Analysis of the existing methods for predicting the scale of possible chemical contamination by accidentally chemically hazardous substances in case of accidents (destruction) at chemically hazardous facilities and transport was conducted. The ways of improvement of the technique presented in the Code of practice SP 165.1325800.2014 are offered, substantiated, and implemented.
The scale of possible chemical contamination must be predicted for scenarios not only with complete, but also with partial destruction of the vessels containing liquid accidentally chemically hazardous substances. The approach was improved and substantiated that allows to determine the following during vessel depressurization: the parameters of outflow of the liquid accidentally chemically hazardous substance from the emergency hole; the amount of this substance spilled freely on the underlying surface in the presence or absence of a pallet (dike).
It is necessary to consider the absorption and spreading behavior of liquid accidentally chemically hazardous substances during spill on the underlying surface. For this, it is proposed to use the coefficients of infiltration and spreading surface, and to determine with their account the equivalent amount of accidentally chemically hazardous substances in the secondary cloud.
In the future, substantiation and calculation of the specified coefficients for a variety of liquid accidentally chemically hazardous substances are required, taking into account a number of factors: the type of underlying surface, spreading time, air temperature, wind speed, precipitation in the form of rain, exposure time, etc.
The proposed ways of the technique improvement will allow to increase the reliability of the forecast of the scale of possible chemical contamination with liquid accidentally chemically hazardous substances in case of accidents.