FMEA/FMECA failure cause

Often too much reliance is placed on the FMEA/FMECA, while ignoring threats that can arise from outside the system (e.g. common cause failures, human error, multiple failures, etc.). 

Detection is related to causes of failure and controls, as shown in Fig. IV/2.1-1. Thus there are two ways to look at it preventive and detection control. In prevention, with the help of existing controls, failure modes are prevented, whereas the other way detects the failure and takes corrective action before it reaches the customer (see Fig. IV/2.2.1-1). FMEA/FMECA identifies the method by which occurrence of failures/failure modes is detected by the operating personnel. Audio... 

Possible combinations of independent, dependent, and simultaneous hazardous events, including failures identified in the FMEA/FMECA technique, that can cause hazards to the system or personnel. Eailures of controls and safety devices should be considered. 

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. 

Failure is the loss of the ability of an item to provide its required function. FMEA is a logical process for identification of failure modes of the elements of a system with focus on causes of failures and the failure effects. FMECA is an extension of FMEA, where quantitative estimations of the likelihood and the severity of each failure mode... 

Failure Mode and Effects Analysis (FEMA)—FEMA is a tabulation of facility equipment items, their potential failure modes, and the effects of these failures on the equipment or facility. Failure mode is simply a description of what caused the equipment to fail. The effect is the incident, consequence, or system response to the failure. It is usually depicted in tabular format and expresses failures in an annual estimation. A FEMA is not useful for identifying combinations of failures that can lead to incidents. It may be used in conjunction with other hazard identification techniques such as HAZOP for special investigations such as critical or complex instrumentation systems. There is also a Failure Modes, Effects, and Criticality Analysis (FMECA), which is a variation of FMEA that includes a quantitative estimate of the significance of the consequence of a failure mode. 

FMEA Failure mode and effect analysis the steps involving risk to measurement of the criticality of causes (frequency multiplied by severity) FMEA a simplified approach to the FMECA method which can be used in the absence of quemtified data processes... 

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