The Algerian company Sonatrach is associated with the production of the liquefied natural gas, propane, butane, gasoline from the crude gas.

The article solves the problem of assessing the integral risk at the GL2Z natural gas liquefaction plant with an analysis of the possible joint effect on the employees of production products complex as harmful and (or) hazardous factors in the form of chemical and thermal factors, provided that a fire or flash occurs considering the error of measuring gas components concentration. Integral risk is understood as probable (expected) damage from the occurrence of an incident or from the realization of an unfavorable outcome, provided that the full group of possible incidents (outcomes) in the system under consideration is considered. Modeling and cause-and-effect analysis of the occurrence of an incident and (or) adverse outcomes in the system is described using factor parametric models of the type «load-bearing capacity», «effect — susceptibility». In this case, most often the realization of an unfavorable outcome is evaluated by the condition of exceeding the parameter or the magnitude of the effect over the susceptibility parameter. Using the example of the system under consideration, a Boolean function of the integral risk indicator is constructed, and a demonstration of the calculation of its probabilistic form is performed. In addition, it is proposed to calculate a probabilistic measure from a unified position of logical and parametric description of both the set of possible incidents and their components in the form of unfavorable outcomes.

To test the proposed method for assessing the integral risk, the initial data were used, with which, provided that the probability of an outbreak of all five components of the crude gas is equal, it was obtained that in a particular analyzed system, the calculated value of the upper limit of the probability of an incident occurrence was 0.9675.