Failure analysis checklist

Several qualitative approaches can be used to identify hazardous reaction scenarios, including process hazard analysis, checklists, chemical interaction matrices, and an experience-based review. CCPS (1995a p. 176) describes nine hazard evaluation procedures that can be used to identify hazardous reaction scenarios-checklists, Dow fire and explosion indices, preliminary hazard analysis, what-if analysis, failure modes and effects analysis (FMEA), HAZOP study, fault tree analysis, human error analysis, and quantitative risk analysis. 

Qualitative techniques, consisting of techniques for primarily hazard identification, such as SLRA (screening level risk analysis), checklist, what-if, what-if/checklist, HAZDP (guide-word hazard and operabiUty study), and FMEiA (failure modes and effects analysis). 

In ANSI/ASSE Z590.3—2011, the Prevention through Design standard, Addendum G comments on only eight hazard analysis and risk assessment techniques, intentionally. They are Preliminary Hazard Analysis, What-If Analysis, Checklist Analysis, What-If Checklist Analysis, Hazard and Operability Analysis, Failure Mode and Effects Analysis, Fault Tree Analysis, and Management Oversight and Risk Tree (MORT). It was also said in Z590.3 that ... 

Functional safety assessment checklists, truth tables, failure analysis, common-cause (or common-mode) failure analysis, reliability block diagrams... 

This approach is based on six function testing and inspection tasks (i) scheduling (ii) preparation, execution, and restoration (iii) failure reporting (iv) failure analysis (v) implementation and (vi) validation and continuous improvements. Thus, the approach is composed of six tasks based on checklists and analytical methods, such as influence diagrams, cause-defense matrices, and operational sequence diagrams (OSD). The six tasks are described as follows [11] ... 

Process hazard analysis (e.g., what-if analysis, checklist analysis, hazard and operability study, failure mode and effects analysis)... 

Process Hazards Analysis. Analysis of processes for unrecogni2ed or inadequately controUed ha2ards (see Hazard analysis and risk assessment) is required by OSHA (36). The principal methods of analysis, in an approximate ascending order of intensity, are what-if checklist failure modes and effects ha2ard and operabiHty (HAZOP) and fault-tree analysis. Other complementary methods include human error prediction and cost/benefit analysis. The HAZOP method is the most popular as of 1995 because it can be used to identify ha2ards, pinpoint their causes and consequences, and disclose the need for protective systems. Fault-tree analysis is the method to be used if a quantitative evaluation of operational safety is needed to justify the implementation of process improvements. 

Although checklists are a useful way of transferring information about human-machine interaction to designers and engineers, they are not a standalone tool and they cannot provide a substitute for a systematic design process. The main concern with checklists is that they do not offer any guidance about the relative importance of various items that do not comply with the recommendations, and the likely consequences of a failure due to a noncompliance. To overcome such problems, checklists should be used in combination with other methods of task analysis or error analysis that can identify the complexities of a task, the relationships among various job components, and the required skills to perform the task. 

V Process hazard analysis (PHA) must be performed by a team of experts, including engineers, chemists, operators, industrial hygienists, and other appropriate and experienced specialists. The PHA needs to include a method that fits the complexity of the process, a hazards and operability (HAZOP) study for a complex process, and for less complex processes a less rigorous process, such as what-if scenarios, checklists, failure mode and effects analysis, or fault trees. 

The PHA procedure can be conducted using various methodologies. For example, the checklist analysis discussed earlier is an effective methodology. In addition, Pareto analysis, relative ranking, pre-removal risk assessment (PRRA), change analysis, failure mode and effects analysis (FMEA), fault tree analysis, event tree analysis, event and CF charting, PrHA, what-if analysis, and HAZOP can be used in conducting the PHA. 

This step is always performed. Using analysis tools and methods such as fault trees, causal factor charting, checklists, predeveloped trees, or alternative methodologies will help to identify the root causes of the failures. 

If there is no hypothesis for the event, use an inductive method to find potential scenarios. Inductive methods speculate a given fault or failure, then look forward in time to determine the probable outcome, that is, What would happen if... Inductive methods include using a Checklist or a Hazard and Operability Analysis (HAZOP). 

Methods for performing hazard analysis and risk assessment include safety review, checklists, Dow Fire and Explosion Index, what-if analysis, hazard and operability analysis (HAZOP), failure modes and effects analysis (FMEA), fault tree analysis, and event tree analysis. Other methods are also available, but those given are used most often. 

Since there are many potential causes of failure, it would be nice to have a checklist to make the analysis organized and somewhat standard. As a guidance, a pretty good checklist is given by the Guide for Pressure-Relieving and Depressuring Systems, better known as API Recommended Practice 521 (API RP 521) table 1 in Section 3 (Table 13.1). 

The above criteria form a sort of a checklist to be followed while formulating the failure hypotheses for a component. The criteria C1-C4 protect against omissions but cannot be solely used as a tool to identify valid failure hypotheses. Application of C1-C4 can force us to consider a large number of possible failure modes, disregarding their credibility. To provide for a more focused set of failure modes we apply additional criteria that provide for early rejection of incredible failure modes. Those that withstand this selection are passed to the subsequent analysis step. 

