Using field feedback to estimate failure rates of safety-related systems
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- 作者：Florent Brissaud
- 关键词：Functional safety ; Safety-related systems ; Safety integrity ; Failure rate ; Field feedback ; Confidence intervals ; Detected failures ; Undetected failures ; PFDavg ; PFH ; Uncertainties
- 刊名：Reliability Engineering & System Safety
- 出版年：2017
- 出版时间：March 2017
- 年：2017
- 卷：159
- 期：Complete
- 页码：206-213
- 全文大小：348 K
- 卷排序：159
文摘
This paper deals with requirements of the IEC 61508 and IEC 61511 for using field feedback to estimate failure rates of safety-related systems. This paper presents how to estimate the failure rates from field feedback with confidence intervals for failures that are detected on-line. This paper presents how to estimate the failure rates from field feedback with confidence intervals for failures that are only revealed by proof tests. Examples show that for the same duration observed and the same number of failures observed, the estimated failure rates are basically higher for failures that are not detected on-line. An approach is proposed to use the estimated failure rates, with their uncertainties, for PFDavg and PFH assessment with upper confidence bounds.