Hazard analysis definitions

Procedural controls, process controls, 98-99 Process controls, 96-100 active controls, 98 inherently safer approach, 97 mitigation techniques, 99 passive controls, 97-98 procedural controls, 98-99 safe operating limits, 99-100 Process definition, documentation, 102-104 Process design, documentation, 105 Process hazard analysis (PHA) risk assessment, 92-93 screening methods, 63 Process risk management decisions, documentation, 105-106... 

Identify major hazards and inherent process risks (toxic, explosive). Systematic quantitative analysis of hazards and definition of measures to reduce them. 

This chapter identifies and consolidates existing user safety and health requirements found in DOE and Federal chemical-related safety and health regulations and National Standards that address hazard analysis of activities involving chemicals (see definition) and chemical products (see definition). 

In order to save time, the leader and scribe may preselect the nodes. In a very simple process, this decision may make sense. Generally, however, the team as a whole should decide on the nodes, partly because all hazards analysis decisions are team decisions, and partly because the definition and selection of a node often is affected by the discussions that have taken place with regard to earlier nodes. Also, if the leader and scribe are from outside the local organization, they may not fully understand all the process parameters that could affect node selection. 

The outcome of the detailed evaluation process is a specific recommendation (or set of recommendations). It is important to clearly distinguish between problem definition and solution development, in the same way as a hazards analysis needs to distinguish between findings and recommendations. Statements such as We propose to increase the reactor temperature, so we need to install a high temperature alarm should be broken down into ... 

Although system architectural features (e.g., redundancy, monitoring and partitioning) are used to help prove the safety objectives set in the Functional Hazard Analysis (see Table 3.3), it is practically impossible to guarantee the correctness and completeness of requirements definition or design implementation. 

Integral part of the risk analysis of a critical system is identification and assessment of hazards that significantly contribute to risk (Rausand Hoyland 2004). The hazard analysis generates data required in the next stage of analysis, which lead to description of risk scenarios, definition of safety functions, evaluation of actual risk levels and required risk reduction. Then the technical specification of safety-related functions to be realized by the system architectures considered to select most justified one. 

The job safety analysis (JSA) [also referred to as the job hazard analysis (JHA)], which is a more simplified form of task analysis, has been a longstanding tool for task and function analysis. JSA has been available and utilized in general industry for many years by the industrial safety community. However, many practitioners do not understand or are simply unfamiliar with the connection between the JSA and the system safety tasks of hazard identification and analysis. It has even been suggested by some in the profession that the JSA itself is a type of oversimplified system safety analysis and, if performed earlier in the job development phase, could be used as the basis of a preliminary hazard analysis for a specific task or set of tasks. However, because JSA is often (if improperly) used to analyze a function only after it has been implemented, much of the data is not factored into the system safety process. The primary purpose of the JSA is to uncover inherent or potential hazards that may be encountered in the work environment. This basic definition is not unlike that previously discussed regarding the various system safety analyses. The primary difference between the two is subtle but important and is found in the end-use purpose of the JSA. Once the job or task is completed, the JSA is usually used as an effective tool for training and orienting the new employee into the work environment. The JSA presents a verbal picture of a specific job. 

Preliminary hazard analysis is one of the early steps in a system safety project. This step also creates assessments of risks associated with each hazard. This step defines possible corrections for the risks. The product of this step is a tabular inventory of hazards for the system under consideration. The PHA fits best during early system stages, such as concept definition, design, and development. 

Step 3. Conducting a Hazard Analysis The actual plan begins by defining the problems that may require emergency responses. The problem definitions result from a hazard analysis and identifying hazardous materials that could affect the community. There are many sources for information about hazardous materials. Included are local companies, users of materials, transportation organizations and companies, and waste handlers and disposers. For each hazardous material, analysts must determine the hazards and quantities present or potentially present in the community. The planning team must know the potential distribution media (air, water, sod, vehicles, rad, etc.) and how each potentially impacts community s residents. 

Challenger accident, the solid-rocket boosters could be considered a subsystem. When the hot gases broke through the O-ring, a component of the subsystem, a total system breakdown began as a cascade effect that ultimately destroyed the orbiter. This analysis should be started no later than the definition phase in the system life cycle and continue until the beginning of the system production phase. Analysis techniques include Fault Hazard Analysis (FHA) and Fault Tree Analysis (FTA), discussed in more detail in the next section (Roland and Moriarty, 1990). 

It is worth noting again that developing job-specific behaviors is very similar to performing a job safety analysis (JSA) or job hazard analysis (JHA). JHAs and JSAs, however, are not normally written as operational definitions of behavior. It is suggested that organizations upgrade their JSAs to behavioral standards (Krause, 1997, p. 185). 

Conformational transition rates can be obtained from computer simulations by simple counting, hazard analysis, or monitoring the decay of conformational correlation functions [39, 40]. The definition of a transition is somewhat arbitrary and different investigators have made different choices. One could... 

Recent developments take the risk assessment subject to a higher level within the practice of safety. By formalizing the hazard analysis and risk assessment process, a better appreciation of the significance of individual risks is achieved. As risks levels are categorized and prioritized, more intelligent decisions can be made with respect to their elimination or reduction. For the hazard analysis and risk assessment process, it is necessary to arrive at definitions of hazards, hazards analyses, risks, and risk assessments. 

System Structure Analysis. After the identification of subsystems to be examined and the definition of undcsired events within the context of preliminary hazard analysis, events which lead to incidents are investigated. These event sequences can be represented as logic structure in a block diagram, a flow diagram, a fault tree, or a decision table. In the presentation which follows (Table 4.9.). a decision table was used. It contains, column by column, the combinations of system states which lead to the undesired event. The presentation permits qualitative identification of weak points in the system. In general, for example, the probability of a system state will decline with the growing number of failed components. The logic structure presentation could form the basis for further quantitative analyses. 

Definition of hazard, risk discussions on likelihood, consequence risk — register, matrix, ranking. Consequence ranking, preliminary hazard analysis tolerance point—ALARP refreshing on mathematics, fault tolerance, plant ageing, and basic functional safety fail safe operations in plants. 

Scope and boundary definition in accordance with system demand description. This is very important in the sense that without this the entire hazard analysis process could be a huge one and effective control will be a serious problem. Description shall include but not be limited to ... 

A system is a part of the universe within a certain domain in space and time. What is an environment Outside the frontier of the system is the environment [1], Here, system shall have an identity, that is, deterministic. There shall be an external boundary to the system. An external boundary is determined by what aspect of system performance is of concern. This is stated here because for quantitative hazard analysis, boundary definition is extremely important. Also, the interface part needs to be considered (See Fig. V/3.0-l). The process definition for qualitative risk analysis is Qualitative Risk Analysis assesses the priority of identified risks using their probability of occurring, the corresponding impact [...] as well as other factors such as the time frame and risk tolerance [..On the contrary, quantitative risk analysis (QRA) as per DNV is Typically, a QRA can be defined as the formal and systematic approach of identifying potentially hazardous events, estimating the likelihood and consequences of those events, and expressing the results as risk to people, the environment or the husiness. ... 

The scope definition section requires the definition of the boundary of the process and equipment under control being assessed, together with its control system. Since in the majority of cases the input to LOPA is taken from preliminary hazard analysis or HAZOP, the scope is more or less otherwise developed from previous analysis. It is necessary to ensure that equipment under control and its environment are sufficiently understood along with scope and boundary including interface before detailed assessment commences. 

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