Conditions for risk based ship survivability approach: a study on the analysis of fire risk

Journal article, 2016

In military operations, balancing risk is central, and a desire to entirely avoid risk may affect the potential for achieving military goals. Therefore, risk is an important aspect for understanding the operational conditions. This study discusses the assessment of operational risk to support ship design decisions. Fire is a common consequence of weapon hits and is currently estimated to cause of 80 percent of naval ship loss. The purpose of this study is to describe and investigate the conditions for a risk-based approach to ship fire survivability, that can link probabilistic survivability theory and survivability measure selection. The aim is to suggest key aspects for a risk-based methodology. To aid in the analysis, this study proposes cause and effect models for the fire risk analysis and describes the fire risk contribution from different types of ignition. The analysis shows that the reliability and validity of identifying potential fires depends on a qualitative and outward-focused analysis of the ships’ intended operation, and the reliability and validity of the analysis on fire consequences depends on the specific data and descriptions used. For example, the magnitude of the fire risk can drastically change due to the operational choices (or unclear operational conditions). This study concludes that the analysis requires understanding of the operational conditions. Subsequently, civilian risk-based approaches to fire risk are too limited because the approaches do not include aspects of the ship design and intended operation. Further, normal military vulnerability tools lack this ability. However, based on a stringent fire ignition analysis, including a definition of the intended operation, the ship design concept and the threats, civilian methods and tools can be used to assess the consequences.