The Cost of Corrosion

Corrosion of metals cost the U.S. economy almost 300 billion per year at 1995 prices. Broader application of corrosion-resistant materials and the application of the best corrosion-related technical practices could reduce approximately one-third of these costs. These estimates result from a recent update by Battelle scientists of an ear-her study reported in 1978. The initial work, based upon an elaborate model of more than 130 economic sectors, had revealed that metalhc corrosion cost the United States 82 billion in 1975, or 4.9 percent of its GNP. It was also foimd that 60 percent of that cost was unavoidable. The remaining 33 bilhon (40 percent) was said to be avoidable and incurred by failure to use the best practices then known. 

In the original Battelle study, almost 40 percent of 1975 metallic corrosion costs were attributed to the production, use, and maintenance of motor vehicles. No other sector accoimted for as much as 4 percent of the total, and most sectors contributed less than 1 percent. The 1995 Battelle study indicated that the motor vehicles sector probably had made the greatest anticorrosion effort of any single industry. Advances have been made in the use of stainless steels, coated metals, and more protective finishes. Moreover, several substitutions of materials made primarily for reasons of weight reduction have also reduced corrosion. Also, the panel estimated that 15 percent of previously unavoidable corrosion costs can be reclassified as avoidable. The industry is estimated to have eliminated some 35 percent of its avoidable corrosion by its improved practices. Table I.l summarizes the costs attributed to metallic corrosion in the United States in these two studies. 

TABLE 1.1 Costs Attributed to Metallic Corrosion in the United States 

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The economic importance of rusting can scarcely be overestimated. Although precision is impossible, it is likely that the cost of corrosion is over 1% of the world s economy. 

The figure of 4 7o of GNP is probably reasonable for other developed countries, although differences may exist because the mix of industries is not the same—see the data in Table 9.1. Differences in climate, and the level of industrial pollution etc. can be very significant. The cost of corrosion in terms of GNP may well be higher in some less developed countries, although it is probably less in the least developed countries. 

When a metallic material of construction (MOC) is selected to contain, transport, and/or to be exposed to a specific chemical, unless we make a correct, viable, and optimum MOC selection, the hfe expectancy of those facihties, in a given chemical exposure, can be very short. For the inexperienced in this field, the direct capital costs of the MOC facet of the production of chemicals, the funds spent to maintain these facilities (sometimes several times those initial capital costs), the indirect costs that are associated with outages and loss of production, off-quahty product (because of equipment and facility maintenance) as well as from contamination of the product, etc., are many times not even considered, let alone used as one of the major criteria in the selection of that MOC as well as its costs to keep the plant running, i.e., a much overlooked cost figure in the CPI. To emphasize the magnitude and overall economic nature of the direct and indirect (nonproductive) costs/losses that result from the action of corrosion of our metallic facihties, equipment, and the infrastructures, within the United States, Congress has mandated that a survey of the costs of corrosion in the United States be conducted periodically. 

Baines, D. (1984) Chem. Engr., London No. 161 (July) 24. Glass reinforced plastics in the process industries. Bendall, K. and Guha, P. (1990) Process Industry Journal (Mar.) 31. Balancing the cost of corrosion resistance. 

The cost of corrosion damage can be large. One company in the Southwest spent over a million dollars on paint maintenance costs alone. Robert Mears surmised that... 

Metallic corrosion is a major engineering and economic problem. In North America and Europe, the cost of corrosion is on the order of 3-4% of gross domestic product (GDP). Not surprisingly, there is an abundance of good books on this topic.1 15 This chapter focuses mainly on corrosion of metals in aqueous systems, as this is the most commonly encountered problem and is a natural corollary of the material of the two preceding chapters. 

Metallic corrosion, although seemingly innocuous, indeed affects many sectors of a nation s economy. The National Bureau of Standards (NBS) in collaboration with Battelle Columbus Laboratory (BCL) studied the costs of corrosion in USA using the input/output model.7 Some elements of the costs of corrosion used in the model are... 

The cost of corrosion in other countries in the world is given in Table 1.4. 

D.R. McIntyre, Evaluation of the Cost of Corrosion-Control Methods, Chemical Engineering, April 1982, 127-132. 

Bendall, K. and Guha, P. (1990) Process Industry Journal (March) 31. Balancing the cost of corrosion resistance. 

Before discussing the results of the NBS-BCL corrosion and fracture studies, it is well to look at the results for the costs of corrosion of other and less complete studies for the U.S. and other countries. The results, taken from Refs. and... 

Corrosion (of metals) and fracture (of all materials) each amounts to approximately of the GNP in the U.S., and probably in other industrialized nations. Wear, the other degradative process of capital equipment, has not been discussed as yet. However, from the results presented in Ref. 15 and 16, it can be concluded that the application of tribology could save 1.1 to 1.5 of the GNP in the U.S. in 1971. From the definition used (16) this represents costs somewhere between avoidable costs and total costs, the reference "World being essentially the World IV of the NBS fracture study. While the subject merits further study, the results indicate that the costs of wear are roughly comparable to the costs of corrosion and fracture, but perhaps somewhat less. It can thus be concluded that the overall costs of these three degradative processes amount to somewhat more than 10 of the GNP. Costs associated with the other degradative process mentioned earlier are not known to this author, but clearly will raise this total. 

