Tokarskyi O. Rationale for the protection of the mountain rescuer from exposure to low temperatures

The dissertation solves the actual scientific and technical task of substantiating and developing ways to increase the level of occupational safety of mountain rescuers, based on the study of the features of search and rescue operations, under the influence of low temperatures of the external environment, due to the systematic harmonization of the thermal insulation characteristics of protective clothing (PPE) and means head protection. The idea of the work is to minimize the impact of dangerous and harmful factors in the production process of search and rescue work due to the introduction of regulations for the use of effective means of protecting parts of the body and head in conditions of exposure to low temperatures and overtime physical exertion. The purpose of the work is to determine regularities in the processes of individual thermal protection of a mountain rescuer in conditions of low temperatures and to obtain characteristics and indicators for the creation of means and relevant regulatory and technical recommendations from the regulations of search and rescue operations. Scientific propositions submitted for defense and their novelty. 1. According to the statistical analysis, it was established that during 2019-2021, 67% of search and rescue operations take place in the autumn-winter period. According to the results of the test surveys of mountain rescuers (n-609), it was established for the first time that 30% of rescuers feel the negative impact of low temperatures of the face and frontal part of the head. The study of the process of maintaining a functionally healthy state of a rescuer in a mountainous area, taking into account the influence of NSF and overtime loads, requires preliminary modeling. For the first time, mathematical modeling using the MatLab software complex was carried out regarding the process of low temperatures: -10ºС, -20ºС, -30ºС on a 4-layer model of a rescuer's head during an overtime load of 600 W. The dependence of the core temperature of the rescuer's body on the thermal insulation level of the set of protective clothing (PC) (Iclo) and simultaneous overtime load was determined. Regression equations provide a tool for correcting the insulation of clothing in the situation of standing without wind and in dynamics to the resulting thermal insulation of PC for real conditions in an emergency situation. For the first time, experimentally established dependences of changes in the temperature of the head (tympanic membrane) of a rescuer under conditions of simultaneous exposure to an ambient temperature of -30ºС and a load of 600 W from the frontal part. According to the established laws of heat and mass transfer, it was determined that the temperature of the 3rd and 4th layers of the head did not decrease due to the metabolic process for 3600 seconds, and was 37.2 ºС without head protection. 2.Ensuring the protection of the rescuer with protective clothing in the conditions of performing search and rescue work in mountainous terrain must take into account the processes of the intensity of the work and the level of thermal insulation of the PC set. It has also been confirmed that the intensity of the work directly affects the thermal balance and heat-mass transfer due to blood perfusion and heat generation. The proposed physical model, which is available as a software, is an improvement on the existing methods of determining insulation in terms of simplicity and accuracy. 3. The performance of PoPP is evaluated on a thermal manikin, as thermal properties may change after the materials have been constructed into clothing and head protection. For the first time, experimentally with the help of an electroencephalogram (EEG) it was established that in the zone of influence of low temperatures of -30 ºС and an overtime load of 600 W, latent processes in the frontal part of the hypothalamus begin already at 17 minutes. Linear regression was used to estimate performance indicators and body temperature Tt and using appropriate thermal insulation of clothing (IREQ). For the first time, the hypotheses of a stable core temperature and a decrease in scalp temperature were accepted to explain latent processes, as well as the hypothesis that the limits of the duration of exposure will be determined by the temperature of the 3rd layer of the frontal part of the head. The impact of low temperatures on the state of injuries and occupational diseases depends on the effective regulation of the PRR. Increasing the level of protection and effective formation of the PRR regulation will allow minimizing the irreversible consequences of the impact of critical temperatures and loads on the mountain rescuer. Keywords: mountain rescuer, personal protective equipment, low temperatures, search and rescue operations.