Ïðîâåäåíà îöåíêà âðåìåíè îáíàðóaeåíèÿ ïîaeàðà êàê ïðîìåaeóòêà âðåìåíè îò íà÷àëà ïîaeàðà äî åãî îáíàðóaeåíèÿ ñðåäñòâàìè ïîaeàðíîé àâòîìàòèêè (äî äîñòèaeåíèÿ ïîðîãîâûõ çíà÷åíèé äëÿ ïîaeàðíûõ èçâåùàòåëåé) íà îñíîâå ñîâðåìåííûõ ïðîãðàììíûõ êîìïëåêñîâ, èñïîëüçóåìûõ äëÿ ìîäåëèðîâàíèÿ äèíàìèêè ïîaeàðà. Ïðîàíàëèçèðîâàíû ñöåíàðèè ðàçâèòèÿ ïîaeàðà â çäàíèÿõ ðàçëè÷íîãî íàçíà÷åíèÿ. Ïðåäñòàâëåíû ðåçóëüòàòû ìîäåëèðîâàíèÿ äèíàìèêè îïòè÷åñêîé ïëîòíîñòè äûìà. Óñòàíîâëåíî, ÷òî òåìï ðàçâèòèÿ ïîaeàðà ÿâëÿåòñÿ îïðåäåëÿþùèì ôàêòîðîì, âëèÿþùèì êàê íà âðåìÿ îáíàðóaeåíèÿ ïîaeàðà, òàê è íà íåîáõîäèìîå âðåìÿ ýâàêóàöèè â öåëîì. Ïîêàçàíî, ÷òî íåó÷åò âðåìåíè îáíàðóaeåíèÿ ïîaeàðà êàê ïðîèçâîäíîé îò òåìïà ðàçâèòèÿ ïîaeàðà íà îñíîâå ðàñ÷åòíûõ ìåòîäîâ ìîaeåò ïðèâåñòè êàê ê óâåëè÷åíèþ íåîáõîäèìîãî âðåìåíè ýâàêóàöèè, òàê è ê óìåíüøåíèþ âðåìåíè íà÷àëà ýâàêóàöèè, ÷òî â ñâîþ î÷åðåäü âëå÷åò çà ñîáîé íåäîñòîâåðíîñòü ïîëó÷åííûõ ðåçóëüòàòîâ.

Introduction. In Russia, based on the provisions of the current regulatory documents, the time for the start of evacuation for a room in which a fire broke out is determined depending on the area of the room. According to some authors, the time of the start of the evacuation of people is a combination of “technical”, which includes the time of detection of a fire, and “psychophysical”, determined by the behavioral and organizational characteristics of the people who make it up. The fire detection time is currently not taken into account.Purpose. Evaluation of the influence of the size of the cells of the computational grid and the inhomogeneity of the computational domain on the estimated time of fire detection.Aims. 1. Establish the qualitative nature of the influence of the size of the cells of the computational grid and the inhomogeneity of the computational domain on the estimated time of fire detection.2. Offer recommendations for determining the estimated time of fire detection.Methods. For research, computer simulation methods were used using the Fire Dynamics Simulator software package.Results and discussion. The use of grids with different cell sizes can significantly reduce the number of cells in the computational domain and, as a result, the computation time. However, this leads to rather contradictory results. The minimum time values are reduced by almost 3–4 times compared to a homogeneous computational grid, and the maximum time increases by 2 times.Conclusions. 1. The size of the cells of the computational grid and the inhomogeneity of the computational domain have a significant impact on the time of fire detection.2. A sufficiently large spread in the values of the estimated fire detection time may indicate an unreliable estimate of the total time for the start of evacuation and incorrect conclusions about the safe evacuation of people and/or the probability of evacuation of people.3. For a correct estimate of the evacuation start time, taken into account the estimated fire detection time, it is recommended to use homogeneous computational grids with cell sizes not exceeding 0.25 m.

Introduction. The analysis of existing methods for determining the estimated time of fire detection by means of fire automatics allows us to conclude that it is advisable to use a more differentiated approach. Within the framework of this article, the assumption about the influence of the distance from the burning plane of the fire seat to the level of installation of fire detectors (to the sensitive elements of point smoke fire detectors) on the estimated time of fire detection was carried out. In particular, such an effect can be observed during a fire involving the burning of furniture, shelving, etc., i.e. in cases where the above distance is potentially shortened. Goals and objectives. The aim of the work is to study the influence of the distance from the burning plane of the fire seat to the level of installation of fire detectors (to the sensitive elements of point smoke detectors) on the estimated time of fire detection. Research methods. To assess the influence of the distance from the burning plane of the fire seat to the level of installation of fire detectors (to the sensitive elements of point smoke fire detectors) on the estimated time of fire detection, computer simulation methods were used using the Fire Dynamics Simulator software package. Results and its discussion. The results of modeling the dynamics of the optical density of smoke in a room at various distances from the burning plane of the fire seat to the level of installation of fire detectors (to the sensitive elements of point smoke fire detectors) are presented. The distance varied in the range from 0.25 to 2.75 m. Conclusions. It has been established that the distance from the burning plane of the fire source to the level of installation of fire detectors (to the sensitive elements of point smoke detectors) does not have a significant effect on the estimated time of fire detection. The difference in the values of the estimated fire detection time for different values of the distance from the burning plane of the fire source to the level of installation of fire detectors and the value obtained on the basis of the existing method for determining the time of the start of evacuation may indicate an unreliable assessment of the total time of the start of evacuation and incorrect conclusions about safe evacuation people and/or the likelihood of people evacuating. To correctly take into account the time of the beginning of the evacuation, further study of this issue and comparison of its "technical" component, obtained by calculation methods, with the results of field experiments is required. Keywords: fire safety, fire protection, fire detection time, fire alarm, evacuation probability, smoke optical density, evacuation time, evacuation start time, fire risk.

PURPOSE. Analysis of using air curtains in various industries of our country including smoke protection systems for buildings shows that air curtains are widely used now. However, until recently, air curtains have not been used in smoke protection systems. Meanwhile, their use will allow solving a number of problems in the field of smoke protection. The aim of the study was to identify fire regulation shortcomings of air curtains use in smoke protection systems, as well as to find possible ways for further research in this field. METHODS. To evaluate the available data theoretical research methods have been used: analysis and synthesis. FINDINGS. The analysis of normative documents on air curtains use in the field of smoke protection, calculation methods of air curtains, as well as research in this field showed the shortcomings of air curtains fire regulation and the problems of calculation methods. Possible ways of research and search for air curtains optimal parameters for the purposes of building smoke protection are determined. RESEARCH APPLICATION FIELD. The results of the regulatory documents analysis on air curtains use in the field of smoke protection, calculation methods of air curtains, as well as previous studies can be used for further research of air curtains for smoke protection in order to obtain optimal parameters to improve their efficiency in fire conditions. In the future this will improve the method of air curtains calculating for smoke protection purposes, as well as eliminate the shortcomings of fire regulation in this field. CONCLUSIONS. According to the results of regulatory requirements analysis it has been found that at present a sufficiently large number of parameters, which can significantly affect the efficiency of air curtains to protect openings in fire conditions are not taken into account. The formulas for calculation methods of air curtains are derived from the equations for an isothermal jet and do not take into account the impact of the jet on heat and mass transfer in the room under fire, as well as the influence of thermogasdynamic conditions on the jet in the room. To determine the optimal parameters of air curtains for the purposes of building smoke protection, a more detailed study of heat and mass transfer processes based on a three-dimensional mathematical model (CFD modeling) and field experimental studies are required.