Document dna1R7X97jme1N8XjgaqkjbV0

ASBESTOS TEXTILE ELECTRICAL INSULATIONS - PROPERTIES PRESENT AND FUTURE IMPORTANCE by Paul O. Nicodemus ANNUAL MEETING OF ASBESTOS TEXTILE INSTITUTE LAQ-WV. 10/93 0Q1847 Hotel Roosevelt. New York. N.Y. February 9, 1968 PLAINTIFF'S EXHIBIT WV-Oi3ffl*l 0003636 ASBESTOS TEXTILE ELECTRICAL IN5ULATI0N5 - PROPERTIES PRESENT AND FUTURE IMPORTANCE By P.O. Nicodeaus.........................................General Electric Company Wire and Cable Department Lowell, Massachusetts Presented at Annual Meeting of Asbestos Textile Institute Hotel Roosevelt New York, N.Y. February 9 1968 LAQ-WV 10/93 00184$ - C003637 ASBESTOS TEXTILE ELECTRICAL D15ULATT0NS - PROPERTIES PRESENT AND FUTURE IMPORTANCE Introduction There are many asbestifora (fiberous) minerals, but only one, chrysotile, is used for electrical insulation. This is a hydrated magnesium silicate which is most correctly expressed by the formula Mg, (oH)4SiaoJ . TSe hydroxyl (OH) ions are loosely bound to the remainder of the molecule and are easily liberated by heat as water, which amounts to approximately 1^ of the total weight of the asbestos. The asbestos fibers, which are actually elongated crystals, when properly opened, range in length from three-quarters of an inch downward. They are soft, silky and very flexible, which allows them to be processed into a variety of textiles and papers. Impurities in the crystal (fiber) structure and between the fibers are the rule, and not the exception. Of importance as electrical insulation are two types of impurities which occur between the fibers - magnetite and inorganic salts. ' Magnetite is a conductive iron oxide which occurs between and at the ends of the fibers in the form of spicules up to one twentieth of an inch in length. Although some of the magnetite is`removed from the asbestos during the fiber opening operation, when present in the finished product, it affects the dielectric properties of the fibers. The amount present in the final product is an important basis for classifying asbestos products used for electrical Insulations. 10/93001849 Inorganic salts which say be present, are metallic chlorides and carbonates. While not generally present in more than trace amounts, the fiber from certain mines do contain measureable quantities. As these salts are usually hydroscopic in high humidities, they take up enough water to lower the volume resistivity of asbestos products containing them. Specification for Asbestos Textiles Used for Electrical Insulating Purposes The basic specification for all asbestos textiles used for electrical insulating purposes is ASTM D'2100. 'Riis specification has been accepted as the asbestos textile standard by all electrical industry standardizing agencies such as, U.L., NEMA, IPCEA, AIEE and USASI, as well as all U.S. Government agencies. This specification classifies asbestos textiles on the basis of the amount of magnetite present (types) and amount of asbestos fiber (Grades) in the finished product. Qes The amount of magnetite present is measured by a magnetic analyzer and is expressed empirically as the magnetic rating (MR). The method is based on the principle of comparing the electromagnetic effect of an unknown sample of asbestos with the electromagnetic effect of a standard magnetite sample. The types are based on the following magnetic ratings: Maximum Magnetic Rating (MR) II .75 IV 2.00 VT u.oo 001850 -2- C003639 The method for determining the magnetic rating (MR) is given in ASTW y-v-od D 1119, Magnetic Rating of Asbestos Used for Electrical Purposes. . cr.l ficance of Asbestos Textile Types The type of asbestos roughly defines the electrical characteristics cf the textile. Generally, the higher the magnetic rating, the poorer the e.ert-rical properties of the material. The three types have the following intended application: Type II is intended for thin-wall primary wire insulation, as on magnet wire and pyrometer wire. Type IV is intended for heavy-wall primary insulation, as on asbestos fixture and appliance wire (UL Types AF and AI) and smokeless lead wire (Type A). Tyne VI is intended for use where the electrical properties of the asbestos textile is of minor importance, i.e., overall wire and cable wraps and braids