Abstract:
The failure mode and effect analysis (FMEA)
employing the risk priority numbers (RPN) have been used
extensively for identifying and prioritizing failure modes
with a view of mitigating their impact on equipment fail-
ure. However, in its traditional form, the prioritization
approach through the RPN lacks the objectivity required
for robust risk assessment, more so, where maintenance
data is available, which could enhance such objectivity.
This paper extends a quantitative approach for prioritizing
failure modes and component failures in facilities, and
more specifically, leverages on maintenance data often
recorded in such facilities. To enhance the objectivity of
the risk prioritization process, the proposed approach
integrates three objective measures—the cost of failure,
failure occurrence rate and percentage downtime effects of
equipment failure. The integrated measures are demon-
strated as more robust for prioritizing risks as opposed to
ordinal indices as the case in the conventional FMEA
approach. Using historical maintenance records, a three-
step ranking approach is proposed for prioritizing critical
failure modes in a thermal power plant where a case study
is discussed. Moreover, the study compares the results
derived from the prioritization approach with that derived
utilizing the conventional RPN method. The comparative
study demonstrates the added value of a more objective and
quantitative prioritization approach for maintenance deci-
sion support. Ultimately, the critical failure modes are
evaluated using a decision scheme to allocate appropriate
maintenance strategies as the final step of risk assessment
(i.e. risk treatment). The proposed approach is viewed as
generalizable, intuitive and offering insights to the main-
tenance practitioners.
