Post-Emergency, Multi-Hazard Health Risk Assessment in Chemical Disasters (PEC)

Report on the Evaluation of Possible Damages Suffered by Chemical and Process Vessels due to Floods

Report (2017)

Authors

N. Khakzad Rostami Safety and Security Science - TPM
P.H.A.J.M. van Gelder Safety and Security Science - TPM
Research Group
Safety and Security Science (TPM) (TU Delft)
Copyright: © 2017 N. Khakzad, P.H.A.J.M. van Gelder
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Published Date

2017

Language

English

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Faculty

Technology, Policy and Management

Department

Values Technology and Innovation

Research Group

Safety and Security Science

Abstract

In the context of natural-technological (natech) accidents, flood-induced damage of chemical and process facilities have received relatively less attention partly due to the scarcity of experimental or high resolution field observations from one hand and partly due to the rarity of such events on the other hand. In the present study, we have investigated the possible damage of a variety of chemical and process vessels such as atmospheric storage tanks as well as pressurized vertical and horizontal vessels. We have introduced a methodology based on load-resistance relationships to assess the vulnerability of vessels in the form of fragility functions. While logistic regression is used to develop
fragility functions for prevailing different failure modes, that is, floatation and buckling, a Bayesian network methodology has been developed to combine the fragility functions, taking into account common causes and conditional dependencies.
The end results have been presented in the form of point estimate total failure probabilities of vessels subject to credible floods. The results of the present study illustrate that although the floatation is the most prominent failure mode in case of floods, the anchorage of target vessels (via bolts), prevent the vessel floatation in almost all cases. In addition, for un-anchored vessels, such as atmospheric storage tanks, filling the tanks at least with as much chemicals (hydrocarbon products or chemicals with a density ranging from 650 to 850
Kg/m3) as equal to the height of flood inundation would significantly reduce the probability of floatation. In case of shell buckling, the height of inundation seems to be a more influential factor than the flow velocity. Besides, it turned out that a small increase in the wall thickness of target vessels would notably decrease the probability of shell buckling.