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Table 4. Estimated Market Shares for Substitute Fibers Replacing Compressed Asbestos Sheet Substitute Fiber Estimated Market Share Reference Aramid 30 Palmetto Packing 1986 Glass Fiber 25 Palmetto Packing 1986 Graphite 15 Union Carbide 1987 Ceramic 5 ICF l986a Cellulose 15 Palmetto Packing 1986 PTFE 10 ICF l986a -8-
Aramid gaskets are usually composed of 20 percent aramid fiber, by weight, and 60 to 65 percent fibers and fillers such as silica and clay. The remaining 20 to 25 percent is the binder which keeps the fibers in a matrix. Typical applications include off-highway equipment, diesel engines, and compressors. These applications require a very strong gasketing material that will withstand moderate temperatures (A.W. Chesterton 1982). Aramid gaskets as a substitute for asbestos sheet gaskets are used because of the fiber’s strength and high temperature resistance. Formulations also include mineral fillers and elastomeric binders. Aramid product costs 1.7 times as much as the asbestos product for some applications, resulting in gaskets that cost $9.72 per square yard. Industry officials project 30 percent of the total asbestos market will be captured by this substitute (ICF l986a, Palmetto Packing 1986). 2. Fibrous Glass Mixtures Fibrous glass is generally coated with a binder such as neoprene, TFE, or graphite in the manufacturing process to make gaskets. Glass fibers are relatively easy to handle and reduce the costs of product formulation. Fibrous glass gaskets are usually divided into two groups, “E” glass gaskets, and “S” glass gaskets, depending upon the type of glass fiber used in the formulation. “E”, glass is one of the more common glass fibers, and is occasionally manufactured into a gasketing which is used as a jacket around a plastic core of carbon or aramid fibers and other materials (OGJ 1986). “E” glass gaskets are suitable for general service applications where the operating temperature is below 1000°F. Above this temperature, the gasketing loses 50 percent of its tensile strength. The materials can be used with most fluids except strong acids and alkalies (A.W. Chesterton 1982). The second type of glass fiber, “S” glass, was developed by NASA and is recognized as the superior glass fiber in use today (OGJ 1986). This material -9- -
Page 1 and 2: XXVII. SHEET GASKETS A. Product Des
Page 3 and 4: Table 1. Fluid and Pressure Ranges
Page 5 and 6: $20.5 million in 1985, based on an
Page 7: Table 3. Substitutes for Asbestos S
Page 11 and 12: esistance. A wire insert is often a
Page 13 and 14: 6. Ceramic Fiber Mixtures Ceramic f
Page 15 and 16: REFERENCES Carborundum. 1986. Produ
Page 17 and 18: Bulk Square braád Rolled (over cor
Page 19 and 20: Table 1. Standards of Asbestos Yarn
Page 21 and 22: A. ‘I’ A. ‘-I PRESSURE ~ Movi
Page 23 and 24: Table 2. Operating Conditions and U
Page 25 and 26: Table 3. Production of Asbestos Pac
Page 27 and 28: een forced to replace the asbestos
Page 29 and 30: Table 4. Estimated Market Share for
Page 31 and 32: useful temperature limit of approxi
Page 33 and 34: 6. Other Substitute Fibers Other fi
Page 35 and 36: Table 6. Data Inputs for Asbestos R
Page 37 and 38: TSCA Section 8(a) submission. 1982.
Page 39 and 40: a viscosity control for waterproofi
Page 41 and 42: Table 1. Production of Asbestos Roo
Page 43 and 44: or talc. The additives ease grindin
Page 45 and 46: Table 2. Manufacturers of Cellulose
Page 47 and 48: Cellulose bodied roof coatings and
Page 49 and 50: equivalent basis, they are favored
Page 51 and 52: compounds. These formulations have,
Page 53 and 54: . Other Roof Coatings and Cements O
Page 55 and 56: Table 4. Data Inputs for Asbestos R
Page 57 and 58: ATTACHMENT B PROJECTED PRICES ANALY
Page 59:
ICF Incorporated. 1986 (July-Decemb
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