Investigation Techniques of Arson Fire in Low-Temperature Warehouses Using ED-XRF

Investigation techniques for fire prevention in low-temperature warehouses were studied using energy dispersive X-ray fluorescence (ED-XRF). In the first experiment, a sample (galvanized steel sheet plus urethane foam plus sandwich panel) was burned with 500 mL of a flammable liquid (gasoline, thinner, kerosene, and light oil)/ Then, the component change of the sample was measured. In the combustion experiment, there was a difference in the heat of combustion depending on the type of flammable liquid; however, as a result of measuring the component change of the sample with ED-XRF after combustion, the largest component change was measured in the combustion experiment with gasoline. The change was in the order of thinner, kerosene, and diesel. Using ED-XRF, it was possible to distinguish the flammable liquid used in the experiment by measuring the component change of the sample resulting from the difference in the combustion heat of the flammable liquid. A second experiment was conducted under the same conditions as the first experiment, assuming a fire brigade fire suppression condition, and the combustion time of the flammable liquid was limited to 600 s. A combustion characteristic of flammable liquids is that the temperature and heat flux reach the maximum value within 300 s after the start of combustion regardless of the type of liquid. Because the change of composition was confirmed in the order of light oil, it was possible to distinguish the flammable liquid used at the fire site using the ED-XRF measurement result.

Prognostication of fire of oil and oil products storage tank farms and engineering and technical solutions

The object of the study is «Severnaya oil depot of the Lipetsk region». This article defines the occurrence and development of a fire in the tank and the dependence of a number of factors, also indicates the type of flammable liquid, the presence of an explosive concentration inside the tank, the place of the fire, the design features of the tank, the presence and condition of fire protection systems. Also, an assessment of the object from the position of fire hazard was carried out, the calculation of forces and means ensuring their timely and effective connection in cases of fire. The necessity of using modern extinguishing means to eliminate the resulting fire is shown.

EXPERIMENTAL STUDIES OF THE RELATIONSHIP BETWEEN THE BOILING TEMPERATURE AND THE FLASH TEMPERATURE OF MIXED HYDROCARBON FUELS

В работе экспериментально показано, что по мере испарения смесевой горючей жидкости при одновременном повышении плотности и снижении упругости пара в многокомпонентных взаиморастворимых композициях температура кипения повышается. В этом случае и температура вспышки смесевой горючей жидкости также будет повышаться. Так, при проливах горючих жидкостей происходит довольно быстрое обеднение легкими фракциями, упругость пара при заданной температуре существенно снижается, а температуры кипения и вспышки, соответственно, повышаются. Полученные в работе зависимости температур кипения и вспышки испытанных смесевых горючих жидкостей характерны и для других различных многокомпонентных жидких композиций. Эти зависимости могут учитываться при разработке планов предотвращения и ликвидации аварий в случае их проливов. Based on the experiments it is shown that as the flammable liquid mixtures evaporate, while increasing density and decreasing vapor tension in multicomponent compositions-soluble, the boiling temperature increases. In this case, the flash point of the mixed combustible liquid will also increase. Thus, in the case of spills of flammable liquids there is a fairly rapid depletion of light fractions, the vapor tension at a given temperature reduces significantly, and the boiling and flash temperatures increase accordingly. The dependences of the boiling and flash temperatures of the tested mixed combustible liquids obtained in this work are also typical for other various multicomponent liquid compositions. These dependencies can be taken into account when developing plans for the prevention and elimination of emergencies caused by their spills.

Furan. Determination in workplace air with gas chromatography

Furan is colorless, highly volatile and flammable liquid with a specific ether odor. In nature it occurs in some species of wood, it is formed during burning process of wood, tobacco, fuels and also in thermal food processing. In industry furan is used as an intermediate in organic synthesis, resins solvent, during production of lacquer, drugs, stabilizers, insecticides and also in production of chemical compounds which have polymeric and coordination structure. Carcinogenic effect on animals was a base of recognition that furan is a substance which is probably also carcinogenic on humans. The aim of this study was to develop and validate a method of determining furan in workplace air. Developed determination method of furan relies on vapor absorption of this substance on coconut shell charcoal. Furan was extracted by 5% butan-1-ol solution in toluene. Obtained solution was analyzed with chromatography. The study was performed with gas chromatograph coupled with mass spectrometer (GC-MS), equipped with non-polar HP-PONA capillary column (length 50 m, diameter 0.2 mm and the film thickness of the stationary phase 0.5 µm). Developed method is linear in the concentration range of 0.05–1.0 µg/ml, which is equivalent to the range of 0.005–0.1 mg/m3 for 10-L air sample. The analytical method described in this paper makes it possible to determine furan in workplace air in the presence of comorbid substances. The method is precise, accurate and it meets the criteria for procedures for determining chemical agents listed in Standard No. PN-EN 482. The developed method of determining furan in workplace air has been recorded as an analytical procedure (see Appendix). This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering.

