Page 478 - Corrosion Engineering Principles and Practice

444 C h a p t e r 1 1 M a t e r i a l s S e l e c t i o n , Te s t i n g , a n d D e s i g n C o n s i d e r a t i o n s 445

11.3.3 Prioritization
Prioritizing maintenance activities is central to a methodical,
structured maintenance approach, in contrast to merely addressing
maintenance issues in a reactive, short-term mode. From the preceding
sections, it should be apparent that life-cycle asset management can
be used to develop a prioritization scheme that may then be employed
in a wider set of funding decisions, not only maintenance “go/no-
go” decisions. This entails the methodical evaluation of each
maintenance action against preestablished values and attributes such
as the key performance indicators described in Chap. 12.
Prioritization methodologies usually involve a numerical rating
system to ensure that the most important work receives the most
urgent attention. The criticality of equipment is an important element
of some rating systems. Such an unbiased, “unemotional” rating will
ensure that decisions are made for the best overall performance of an
engineering system, rather than overemphasizing the performance of
one of its parts.
Understanding the potential deterioration mechanisms that
may lead to equipment failures, their likelihood of occurrence, and
the potential consequences of the failures are key elements in a
risk conscious environment. The challenge faced by corrosion
engineers is to provide plant inspection personnel with a sound
technical understanding of potential deterioration mechanisms for
use in developing a practical and effective strategy to limit the risk
of potential equipment failures. In this way a corrosion engineer
can demonstrate the value of proactive corrosion control and use
the results of a prioritization analysis to influence the decision
makers and stakeholders in plant equipment integrity and
reliability [14].
Using risk assessment techniques such as those described in
Chap. 12 provides a sound basis for prioritizing and managing the
inspection program for plant equipment. With this approach, the risk
associated with the continued operation of each piece of plant
equipment is ranked by assessing the likelihood of its failure versus
the severity of failure consequences.

11.4 Materials Selection Road Map
A materials selection roadmap may be a good way to highlight the
major steps needed to assess whether a new design may be susceptible
to corrosion and how potential problems can be effectively mitigated
or eliminated. In critical situations where corrosion can lead to high
risk situations or serious safety concerns, it is usually preferable to
involve a professional or a team of professionals that have the
credentials to ensure that all aspects of the design are thoroughly
investigated.