Monthly Archive for: ‘September, 2013’

When to Use a Risk Matrix and Risk Tolerable Criteria


We don’t recommend using a risk matrix during PHAs/HAZOPs. matrices are good tools to teach risk concepts, but in a well led PHA/HAZOP they reduce quality more than they increase quality. To see much more details, download and read this free paper: We use a risk matrix and a risk tolerance criteria only when doing a LOPA (to address …

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When should PHAs (HAZOPs, etc.) Be Performed During Major Projects?


The short answer is you need to perform PHAs in phases, from conceptual stage, through preliminary and detailed design, and then complete these during the pre-commissioning stages (as mentioned by Bryan). The PHAs build upon each other and the completion of the final phase PHA becomes the Baseline PHA. The tools used change from phase-to-phase, with What-if and some high …

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