The analysis of failure data in the presence of critical and degraded failures
Reported failures are often classified into severityclasses, e.g., as critical or degraded. The critical failures correspond to loss of function(s) and are those of main concern. The rate of critical failures is usually estimated by the number of observed critical failures divided by the exposure ti...
Saved in:
Published in | Reliability engineering & system safety Vol. 58; no. 2; pp. 97 - 107 |
---|---|
Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
Elsevier Ltd
01.11.1997
|
Online Access | Get full text |
Cover
Loading…
Summary: | Reported failures are often classified into
severityclasses, e.g., as
critical or
degraded. The critical failures correspond to loss of function(s) and are those of main concern. The rate of critical failures is usually estimated by the number of observed critical failures divided by the exposure time, thus ignoring the observed degraded failures. In the present paper failure data are analyzed, applying an alternative estimate for the critical failure rate, also taking the number of observed
degraded failures into account. The model includes two alternative failure
mechanisms, one being of the shock type, immediately leading to a critical failure, another resulting in a gradual deterioration, leading to a
degraded failure before the
critical failure occurs. Failure data on safety valves from the OREDA (Offshore REliability DAta) data base are analyzed using this model. The estimate for the critical failure rate is obtained and compared with the standard estimate. |
---|---|
ISSN: | 0951-8320 1879-0836 |
DOI: | 10.1016/S0951-8320(96)00084-1 |