THE APPLICATION OF RISK CALCULATION METHODS FOR ANALYSIS AND PREVENTION OF INDUSTRIAL INJURIES

Abstract

The article was tasked with analyzing electrical injuries at metallurgical enterprises in Ukraine based on the construction of a „fault tree”. One of the reasons for choosing the lesion from the action of electric current is its high danger – the proportion of electrical accidents with a fatal outcome in the total workplace injuries reaches 40%. The fault tree is a graphical model of various parallel and sequential fault messages (events related to the failure of system elements, personnel errors, equipment unavailability), leading to the realization of a predetermined undesirable event, in this case – electric shock. Building a tree of failures allows you to calculate the probability of system failure, to find the most dangerous basic events and their combinations. A failure tree was compiled for the case of electric shock at a metallurgical plant. Minimal sections have been found, that is, rows of basic events that cause the onset of the upper (undesirable) event – electric shock. The probability of the minimum sections is calculated. Based on the significance indicators for Birnbaum and Fussell-Veseli, the basic events that make the greatest contribution to the risk of electric shock are determined. The first group of events concerns touching open conductive parts, the second – touching non-conducting parts that happened to be under voltage. Together, these two sections provide a 65% contribution to the overall risk. The defining basic events that make the greatest contribution to the risk are the erroneous voltage supply and the failure or absence of protection - grounding, zeroing, shutdown. These basic events are very dangerous – they are highly likely to lead to electric shock. To reduce the risk of electric shock, it is necessary to eliminate the erroneous voltage supply, or minimize this possibility. Ways of implementation – strengthening supervision over the implementation of work on current carrying parts, the observance of the system of work orders, for conducting briefings. As a technical measure, blocking of current switching devices is used during repair work. It can be recommended to use protective devices, which, depending on the network circuit and the specific situation, react to the potential of the case, earth fault current, zero-sequence current, operating current, and the like.