Most realize that damage due to corrosion of metals is costly - but what specifically is that cost and what is included in the total? A study completed in 2002 sponsored by the Federal Highway Administration (FHWA), the National Association of Corrosion Engineers (NACE International) and implemented by CC Technologies Laboratories (now part of DVN) addressed those questions.
The FHWA/NACE study evaluated costs of corrosion in (26) U.S. industry and government sectors known to have corrosion problems and extrapolated those costs to all sectors of the economy. The two-year study concluded that the estimated direct cost of corrosion for the entire nation was $276 billion in 1998 or 3.1% of the Gross Domestic Product (GDP) for that year. The authors also conservatively estimated that the indirect costs were about equal to the direct costs. Thus the total cost of corrosion failures in the U.S. in 1998 was estimated to be $552 billion or about 6% of the GDP.
Direct costs were defined as those specific burdens on the owners or operators of the given physical asset. These included use of more expensive alloys to better resist corrosion, use of other forms of corrosion control, or managerial costs such as additional inspection, maintenance and repair/replacement plus the value of loss of productive manufacturing time or unavailability. The latter area is especially expensive in industries or other functions where 24/7 operation is essential or near 100% availability is critical to safety or national defense.
Indirect costs are those that the general public, i.e., non-owners of the asset, experience as a result of corrosion-induced failures. These costs are more difficult to assess but they may include such diverse areas as increased commuting/drive time (and thus loss of productive work time or time with family) as roads or bridge decks are being repaired or replaced due to rebar corrosion, environmental damage or hazardous fluid releases due to corrosion failures or increased consumer prices for a range products and services due to the need to resist corrosion.
The FWHA/NACE study results can be updated to current cost values when inflation based on the U.S. Consumer Price Index (CPI) is applied to the 1998 numbers. This is accomplished using the federal government's "U.S. Inflation Calculator" (at www.usinflationcalculator.com ) and related CPI values for 1998 and for 2013. The two CPI values, available at www.bls.gov/pub/special.requests/cpi/cpiai.txt, are 163 for 1998 and an average of 231.9 (through April) for 2013. The resulting current total cost (direct plus indirect) of corrosion failures for 2013 are thus determined to be approximately $785 billion.
It is important to note that while corrosion control will benefit from more R&D and better understanding of the various mechanisms and their control, very often major reductions in these costs can be accomplished by simply applying well established knowledge and methods. However, this requires more wide spread knowledge of the technology by all engineers and other decision makers and not just corrosion specialists.
Gerald O. Davis, PE, President and co-owner of DM&ME, has over 40 years experience in Materials Engineering and Business. Mr. Davis is a Forensic Expert in Materials Usage, Corrosion, Metallurgy, Mechanical Failure, & Root-Cause Failure Analysis. His recent background includes work as a corrosion researcher, senior engineer, and program manager for Battelle Memorial Institute, DNV, Inc., Henkels & McCoy, Inc., respectively and, since 2004, as president of DM&ME.
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