Document pB24J1L4vj7OOM1z2yBN3kBkB

FILENAME: Flintkote (FLK) DATE: 1978 Aug DOC#: FLK030 DOCUMENT DESCRIPTION: EPA Report United States Env: ~ ^ntal Protection Ag r v -*` Office of Tcx:c Substancp Washington DC ) E ?A 560 '6-78-005 August 1978 Toxic Substances ' Chemical Market Input/Output Analysis of Selected Chemical Substances to Assess Sources of Environmental Contamination Task 111Asbestos CHEMICAL MARKET INPUT/OUTPUT ANALYSIS OF SELECTED CHEMICAL SUBSTANCES TO ASSESS SOURCES OF ENVIRONMENTAL CONTAMINATION: TASK III.. ASBESTOS William M. Meylan Philip H. Howard Sheldon S. Lande Arnold Hanchett Contract No. 68-01-3224 - task III SRC No. L1273-08 August 1978 Project Officer - Joseph J. Breen Prepared for: U.S. Office of Toxic Substances Environmental Protection Agency Washington, D.C. 20460 NOTICE This report has been' reviewed by the Office of Toxic Substances, EPA, and approved for publication. Approval does not signify that the contents necessarily reflect the views and policies of the Environmental Protection Agency, nor does mention of trade names or commercial products constitute endorsement or recommendation for use. (; ) ii 11.0 ASBESTOS FLOORING ( Asbestos floor tiles are produced in the United States for use in comaer- cial applications, offices, and homes. The shortest grades of asbestos fibers are used in vinyl and asphalt floor tile manufacture. The asbestos fibers are used to impart strength, dimensional stability, and resistance to the cold. At present, vinyl asbestos floor tile (VAT) accounts for most of the asbestos used in this category, with asphalt tile serving some special applications and appli cations >vhere darker shades are permissible. 11.1 Use Quantity, Shipment Values, and Industrial Firms U.S. demand- for asbestos in flooring products has ranged from 113 to 218 thousand short tons annually during the 1967 to 1976 period; in 1976, 11.' thousand short tons of asbestos were used in flooring products (Clifton, 1977) Only the chrysotile variety of asbestos is used. According to the 1976 figures, about 15.62 of the total U.S. market for asbestos was consumed in the product::, of flooring. This is the third largest use of asbestos fiber, ranking behind roofing and A-C pipe. Table 11.1 lists the shipment values and quantities of asbestos floor tile as given by the Census Bureau. In 1967, asphalt-asbestos floor tile made up about 15% of the asbestos floor tile market compared to vinyl-asbestos tile' 85%; however, by 1972 the market for asphalt-asbestos tile had fallen to compr.t only 5% of the asbestos floor tile values. Competitive pressures from alturr.^:.* flooring products is the primary reason for the decline of the asphalt-asbestos market. In fact, in recent years the vinyl-asbestos floor tile market has bee: less than spectacular as a result of strong eomoetition from carp etin g and 182 r^ r^ 183 Table 11.1 Shipment Values and Quant1Ties of Asbestos Floor Products (ll.S. Bureau of the Census 1972) : SIC Product Code Product 32925 11 32926 -- 32926 13 32926 15 32926 00 Asphalt Floor Tile Vinyl Asbestos Floor Tile Plain backed Adhesive backed Vinyl asbestos, n.s.k. Total. Product Shipments, Including interplant transfer 1972 . Quantity ! (million sq yd) Value (million $) 1967 Quantity (million sq yd) j Value (million $) 9.8 -- 129.4 -- -- 'I 9.1 199.3 151.3 ~>j 48.0 - J 28.0 143.5 143.5 25.0 153.5 153.5 J ! linoleum (Igve, 1974). ) The market for all types of vinyl (PVC) flooring, which includes vinyl-asbestos and all other kinds of vinyl floorings, declined froo about 50% of all basic floor coverings in 1961 to only 30% in 1971. As a point of reference, about 67% of all vinyl flooring in 1969 was of the vinyl-asbestos type (Frey, 1976). The phenomenal growth in the use of tufted carpets in both residential and commercial buildings is the main reason for the decline.' Hov- ever, vinyl flooring is now believed to have firmly established its market share according to 1971 figures (Frey, 1976). This implies that significant increases in the use of asbestos for flooring are not likely to occur in the foreseeable future. Table 11.2 lists the major manufacturers of asbestos-flooring products along with their respective locations and estimated 1975 sales. The 1976 floor tile consumption of 113 thousand tons of asbestos would produce roughly 105 million sq. yds. of asbestos flooring. 11.2 Manufacturing Process Technology Floor tile manufacture involves proprietary production line processes highly developed by the individual manufacturers. Equipment layout, process description and compound formulations are held very confidential because the industry is highly competitive (Daly et al., 1976). The asbestos content of the tile ranges from 8-30% by weight (Carte*.. 1974) and usually comprises very short fibers, grades 5 and 7 (Table 4.10, p. 4 6 ) . Each square foot of tile may contain upwards of 0.13 pounds asbestos * fibers (Daly et al., 1976). PVC resin serves as the binder and makes up 15-;; of the tile; chemical stabilizers usually represent about 1%. Limestone ar.d other fillers make up 55-70% of the weight. Pigment content usually averasw about 5%, but may vary widely depending upon the materials required to procure the desired color (Carton, 1974). 