United States Environmental Protection Agency Atmospheric Research and ~ A Exposure Assessment Laboratory ** Research Triangle Park NC 27711 '> Research and Development EPA/600/S3-89/040 Sept. 1989 &EPA Project Summary Characterization of Painted Surfaces in the United States from the Perspective of Potential Damage from Acidic Deposition Frederick W. Lipfert Data are reviewed on the types and applications of exterior paints used in the United States, from the perspective of potential damage by air pollution or acidic deposition. Residential buildings are the most economically important subset of the painted structures in the United States for painting costs; this ranking is likely to continue in the future. Painting over existing finishes is an important class of situations for re- search, because these conditions are more common and more difficult than virgin surfaces. Automobile finishes are a high-value use of paint, but the importance of acid deposition as a reason to repaint has not been established. Based on consumer surveys, the most important mode of paint failure is peeling, which accounts for about half of residential paint problems. Such problems, often occur witWn two to three years after painting;. Color changes (deterioration^ are next in importance, followed by chalking and erosion. Painting solely to change color or to aid in the resale of the property is of minor im- portance. Paints containing acid- sensitive components, especially oil- based glossy paints, may be found in today's retail market in all price ranges. Trends in paint usage and performance are generally supportive of (or not inconsistent with) the hypothesis that air pollution or acid rain may be having some adverse effects, although such data are by no means conclusive. The report recom- mends that selections of coatings and substrates for acid deposition research should include those com- binations that are widely used (latex over wood and over previous paint) and those that are sensitive to acid deposition (paints containing CaCO3; alkyd paint over steel). This Project Summary was devel- oped by EPA's Atmospheric Research and Exposure Assessment Laboratory, Research Triangle Park, NC, to an- nounce key findings of the research project that is fully documented in a separate report of the same title (see Project Report ordering information at back). fntroduction The National Acid Precipitation As- sessment Program (NAPAP) is responsi- ble for developing an understanding of the causes and effects of acidic dep- osition and for supporting decision- making on strategies to reduce acid dep- osition. Damage to structural materials is an important component, since the po- tential economic effects are large by vir- tue of the many structures exposed to acid deposition. The U.S. Environmental Protection Agency conducts research on ------- acid deposition damage to common con- struction materials, which include metals and painted surfaces. This research pro- vides guidance to the EPA research pro- gram on the mechanisms of damage to painted surfaces by acid deposition. Results and Discussion Data on the types and applications of exterior paints used in the United States were reviewed from the perspective of potential damage by air pollution or acidic deposition. Sources of information included data from the Census of Manu- factures on factory shipments of paint and allied products, statistics on the con- struction industry, data on consumer ex- penditures for residential repairs and alterations, and data from consumer sur- veys. This information shows that resi- dential buildings are the most eco- nomically important subset of the painted structures in the United States in terms of the costs of painting. The trends for new construction suggest that this rank- ing is likely to continue in the future. Table 1 presents preliminary data from the 1987 Census of Manufactures including shipment volumes (million gal- lons), factory values (million dollars), and m-place values which include estimated mark-ups and application labor (billion dollars), for outdoor paint applications. The annual in-place value of archi- tectural coatings is the highest category, followed by automotive (and other trans- portation equipment) paints. Maintenance paints, coil coatings, and traffic marking paints have substantially lower in-place values. The ranking of automotive fin- ishes must be discounted because of the high proportion of painting done to repair body damage, rather than because of Table 1. paint failure. Considering that a car may be ten or more years old by the time its refinished paint nears failure, extending the life of this paint would appear to have only marginal value relative to the re- maining value of the car. In addition, the importance of acid deposition as a cause of failure of automotive finishes has not been established. To gain insight into the uses of archi- tectural coatings, estimates were made for new construction, maintenance paint- ing, residential maintenance, and painting costs for various other types of struc- tures, based on published data. The es- timate for 1977 for residential painting, including the estimated value of do-it- yourself labor, was about $14 billion; by 1986, the estimated value had risen to about $20-30 billion. A 1977 input- output analysis of the US construction in- dustry estimated that $147 million was spent for maintenance painting costs to non-buildings and $1 1 billion for build- ings, which confirmed the relatively low rank of maintenance painting. In addition, the 1979 national expenditure for corro- sion