Up to this point, possible pipeline failure initiators have been assessed. These initiators define what can go wrong. Actions or devices that are designed to prevent these failure initiators have also been considered. These preventions affect the How likely is it? follow-up question to What can go wrong?

The last portion of the risk assessment addresses the question What are the consequences? This is answered by estimating the probabilities of certain damages occurring. The consequence factor begins at the point of pipeline failure. The title of this chapter, Leak Impact Factor, emphasizes this. What is the potential impact of a pipeline leak? The answer primarily depends on two pipeline condition factors: (1) the product and (2) the surroundings. Unfortunately, the interaction between these two factors can be immensely complex and variable. The possible leak rates, weather conditions, soil types, populations nearby, etc., are in and of themselves highly variable and unpredictable. When the interactions between these and the product characteristics are also considered, the problem becomes reasonably solvable only by making assumptions and approximations.

The leak impact factor is calculated from an analysis of the potential product hazard, spill or leak size, release dispersion, and receptor characteristics. Although simplifying assumptions are used, enough distinctions are made to ensure that meaningful risk assessments result.

The main focus of the LIF here is on consequences to public health and safety from a pipeline loss of containment integrity. This includes potential consequences to the environment. Additional consequence considerations such as service...