184 ! ) Table 11.2. Major U.S. Manufacturers of Asbestos i'i 'ring ''ur.ufacturer Plant Location * Estimated 1975 Sales c f Asbestos Flooring (millions of dollars) American Biltrite Rubber - LaMirada, Cal. Armstrong Cork Co. South Gate, Cal. *") Kankakee, 111. C Jackson, Miss. ( Lancaster, Pa. linRote Los Angeles, Cal. Chicago, 111. New Orleans, La. A: Corp. Long Beach, Cal. Joliet, 111. Vails Gate, N.Y. Houston, Tex. j.;r.:ile Floors Brooklyn, N.Y. TOTAL 5.7 36.5 20.3 14.4 6.6 14.4 15.0 17.4 8.7 29.5 168.5 Econooic Information Systems, Inc.; SRC Es tima tes yjnetary vales are in 1975 dollars. titiae i 185 j i Most floor tile manufactured today uses a vinyl resin, although sone asphalt tile is still being produced. The manufacturing processes are very similar and the water pollution control aspects are almost identical for the two forms of tile (Carton, 1974). Figure 11.1 shows the general manufacturing process. The ingredients are weighed and mixed dry. Liquid constituents, if required, are then added and thoroughly blended into the batch. After mixing, the batch is heated to about 150 degrees C and fed into a mill where it is joined with the remainder of a previous batch for continuous processing through the rest of the manufacturing operation. The mill consists of a series of hoc rollers that squeeze the mass of raw tile material down to the desired thickne* During the milling operation, surface decoration in the form of small colored chips of tile (mottle) are sprinkled onto the surface of the raw tile sheet and pressed in to become a part of the sheet. Some tile has a surface decoration embossed 'and inked into the tile surface during the rolling operation. This may be done before or after cooling. After milling, the tile passes through calenders until it reaches the required thickness and is ready for cooling. Tile cooling is accomplished in many ways and a given tile plant may use or., or several methods. Water contact c o d i n g in which the tile passes through t water bath or is sprayed with water is used by some planes. Others ue non contact cooling in which the rollers are filled with water. In some pier.:.., the sheet of tile passes through a refrigeration unit where cold air is blowr. onto the tile surface. After cooling, the tile is waxed, stamped inco squar, inspected, and packaged. Trimmings and rejected tile squares are chopped up and reused (Carton, 1974).' 186 Figure 11.1. Asbestos Floor Tile Manufacturing Operations (Carton, 1974) 11.3 Quantities of Asbestos Released to the Environment from Manufacture In the manufactur of asbestos vinyl tile, water is used only for cooling purposes. Both contact and non-contact cooling are usually employed. Water does not come into contact with the tile until it has been heated and rolled into its final form. In this stage it is completely inert to water (Carton,'1974). Therefore, wastewaters will contain little, if any, asbestos fibers. Stewart et al. (1976) found asbestos concentrations of less than 10^-10^ fibers per liter in wastewaters from Armstrong's Kankakee, 111. floor tile plant. Additionally, trimmings and rejected tile squares are chopped up and reused. Therefore, there are only minor amounts of manufacturing scraps dis posed to landfills. The only major source of asbestos release to the environment from floor tile manufacture is from baghouses, both air emissions and collection dumpings. There are no direct data available by which to make direct estimatio of these baghouse collections and emissions; however, the manufacturing process in this regard, is similar to that of the mastic asphalt mix for roofing. As developed in section 9.3.4, it was estimated that perhaps 0.2% of production volumes, for the mastic roofing mix, were collected by baghouses. Applying this figure to floor tiles, about 227 tons of asbestos fibers are annuaixy collected in baghouses. The Siebert et a l . (1976) baghouse efficiency of S?*-- indicates that 0.0227 tons of fibers are emitted into the atmosphere annuallyThe alternate method for predicting baghouse emissions given in section 7.3.1 would estimate emissions to be on the order of one ton. ) 11-4 Release of Asbestos from AShestos Flooring Use By far, the major release of asbestos to the environment from, flooring use occurs at replacement time when old flooring is removed and disposed to landfills. Service time for asbestos floorings depends upon the severity of use; accordingly, service life may vary from 10 to 30 years. Therefore, a healthy percentage of production is intended as flooring replacements. This percentage may be in the neighborhood of 40-60%. During the service' iife of an asbestos floor various forces act upon it and the result may be a release of free asbestos fibers. Forces such as walking, scrapping, cleaning, and machine scrubbing may be sufficient to break down the vinyl matrix and allow asbestos to escape. However, there has been no study conducted to