## 5 Conclusions  
In this paper, the ideas on the possibilities of using the acoustic method in fire extinguishing were further developed. The effect of combustion of various polymers on the acoustic parameters of the environment and the possibility of using them for monitoring the environment were shown, and the correlation between the extinguishing parameters and the distance to the ignition source was determined. The results on the extinguishing of flames by the acoustic method are presented in the range of two frequencies of the extinguisher, i.e., 15 and 19 Hz, depending on the distance of the flame source from the extinguisher outlet. The research showed the effectiveness of acoustic waves emitted from the sound source in extinguishing flames of organic substances on the basis of paraffin wax. For the purpose of the experiment, a point flame source was used to unambiguously determine whether the flames were successfully extinguished. Generated, amplified, and focused sound waves of a low frequency and high or very high acoustic power allow the creation of local conditions in which the flame cannot sustain itself, as its continuous exposure in the acoustic field leads to its complete extinguishment without the need for chemicals. The power level required to extinguish the flames and the sound pressure level at the point where the flames were extinguished were analyzed. It was shown that with an increase in the distance between the waveguide outlet and the flame source, the required power necessary to extinguish the flames increases. Furthermore, there is a correlation between the increased power and the wave frequency, and the extinguishing effect depends on the frequency (as the frequency approaches that for which the minimum impedance was recorded, a lower value of power necessary to extinguish the flames is noted). The acoustic pressure at which the flames were successfully extinguished was in the range between 120 and 130 dB and, in practice, did not exceed a value of 128 dB. The pressure level decreased with the increasing distance between the waveguide outlet and the flame source. The diagrams confirmed these findings. When studying the features of monitoring in smoke-filled areas during the combustion of organic compounds, correcting parameters were determined and correction factors were calculated for the development of acoustic action sensors: the angle of incidence, the wave resistance of the medium, the temperature, and the concentration of suspended particles. The dependence on the temperature gradient of the combustion products from various organic materials was determined, as well as the correcting correction value of the readings of the distance of the acoustic device, which is equal to +2.8 cm. Through the studies, it was determined that combustion products reduce the velocity of distribution of acousticwaves in the medium. The combustion of different materials, such as plastic, styrofoam, textile, gypsum plasterboard, wood, and motor oil, produces varying degrees of smoke and the concentration of combustion products. The loss of the velocity of acoustic waves in a medium filled with combustion products is shown to vary in the range from 8% to 25%, depending on the physical and chemical properties of the burning material. The basis for the practical creation of an acoustic device, which differs from known ones by additional characteristics, namely, the ability to function effectively in conditions of high temperatures, dense smoke, and air pollution, has been developed. Further ways of developing the application of the acoustic method in the extinguishing of organic compound fires and providing monitoring in the smoke-filled areas were noted. The obtained results can become part of ecological-technical and ecological-economic solutions at the state and municipal levels, as well as a contribution to the national policy of individual states, aimed at supporting and developing ecological approaches while ensuring the goals of sustainable development. Conceptualization, V.L., G.W.-J. and J.L.W.-J.