Abstract. The design, construction and exploitation of electrical equipment intended to be used in potentially explosive atmospheres presents a series of difficulties. Therefore, the approach of these phases requires special attention concerning technical, financial and occupational health and safety aspects. In order for them not to generate an ignition source for the explosive atmosphere, such equipment have to be subjected to a series of type tests aiming to decrease the explosion risk in technological installations which operate in potentially explosive atmospheres. Explosion protection being a concern of researchers and authorities worldwide, testing and certification of explosion-proof electrical equipment, required for their conformity assessment, are extremely important, taking into account the unexpected explosion hazard due to potentially explosive atmospheres, risk which has to be minimized in order to ensure the occupational health and safety of workers, for preventing material losses and for decreasing the environmental pollution. Besides others, one of the type tests, which shall be applied, for explosionproof electrical equipment is the impact resistance test, described in detail in EN 60079 which specifies the general requirements for construction, testing and marking of electrical equipment and Ex components intended for use in explosive atmospheres. This paper presents an analysis on the requirements of the impact resistance test for explosion-proof electrical equipment and on the possibilities to improve this type of test, by making use of modern computer simulation tools based on finite element analysis, techniques which are widely used nowadays in the industry and for research purposes.

The increase in energy consumption is closely correlated with the continuous evolution of human society, which implies both the depletion of fossil fuels and the increase in pollution levels. One solution to these problems is to obtain electricity from renewable sources but also to use alternative fuels for car transportation. Within the paper, there are presented the necessary conditions for the design of hydrogen gas stations in accordance with the legal requirements in force regarding the protection to explosion.

Directive 2014/34/EU of the European Parliament and of the Council regulates the placing on the market of equipment and protective systems intended for use in potentially explosive atmospheres. The importance of using explosion-proof equipment (certified in compliance with provisions of standards for electrical and non-electrical equipment) is crucial for avoiding catastrophic explosion-type events which may result in human victims, important material losses or may have significant consequences upon the environment. The current paper addresses a possible scenario of a pressure vessel explosion and the computational simulation and analysis of the dispersion of hazardous substances (toxic or explosive) released in the environment following the explosion-type event, in order to highlight the possible consequences. Such computational simulations may be of benefit for employers, who wish to take proactive measures in order to increase the occupational health and safety level within their activity. In this regard, results of computational simulations can be integrated by the companies in the development of emergency response plans, aiming at minimizing the hazardous effects of the releases of toxic/explosive gases upon the workers and surrounding atmosphere.

The purpose of this paper is to present the tests carried out on cable entries with a flameproof enclosure protection type used in potentially explosive atmospheres. Assessment of explosion-protected electrical equipment is accomplished through tests carried out in accordance with the standard SR EN 60079-0, which includes all general requirements for explosion-protected electrical equipment. The requirements of this standard are supplemented with those for each type of protection in separate standards. To elaborate this paper, the requirements in force were studied. It resulted that a stand for sealing test of cable glands with flameproof enclosure protection type is required. This test is essential in the process of certification of the equipment used in explosive areas. In the first stage of the project, the test stand was conceived, whose design has been considered taking into account the specifications of the reference standard for electrical equipment used in potentially explosive atmospheres. The paper also presents the stand for sealing test of cable glands (with type of protection flameproof enclosure).

The intrinsic safety type of protection significantly increased in complexity during the last decades. Thus, it even provides the opportunity to use highly complex electronic circuits without involving a significant explosion risk within the oil industry or in power plants, but not limited to those two. In order to achieve this performance, the type of protection is based on three pillars: limiting of energy, heat and also fault tolerance. The potential failure of components, connections, and separations are taken into consideration for intrinsic safety evaluations. This paper focuses on scenarios of separation faults in intrinsic safety circuits. The introduction part of the paper provides a summary of requirements for the intrinsic safety type of protection. The separation requirements are also highlighted. This part also explains the "countable" concept regarding the separation faults. The second part of the paper is dedicated to the fault scenarios assessment. Also, this part shows the theoretical model which yields the magnitude of the fault scenarios group. The built-up algorithm for effective localization of the separation faults on a real electronic board is presented in the second part of the paper. This algorithm was implemented using Visual Basic for Applications script and National Instruments Ultiboard software. In the third part of the article, the obtained results are reported and discussed. In order to have a comprehensive image, there was proposed a graph in which links are considered separation distances and elements conductive tracks. Another tool proposed and used was separation distances histogram. The influence of increased finesse on the number of non-countable separation faults was also discussed. The main outcome of the paper is represented by the high impact of non-countable separation faults number over the number of separation failure scenarios. For example, the circuit analysis showed the potential for over sixteen million failure scenarios.