Springer Science and Business Media LLC

It is common cause that the arcing of high voltage electrical conductors produces a shower of sparks. The flame temperature of aluminium burning in air is reported as having been measured as 3800 K (3527°C) [1]. After ejection from the point of arcing, a globule of aluminium is likely to be at or above its boiling point (2700 K or 2427°C) and surrounded by an aluminium vapour cloud which is promptly ignited and burns with a diffusion flame. If during the luminous period a spark was to fall onto dry veld grass then, provided it had sufficient energy not to be quenched, it would almost certainly cause ignition. Should the flame around a boiling globule be extinguished while it was still of finite size and were such a particle to fall into dry veld grass while its temperature was between 300 and 400°C or above it could cause ignition of the grass. In the present paper, ignition of the veld grass is determined by the temperature-trajectory history of hot particles of different sizes and initial conditions after their projection into a high velocity gusting airstream. This paper complements that of Mills and Xu Hang on trajectories of sparks from arcing aluminum cables [2] and that of Fernandez-Pello and Tse on the flight paths of metal particles and embers generated by power lines in high winds—a potential source of wildland fires [3]. The present study was commissioned in an attempt to establish the likelihood, or otherwise, that the occurrence of a particular veld fire could have been due to hot aluminium particles ejected from the clashing of high voltage overhead transmission lines. From in situ measurements, the fire started some 10.7 m horizontally from the clashing of the overhead conductors. Sets of graphs were obtained by computational experiment with the objective of verifying the starting point of the fire. These sets comprised: Time versus Particle Temperature, Time versus Vertical Penetration, Time versus Horizontal Penetration and Horizontal Penetration versus Vertical Penetration. Not all of the set of graphs satisfied the requirement of starting a fire at the given point. Sets H, I and J provided the definitive clue that the fire would have started by hot aluminium particles. The investigation was done in phases corresponding to the different set of graphs. Two models were subsequently elaborated called herein less rigorous and more rigorous. The effects of downward, upward and negative horizontal ejection velocities were also examined. The aim of the paper was to reconstruct the conditions prevailing on the day of the fire. The results obtained show that the probability the fire having been started by the hot aluminium particles ejected by clashing overhead conductors was high.

A simple model that divides the heat flux to the bodies engulfed in a diffusion flame into different components, namely radiation and convection is studied. Different sizes of brass and stainless steel (SS 304L) rods varying from 25.4 mm to 50.8 mm in length and 25.4 mm in diameter are used as specimens in this study. Experiments are conducted with each body inside a diesel pool fire of different diameters, namely 0.5 m, 0.7 m and 1.0 m. The temperature history of the body engulfed in a pool fire is measured to compute the thermal energy absorbed by the lumped body. Using an energy balance, the total energy is divided into three different components. The gas velocity in the flame is measured to be 1.53 m/s to 1.79 m/s for the diesel pool fires of 0.5 m to 1.0 m in diameter. The dominant mode of heat transfer in this study is radiative in nature. This simple model is reasonably able to predict the heat flux incident on to the lumped bodies engulfed by diesel pool fires using the measured temperature history. A three dimensional formulation for an axi-symmetric pool fire of a measured flame shape, flame temperature and a gray flame absorption coefficient is employed to predict the temperature of the body engulfed in pool fires. This formulation has to be modified to capture the absolute temperature values of the flame.

In this paper, a method is proposed for spontaneous fire whirl analysis and prediction due to non-regularly or randomly distributed flame sources, by defining an equivalent gap fraction and providing an adapted criterion. The topological structure of the flame source configuration, the eccentric direction of each equivalent gap and the integrated effect of all the gaps are considered. By the application of the equivalent gap fraction criterion, predictions can be made in a real fire disaster for the likelihood, the rotating direction and the rough intensity of the swirl and then suggestions can be provided for configuration design to prevent fire whirls or to reduce the damage.

Is a Hazen and Williams friction loss factor of 120 adequate to allow for deterioration in sprinkler piping over the years? Just how much deterioration does take place and what are the factors contributing to it? This analysis was made for the Fact Finding Committee of the National Automatic Sprinkler and Fire Control Association.

Since fire and burns are the second leading cause of injury to young children up to age 4, fire and burn prevention education and training must reach the people who care for young children to be effective. Increasingly larger percentages of young children are cared for in out-of-home settings, including child-care centers and family child-care facilities. The majority of children, however, are still cared for by their parents or other relatives, for all or part of the day. Thus, there was a need for an injury prevention program for child-care providers in different settings. A group of experts in a variety of fields developed a burn prevention curriculum as part of a comprehensive injury prevention project. These experts represent a variety of related fields, including injury prevention, early childhood education, child-care administration, instructional design, and evaluation. Operators of child-care facilities, parents, and care providers were involved in the planning and implementation of a training workshop. The program was tested with 141 child-care providers at seven sites. Subjects included child-care center staff, family child-care operators, and parents of young children. Materials included an instructor manual, coursebook, video, and test booklet. Subjects' knowledge, attitudes, and practices intentions were tested before and after the training. Subjects also completed a program evaluation. Results indicated significant improvement in knowledge, attitudes, and practices intentions for the total group and for subjects at each site. Gains made by center staff and family day-care providers were significant on all three measures, as they were for parents on knowledge and practices. Measures of attitudes and injury prevention practices indicated a high level of acceptance of program goals. A large majority of the subjects said the program was useful and interesting. An analysis of the test results by objective indicated that subjects had improved their knowledge scores on each objective. They had the highest achievement on topics related to understanding characteristics of burns and understanding the hazards and prevention techniques related to smoke, matches, lighters, and hot surface burns. An important finding was that child-care providers in different environments can be instructed in burn prevention using the same program.

Suppression of high-voltage (HV) electrical fires is difficult because it requires fire-extinguishing agents with good isolation properties as well as high fire-suppression efficiency. In the work presented herein, water mist with and without various water mist additives (WMAs) was utilized to suppress HV transformer oil fires. The WMAs included ionic alkali-metal salt and fluorocarbon surfactant, and nonionic hydrocarbon and fluorocarbon surfactants. At the same concentration, the surfactants were more efficient at extinguishing fires compared with the alkali-metal salt. The fluorocarbon surfactant was more efficient at extinguishing fires than the hydrocarbon surfactant, achieving flame extinction in 18 % of the time required when using natural water (NW). Besides, the effects of WMAs on the insulating properties of the water mist were studied. The gap breakdown test showed that the NW mist could increase the breakdown voltage of air by up to 5 % at 70-cm gap distance. Comparatively, the nonionic WMAs did not affect the insulating property of the NW mist, with the mist containing 1.0 % ionic KHCO3 solution enabling a reduction of up to 16 % in the breakdown at 70-cm gap distance while increasing the leakage current of the simulated insulator by up to 250 % at its nominal voltage. Finally, field tests were performed where NW mists were discharged onto a charged 220-kV high-voltage transformer. This study proves that NW mist and mists with nonionic WMAs are suitable for protecting HV electrical equipment, having important implications for extending the applications of water mist.

Insulated and uninsulated boots for use by aircraft crash crew fire fighters were evaluated and compared for the protection, comfort, convenience, and durability they offer the wearer.