Page 477 - 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

This information is imperative for predicting medium- and long-term
maintenance requirements, projecting remaining service life, develop-
ing long-term maintenance and replacement strategies, planning future
usage, and determining the available reaction time to damage. There-
fore, CAS is in direct contrast to a short-term strategy of fixing serious
defects as they are found. CAS includes three basic steps[12;13]:

1. A facility is divided into its systems and subsystems, forming
a work breakdown structure (WBS).
2. Standards are developed to identify deficiencies that affect
each component in the WBS and the extent of the deficiencies.
3. Each component in a WBS is evaluated against the standard
or reference component.

CAS provides the maintenance managers the analytical informa-
tion needed to optimize financial resource allocation for repair, main-
tenance, and replacement of assets. Through a well-executed CAS
program, information will be available on the specific deficiencies of
a system or component, the extent and coverage of that deficiency,
and the urgency of repair. The following scenarios indicate a need for
CAS in corrosion control strategies:

• Assets are aging, with increasing corrosion risks.
• Assets are complex engineering systems, although they may
not always appear to be (for example, ordinary concrete is
actually a highly complex material).
• Assets fulfilling a similar purpose have variations in design
and operational histories.
• Existing asset information is incomplete and/or unreliable.
• Previous corrosion maintenance/repair work was performed
but poorly documented.
• Information on the condition of assets is not transferred
effectively from the field to management, leaving the decision
makers ill-informed.
• Maintenance costs are increasing, yet asset utilization is
decreasing.
• There is great variability in the condition of similar assets
from poor to excellent. The condition appears to depend on
local operating microenvironments but there is no knowledge
on where the next major problem will appear.
• The information for long-term planning is very limited or
nonexistent.
• Commitment within an organization to conduct long-term
strategies and plans for corrosion control is limited or lacking.