FMECA Criticality Analysis

We previously encountered failure modes and effects (FMEA) and failure modes effects and criticality analysis (FMECA) as qualitative methods for accident analysis. These tabular methods for reliability analysis may be made quantitative by associating failure rates with the parts in a systems model to estimate the system reliability. FMEA/FMECA may be applied in design or operational phases (ANSI/IEEE Std 352-1975, MIL-STD-1543 and MIL-STD-1629A). Typical headings in the F.Mld. A identify the system and component under analysis, failure modes, the ef fect i>f failure, an estimale of how critical apart is, the estimated probability of the failure, mitigaturs and IHissihiy die support systems. The style and contents of a FMEA are flexible and depend upon the. ilitcLiives of the analyst. 

FMECA - Failure Modes, Effects and Criticality Analysis. 

All of these factors determine the stress experienced by the workers and the extent to which operational errors will be recovered before disastrous consequences have ensued. In this context, hazard identification techniques, such as hazard and operability studies (HAZOP), failure modes and effects and criticality analysis (FMECA), fault trees, and others are useful in making the process environment more forgiving. 

FMECA Failure Modes and Effects of Criticality Analysis... 

Failure modes effects criticality analysis (FMECA)... 

Perhaps the key to detcrnuiiiiig die consequences of an accident is die study of accident mininiization/prcvendon. This topic receives extensive treatment in Section 17.2. The estimation (not calculadon) of consequences is treated in Section 17.3, which is followed by evacuation procedures (Section 17.4). The next section e.xaniiiies failure modes, effects and critical analysis (FMECA). The cluipter concludes with vulnerability analysis (Section 17.6) and event tree analysis (Section 17.7). 

Failure mode, effects, and criticality analysis (FMECA) This method tabulates a list of equipment in the process along with all the possible failure modes for each item. The effect of a particular failure is considered with respect to the process. 

In the FMECA procedure [2,3,256], an exhaustive list of the equipment is first made. Every item on the list is then reviewed for possible ways in which it can fail (the failure modes are open, closed, leaks, plugged, on, off, etc.). The effects of each failure mode are then recorded and a criticality ranking of every item of equipment is calculated. A limitation of this procedure is that combinations of failures which may cause an incident are not really identified. Failure modes and effects analysis (FMEA) is the same procedure without the criticality analysis. 

From those techniques given in Table 1 my personal preference is for failure mode, effects, and criticality analysis (FMECA). This technique can be applied to both equipment and facilities and can be used to methodically break down the analysis of a complex process into a series of manageable steps. It is a powerful tool for summarizing the important modes of failure, the factors that may cause these failures, and their likely effects. It also incorporates the degree of severity of the consequences, their respective probabilities of occurrence, and their detectability. It must be stressed, however, that the outcome of the risk assessment process should be independent of the tool used and must be able to address all of the risks associated with the instrument that is being assessed. 

The next section e. aniines failure m es, effects and critical analysis (FMECA). The cliapter concludes with xaihierability analysis (Section 17.6) and event tree analysis (Section 17.7). 

The principles utilized in these expert systems are general purpose and based on failure modes, effects and critically analysis, FMECA, a sub-process of reliability centred maintenance, RCM, and statistical process control, SPC. The analysis paradigm includes ... 

Figure 13.8. a) Comparison of safety risk assessment and risk management and b) general principles of FMECA approaches (failure mode, effects and criticality analysis) applied to materials in contact with food... 

FMEA is a prospective hazard analysis technique which is widely used in many domains and increasingly in the service industries [4]. The methodology has its origins in military systems and the aerospace industry in the 1960s. Subsequently the automotive and chemical engineering sectors adopted the tool - indeed in some regulated industries application of the technique is now mandatory. The objective of the tool is to identify what in a product can fail, how it can fail, whether failure can be detected and the impact that will have. The technique can be supplanented with a Criticality Analysis which takes into account the severity of the failure. When this extension is employed, the technique is often called FMECA. 

In this chapter we explore the Failure Modes Effects Analysis (FMEA) and the Failure Modes Effects Criticality Analysis (FMECA) which, as the name suggests, simply is an extension of the FMEA.i This chapter will use the acronym EMEA and highlight those instances where is extended to include EMECA. 

Borgovini, Pemberton, R., Ross, S., 1993. Failure Mode, Effects and Criticality Analysis (FMECA). Reliability Analysis Center. 

BS5760, 1991. Reliability of Systems, Equipment and Components Part 5 Guide to Failure Modes, Effects and Criticality Analysis (FMEA and FMECA). British Standards Institute. 

HSE assessments have a long tradition within the oil-and gas industry. These assessments use a wide range of methodologies, from the strict quantitative methods such as QRA (Quantitative Risk Analysis) and FMECA (Failure Mode Effect and Criticality Analysis) to the more qualitative methods such as HAZOP (HAZard OPerability analysis). Most methods combine qualitative and quantitative data and approaches. For example, an FMECA basically uses generic failure data, expert judgments are likewise important. 

Results are the product of the analysis of (reliability) models. There are different types of results, such a system model (FT/RBD) results (including cut-sets, probabilities, and rates), FMECA criticality results, and prediction standard results. 

In most organizations that have a reliability effort separate from the safety or system safety effort, an FMEA is considered a reliability tool. The safety version is called a failure modes and effects criticality analysis (FMECA). 

Used originally as a reliability tool, the FMEA is now often used to identify and prioritize safety problems associated with hardware failures. This is usually done by including a risk assessment code (RAC) in the analysis (Table 14-1). (Note When a RAC or other method of quantifying is used to identify critical safety items, some organizations and analysts call the technique failure mode and effects criticality analysis [FMECA].)... 

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