HAZOP: Hazard and Operability Analysis Unlike most techniques, HAZOP can identify hazards Based on model of accidents that assumes they are caused by deviations from design or operating intentions Purpose is to identify all possible deviations from the designs expected operation and all hazards associated with these deviations Software Deviation Analysis(Jon Reese System Hazard Analysis HAZOP Guidewords Guideword Meaning NO NOT The intended result is not achieved, but nothing else happens NONE (such as no forward flow when there should be) MORE More of any relevant physical property than there should be (such as higher pressure, higher temperature, higher flow, or higher viscosity) LESS Less of a relevant physical property than there should be AS WELL AS An activity occurs in addition to what was intended, or more components are present in the system than there should be (such as extra vapors or solids or impurities, including air water, acids, corrosive products) PART OF Only some of the design intentions are achieved (such as only one of two components in a mixture) REVERSE The logical opposite of what was intended occurs(such as backflow instead of forward flow) OTHER THAN No part of the intended result is achieved, and something completely different happens(such as the flow of the wrong material)c System Hazard Analysis Leveson − 153 HAZOP: Hazard and Operability Analysis Unlike most techniques, HAZOP can identify hazards. Based on model of accidents that assumes they are caused by deviations from design or operating intentions. Purpose is to identify all possible deviations from the design’s expected operation and all hazards associated with these deviations. Software Deviation Analysis (Jon Reese) c Leveson − 154 System Hazard Analysis HAZOP Guidewords NONE NO, NOT, Guideword The intended result is not achieved, but nothing else happens Meaning (such as no forward flow when there should be) MORE or higher viscosity). (such as higher pressure, higher temperature, higher flow, More of any relevant physical property than there should be LESS Less of a relevant physical property than there should be. AS WELL AS water, acids, corrosive products). (such as extra vapors or solids or impurities, including air, components are present in the system than there should be An activity occurs in addition to what was intended, or more PART OF one of two components in a mixture). Only some of the design intentions are achieved (such as only REVERSE backflow instead of forward flow). The logical opposite of what was intended occurs (such as OTHER THAN material). completely different happens (such as the flow of the wrong No part of the intended result is achieved, and something