determine if, or how much, asbestos may be released during use or cleaning. Such a study may be desirable. The following hypothetical example of asbestos fiber release from flooring use is intended to illustrate a potential magnitude of emissions which can be theoretically calculated from various assumptions. Daly et_ al. (1976) have reported chat each sq. ft. of tile may contain up to 0.13 lb asbestos; therefore, it is assumed that each sq. ft. of tile contains 0.13 lb asbestos. Additionally, the following assumptions are made; (!) the average service-iife o: an asbestos floor is 20 years; (2) approximately 10% of the flooring is worn avay during the service-life by use and cleaning; and (3) about 1% of the "wornavay-flooring" becomes airborne. It is visualized that wear on the floor will sot be even over the entire surface because sections may be covered may be covered by equipment, desks, etc.; however, it is assumed that sections of the iloor which are worn away disperse airborne fibers uniformly throughout the 189 y. i, -- , entire room. .Therefore, the following computation can be made which gives the amount of asbestos emitted per day, on average, from each square foot of asbes tos tile: 0 . 1 3 i h-f-ftf. X gear X 0.01 airborne X .453.6 . ft 20 yrs lb 0,003 g S E S - S .1 * * 3.6 x 1 0 6 -- "3 yr/ft yr/ft . s.2 x 303*8 fitted day/ft It is now assumed that each square foot of tile is installed 10 feet below the 3 ceiling; therefore, each square foot is topped by 10 ft of air. Assuming 2 ventilation design requires 15 air changes per hour, then 1 ft of tile will be 3 3 topped by approximately 3600 ft of air each day, which is equivalent to 102 s of air each day. Therefore, assuming uniform mixing of air and airborne asbes tos fibers, the average asbestos concentration of the air is raised daily by: emitted . ?0 S S _ . g x 10-> SSL 102 m m cm 3 Using,the conversion factor of 10 asbestos fibers per nar.ogram, the *-- cc.v- centration of 80 ng/m3 is equivalent to 0.08 fibers/cm3 . The above assumptions predict that the average asbestos concentration of the air above an asbestos floor can theoretically be raised by daily use of the floor by 0.08 fibers/c.-; . This 0.08 fiber figure is based upon the estimation that 1 nanogram equals *0 fibers which is, in turn, based upon electron microscopy count. Rohl jj. L* 190 ) ) `'.9*3) have indicated that the number of fibers visible by electron microscopy ii perhaps one hundred fold as compared to an optical microscopy method which -.jncs only fibers of 5 um in length or longer. The optical microscopy method counting fibers 5 pm or longer is used for determining compliance with OSHA regulations. On this basis, the concentration of fibers emitted by asbestos locring, if measured by the OSHA optical microscopy method, 3 .:1c would be 0.0008 fibers/cm . in the above exam- It should be noted that the example given above is only supposition, rcr.itoring is required to determine actual concentrations, if any. Under practi cal conditions, it would be unlikely that all fibers released by use would rccoae airborne. A large percentage would probably be incorporated into water .-.i for cleaning purposes which would then be released into wastewaters. This the reason for assuming that only 17 of worn material would become airborne. 11.5 Alternative Products to Asbestos Flooring Asbestos flooring competes principally with carpeting, linoleum, and * vinyl flooring. At present, about 95% of all asbestos flooring is vinyl- . bestos. As indicated earlier, in section 10.1, all types of vinyl floor " votings make up about 30% of the flooring market; and, in 1969, about two- t-.iris of the vinyl market was asbestos-vinyl. Therefore, in the late 1960's Jr~ perhaps, early 19.70's, vinyl-asbestos flooring covered about 20% of the :::al flooring market. However, this 20% figure has decreased and is decreasing crcvhat due to the popularity of various types of non-asbestos-vinyl flooring. recent years,, coated types of vinyl flooring (plastisol-coated felts) have 5ive- strongly into flooring markets of all cost levels at the expense of vinyllibestos tile (Frey, 1976). 191 \ V) ) The newer types of vinyl flooring are produced as roll goods and typically have a felt or other backing (e.g., asbestos felt coated with styrene- butadiene latex). This backing receives a foamed plastisol coating, the surface of which is decorated with a pattern by rotogravure printing or so-called chem ical embossing, and then is covered with a clear plastisol wear layer (Frey, 19/6). Y\ Apart from reinforcing the final product, the asbestos fibers perform a function in giving the polymer sheets "wet-strength" during the manufacturing process (Green and Pye, 1976). Alternative fibers to asbestos do not have all of the performance characteristics unique to asbestos. As far as asbestos flooring is concerned, the alternative fibers mentioned in other sections or this report are potentially useable, but the final product is somewhat in fe ric v and more expensive. .Whether such a product is marketable at this time is doubL ful. ( ) 192