It is proposed to use the new approach to assessing quantitative risk indicators. This approach allows to consider the temporal non-stationarity of the number of processes, including the development of an accident and the spatial movements of people.

The greatest uncertainty in the risk analysis with an explosive and fire hazard component is not the frequency of initiating events used, but, for example, data on the probability of ignition. The range of variation of this probability is about two orders of magnitude (relatively speaking, from 1 % to 100 %), and the criteria and factors that determine the choice of this value are not always clearly defined. The paper proposes an approach that considers the probability of ignition as a dependence on the time that passed after the start of emergency depressurization. Knowing this dependence, it is possible to consider several scenarios with different ignition time after the start of the release and assign certain consequences and probabilities to each scenario. Moreover, it is possible for each single scenario on a specific piece of equipment (pipeline section) to obtain non-stationary, namely time-varying potential risk fields.

The example of an accident on the oil pipeline is considered, the risk indicators of such an accident are calculated, it is shown that the risks can change over time, namely they are non-stationary characteristics.

Further, this fact is transformed into the development of theoretical foundations for quantitative risk assessment, considering the non-stationarity of various processes occurring during emergency situations arising during the operation of equipment, individual behavior of people and changes in external conditions.

The results obtained show the importance of considering the changes that occur during an emergency on the main oil and product pipelines. It is concluded that the proposed approach allows to reduce the conservatism of assessments provided by traditional methods. In real practice this approach can reasonably reduce the risk indicators by several times, sometimes by orders of magnitude.

It is proposed to use the new approach to assessing quantitative risk indicators. This approach allows to consider the temporal non-stationarity of the number of processes, including the development of an accident and the spatial movements of people.

The greatest uncertainty in the risk analysis with an explosive and fire hazard component is not the frequency of initiating events used, but, for example, data on the probability of ignition. The range of variation of this probability is about two orders of magnitude (relatively speaking, from 1 % to 100 %), and the criteria and factors that determine the choice of this value are not always clearly defined. The paper proposes an approach that considers the probability of ignition as a dependence on the time that passed after the start of emergency depressurization. Knowing this dependence, it is possible to consider several scenarios with different ignition time after the start of the release and assign certain consequences and probabilities to each scenario. Moreover, it is possible for each single scenario on a specific piece of equipment (pipeline section) to obtain non-stationary, namely time-varying potential risk fields.

The example of an accident on the oil pipeline is considered, the risk indicators of such an accident are calculated, it is shown that the risks can change over time, namely they are non-stationary characteristics.

Further, this fact is transformed into the development of theoretical foundations for quantitative risk assessment, considering the non-stationarity of various processes occurring during emergency situations arising during the operation of equipment, individual behavior of people and changes in external conditions.

The results obtained show the importance of considering the changes that occur during an emergency on the main oil and product pipelines. It is concluded that the proposed approach allows to reduce the conservatism of assessments provided by traditional methods. In real practice this approach can reasonably reduce the risk indicators by several times, sometimes by orders of magnitude.

- Lisanov M.V., Sumskoy S.I., Shvyryaev A.A. Uncertainties of the Quantitative Emergency Risk Assessment at Oil-Gas Facilities. Vesti gazovoy nauki = News of Gas Science. 2018. № 2 (34). pp. 125–134. (In Russ.).
- Kolesnikov E.Yu. Quantitative Assessment of Emergency Risk: Analysis of Uncertaint. Bezopasnost truda v promyshlennosti = Occupational Safety in Industry. 2018. № 2. pp. 64–70. (In Russ.).
- Lisanov M.V., Savina A.V., Degtyarev D.V., Samuseva E.A. Russian and Western Pipelines Accident Data Analysis. Bezopasnost truda v promyshlennosti = Occupational Safety in Industry. 2010. № 7. pp. 16–22. (In Russ.).
- Spouge J. A guide to quantitative risk assessment for offshore installations. CMPT, 1999. 750 p.
- Daycock J.H., Rew P.J. Development of a Method for the Determination of On-Site Ignition Probabilities. Available at: https://www.hse.gov.uk/research/rrpdf/rr226.pdf (accessed: August 12, 2020).
- Rew P.J., Spenser H., Atkins W., Franks A. A framework for ignition probability of flammable gas clouds. Available at: https://www.icheme.org/media/12096/xiii-paper-14.pdf (accessed: August 12, 2020).
- Eckhoff R.K., Thomassen O. Possible sources of ignition of potential explosive gas atmospheres on offshore process installations. Journal of Loss Prevention in the Process Industries. 1994. Vol. 7. Iss. 4. pp. 281–294.
- Menon S.K., Boettcher P.A., Ventura B., Blanquart G., Shepherd J.E. Investigation of hot surface ignition of a flammable mixture. Available at: https://sites01.lsu.edu/faculty/smenon/wp-content/uploads/sites/133/2017/02/WSSCI12v1.pdf (accessed: August 12, 2020).
- Methodological bases for the analysis of hazards and risk assessment of accidents at hazardous production facilities: safety guide. Available at: http://docs.cntd.ru/document/1200133801 (accessed: August 12, 2020). (In Russ.).
- Sumskoi S.I., Sverchkov A.M. Modeling of Non–equilibrium Processes in Oil Trunk Pipeline Using Godunov Type Method. Physics Procedia. 2015. Vol. 72. pp. 347–350.
- Sumskoy S.I., Agapov A.A., Sofin A.S., Sverchkov A.M., Egorov A.F. Simulation of Abnormal Leakages on Trunk Pipelines. Bezopasnost truda v promyshlennosti = Occupational Safety in Industry. 2014. № 9. pp. 50–53. (In Russ.).
- Sumskoi S.I., Sverchkov A.M., Lisanov M.V., Egorov A.F. Modelling of non–equilibrium flow in the branched pipeline systems. Journal of Physics: Conference Series. 2016. Vol. 751. № 1. pp. 12–22.
- TOXI+Fluid Hammer Software Tool. Software for industrial safety TOXI+. Available at: https://toxi.ru/produkty/programmnoe-sredstvo-toxigidroudar (accessed: August 12, 2020). (In Russ.).
- Agapov A.A., Lazukina I.O., Marukhlenko A.L., Marukhlenko S.L., Sofin A.S. Use of Software Complex TOXI+Risk for Fire Risk Assessment. Bezopasnost truda v promyshlennosti = Occupational Safety in Industry. 2010. № 1. pp. 46–52. (In Russ.).