expected that Turks go through more or less the same housing career as indigenous households, in this case as Swedes, but this is not true. The study reports that Turkish immigrant households are less likely to move out of the municipal rented sector and have a higher probability of remaining in certain immigrant-dense areas of the municipality than indigenous Swedish households.     

Cyanide and fire victims: A hazard in focus

The insidious accumulation of hydrogen cyanide from smouldering fires in dwellings to levels that render victims unconscious and facilitate intoxication by carbon monoxide by increasing the ventilation rate may occur more frequently at the present time through the mounting trend toward the use of cheap synthetic materials in building construction and house furnishings. Although in many cases fatalities appear to be due primarily to carbon monoxide, the proportion of deaths in which cyanide intoxication is a decisive contributory factor may have been underestimated. In the circumstances of an emergency the possibility of extensive exposure to cyanide cannot be excluded. Treatment of all fire victims overcome by toxic fumes with an innocuous cyanide antidote immediately upon removal from the affected premises therefore appears necessary.     

Use of fire statistics in behavioural studies

This paper gives data on information available on casualty incidence and behaviour from fire brigade reports. The data presented appear to refute several popular beliefs about the typical casualty fire.Fire brigade data are large in volume and cover a wide range of fires but provide only limited information on each individual fire. Thus, for further information on behaviour patterns, some fires will have to be investigated in detail.     

城乡火灾风险与社会性指标的关联性研究

为探究社会性因素对城乡火灾风险的影响权重,基于火灾历史数据计算GDP、常住人口和受教育程度等指标与城乡火灾风险的关联性。计算分析发现,GDP 总量与火灾数量呈现正相关关系,在省份维度GDP 总量与火灾数量呈现强相关,在城市维度GDP 总量与火灾数量呈现中等相关;各省常住人口与本省火灾数量呈现强相关关系,但经济欠发达省份的关联性较弱;居民受教育程度较低时,教育水平与火灾发生数量呈负相关,高教育阶段时,教育水平与火灾发生数量呈正相关。     

Fire Department Attended and Unattended Fires: Estimates from the 2004–2005 National Sample Survey and Comparison with Previous Surveys

Previous national surveys in 1974 and 1984 have shown that although attended and unattended fires differed substantially in severity and fire losses, there were between 10 and 29 unwanted residential fires for every fire reported to, or attended by, U.S. fire departments. The study objective was to obtain new estimates of fires not attended by fire departments. Interest in unattended fires derives from the understanding that most fires begin small, then unless controlled, grow until fire department assistance is needed. To update these analyses, a national telephone survey was conducted during 2004 and 2005. The survey had 916 respondents who reported one or more residential fires during the previous 90-day period. The principal methodological issues in analyzing the survey data included: (1) determining the optimum recall period to balance sampling variance and bias, and (2) imputing incompletely specified fire dates. The resulting estimates were 7.2 million unattended residential fires per year, a 69% decrease from the 1984 survey estimate of 22.9 million fires. During the same time period, fire department attended residential fires decreased by 36%. The greater decrease in unattended fires is at variance with the conjecture in the 1984 survey that increasing availability of smoke alarms would result in more fires detected at an earlier stage when they could be controlled by residents; a conjecture that would predict a greater decrease in attended rather than unattended fires.     

Ignition of Combustible Fuel Beds by Hot Particles: An Experimental and Theoretical Study

The process of spotting occurs in wildland fires when fire-lofted embers or hot particles land downwind, leading to ignition of new, discrete fires. This common mechanism of wildland fire propagation can result in rapid spread of the fire, potentially causing property damage and increased risk to life safety of both fire fighters and civilians. Despite the increasing frequency and losses in wildland fires, there has been relatively little research on ignition of fuel beds by embers and hot particles. In this work, an experimental and theoretical study of ignition of homogeneous cellulose fuel beds by hot metal particles is undertaken. This type of well-characterized laboratory fuel provides a more controllable fuel bed than natural fuels, and the use of hot metal particles simplifies interpretation of the experiments by reducing uncertainty due to unknown effects of the ember combustion reaction. Spherical steel particles with diameters in the range from 0.8 mm to 19.1 mm heated to temperatures between 500°C and 1300°C are used in the experiments. A relationship between the size of the particle and temperature required for flaming or smoldering ignition is found. These results are used to assess a simplified analysis based on hot-spot ignition theory to determine the particle size-temperature relationship required for ignition of a cellulose fuel bed.     

Analysis of Vehicle Fire Statistics in New Zealand Parking Buildings

The risk of fire in parking buildings is dependant on the probability of a fire occurring and the severity of the fire. This paper reviews the research data available on vehicle fires and suggests the severity of such a fire for a risk analysis. The paper then examines the historical data for vehicle fires in New Zealand parking buildings from 1995 to 2003 to determine the probability of the occurrence of such fires and the likelihood of multiple vehicle involvement. It is found that annual vehicle fire frequencies in parking buildings are generally lower than those in buildings of other occupancies but increases with the annual usage ratio.     

高层建筑消防隐患及防火策略研究

随着建筑行业的有序发展,建筑类型逐渐多元化,高层建筑的数量也越来越多,与此同时,高层建筑的消防隐患和矛盾也日益突出,这也要求相关单位能够在总结经验和建立应急预案的基础之上,推出更为有效的防火和监督方法.文章主要研究高层建筑的消防隐患,总结高层建筑火灾发生的特点,提出了防火监督的方法.