Identification can be as simple as asking what-iP questions at design reviews. It can also involve the use of a checklist outlining the normal process hazards associated with a specific piece of equipment. The major weakness of the latter approach is that items not on the checklist can easily be overlooked. The more formalized hazard-assessment techniques include, but are not limited to, hazard and operability study (HAZOP), fault-tree analysis (FTA), failure mode-and-effect analysis (FMEA), safety indexes, and safety audits. 

HAZOP and What-If reviews are two of the most common petrochemical industry qualitative methods used to conduct process hazard analyses. Up to 80% of a company s process hazard analyses may consist of HAZOP and What-If reviews with the remainder 20% from Checklist, Fault Tree Analysis, Event Tree, Failure Mode and Effects Analysis, etc. An experienced review team can use the analysis to generate possible deviations from design, construction, modification, and operating intent that define potential consequences. These consequences can then be prevented or mitigated by the application of the appropriate safeguards. 

At the scheduled meeting, the complete package of information is reviewed and discussed. This is the time the "What if " questions are asked, or the Checklist used. If a Failure Mode Effect analysis is used, this information also will have been provided and discussed. 

Identify hazardous chemicals from databases as discussed in Section 16.4.4 and from local legal regulations. Identify the potential for hazards from the checklist for reactivity (in Section 16.4.4) and from HAZOP-type studies or fault-tree analysis (Crowl and Louvar, 1990). In HAZOP studies, use checklist key words as triggers to systematically analyze the impact of changes to flow rate, temperature, pressure, composition, level, viscosity, heat transfer, reaction, and conditions and the potential for barrier failure and startup and shutdown to cause hazards. 

There are various types of analyses that are used for a process hazard analysis (PHA) of the equipment design and test procedures, including the effects of human error. Qualitative methods include checklists, What-If, and Hazard and Operability (HAZOP) studies. Quantitative methods include Event Trees, Fault Trees, and Failure Modes and Effect Analysis (FMEA). All of these methods require rigorous documentation and implementation to ensure that all potential safety problems are identified and the associated recommendations are addressed. The review should also consider what personal protective equipment (PPE) is needed to protect workers from injuries. 

ANALYSIS DOCUMENTATION. PrHA report documentation should include the PrHA worksheets, checklists, logic diagrams, human reliability analyses, and any other analysis made to better understand the scenarios. The PSM Rule requires that human factors that impact scenarios as cause or protection be expanded to analyze the basic cause of errors or response failures. For example, a cause may identify that an operator can turn the wrong valve to initiate an accident. The PSM Rule requires that basic causes also be identified. For example, valve is not labeled the operator has not been trained on the operation or the operator forgot the step. There may be more than one basic cause. (See also Section 3.2, paragraph on Human Factors.)... 

It is very clear from the complexity of the situations described in the case studies of the last two chapters, that simple factors of safety, load factors, partial factors or even notional probabilities of failure can cover only a small part of a total description of the safety of a structure. In this chapter we will try to draw some general conclusions from the incidents described as well as others not discussed in any detail in this book. The conclusions will be based upon the general classification of types of failure presented in Section 7.2. Subjective assessments of the truth and importance of the checklist of parameter statements within that classification are analysed using a simple numerical scale and also using fuzzy set theory. This leads us on to a tentative method for the analysis of the safety of a structure yet to be built. The method,however, has several disadvantages which can be overcome by the use of a model based on fuzzy logic. At the end of the chapte(, the discussion of the various possible measures of uncertainty is completed. 

What-lf Hazard Analysis. This hazard assessment method utilizes a series of questions focused on equipment, processes, materials, and operator capabilities and limitations, including possible operator failures, to determine that the system is designed to a level of acceptable risk. Users of the What-If method would identify possible unwanted energy releases or exposures to hazardous environments. Bulletin 135 contains procedures for use of a What-If checklist. For some hazards, a What-If checklist will be inadequate and other hazard analysis methods may be used. 

The team must use appropriate hazard analysis methodology and consult with those involved with the process operation and maintenance. Specified methods include what-if , checklist, what-ifVchecklist combination, failure modes and effect analysis, hazard and operability study, fault tree analysis, or an equivalent method. The team must identify process hazards review... 

Failure Mode and Effect Analysis (FMEA) - mostly used in the design stage of products, this checklist procedure not only identifies potential problems, but also assess their likelihood and the consequences of failure... 

A conprehensive product release process ensures that products are very mamre when released. Parallel to the comprehensive quality management process the safety process starts with general safety requirements which are checked for applicability and allocated to the project respectively. It continues with several tasks like performance of an Functional Hazard Assessment, production of an hardware RAM Modelling and Prediction Report and a Failure Modes, Effects and Criticality Analysis for a typical configuration and the use of the previously mentioned hazard checklist. Finally all issues of the product release checklist are to be fulfilled to get the official release. 

A management-risk analysis method would not only inform safety cases, it would also be complimentary to an organisation s audit function. For example, a checklist to inform audits could be made of processes or activities that are deemed particularly risky or that rely on assumptions in which there is limited confidence. In addition, the frequency or thoroughness of audits and the focus of safety assessments may also be increased for parts of a management system that are considered similarly risky, or whose failures could lead to particularly severe consequences. In these ways, both the efficiency and the effectiveness of audits and safety assessments could be improved. 

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