Page 134 - Challenges in Corrosion Costs Causes Consequences and Control(2015)

112 CORROSION COSTS

was made on the basis of the general knowledge of the types of capital, their materials
of construction, and the severity of corrosion in service.
The discussion in B.C.L. stated that although the ranges of replacement lives and
changes from World I and World II or World III did not reflect actual service lives,
they did represent the magnitude of the effects of corrosion.
Because of the lack of quantitative data for replacement lives and the effect of
corrosion on replacement lives, it was recognized that estimates of costs associated
with this element have a greater degree of uncertainty than that of other elements.
Another factor of importance with respect to the corrosion costs is the disruption
cost of corrosion. When a structural system corrodes, the costs consequences are the
sum or all of: (i) repairs; (ii) replacement; (iii) disruption to third parties dependent
on that system.
Thus, if a bridge corrodes, there will be costs of repair or replacement. In addi-
tion, there may be disruption costs to the users of the bridge as a consequence of
reduced opportunities of use. Similarly, if a high pressure gas pipeline fails because
of corrosion, the disruption costs to a third party incurred as a result of diminished
or halted gas supplies would far outweigh the immediate incurred costs of repair and
replacement of the gas pipeline. It is known that disruption costs to third parties can
exceed by a factor of 10 times the direct costs of repair and replacement. If the direct
costs are of the order of $10 million, which may be considered as reasonable for the
gas pipeline case, the total costs including disruption costs are therefore likely to be
large. If the cause of the corrosion failure had been avoidable because of the avail-
able existing information, then the disruption costs incurred by the community would
have been avoidable.
In such cases, the third parties in question have little or no control over the use
of suitable corrosion control measures. Thus, in such cases where the savings from
corrosion prevention measures accrue to different persons or bodies from those who
would have to bear the costs of the corrosion prevention measures, then the govern-
ment alone can tax such beneficiaries for the overall benefit of the community.
Another specialized cost of relevance occurs when design codes require excessive
expenditure on measures to protect against corrosion because of an expected low
level of capability for anticorrosion maintenance. Thus, for example, for a construc-
tion project, if it is incorrectly assumed that the capability for suitable anticorrosion
maintenance is inadequate such that unnecessary overspecifications for corrosion
protection measures are selected, then the costs of the construction project would
be greater than necessary. If, under this context, adequate capabilities for anticorro-
sion maintenance had in fact existed, then the extra costs incurred would have been
avoidable.
In Australia, unnecessary overspecification of corrosion protection measures
occurs because of concern over sufficient long-term anticorrosion maintenance
because of a lack of awareness of the extent of likely corrosion effects.
The costs incurred unnecessarily either by an industrial organization or by the
community could be probably reduced by an improvement in the available informa-
tion dissemination process for corrosion prevention measures.