Problems of calculation of classes and sizes of explosive zones round external equipments

Oleg Kulakov

National University of Civil Defence of Ukraine

http://orcid.org/0000-0001-5236-1949

Albert Katunin

National University of Civil Defence of Ukraine

http://orcid.org/0000-0003-2171-4558

Elena Lyashevska

National University of Civil Defence of Ukraine

http://orcid.org/0000-0002-1469-4141

DOI: https://doi.org/10.52363/2524-0226-2021-33-13

Keywords: explosive zone, external equipments, explosive environment, hypothetical volume, wind speed, time of existence

Abstract

Found out features of determination of classes and sizes of explosive zones that is created by explosive gas atmospheres round external equipments. National classification comes true by two methods, one of that is determined, and other - by a calculation. Explosive gas atmospheres round external equipments can form the explosive zones of classes 0, 1, 2. At application of calculation method initial parameters are climatic terms, properties are dangerous substances, degree of source and  level of ventilation. Intensity of source of liquid is determined, settle accounts hypothetical volume of explosive environment, compared that to the fixed value of general volume that is ventilated. An of hypothetical volume and time of existence of explosive environment depend on speed of wind on a hyperbolical law.  For example of the external equipments it is shown as an untight muff of above - ground gas pipeline of natural gas, that speed of wind is substantial influences on the size of hypothetical volume of explosive environment. At of speed that answers quiet wind after a scale of Beaufort, round the external equipment the explosive zone of class is created 1. At of speed that answers easy wind after a scale of Beaufort, round the external equipment the explosive zone of class is created 2. If decline of ambient temperature results in diminishing of size of hypothetical volume of explosive environment. Intensity of source of hazardous substance substantially influences on the class of explosive zone. For every type of hazardous substance it is necessary to determine the maximum value of intensity of source, higher that the explosive zone of class takes place 1, and below is an explosive zone of class 2. Time of existence of explosive environment does not depend on ambient and intensity of source temperature and quickly diminishes with the increase of speed of wind.

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