Hazard pointers Exposures Events /scenarios Consequences
Origin of effectsNatural Extreme waves Slamming on deckPersonnel
Environment
EconomyOverturning of structurePersonnel
Environment
Economy
Fatigue damage Loss of bracing member EconomyFatigue damage and extreme wave Loss of bracing member and subsequent collapsePersonnel
Environment
EconomyMan made Ship collision CollapsePersonnel
Environment
Economy
Ship collision Damage EconomyIgnition/open fire ExplosionPersonnel
Environment
EconomyEnergy potential Leak of pressure vessel Ignition and ExplosionPersonnel
Environment
EconomyFunctionality Riser failure Ignition and ExplosionPersonnel
Environment
Economy
Riser failure Spill of oil and gas Environment EconomyTable 4.2: List of exposure pointers, exposures, events and event scenarios and consequence
categories.
4.7 Tools for Risk Analysis
Having identified the different sources of risk for an engineering system and/or activity and
analysed these in respect to their chronological and causal components, logical trees may be
formulated and used for the further analysis of the overall risk as well as for the assessment of
the risk contribution from the individual components.
In the present chapter the basic aspects of some of the most commonly used types of logical
trees will be considered, namely fault trees, event trees, cause-consequence charts and
decision trees. In a later chapter the new concept of Bayesian Probabilistic Nets will be
introduced and it will be seen see how these may efficiently replace the more traditional
methods.
Fault trees and event trees are by far and large the most well-known and most widely applied
type of logical trees in both qualitative and quantitative risk analysis. Two of the most
important risk studies involving fault tree and event tree analysis were the US nuclear safety
study and the UK Canvey study of chemical process industries. Even though more modern
risk analysis techniques such as e.g. Bayesian Probabilistic Nets have been developing over