On the question of the required foam expansion ratio for sublayer extinguishing of oil and oil products fires in vertical steel tanks

Возможность эффективного тушения резервуаров подслойным способом во многом зависит от подъема пены на поверхность горючей жидкости. Критически рассмотрены существующие методики испытаний высоконапорных пеногенераторов для подслойного пожаротушения. Предложены расчетные формулы для определения величины минимальной кратности пены, способной к подъему, в зависимости от состава и плотности горючей жидкости, высоты столба горючей жидкости, типа используемого пенообразователя. Обоснованы условия применения существующих систем подслойного пожаротушения для резервуаров с различной высотой стенки. During the certification tests of high-pressure foam generators for sublayer oil and oil products fire extinguishing in the tanks there is created a conditional back pressure at the generator output, and the foam expansion ratio is measured when this back pressure is no longer present. In accordance with the standardized methodology the foam expansion ratio is measured in the measuring container by weight. The derived foam after passing throughout the pipeline is supplied to the measuring container where the foam expansion ratio is measured under the atmospheric pressure. In practice, during fire extinguishing the flammable liquid exerts a constant excess pressure on the formed foam. The expansion ratio of the foam decreases in proportion to the pressure value of the column. As a result, the foam expansion ratio can reduce to a value when the Archimedean buoyant force no longer occurs. In this case, the foam cannot be supplied to the surface of the flammable liquid and the fire cannot be extinguished. The back pressure created at the tank base depends on the height of the tank wall (level of the liquid fuel filling) and on its density. Foam rise is possible if the foam density is lower than the fuel density. Light oil products extinguishing requires greater expansion ratio foam than heavy oil products extinguishing. At the same time, heavy oil products cause greater back pressure and a decrease in the foam expansion ratio. Alcohols in the composition of modern high-octane gasolines produce an additional defoaming effect on the foam, which questions the feasibility of using a sublayer fire extinguishing system of modern high-octane gasolines. The article evaluates a set of parameters that affect the required foam expansion ratio for sublayer extinguishing of oil and oil products fires in tanks and justifies the minimum value of its expansion ratio.

The Latest Trends in Electric Vehicles Batteries

Global energy demand is rapidly increasing due to population and economic growth, especially in large emerging countries, which will account for 90% of energy demand growth to 2035. Electric vehicles (EVs) play a paramount role in the electrification revolution towards the reduction of the carbon footprint. Here, we review all the major trends in Li-ion batteries technologies used in EVs. We conclude that only five types of cathodes are used and that most of the EV companies use Nickel Manganese Cobalt oxide (NMC). Most of the Li-ion batteries anodes are graphite-based. Positive and negative electrodes are reviewed in detail as well as future trends such as the effort to reduce the Cobalt content. The electrolyte is a liquid/gel flammable solvent usually containing a LiFeP6 salt. The electrolyte makes the battery and battery pack unsafe, which drives the research and development to replace the flammable liquid by a solid electrolyte.

Investigation Method for Carpet Fires by Analyzing Carbonation Patterns and Oil Vapor

We present a fire investigation method for carpets by analyzing the carbide pattern and oil vapor. The combustion of carpets is dominated by laminar and turbulent flow, and the combustion pattern on the floor surface is shaped like a halo pattern. The combustion pattern on flooring material sprayed with an flammable liquid takes a donut-shaped and a circular pattern in which the core is burned. Surface analysis by substance microscopy showed that the boundary surface was melting and recombining, regardless of whether or not the carpet was treated with flame retardant. In the analysis of the capture of oil vapor using a gas detector tube after combustion was completed, the general carpet was discolored to dark green with one to two divisions, and combustion of ordinary carpets and gasoline exhibited two to three divisions. It was found that one to two divisions of flameproof carpets were discolored to dark green, and combustion of flameproof carpets and gasoline produces five to six divisions. The differences in combustion products could not be clearly distinguished using gas chromatography and mass spectrometry (GC & MS), but the strengths of their response patterns were found to be different.