BS PD IEC/TR 63039:2016

BS PD IEC/TR 63039:2016 provides guidance on probabilistic risk analysis (hereafter referred to as riskanalysis) for the systems composed of electrotechnical items and is applicable (but notlimited) to all electrotechnical industries where risk analyses are performed.This document deals with the following topics from the perspective of risk analysis:

• defining the essential terms and concepts;
• specifying the types of events;
• classifying the occurrences of events;
• describing the usage of modified symbols and methods of graphical representation forETA, FTA and Markov techniques for applying those modified techniques complementarilyto the complex systems;
• suggesting ways to handle the event frequency/rate of complex systems;
• suggesting ways to estimate the event frequency/rate based on risk monitoring;
• providing illustrative and practical examples.

The relationship between the events covered by this document and associated risks aredescribed in Table 1. Risk is defined as the effect of uncertainty on objectives (see 3.1.1).The uncertainty is here assumed to be composed of two elements: the epistemic and aleatory.The epistemic is categorised into the known and unknown, and the effect of the aleatory isclassified into the controlled and the uncontrolled, respectively. Therefore, the risk associatedwith the known event of which impact is controlled is the controlled risk, and the riskassociated with the known event of which impact is not controlled is the uncontrolled risk.Favourable meta-risk is of an unknown event of which impact can be casually controlled evenif this unknown event appears, and unfavourable meta-risk is of an unknown event of whichimpact cannot be controlled.For example, the risks resulting from random hardware failures of electrotechnical items willbe categorised into the controlled or uncontrolled risks, while the risks owing to software bugscould be classified into the favourable or unfavourable meta-risks. This document covers thecontrolled and uncontrolled risks resulting from the events that can be assumed to occurrandomly and independently of time.Cross References:IEC 60050-192IEC 61703ISO Guide 73:2009ISO 9000:2015 ISO 31000:2009IEC/ISO 31010:2009IEC 60050-192:2015IEC 60300-3-1:2003IEC 61703:2001IEC 61078:2006IEC 60812:2006IEC 61508IEC 61882:2016IEC 61508IEC 61025:2006IEC 61165:2006IEC 62502:2010IEC 61508-6ISO/IEC Guide 51:2014IEC 61508-1:1998IEC 61508-4:2010IEC 61508-4:1998IEC 61511IEC 61508-1:2010IEC 61508-5