• Energy Research

The power outages that have occurred in recent years around the world point to widespread problems with consequences for the lives and health of the population, but also material damage. This is a case study that focuses on the evaluation of the preparedness of the population of a selected region in the Czech Republic for a long-term power outage. This article deals with a case study that focuses on the evaluation of the preparedness of the population of the Karlovy Vary region in the field of emergency survival. Part of the study is the evaluation of the respondents’ answers, which provides an overview of the actual state of preparedness for power outages on a sample group of respondents in the Karlovy Vary region. The research method used was a survey using questionnaires. The obtained information was subsequently statistically evaluated by nonparametric correlation using Kendall’s taub. From the presented results of the survey, it is clear that the inhabitants of smaller municipalities are better prepared for a power outage and can create basic conditions for emergency survival.

Ensuring territorial safety is one of the state’s main tasks, and the public administration plays a primary role in fulfilling it. The safety and sustainability of a territory is ensured by, inter alia, safety planning, including spatial planning. Spatial planning contains safety requirements for population protection. The requirements for ensuring the safety of the population included in the spatial plan vary significantly between countries. The existing population protection requirements contained in the spatial plan have been unsatisfactory for a long time. The main issue is that they are out of date and difficult to apply. The article presents a new proposed method for determining requirements for the protection of the population, which is based on evaluating the risks in the cities and territory. The specific population protection requirements are determined based on the resulting risks and their scaling. The requirements are classified as general when the territory is not faced with external risks or specific when there are such risks. The method is applied to the conditions of the Czech Republic. In terms of national standard specifics, there are requirements in areas of public infrastructure, public utility buildings, and public benefit measures. The method for determining population protection requirements can be considered applicable in a general form by various countries if the national standards specifics or other aspects are taken into account.

The paper discusses the results of a study carried out to determine the thermal condition of a conveyor power unit using a thermal imaging camera. The tests covered conveyors in the main haulage system carrying coal from a longwall. The measurements were taken with a thermal imaging diagnostic method which measures infrared radiation emitted by an object. This technology provides a means of assessing the imminence and severity of a possible failure or damage. The method is a non-contact measuring technique and offers great advantages in an underground mine. The thermograms were analysed by comparing the temperature distribution. An analysis of the operating time of the conveyors was also carried out and the causes of the thermal condition were determined. The main purpose of the research was to detect changes in thermal state during the operation of a belt conveyor that could indicate failure and permit early maintenance and eliminate the chance of a fire. The article also discusses the construction and principle of operation of a thermal imaging camera. The findings obtained from the research analysis on determining the thermal condition of the conveyor drive unit are a valuable source of information for the mine’s maintenance service.

Electricity is the most important form of household energy and one of the most important forms of energy for industry and transport. Electrical distribution in construction and transport is almost exclusively implemented using electrical cables. One of the unresolved problems associated with electrical cables is the release of smoke and the resulting reduction of visibility in case of fire in the area. In this study, a new approach was developed to assess the reduction of visibility in an area affected by an electrical cable fire. This approach is based on the determination of the critical ratio of smoke volume (in the smoke layer and exhausted from the fire compartment) to the length of the burning cable, through which the visibility of reflective and illuminated signs was reduced to a lower limit value (a standard of 10 m). The input data for this approach was the extinction area of the smoke released from one meter of burning cable and the length of the cables in the area. This approach was used to test two power cables (CHKE-V J3x1.5 and CHKE-R J3x1.5) and one signal cable J-H(St)H 1 × 2 × 0.8 with the B2ca, s1, d1, a1 fire reaction class. The smoke extinction area of the examined cables was determined using a cone calorimeter at a heat flux of 50 kW/m2. The obtained data showed that in order to maintain a visibility of 10 m for reflective signs, the critical ratio of smoke volume to length of burning cable was 7.5 m3/m. For illuminated signs, the critical ratio was 2.8 m3/m. The relationship between burning length and visibility allows the calculation of visibility in the fire compartment affected by cable fire only from cables length.

The sustainability of the indoor environment of buildings is also related to the conditions that arise in the case of fires. Fires in buildings are characterized by the formation of combustion products, which can significantly endanger the life and health of people. One of the major sources of danger is smoke. If there is no smoke exhaust into the outside environment during the development of the fire, the building is gradually filled with smoke. The important characteristic of the smoke layer is the level of the smoke layer, which changes over time. Several methods have been derived for determining the descent of the smoke layer in an enclosed area of space, which mainly differ in terms of the application area and limits of use. The methods used in the Czech Republic for the assessment of smoke layer descent in the case of fires do not have a clear rationale and in many cases lead to completely misleading results. For this reason, in connection with the standards for the assessment of the buildings in the Czech Republic, a new calculation technique (CSN) has been derived, which has been compared with the selected simple calculation techniques in large buildings. The deviations between the results have been evaluated by the percentage bias method (PBIAS), while the largest deviation, compared to the ISO standard technique, did not exceed 20%. The CSN calculation technique shows a favourable compliance with the technique presented by the ISO standard, where the deviation did not exceed 1.6%. In response to the proposed standards in the Czech Republic, the CSN calculation technique enables the assessment of safe evacuation in relation to the smoke layer interface and can be a considered perspective.

The current safety situation and the conclusions of a number of strategic and conceptual works require a broader integration of the population protection system into the areas of construction management. The approaches adopted by individual countries to this matter differ greatly. In the Czech Republic, the definition of constructions to which it is necessary to apply population protection requirements has not been dealt with sufficiently. The construction technical requirements from the point of view of population protection are also not sufficiently dealt with. This article presents a new draft procedure for designating the requirements for the relevant constructions of population protection in the Czech Republic. In addition, possible external hazards affecting the constructions or their strategic importance functions were assessed. In conclusion, the general, specific, and strategic requirements for constructions are set. The procedure is applied to the conditions of the Czech Republic, but it is also applicable in other countries. The area of public protection is closely related to Industry 4.0. Ensuring the protection of the population, as well as the safety of workers, employers, and production facilities, is one of the basic preconditions for the development of the industry.