Peculiarities of amplitude spectra of the third order for the early detection of indoor fires

The object of the study is the selective coefficient of variation of dangerous parameters of the gas environment during the ignition of materials. The measure of the sample coefficient of variation of an arbitrary hazardous parameter of the gas environment observed at an arbitrary time interval is substantiated. The representativeness error of the measure of the sampling coefficient of variation, which depends on the value of the measure and the sample size, was determined. The measure allows you to numerically determine its value for an arbitrary observation interval. The difference in the measure at the intervals corresponding to the reliable absence and occurrence of ignition allows to detect the occurrence of ignition of the material. According to the results of laboratory studies, the measures of the sample coefficient of variation for carbon monoxide concentration, smoke density, and temperature of the gas medium in the laboratory chamber at intervals of absence and appearance of ignition of alcohol, paper, wood, and textiles were determined. It was established that the dangerous parameters of the gas environment at the intervals of absence and presence of ignition are characterized by different values of the increase in the measure of the sample coefficient of variation. For example, it is determined that the ignition of alcohol causes the maximum increase in the measure for carbon monoxide concentration from 0.135 to 0.441, for smoke density from 0.629 to 0.805, and for temperature from 0.001 to 0.115. When paper catches fire, the measure for carbon monoxide concentration and temperature increases from 0.0026 to 0.140 and from 0.0019 to 0.05, respectively. When burning wood, the measure for carbon monoxide concentration and temperature increases from 0.0072 to 0.177 and from 0.0067 to 0.016, respectively. The obtained results, provided that the hazardous parameters of the gas environment in the premises are measured and the sample coefficient of variation is calculated in practice, make it possible to use them in the creation of early fire detection systems

Section: Discussion Of Results Of the Study Of Sample Coefficients Of...mentioning

confidence: 47%

Section: Literature Review and Problem Statementmentioning

confidence: 99%

Section: Literature Review and Problem Statementmentioning

confidence: 99%

Section: Literature Review and Problem Statementmentioning

confidence: 99%

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Features of the coefficient of variation of parameters of the gas environment in fire in the premises

Pospelov,

Bezuhla,

Kozar

et al. 2023

“…Features of the spectra of changes in hazardous parameters of GE of the order above the second, capable of detecting nonlinearity, are not investigated. Paper [38] investigates the features of amplitude spectra for hazardous GE parameters in a laboratory chamber. At the same time, it is shown that third-order amplitude spectra make it possible to identify nonlinear relationships of frequency components in the spectrum of change in hazardous GE parameters.…”

Section: Literature Review and Problem Statementmentioning

confidence: 99%

Revealing the peculiarities of average bicoherence of frequencies in the spectra of dangerous parameters of the gas environment during fire

Поспелов¹,

Andronov

Rybka

et al. 2023

The object of this study is a change in the hazardous parameters of the gas environment when materials are ignited in the premises. The subject is the features of the average bicoherence of the frequencies of the spectra of changes in the hazardous parameters of the gas environment when materials are ignited. The importance of such studies is based on the fact that the examined features can be used for the early detection of fires. The value of the average bicoherence is proposed to be determined for each frequency, taking into account the average value of the cosine argument of the complex bispectrum for a given frequency interval. It was established that the values of the average bicoherence of the spectrum of changes in the temperature of the gaseous medium in the interval of no ignition of the materials, averaged by frequency in the range of 0–2 Hz, lie in the range from ‒0.052 to ‒0.35. At the same time, the frequency-averaged values of mean bicoherence at the ignition interval of materials lie in the range of ‒0.128 to +0.155. Averaged in the frequency range of 0–2 Hz, the value of the mean bicoherence of the spectrum of changes in smoke density in the interval of absence of ignition of materials lies in the range from ‒0.018 to +0.568. In the presence of fires, this value is in the range from –0.244 to +0.23. At the same time, the average value of the average bicoherence of the spectrum of changes in the concentration of carbon monoxide of the gas medium for test materials, averaged in the range from 0 to 2 Hz, ranges from +0.016 to +0.109. In the case of ignition of materials, the average values range from +0.0007 to +0.053, except for ignition of wood (+0.117). In general, the revealed features of the average bicoherence of the frequency components of the spectra of changes in the hazardous parameters of the gas environment indicate the possibility of their use to identify fires and prevent fires

Comparison of bicoherence on the ensemble of realizations and a selective evaluation of the bispectrum of the dynamics of dangerous parameters of the gas medium during fire

Поспелов¹,

Rybka

Polkovnychenko

et al. 2023

The object of the study is the bicoherence of the bispectrum assessment of the dynamics of dangerous parameters of the gas environment during the ignition of materials. The subject is a measure of bicoherence of the bispectrum estimation from the ensemble of realizations and selective bispectrum estimation for the dynamics of hazardous parameters of the gas environment. The practical importance of the research is the use of the measure of bicoherence of the bispectrum for the early detection of fires. The measure of bicoherence of the dynamics of hazardous parameters of the gas environment is substantiated, which allows them to be numerically compared for the studied bispectrum estimates. As such measure, it is proposed to use the integral value of bicoherence for a given frequency interval, which makes it possible to numerically compare the bicoherence of bispectrum estimates for arbitrary time intervals of the dynamics of hazardous parameters of the gas environment. On the basis of the proposed measure for the frequency range of 0.2–2 Hz, a comparison of the integral bicoherence of the bispectrum estimates was made. The numerical value of the measure was determined for three fixed time intervals of the dynamics of hazardous parameters of the environment, corresponding to the absence of ignition, the occurrence of ignition, and the subsequent burning of test materials in the laboratory chamber. According to the results of the comparison of such values, it was established that the bicoherence of the bispectrum estimation from the ensemble of realizations is the most appropriate for detecting fires. When ignited, the numerical value of the measure for all test materials is about 90°. This means that the nature of the dynamics of hazardous environmental parameters in the event of fires becomes random. In this regard, the proposed measure is recommended to be used as a test for early detection of fires.