Risk analysis, defined

Because of the complexity of chemical processes, the response selection should be tailored to the characteristics and requirements of each plant and safety function. A hazard and risk analysis defines for each hazard scenario when action should be taken, giving the initiating causes, consequence severity, and protection layers. The potential for common cause should also be evaluated to ensure the actions can be implemented in the presence of the initiating cause and the SIF device fault. 

PreUminary risk analysis defines the Equipment Under Control (EUC), its limits, its environment, all modes of operation, the dangers and risks associated with the equipment and its control system. An inventory of risk is established and the risks that are covered by the system are confirmed. In our case, it was initially decided... 

Risk-Based Inspection. Inspection programs developed using risk analysis methods are becoming increasingly popular (15,16) (see Hazard ANALYSIS AND RISK ASSESSMENT). In this approach, the frequency and type of in-service inspection (IS I) is determined by the probabiUstic risk assessment (PRA) of the inspection results. Here, the results might be a false acceptance of a part that will fail as well as the false rejection of a part that will not fail. Whether a plant or a consumer product, false acceptance of a defective part could lead to catastrophic failure and considerable cost. Also, the false rejection of parts may lead to unjustified, and sometimes exorbitant, costs of operation (2). Risk is defined as follows ... 

ERPG is defined in the section on hazard and risk analysis. 

Risk is defined as the combination of the expected frequency and consequence of accidents that could occur as a result of an activity. Risk analysis is a formal process of increasing one s understanding of the risk associated with an activity. The process of risk analysis includes answering three questions ... 

A leader in applying PSA to other parts of the chemical process industry has been the AlChf. s Center for Chemical Process Safety. A major difference between PSA for nuclear power and PSA for chemical processing has been the lack of government regulations that require risk analysis for chemical processes. A primary impetuous has been the Occupational Safety and Health Administration s (OSHA) PSM rule that defines the application of PSA to the chemical industry for ihc proteciion of the public and workers. In addition, the Environmental Protection Agcrii, . (EPA) regulates waste disposal. 

Guidelines for Chemical Process Quantitative Risk Analysis (CPQRA Guidelines) builds on the earlier work to show the engineer how to make quantitative estimates of the risk of the hazards identified. The quantitative estimates can identify the major contributors to risk. They can also help to define the most effective ways to a safer process by indicating relative risk reduction from proposed alternate process safeguards and measures. 

AlUiougli the terms emergency and accident are discussed from a risk analysis point of view in Parts IV and V, Uiey are now defined in relatively general tenns, to help the reader differentiate between the two and to understand their application to the general subject of process occurrences . 

Define and compare the following pairs of parameters used in health risk analysis ... 

Risk is defined as a measure of human injury, environmental damage, or economic loss in terms of both the incident likelihood (probability) and the magnitude of the loss or injury (consequence) (AICHE/CCPS, Guidelines for Chemical Process Quantitative Risk Analysis, 2d ed., American Institute of Chemical Engineers, New York, 2000, pp. 5-6). It is important that both likelihood and consequence be included in risk. For instance, seat belt use is based on a reduction in the consequences of an accident. However, many people argue against seat belts based on probabilities, which is an incorrect application of the risk concept. 

In 1993, the Center for Chemical Process Safety (CCPS) published Guidelines for Safe Automation of Chemical Processes (referred to henceforth as Safe Automation). Safe Automation provides guidelines for the application of automation systems used to control and shut down chemical and petrochemical processes. The popularity of one of the hazard and risk analysis methods presented in Safe Automation led to the publication of the 2001 Concept Series book from CCPS, Layer of Protection Analysis A Simplified Risk Assessment Approach. This method builds upon traditional process hazards analysis techniques. It uses a semiquantitative approach to define the required performance for each identified protective system. 

The first step in protection against explosions is to identify if they have the possibility of occurring at the facility and to acknowledge that fact. This may be for both internal and open air explosions. Once it is confirmed an estimate of their probability and severity should be defined by a risk analysis. If the risk level is indicated as unacceptable additional measures for prevention and mitigation should be implemented. 

Qualification of a capillary electrophoresis instrument is performed using failure mode, effects, and criticality analysis as the risk analysis tool. The instrument is broken down into its component modules and the potential failures of those components identified. The potential effect of those failures is defined and the risk characterized. Any current evaluation of those failures is identified and any recommended actions to mitigate the risk defined. 

Risk assessment—The process by which the results of a risk analysis are used to make decisions either through a relative ranking of risk reduction strategies or through comparison with risk targets. Risk assessment is often defined as the qualitative estimation of probability and consequence of an incident or incidents. 

SRA provides an open forum for all those who are interested in risk analysis. Risk analysis is broadly defined to include risk assessment, risk characterization, risk communication, risk management, and policy relating to risk. ... 

In defining units of analysis it is also important to take account of Vose s (2000, p 201) cardinal rule of risk analysis modeling every iteration of a risk analysis model must be a scenario that could physically occur. ... 

