Systematic potential approach

HAZOP Acronym for hazard and operability review. This is a formal, systematic, critical approach for identifying the qualitative potential of hazards and operating problems associated with an existing or new system or piece of equipment caused by deviations to the design intent and their resulting consequential effects. 

The technical problems involved with any attempt to use analogously systematic research approaches to a potential transmitter in the central nervous system are great. Peripheral synapses can be isolated by microdissection, they can remain functional in an isolated profusion experimental situation for hours, and their activation can be manifested by clearly defined and measurable phenomena (such as the miniature end-plate potential or the contraction of smooth muscle). The central nervous system has little in the way of focal synaptic regions. The dendrites and the cell bodies of central neurons are densely covered with synapses, many of which may be of a chemically heterogenous nature. In addition, the extra-neuronal space is packed with a tangle of glia, closely approximating the membranous surfaces of nerve cells and possibly intrinsically important to their function. This makes the isolated, chemical manipulation of central synapses extremely difficult. (Mandell and Spooner 1968, p. 1443)... 

A systematic, preventive approach to food and pharmaceutical safety that includes physical, chemical, and biological hazards as a means of prevention rather than finished product inspection. It has seven key principles, which are conduct a hazard analysis, identify critical control points, establish critical limits for each critical control point, establish critical control point monitoring requirements, establish corrective actions, establish record-keeping procedures, and establish procedures for ensuring the HACCP system is working as intended. HACCP is used in the food industry to identify potential food safety hazards, so that key... 

DOE recommends the use of a systematic approach to training, in which the content of training is commensurate with the potential hazards, exposures, worker roles and responsibilities, and requirements of the project (see Eigure 8-1) [1]. The description of this systematic approach sounds like a great idea. However, in some cases the execution of the systematic approach is difficult to attain. In general, training classes aim content and level to reach at least 80 percent of attendees. 

When performing human reliability assessment in CPQRA, a qualitative analysis to specify the various ways in which human error can occur in the situation of interest is necessary as the first stage of the procedure. A comprehensive and systematic method is essential for this. If, for example, an error with critical consequences for the system is not identified, then the analysis may produce a spurious impression that the level of risk is acceptably low. Errors with less serious consequences, but with greater likelihood of occurrence, may also not be considered if the modeling approach is inadequate. In the usual approach to human reliability assessment, there is little assistance for the analyst with regard to searching for potential errors. Often, only omissions of actions in proceduralized task steps are considered. 

The use of a model of human error allows a systematic approach to be adopted to the prediction of human failures in CPI operations. Although there are difficulties associated with predicting the precise forms of mistakes, as opposed to slips, the cognitive approach provides a framework which can be used as part of a comprehensive qualitative assessment of failure modes. This can be used during design to eliminate potential error inducing conditions. It also has applications in the context of CPQRA methods, where a comprehensive qualitative analysis is an essential precursor of quantification. The links between these approaches and CPQRA will be discussed in Chapter 5. 

A systematic approach was undertaken for the BRP PRA to identify all potential sources of common mode failure. The first step in the treatment of common mode failures was a compilation of a detailed list of common mode initiators. To achieve this, available literature on common mode failure analysis was reviewed. The next step was to qualitatively assess the potential effects of these initiators on BRP systems. The initiator categories and the systems selected for examination are presented in Table VI.1 of the BRP PRA. 

Begin by listing all potential causes or combinations of causes, using a brainstorming approach. Then, systematically rule out each cause. Do not eliminate uncommon causes too quickly—if it were an easy problem it would have already been taken care of it. Additionally, ensure that limits outlined by process and equipment documentation are consistent with the actual operation of the unit. 

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