Meredith, R. E. The Cost of Corrosion and the Need for Research. Report to Office of Energy Systems, U.S. Department of Energy,... 

Beyond the costs of corrosion are the safety concerns. Human lives depend upon the safe operation of a range of metallic structures that are prone to the ravages of corrosion. Obvious examples are airplanes made from high-strength aluminum alloys and pressure vessels that could endanger many lives if ruptured. 

Studies on the cost of corrosion have drawn the attention of several countries, namely, the United States of America, the United Kingdom, Japan, Australia, Kuwait, Germany, Finland, Sweden, India, and China. The studies have ranged... 

The review of prior studies on the costs of corrosion has provided useful background and direction for further study. The studies addressed only the extent and magnitude of possible savings, not the means of realizing such savings. 

The review of the prior studies on the costs of corrosion is useful in the current and future studies. Both technical content and methods have been reviewed. Some specific areas where the previous studies have proven useful are ... 

Gathering background and reference information on the costs of corrosion and corrosion control methods. 

The costs of corrosion have been a subject of interest to many researchers and the methods used for data collection and economic analysis are reviewed in chronological... 

The committee summarized the findings as follows We conservatively estimate the cost of corrosion in the United Kingdom as 1365 million per annum which amounts to 3.5% of the GNP in the year 1970. We believe that a saving of approximately 310 million per annum could be achieved with better use of current knowledge and techniques. The estimated savings represent approximately 20-25% of the total national corrosion costs. 

The Hoar report determined the cost of corrosion for the industry sectors of the economy (2). The cost of corrosion for each industry sector was added together to arrive at the cost of corrosion for the entire UK economy. The report identified the sources for the cost of corrosion by sectors of the economy. It evaluated and summarized the direct expenditures (costs to owner/operator) in each economic sector. Indirect costs (costs for user) were not included in the studies. 

Factors bearing on costs The UK Committee and industrial organization listed 16 factors that could lower the cost of corrosion. The factors prioritized by combined judgment of experts in the field are as follows ... 

Japan conducted a survey of the cost of corrosion to its economy in 1977 through the Committee on Corrosion and Protection (3). The committee was chaired by G. Okamoto and was organized by the Japan Society of Corrosion Engineering and the Japan Association of Corrosion Control. The studies were supported by the Ministry of International Trade and Industry. 

I Total Costs The survey determined that the annual cost of corrosion to Japan was approximately 2.5 trillion yen (US 9.2 billion) in 1974. Estimated GNP of Japan was 1.36 trillion for the year 1974 and the cost of corrosion was about 1-2% of Japan s GNP. This study included only direct costs. The total costs would be much higher if indirect costs were included. 

Method to Estimate Costs of Corrosion Japan s committee estimated the cost of corrosion by ... 

The Uhlig methodology was used to determine the corrosion costs on the basis of the cost of corrosion protection products and services such as coatings, inhibitors, corrosion-resistant materials, and cathode protection. The total cost amounted to 2.5 trillion yen (US 9.2 billion). Paint and protective coatings accounted for nearly US 6.1 billion. Surface treatments and corrosion-resistant materials accounted for nearly two-thirds of the corrosion costs. Surface treatments and corrosion-resistant materials amounted to nearly one quarter and one-tenth of the costs, respectively. The remaining 5% of the cost was assigned to other corrosion control methods (Table 2.4). 

The Hoar methodology was applied to determine the cost of corrosion by specific industry sector. The results are summarized in Table 2.5. 

Even after accounting for the differences between Uhlig and Hoar approaches, the difference of about 400 billion yen remains to be accounted, which may be ascribed to the difficulties and uncertainties in the estimation of the costs of corrosion. 

In response to a congressional directive, the National Bureau of Standards (NBS, now the National Institute of Standards and Technology (NIST)) studied the cost of corrosion in the United States. The analysis required in the study was contracted to Battelle Columbus Laboratories (BCL). The results of this work were published as NBS reports (4-6). 

Method to Estimate Corrosion Costs The Battelle-NBS study (4-6) used an input/output methodology to estimate the cost of corrosion for the U.S. economy. 

The U.S. economy was divided into 130 industrial sectors in the input model. For each industrial sector, experts were asked to estimate the costs of corrosion prevention such as the use of coatings, inhibitors, and the cost of repair and replacement of corroded parts. 

Sector Costs on the Basis of the Input-Output Model The Battelle-NBS study used the lO model to estimate the cost of corrosion to sectors. In addition to the 10 model, the report focused on four areas federal government, personally owned automobiles, the electric power industry and loss of energy and materials. 

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