Defining the features of amplitude and phase spectra of dangerous factors of gas medium during the ignition of materials in the premises

The object of this study is the dynamics of skewness and kurtosis of the selective distribution of dangerous parameters of the gas environment in the current time when materials are ignited. The theoretical substantiation of the methodology for determining the dynamics of skewness and kurtosis based on a sample of an arbitrary size of dangerous parameters of the gas medium moving in the current time of observation has been performed. Thresholds for current skewness and kurtosis are determined depending on sample size and null hypothesis significance levels. The procedure makes it possible to investigate the peculiarities of the dynamics of skewness and kurtosis and to identify moments of time for which alternative hypotheses (stability of parameter dynamics) are valid. Laboratory experiments were conducted to study the dynamics of skewness and kurtosis in terms of carbon monoxide concentration, smoke density, and the temperature of the gas environment during the ignition of alcohol and textiles. The results indicate that the investigated dangerous parameters are generally not Gaussian in the observation interval. It was found that the nature of the dynamics of measures of the current sample distributions of dangerous parameters depends on the type of ignition material and the dangerous parameter. It was established that in the absence of ignition, the dynamics of skewness and kurtosis of dangerous parameters is characterized by different directional skewness and kurtosis. In the event of ignition, the dynamics of skewness and kurtosis are fluctuating (from –4 to 18), which indicates the instability of the development of the dangerous parameter over time. The specified procedure creates an opportunity to detect the instability of the development of a dangerous parameter, which in practice makes it possible to detect the occurrence of fires (with a given reliability) in order to eliminate them and prevent the occurrence of a fire

Section: Justification Of a Methodology For Determining The Dynamics ...mentioning

confidence: 99%

Section: Literature Review and Problem Statementmentioning

confidence: 99%

Dynamics of skewness and kurtosis of dangerous environmental parameters in the event of fire

Pospelov,

Andronov,

Bezuhla

et al. 2023

“…Temperature measurements were made by D TPT-4 (Ukraine) [48], smoke density by D IPD-3.2 (Ukraine) [48], and CO concentrations by D Discovery (Switzerland) [49]. It was assumed that the peculiarities of the influence of Z TM on the temperature, smoke density, and CO concentration of HS in LC are similar to those of the same TM in real rooms [50].…”

Section: The Study Materialsmentioning

confidence: 99%

Method for early ignition detection based on the sampling dispersion of dangerous parameter

Pospelov,

Rybka,

Krainiukov

et al. 2024

The object of the study is the selective dispersion of dangerous parameters of the gas environment during material fires. The practical importance of research consists in using the difference of sample dispersions of dangerous parameters of the gas environment on the intervals of absence and presence of ignition of materials for detection of ignition. The theoretical substantiation of the method of detecting fires in premises based on sample dispersions of current measurements of an arbitrary dangerous parameter of the gas environment, corresponding to the general populations of reliable absence and presence of fire, has been carried out. The method, at a given level of significance, determines the unbiased uniformly most powerful fire detection rule. This makes it possible to determine how much differences in sample variances are significant with a given level of significance and are caused by ignition or are random factors. Laboratory experiments were conducted to verify the proposed method. It was established that the influence of ignition on the value of the difference in the sample dispersion at the corresponding intervals of monitoring the carbon monoxide concentration, smoke density, and temperature of the gaseous environment of the laboratory chamber is different and depends on the type of ignition material. At the same time, the minimum difference of the sample dispersions is characteristic for observing the smoke density for all the studied materials. However, early detection of ignition of alcohol, paper, wood, and textiles when observing the smoke density is carried out when the threshold is exceeded by 9.01, 5.31, 2.13 and 2.55 times, respectively. It is shown that the method of early detection of fires, which is based on the detection of significant differences in sample dispersions of data from the relevant general populations

“…In this case, the sample distributions or their moments have known reliability estimates [38]. In [39], the amplitude and phase spectra of the OP HS dynamics are studied for typical samples belonging to the intervals of the absence and presence of PM in the laboratory chamber. It has been established that the features of the dynamics of the OP HS are manifested to a greater extent for the high-frequency components of the phase spectrum.…”

Section: Literature Review and Problem Statementmentioning

confidence: 99%

Determining the features of histograms of dangerous parameters of the gas environment in the absence and occurrence of fire

Pospelov,

Rybka,

Bezuhla

et al. 2023

The object of research is histograms of the dynamics of dangerous parameters of the gas environment, the values of which are measured in real time at the intervals of absence and ignition of materials. The method of determining histograms during a typical selection of measurements is described. This method allows one to determine histograms for samples of an arbitrary position and the size of the data interval of measurements of the dynamics of dangerous parameters of the gas environment. On the basis of histograms on the intervals of the absence and occurrence of fires of test materials, indicators of their summary statistics can be determined. Laboratory experiments were conducted to study the features of the histograms of carbon monoxide concentration, smoke density, and temperature of the gas medium for intervals of reliable absence and appearance of ignition of materials in the form of alcohol and textiles. The results of the analysis of the histograms clearly show that the dynamics of the studied dangerous parameters at the indicated intervals differ from the Gaussian. At the same time, the histograms differ in shape, which depends on the type of ignition material and the corresponding dangerous parameter. Based on the features of the histograms of the dynamics of dangerous parameters on the intervals of the absence and appearance of fires of test materials, the simplest indicators of summary statistics in the form of the range, number, and position of the modes are determined. It was established that when alcohol ignites, the variation range of carbon monoxide concentration, smoke density, and gas temperature increases from 0.545, 0.068, and 0.161 to 7.121, 0.523, and 8.71, respectively. At the same time, the range of variation of these parameters during textile ignition increases from 0.182, 0.205, and 0.323 to 0.394, 0.386, and 2.903, respectively. The obtained results in aggregate or one by one can be used in practice for early detection of fires in order to prevent the occurrence of fires in premises