or cable fillers. Grades The word "grade" as used in the asbestos textile Industry, indicates a system of classification based on the percentage of asbestos by weight, in the finished product. The standard grades with the percentage of asbestos content for each grade are listed in Thble I. Grade Underwriters A AA AAA AAAA . ' * ... Table'I Percentage of Asbestos by Weight - 80 to 85 exclusive *8flC5 to A90rt 90 to 95 95 to 99 99 to 100 inclusive 10/93 001851 3- - j nnn^Rin As the percentage of long fiber asbestos available is relatively low as compared with the short fiber, they are used in the higher grades of asbestos textiles to improve processability and to impart strength for the desired serviceability to the end product. As the grades decrease in asbestos content, the shorter the average length of asbestos fiber used. In order to process these short asbestos fibers into textiles, and give them strength, long organic fibers, usually cotton or rayon, known as carrier fibers, are blended with the asbestos fibers prior to processing. The grade of asbestos textile used is largely dependent on the service temperature required of the insulation. Lectrical Properties of Asbestos Insulations The effect of magnetite and mineral salts on the electrical properties of asbestos has been noted. Independent of these impurities, asbestos insulations have certain characteristics. The electrical properties of untreated asbestos insulations remain fairly constant regardless of temperature. The electrical' properties of treated asbestos insulations are somewhat dependent on the electrical and/or thermal characteristics of the treating compound. Treated or untreated asbestos textile , insulations in general, provide no better electrical insulations than an air space of equivalent thickness, and vary with the relative humidity of the air. LAQ-WV 10/93 001852 - J. - Vvrt - 0003641 V The volume resistivity of chrysotile fiber varies from about 500 megohm inches for good chrysotile, under dry conditions, to less than .01 megohm inch for poor chrysotile at 90^ relative humidity. * The dielectric strength of asbestos textile insulations will vary from about 75 volts per mil for Type II asbestos insulations thoroughly impregnated with wax-like materials, at low humidities, to less than 30 volts per mil for untreated and paint- or varnish-impregnated ^rpe IV insulations at 90 relative humidity. This is not true, however, of asbestos papers which, when saturated and surface coated with resins, give dielectric strength in excess of 300 volts per mil. Asbestos Insulation at Elevated Temperatures There are three inherent factors which have an important bearing upon the serviceability of asbestos insulations at elevated temperature. 1. The percentage of asbestos in the insulation. 2. The type of compound used to saturate and/or finish the insulation. 3. The design and construction of both the asbestos textile being used and _the insulating system. At temperatures above 250*F, in the presence of air, any organic-carrier fiber or reinforcing strands present, rapidly oxidizes to water and carbon * Testing of Asbestos Fibers Dr. J.W. Axelson, Johns-Manville Corp. Asbestos Textile Institute Meeting October 8, 1965 G LAQ-WV . 10/93 001853 5- ", <r. M- . C0C3<2 j.i: '`-lie this reduces the physical properties of the lower grades of as:* * .-.tile, it does not affect the electrical properties except during th- - -* *.ir.e the organic fibers are oxidizing or burning off. Tr.s higher the -r--ravure, the shorter is the time the electrical properties are affected. Th:: . c:`. true, however, if the asbestos is enclosed in a manner which will ?rev-.v complete oxidation of the organic fibers. In this case, the organic fif.eriorate to carbonaceous matter which decreases the electrical properties of .zsuiation proportional to the amount of organic fibers present, lowering bot.