## 3 Results and Discussion
Justification of the Effect of the Smoke-Filled Rooms Due to the Burning of Various Organic Compounds on Its Acoustic Characteristics  
2.1 Determination of the Acoustic Characteristics of the Smoke-Filled Environment Due to the Combustion of Organic Substances  
The increased temperature of the environment, characteristic of fires, significantly affects the speed of the propagation of acoustic waves, changing their physical parameters and making it difficult to predict propagation trajectories. When critical temperatures are reached during a fire, the acoustic properties of not only air, but also other materials, such as walls and ceilings, change. This leads to significant changes in the wave resistance indicators of the environment, which complicates the monitoring process in conditions of the smoke-filled areas due to the burning of organic compounds. In this case, acoustic waves are one of the key means of transmitting information in a smoke-filled area, when traditional methods of communication can be disrupted due to the presence of physical obstacles or adverse conditions. This is especially true for emergency situations, such as man-made disasters or armed conflicts, where the physical parameters of the environment greatly complicate the propagation of signals. The improvement of information transmission technologies using acoustic waves, taking into account specific parameters of the environment, such as the concentration of suspended particles (formed during the combustion of organic compounds), temperature, and wave resistance, is a necessary condition for ensuring monitoring under complex and heterogeneous conditions. As mentioned above, the different chemical composition of compounds formed during the combustion of various organic substances (for example, the presence of methane and soot, formed due to incomplete combustion), causes the additional scattering of acoustic waves. When the possibilities of monitoring in smoke-filled areas during the combustion of organic compounds are investigated, the limits of the concentration of suspended particles are determined on the time required to fill the flask to the state when the optical transparency is reduced to a minimum. The results of the research are presented in Table 2.  
According to the results obtained, the products of the combustion of the materials show a different degree of influence on the propagation of acoustic waves, which is determined both by the velocity of reaching the critical concentration of the combustion products and by the change in the physical parameters of the environment. In particular, motor oil and drywall stand out as extreme examples in terms of exposure. Motor oil exhibits the greatest influence on acoustic waves. In 15.7 s, the critical concentration of combustion products is reached, and the temperature coefficient (K = 1.04) indicates significant changes in the characteristics of the medium. The 25% loss of velocity is explained by the presence of heavy aerosols and toxic substances formed during combustion. This makes grease one of the most unfavorable materials for the propagation of acoustic waves, creating significant obstacles to the operation of acoustic navigation systems. Gypsum plasterboard can be characterized as a relatively favorable material from the point of view of the propagation of acoustic waves, since its combustion products have a minimal effect on the acoustic properties of the environment. The time to reach the critical concentration is 78.5 s, which is the longest indicator. The temperature coefficient (\(K\) = 1.018) and the 8% loss of velocity testify to the limited influence of its combustion products on the physical properties of the medium. In the presence of gypsum plasterboard combustion products, acoustic waves retain their characteristics.