protection of highway bridges was estimated at $130-160 million (which was about half of what was needed for adequate corrosion protection). Even after accounting for inflation, this cate- gory would not rank high in Table 1. However, the costs of bridge failure due to inadequate maintenance have not been considered; a 1984 estimate of spending on new and rehabilitated bridges excluding maintenance was about $5 billion. According to several consumer sur- veys, the most important mode of paint failure appears to be peeling and flaking, which, in its various manifestations, 7987 Paint Shipments and Associated Costs (exterior uses) accounts for about half of resident! paint problems. Figure 1 shows the di tribution of reasons for repainting give by respondents to a large mail survey 1975. This survey and others indica that such problems often occur within tv\ to three years after application, althouc manufacturers' test panel results seldoi identify peeling as an important mode < paint film failure. Based on several su veys, color changes (deterioratioi ranked next in importance. Althoug chalking and erosion have been ol served, their roles in decisions to repai are less apparent. Painting solely 1 change color or for resale of the proper appears to be of minor importance. In Figure 2, the 1975 consumer surve data have been segregated by Censt Region and according to whether or m there was prior peeling, which is seen I have a major influence on the percentag of respondents with new paint peelini The West region had the fewest peeliri problems. The probability of new peelin was increased by about a factor of thre if peeling had occurred previously, in s regions and for all types of paint. Th performance of a given type of paint wa dependent on the type of paint alread on the surface. In the absence of pr« vious peeling, latex paint applied over a oil-based paint was usually the mo; likely to peel, especially in the Nort Central or Northeast Regions. With pre vious peeling, the differences wer smaller but latex over latex was often th worst, suggesting that a deteriorated oi based paint surface may provide bette adhesion for repainting. Although the Northeast and Nort Central Regions rank highest in aci deposition and had the poorest pair Shipments Factory Cost In-place Value Classification million gal. million $ billion $ Architectural Coatings (exterior) Oil-based 80 $807 Water-based 123 944 Automotive Finishes new vehicles 73 1323 refimshing 44 904 Coil Coating 20 303 Industrial Main- tenance Paints 28 313 Traffic Marking Paints 19 95 $9.5 14.6 6.0 11.0 2.0 2.8 0.7 ------- Reasons for repainting 1975 mail survey Other (5.8%) Unpainted sfc (4.5%) Erosion (17.4%) To change color (8.6%) Dirt (9.9%) Mildew (2.8%) Orig. color chg (5.1%) Figure 1. Distribution of reasons for repainting (1975 mail survey). ------- 2 3 Years since repainting Figure 2. Percent of respondents with paint peeling or flaking (1975 mail survey). performance, there are many other re- gional environmental differences to con- sider besides acid deposition in evalu- ating differences in paint performance. For example, the North Central Region surfers more from weather extremes be- cause of its continental climate; also the winter ultraviolet radiation exposure of a vertical wall may be higher in more northern latitudes because of the low sun angles and reflection from snow covered ground surfaces. Nevertheless, the trends in paint usage and performance are generally supportive of (or at least not inconsistent with) the hypothesis that air pollution or acid rain may be manifesting some adverse effects, al- though such data are by no means conclusive. Not all paint formulations are expected to be sensitive to acid deposition. Previ- ously it was thought that the cheapest paints might be the most sensitive, but acid-sensitive paint components may be found in today's retail market m all price ranges, especially in oil-based glossy paints. These components include calcium carbonate (CaCOj), which is an inexpensive pigment used an extender (thickener), and zinc oxide (ZnO), which is used as a pigment and in conjunction with mildewcides. Recommendations The report recommends that selec lions of coatings and substrates for re search on the effects of acid depositioi should include both those combination that are most widely used (latex ove wood and over previous paint) and thosi that are sensitive to acid depositioi (paints containing CaCOa, alkyd pain over steel) Although both new construe tion and maintenance painting are eco nomically important, the more difficul conditions involved in painting over exist mg finishes make this an important clas: of situations for research. ------- Frederick W. Lipfert is with Brookhaven National Laboratory, Upton, NY 11973 J. W. Spence is the EPA Project Officer (see below). D. £ Renard is the Army Project Officer (see below). The complete report, entitled "Characterization of Painted Surfaces in the United States from the Perspective of Potential Damage from Acidic Deposition," (Order No. PB 89-181 2261 AS; Cost: $15.95, subject to change) will be available only from: National Technical Information Service 5285 Port Royal Road Springfield, VA 22161 Telephone: 703-487-4650 The EPA Project Officer can be contacted at: Atmospheric Research and Exposure Assessment Laboratory U.S. Environmental Protection Agency Research Triangle Park NC 27711 United States Center for Environmental Research Environmental Protection Information Agency Cincinnati OH 45268 Official Business Penalty for Private Use $300 EPA/600/S3-89/040 000085833 PS ------- |