DANSK DSF/PREN IEC 61025 PDF

Fault tree analysis (FTA) is used to identify and analyse combinations of events, conditions and factors that cause or can potentially cause or contribute to the occurrence of a defined undesirable outcome, referred to as the "top event". This document describes the (FTA) technique and provides guidance on its application. This includes: – definition and description of commonly used terms and symbols; – purpose, applications and limitations of FTs; – a description of basic concepts and principles; – a description of the steps involved in scoping, constructing and developing the FT; – guidance on performing qualitative and quantitative analysis of the FT, including discussion of requirements and limitations of the associated mathematical models; – identification of basic items that should be included when documenting and reporting the FTA; – methods for performing FTA when some of the commonly used assumptions are not satisfied (e.g., non-coherent FTs, dynamic FTs); – example applications in support of the above; – procedures for calculating dependability measures (unavailability, failure frequency and unreliability) for different types of system, with constant or time dependent probabilities or with non-repaired or repaired items)