(a) Explain the principles of HAZOP. Hazard and operability (HAZOP) studies are undertaken by the application of a formal, systematic, and critical approach to examine the process and engineering intentions of a process design. The potential for hazard is thus assessed, and the chances of malfunction of an individual equipment and its consequences for a whole system, are identified. The examination of the design is structured around a specific set of guidewords, and then ensure complete coverage of all possible problems while allowing sufficient flexibility for an imaginative approach. The overall aims to which any HAZOP should be addressed are: 1. To identify all deviations from the way the design is intended to work, their causes, and all the hazards and operability problems associated with these deviations. 2. To decide whether action is required to control the hazard or the operability problem, and if so, to identify the ways in which the problems can be solved. 3. To identify cases where a decision cannot be taken immediately and to decide on what information or action is required. 4. To ensure actions decided are followed through. HAZOP can be used on new plant, part of the plant or existing facilities, but is always best done at the design stage. Any change or modification to such plant, temporary or permanent must also undergo a HAZOP to ensure plant safety is not jeopardised by the change.
(b) Explain the principles of FTA (Fault Tree Analysis) Fault tree analysis is one of many symbolic "analytical logic techniques" found in operations research and in system reliability. In many cases there are multiple causes for an accident or other loss-making event. Fault tree analysis is one analytical technique for tracing the events which could contribute. It can be used in accident investigation and in a detailed hazard assessment. It uses a top-down block diagram approach by working backwards from a top event or undesired occurrence. The fault tree diagram...
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