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Process Hazard <br />6 What -if Worksheets <br />2020 <br />For those deviations that were considered by the PHA study team to be credible, the <br />following information was recorded in the PHA study worksheets: <br />E/A Control: During the hazard review study, the team identified existing <br />engineering and administrative controls for the ammonia refrigeration systems. Those <br />engineering/administrative controls were documented in the "E/A Controls" column. <br />It is important to note that the controls listed cover all systems unless otherwise <br />noted; e.g. System 1 only, System 1, 2, etc. Engineering and administrative controls <br />are existing safeguards which can: <br />1. Prevent a scenario or a hazardous situation from occurring, <br />2. Provide an alarm when a hazardous situation is occurring, or <br />3. Mitigate the consequences of a hazardous situation. <br />Consequence (C): a semi -quantitative ranking of the worst consequence associated <br />with each credible scenario. Definitions are shown in Figure 2. <br />Frequency (F): a semi -quantitative ranking of the probability of a cause occurring, <br />which leads to a consequence of concern, given the stated level of safeguards. <br />Definitions are shown in Figure 2. <br />Risk Ranking (RR): a numerical ranking of the "risk," considering both the <br />Consequence and Frequency of an occurrence (see Figure 3). Lower numbers <br />correspond to lower risk, and higher numbers correspond to higher risk in the risk <br />ranking system used for this project. <br />Comments: supplemental relevant information that is provided to document team <br />discussion related to a specific what -if scenario. <br />Recommendations: recommendations include design, operating, or maintenance <br />changes that reduce or eliminate Deviations, Causes and/or Consequences. If <br />additional information was required, these requests were also formulated as What -if <br />Actions. <br />6.1 Risk Ranking <br />To address the requirement for a qualitative evaluation of the range of possible <br />consequences, a risk matrix was used. The risk matrix approach was <br />implemented item -by -item, as the study progressed. After documenting the <br />14 <br />