**5. Conclusions**

In this chapter, we discussed failure modes and vulnerability of process vessels – with emphasis on atmospheric storage tanks – in the event of hurricanes. It was demonstrated how physics-of-failure models and Bayesian network can be used to assess the failure probabilities of storage tanks due to the impact of flood, wind, and rainfall.

Although the physics-of-failure models can directly be used to develop mathematical relationships for estimating the failure probabilities (see Eq. (11) as an example), such mathematical relationships cannot seem to efficiently account for dependencies when modeling and combining interdependent failure modes. These interdependencies may arise when one root node contributes to several failure modes or when one failure mode excludes or contributes to another failure mode. An example for such interdependencies includes the accumulation of rainfall on the rooftop of a floating- roof tank ("H\_ac" in **Figure 6**), which causes the roof to sink ("Roof\_sinking") but reduces the likelihood of tank's floatation ("Floatation") and sliding ("Slide") due to its added weight.

The application of BN, on the other hand, enables the analyst to consider the dependencies among the failure modes, which would otherwise result in inaccurate failure probabilities. **Table 5** summarizes the modeling features of the methodologies discussed in this chapter.

### **Acknowledgements**

The financial supports by the Natural Sciences and Engineering Research Council of Canada (NSERC) via Discovery Grant, and by the Faculty of Community Services, Ryerson University, Canada, via Publication Grant is much appreciated.

## **Author details**

Nima Khakzad Ryerson University, Toronto, ON, Canada

\*Address all correspondence to: nima.khakzad@ryerson.ca

© 2022 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

*Vulnerability Assessment of Process Vessels in the Event of Hurricanes DOI: http://dx.doi.org/10.5772/intechopen.109430*
