PSI - Issue 20

Ivanov V.N. et al. / Procedia Structural Integrity 20 (2019) 222–229 Ivanov V.N. et al. / Structural Integrity Procedia 00 (2019) 000–000

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For example, table 1 shows the service life of some elements of the heating system and heating networks in the conditions of the city of Yakutsk, calculated from these data.

Table 1. The duration of the effective operation of the elements heating systems.

Duration of operation to overhaul (replacement), (years) Regulatory data For Yakutsk

Elements of heat supply systems for buildings

Pipelines

30 25 12

24 19 10

Risers with closed circuits

Brownies Highways

In Yakutsk conditions, the service life of elements of heating systems and heat networks is almost 18% shorter than is customary in the reference data. Knowledge of the estimated service life depending on the terrain will allow you to plan overhauls and effectively use the turnaround time. Difficult and crucial tasks arise before the service operation in extreme conditions: in case of accidents in the heat supply system, especially during the cold period of the heating season shown by Inga Šar ū nien ė et al (2016), Shanshan et al (2017), Wojdyga (2009). The specific nature of the climatic conditions of the North puts forward special requirements for a comprehensive solution to the problem of human security and its environment in the event of natural and man-made accidents and disasters. Examples of major accidents show that the safety of the population, industrial enterprises and social and cultural facilities in Yakutia in winter is mainly determined by the reliability of energy supply. Emergencies associated with the violation of heat supply of buildings pose a potential danger of unacceptable deterioration of the thermal conditions in the premises. All this can cause serious material and moral damage, even bring a threat to the safety of human life and production, pointed by Kononovich (1989), in Recommendations (1987), by Kilatchanov and Shomoev (1999). Engineering communications are in the zone of low temperatures. Field studies show that the temperature near the floor decreases by 5 ... 10°C than in the middle zone of a room 1.5 m from the floor. Under these conditions, at the termination of circulation or low velocity of the coolant, there is a risk of its freezing. The time during which the temperature of the coolant decreases to the crystallization temperature can be determined by Kolodeznikova (2018), Zhirkova (2013), Dulkin et al (2014), SP (2004): ݐ ൌ ቀ ଶగ ଵ ఒ ೔ ݈݊ ௗ ೞ೟ೝ ௗ ೚ೠ೟ െ ఈగௗ ଵ ೞ೟ೝ ቁ ቀ ߨ ௗ ೔ మ ೙೟ ସ ߩ ௖ ܿ ௖ ൅ ߨ ௗ ೐మ ೣ೟ ିௗ ೔ మ ೙೟ ସ ቁ ݈݊ ቀ ௧ ೎ೝ ି௧ ೚ೠ೟ ௧ ೎ ି௧ ೚ೠ೟ ቁ (2) 3. Results and discussion Analysis of the time of cooling water in the return pipe of heat networks is shown in figures (fig. 1, 2). The calculation was made with different parameters of the coolant: 95-70 (° С ) and 80-60 (° С ). As thermal insulation, the most used in the North are mineral wool mats with thermal conductivity λ = 0.06 (W/m·°C) and thickness δ = 0.100. Analysis of accidents of heating systems and heating networks of Yakutia (12-apartment residential building of health workers in Markha, an accident in Block A of the NRC and OMTsZ buildings, freezing of hospital complexes in Nyurba, Vilyuisk, Zhigansk, Olenek, etc.) showed that first of all there was a freezing of the heating systems of the terminal branches, staircases, at the entrances and in buildings with low thermal resistance connected to external networks and only then in the heat networks. Changes in the air temperature in a residential area after the heating is turned off are shown in Table 2. Thus, lowering the air temperature in residential premises to 10...12° С is an indicator of the critical thermal condition of the building, since at the same time the temperature conditions of the room become extremely unfavorable for a person, emergency conditions for the work of engineering equipment are created. The analysis of the time to reduce the temperature in a residential area to a critical level during an accident of the heat supply system, which is given above (Table 2), indicates the rapid development of this phenomenon depending