Since risk analysis plays an important role in public policy decision making, efforts have been made to devise a means by which to identify, control, and communicate the risks imposed by agricultural biotechnology. A paradigm of environmental risk assessment was first introduced in the United States by Peterson and Arntzen in 2004. In this risk assessment, a number of assumptions and uncertainties were considered and presented. These include (1) problem formulation, (2) hazard identihcation, (3) dose-response relationships, (4) exposure assessment, and (5) risk characterization. Risk assessment of plant-made pharmaceuticals must be reviewed on a case-by-case basis because the plants used to produce proteins each have different risks associated with them. Many plant-derived biopharmaceuticals will challenge our ability to define an environmental hazard (Howard and Donnelly, 2004). For example, the expression of a bovine-specihc antigen produced in a potato plant and used orally in veterinary medicine would have a dramatically different set of criteria for assessment of risk than, as another example, the expression of a neutralizing nonspecihc oral antibody developed in maize to suppress Campylobacter jejuni in chickens (Peterson and Arntzen, 2004 Kirk et al., 2005). 

Recognizing that heading off a potential problem is usually better (cheaper and less embarrassing) than coping with a nonconformance, the standard requires the laboratory to engage in preventive actions. This is defined as a proactive process to identify opportunities for improvement. The use of trend and risk analysis of proficiency testing data (see chapter 5) is mentioned as a possible preventive action. 

The results of any risk analysis should be well documented as they become the key input into the qualification and validation process. They are the basis for defining tests in the IQ, OQ, and PQ phases. It is often impossible to say prior to a risk analysis what steps of qualification need to be performed. It depends on the risks and measurements defined during the risk analysis. Equally important, this procedure increases the efficiency of the qualification process. In the past, the decision on which qualification tests to perform was outlined by writing qualification protocols. These usually prompted long and expensive discus-... 

Written procedures shall define how the system will be used and controlled, and periodic review of these procedures and the validation documentation status must be carried out. The periodic review procedure should define responsibilities and should include predetermined criteria for reporting that computer system validation is being satisfactorily maintained in alignment with the project validation plan. A GMP risk assessment should form part of each periodic review to reconfirm (or not) the findings of the previous risk analysis and provide information for any revalidation that is considered necessary. 

In fact, considering risk as a product is somewhat restrictive it is more general to consider it as a combination of the terms, severity and probability, that characterize the effects, that is, consequences and impact of a potential accident and its probability of occurrence. This also means that the risk is linked to a defined incident scenario. In other words, the risk analysis will be based on scenarios that must first be identified and described with the required accuracy, in order to be evaluated in terms of severity and probability of occurrence. 

The accepted risk is a risk inferior to a level defined in advance either by law, technical, economical, or ethical considerations. The risk analysis, as it will be described in the following sections, has essentially a technical orientation. The minimal requirement is that the process fulfils requirements by the local laws and that the risk analysis is carried out by an experienced team using recognized methods and risk-reducing measures that conform to the state of the art It is obvious that non-technical aspects may also be involved in the risk acceptation criteria. These aspects should also cover societal aspects, that is, a risk-benefit analysis should be performed... 

Thus, the risk analysis must be well prepared, meaning that the scope of the analysis must be clearly defined data must be available and evaluated, to define the safe process conditions and the critical limits. Then, and only then, the systematic search for process deviations from the safe conditions can be started. The identified deviations lead to the definition of scenarios, which can be assessed in terms of severity and probability of occurrence. This work can advantageously be summarized in a risk profile, enhancing the major risks that are beyond the accepted limits. For these risks, reduction measures can then be defined. The residual risk, that is, the risk remaining after implementation of the measures, can be assessed as before and documented in a residual risk profile showing the progress of the analysis and the risk improvement. These steps are reviewed in the next sections. 

Once the safety data have been collected and documented, they must be evaluated with regard to the process conditions in terms of their significance for process safety. With the interpretation of the safety data, the process conditions that provide safe operation and the limits that should not be surpassed become clear. This defines the critical limits of the process, which are at the root of the search for deviations in the next step of the risk analysis. 

During the risk analysis, the measures must be accurately described to establish terms of reference, but no detailed engineering must be done during the analysis. It is also advisable to define a responsible person for the design and establishment of these measures. 

This is the last step of risk analysis. After having completed the risk analysis and defined the measures to reduce risks, a further risk assessment must be carried out to ensure risks are reduced to an accepted level. The risks cannot be completely eliminated risk zero does not exist, thus a residual risk remains. This is also because only identified risks were reduced by the planned measures. Thus, the residual risk has three components ... 

Thus, a rigorous and consciously performed risk analysis should reduce both of the last components. This is the responsibility of the risk analysis team. Hence, it becomes obvious that risk analysis is a creative task that must anticipate events, which may occur in the future and has the objective of defining means for their avoidance. This may also be seen in opposition to laws that react on events from the past Therefore, it is a demanding task oriented to the future, which requires excellent engineering skills. 

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