PHA, LOPA, and QRA

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PHA, LOPA, and QRA 2017-06-25T19:58:07+00:00

Risks associated with process plant operations are analyzed using different techniques, each suited to the task at hand.

Process Hazards Analysis (PHA) describes a range of techniques that examine risk using qualitative measures of severity & hazard likelihood by a team of experts in engineering and operations.   Although decisions on risk are qualitative, a risk matrix guides them.   Safeguards may be deemed adequate, or it may be advisable to examine the adequacy of Independent Protection Layers (IPL) using a semi-quantitative technique called Layer of Protection Analysis (LOPA), which quantifies risk using an order-of-magnitude approach.  This is particularly effective for establishing the basis-of-design for Safety Instrumented Systems (SIS), but it can be used to examine almost any process hazard that involves deviation from normal operating conditions.

LOPA takes additional time & effort, but promotes more consistent risk decisions.   Quantitative Risk Analysis (QRA) is usually reserved for relatively complex and a narrowly defined risk problem, which cannot be easily examined using the more conservative PHA and LOPA techniques.  QRA quantifies risks with precision using models to predict hazard severity and fault-propagation models to calculate likelihood of the hazard.  Corporate risk guidelines are the basis of consistent risk decisions using PHA, LOPA, or QRA.

Kenexis provides engineers with expertise in facilitation of PHA studies, which usually address an entire process, as well as leadership for analyzing hazards that rise meet screening criteria for further study using LOPA.  PHA and LOPA are usually adequate to make informed risk-decisions for +90% of process hazards.  Kenexis facilitators are trained to ensure the risk analysis techniques are applied efficiently, consistently and within industry best practices for PHA and LOPA studies.   When need arises, Kenexis will provide skilled analysts that apply focused QRA methods to hazards that have a complex relationship between causes, and protection layers.  Our risk analysts are specialized in effectively communicating the results of these analysis and the recommended safeguards in practical terms that are understood by engineering, operations, and site management.

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