Release scenarios overview

Chapter 2—Overview of Release Scenarios and Postrelease Mitigation This chapter provides an overview of the different types of releases that can occur, the consequences of the discharges, and a general description of available postrelease mitigation measures. 

Overview of Release Scenarios and Postrelease Miti tion... 

Fire hazard analysis (FHA) is the process to determine the size, severity, and duration of a scenario and its impact on personnel, equipment, operations, and the environment. Chapter 5 provided details of performing an FHA. The following paragraphs provide an overview of the FHA process. For example, one scenario could be a seal failure where the material being released is ignited and afire results. In assessing consequences, several questions must be considered ... 

The literature indicates numerous, often widely different values for assigning probabilities to scenarios such as those of Figs. 10.2, 10.3 and 10.4. This reflects uncertainties due to lack of knowledge (epistemic) and stochastic (aleatory) effects. If properly treated these uncertainties should be represented by probability distributions. Table 10.15 gives an overview of conditional probabilities for the consequences of a puff release of a pressurized flammable gas from various sources. Not only are the differences in probabilities evident but also the differences as to the endpoints. 

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