AS NZS IEC 60812 pdf download

AS NZS IEC 60812 pdf download.Failure modes and efects analysis (FMEA and FMECA)
1 Scope
This document explains how failure modes and effects analysis (FMEA), including the failure modes, effects and criticality analysis (FMECA) variant, is planned, performed, documented and maintained. The purpose of failure modes and effects analysis (FMEA) is to establish how items or processes might fail to perform their function so that any required treatments could be identified. An FMEA provides a systematic method for identifying modes of failure together with their effects on the item or process, both locally and globally. It may also include identifying the causes of failure modes. Failure modes can be prioritized to support decisions about treatment. Where the ranking of criticality involves at least the severity of consequences, and often other measures of importance, the analysis is known as failure modes, effects and criticality analysis (FMECA). This document is applicable to hardware, software, processes including human action, and their interfaces, in any combination. An FMEA can be used in a safety analysis, for regulatory and other purposes, but this being a generic standard, does not give specific guidance for safety applications.
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions For the purpose of this document, the terms and definitions given in IEC 60050-1 92 and the following apply. ISO and IEC maintain terminological databases for use in standardization at the following addresses: • IEC Electropedia: available at http://www.electropedia.org/ • ISO Online browsing platform: available at http://www.iso.org/obp 3.1.1 failure mode DEPRECATED: fault mode manner in which failure occurs Note 1 to entry: A failure mode may be determined by the function lost or other state transition that occurred.Note 2 to entry: Examples of hardware failure modes might be for a valve, “does not open”, or for an engine, “does not start”. Note 3 to entry: A human failure mode is determined by the function lost as a result of human action, whether committed or omitted. [SOURCE: IEC 60050-1 92:201 5, 1 92-03-1 7, modified — Note 1 has been modified, Note 2 and Note 3 have been added.] 3.1.2 failure effect consequence of a failure, within or beyond the boundary of the failed item Note 1 to entry: For some analyses, it may be necessary to consider individual failure modes and their effects. Note 2 to entry: Failure effect also covers the consequence of a failure, within or beyond the boundary of the failed process. [SOURCE: IEC 60050-1 92:201 5, 1 92-03-08, modified — Note 2 has been added.] 3.1.3 system combination of interacting elements organized to achieve one or more stated purposes Note 1 to entry: A system is sometimes considered as a product or as the services it provides. Note 2 to entry: In practice, the interpretation of its meaning is frequently clarified by the use of an associative noun, e.g., aircraft system. Alternatively, the word “system” is substituted simply by a context-dependent synonym, e.g., aircraft, though this potentially obscures a system principles perspective. [SOURCE: ISO/IEC/IEEE 1 5288:201 5, 4.1 .46, modified — Note 3 has been deleted.] 3.1 .4 item subject being considered Note 1 to entry: The item may be an individual part, component, device, functional unit, equipment, subsystem, or system. Note 2 to entry: The item may consist of hardware, software, people or any combination thereof. Note 3 to entry: The item is often comprised of elements that may each be individually considered. Note 4 to entry: IEC 60050-1 91 :1 990 (now withdrawn; replaced by IEC 60050-1 92:201 5) identified the term “entity” as an English synonym, which is not true for all applications.3.1 .8 scenario possible sequence of specified conditions under which the system, item or process functions are performed Note 1 to entry: Conditions may include activities or factors outside the defined item or process boundaries under study which may affect the performance of the item or process. Note 2 to entry: Physical conditions include all environmental factors such as temperature, humidity, light levels, shock, contamination, radiation levels. Note 3 to entry: Organizational conditions include factors such as staffing levels, physical/psychological stresses. 3.1 .9 failure cause set of circumstances that leads to failure Note 1 to entry: A failure cause may originate during specification, design, manufacture, installation, operation or maintenance of an item. Note 2 to entry: Examples of a failure cause may be contamination or inadequate lubrication which leads to the failure mode of bearing seizure. Note 3 to entry: Failure causes for a process might include human error mechanisms such as stimulus overload, memory failure, misunderstanding, false assumption. [SOURCE: IEC 60050-1 92:201 5, 1 92-03-1 1 , modified — Note 2 and Note 3 have been added.]