Critical single failure points

Any and all critical single failure points (CSFPs) that were identified during the FMEA should also be provided in this section. The specific failure mode and its effect(s) should be listed and discussed here. The discussion should detail any acceptance or rejection rational to justify the recommended actions, which are provided later in the report. 

Critical Hem A single failure point and/or a redundant element in a life- or mission-essential application where ... 

Critical and potentially critical faults to common components (such as faults to CPU/RAM/ROM) typically inhibit nearly the entire processing of data and are therefore more far reaching than a fault of a single output point. Failure modes that carry a high failure probability have to be detected with more confidence. Furthermore, the detectability of failure modes should be taken into account. 

The primary advantages of an FMEA are that critical single-point failures can be identified and that reliability can be evaluated in detail. It may identify areas or parts with poor reliability and allow early and cost-effective design changes. If it is performed functionally early in the project, it may reduce the amount of more detailed FMEA needed. 

At face value, on the basis of the information provided, the complexity of the system described above appears to offer numerous opportunities for critical single-point failures. Therefore, the analyst should begin the FMEA process by first attempting to identify any and all nonpassive components and/or subassemblies that, depending on the type or mode of failure, could possibly have an undesirable effect. Table 10.1 lists each identified subsystem and related components in the overhead bridge crane system used in this example. Once such a list has been developed, the analyst will find it much easier to evaluate each subsystem or component, its possible failure mode(s), and the resultant effect(s) of any failure. Also, subsequent FMEAs may typically be performed during the operational phase of the crane life... 

We can guess how you ll respond, 007. You ll point to your unbroken streak of more than forty years of successfully defeating megalomaniacs and evil international conspiracies, and ask why we want to hx something that isn t broken. We concede you have a point really, how critical can these flaws be when they haven t resulted in a single failure in so long ... 

Fault tree methods were used to analyze this complex facility to reduce the required assay points and to ensure full coverage of the facility by the double-contingency principle. Tliat principle states that defense against a criticality accident must incorporate sufficient barriers so that no single failure can by itself produce the accident. 

These studies may also point out locations or items of equipment that are critical or single point failures for the entire facility. Where such points are identified special emphasis should be to ensure that events leading up to such circumstances are prevented or eliminated. 

Heat transfer systems are normally provided to utilize available process heat, to economize heat for distillation purposes or to preheat fuel supplies before usage. They are generally considered a secondary process support system to the main production process, however they may be so critical to the process that they might be considered a single point failure if not adequately designed. 

---