-. cr.e dielectric strength and volume resistivity. At temperatures above UOO*F, asbestos begins to loose water of hydration. This gradually lowers the physical properties, i.e., tensile strength and/or abrasion resistance, until a temperature of 900*F is reached, then the physical yroperties decrease rapidly. This loss of"water of hydration will vary somewhat with the origin and grade of fiber. The loss of water of hydration at various times and temperature fo- a Canadian chrysotile fiber, Grade 1*KL2, is given in Table II, compiled by JM Research, 19^1. After one hour at l800*F, all the water of crystallization is lost (approximately lU) and although the asbestos retains its fiberous form, the tensile strength and/or abrasion resistance approaches zero. In general, the higher the asbestos content, the higher the temperature the asbestos will withstand. 'Rie effect of long term heat aging on the physical properties at various temperatures is given in Table III. LAQ-WV 10/93 001854. -6 - %. "003543 NJ cc ccci Wco1 rcc* vcci cNcJ pp cc ccc scco 9oc9 NJ oo oOo' VooI ccc* * C om bined W a te r, by d ir e c t d e te rm in a tio n s 14.207. ** r* VI VI VI V) c V NJ P- o o o NJ Nl c vi o 0c0 NJ NJ oVI pNJ b sO Cl NJ VI NJ v VI NJ O 00 Cl NJ Cl SO ~p .PERCENTAGE WATER OF C R Y S TA LLIZA TIO N LOST BY HEATING CANADIAN CIIRYSOTILE ASBESTOS F IB E R , GRADE 4M 12, AT ' VARIOUS TEMPERATURES AND PERIODS VI VI VI VI -- r" NJ -- -- o o o 00 VO NJ N* Vl NJ VcJ NJ v p. p Cl VI pp 00 NJ 09 v0 Cl VI tCtl NJ p.. p- p. pp pp VI Vl VI VI NJ NJ NJ oo c VO VI 00 NJ v VI VI Vi _ s 0c0 b 09 NJ X* NO NJ NoJ NJ VI c . p pp p. VI VI VI Nl NJ NJ oo c 00 NJ VI VI O' VI Cl VI sO s VI NJ NJ v NNOl Col NJ O' VI pNpJ * VI NJ pm o o Cl Cl pm NJ CN NO VI sc s O' Cl pm 00 Vl V* pm p*p p^ H V V Nl Vl NJ pm p^ c 5 vNJi VI so NJ vi 00 NJ NJ VI V) s VI NJ bo Col CS 00 cn Cl o *1 -- pm VI pm NJ VI Vl NJ pm pm Cl 00 b VI * lo NJ Cl NJ 0* o NJ Ci VJ IO m > H pm 00 oZ pp pm VI VI 00 VI NJ NJ pp o Cl VI "co 00 VI VI NJ bo NJ iO CNJl pp <C o epcn p. VI pm V I pp VI Cl V I NJ pm pm o NJ nj Cl 00 pm Cl VNJI NJ NJ cX* v Vi VJ Nl Cl VI NJ X* v nj NJ pp V NJ o* pp VI c OB 00 0N0J O' b Cl NJ Cl s pp o pm VJ VI o 0x0- X* 00 Vpp pp o O' NJ pp pm o o AV*I V *s NJ NJ 0o0 s VI VI VI 00 VI sO NNJl p. VI VI pppp NJ s VI b VI VI c Vi NJ b VI pm NNJJ o s00 Q sQO pm C00l p V V00 NJ c* C l VI cNJ NJ p p c pm NJ VI o SO NJ Q 0 0 NJ VI OVI' *120 hours LAQ-WV 10/93 001855 0003644 ^ i' While it is impossible to give definite temperatures that the various grades of asbestos textiles will safely stand, Tbble IV, gives the limiting temperatures at which the various grades are generally used, based on retention of physical properties. Grade Temperature Underwriters A AA AAA AAAA I*50*F 550*F 600 *F 750*F 900*F Table IV Max. amount of organic reinforcing strand and/or carrier fiber allowed. 20* 15* 10* % 1% The electrical properties of untreated asbestos insulations at these temperatures remain fairly constant and saturated asbestos insulations are dependent on the electrical and thermal properties of the saturating compound used. Where physical properties are not important, as in low-voltage pyrometer vires Insulated with untreated, felted. Grade AAAA asbestos and quartz fiber braid, or with felted Grade AAAA asbestos saturated with special compounded metallic oxides combined with silicates or phosphates have been used for temperatures in excess of 1500*F. At these temperatures, the electrical properties of the asbestos is roughly equivalent to silicate clays. \ Other Properties of Asbestos Textiles 1. Radiation resistance Asbestos has exceptionally good resistance to nuclear radiation and will withstand an integrated epithermal neutron flux of approximately 10so NVT LAQ-WV. 10/93001858 -9- ''''03645 3DU*1STSH uoTS-aiqv JO/POT qqSusaas snsustf, JO uoTauaqaa zw - ,,-WV . ,0/93 001857 -8 - 0003646 >f:r; significant structural changes occur.** 2. Saturating Characteristics of Asbestos a) As the water of crystallization of asbestos exists as negative hydroxyl (0H`) ions, the fibers are wet most readily by water and polar solvents. Sat urating compounds should therefore be dissolved in water or in polar solvents. b) Paradoxically, the asbestos fibers carry a positive electrical charge, so pigaent particles in treating compounds should be negatively charged so they will cling to the asbestos fibers. c) The refractive index of asbestos fibers is 1.50 to 1.55* This is also the refractive index of the solids of many asbestos saturating varnishes. On thin-walled insulations, as asbestos-insulated magnet wire, this results in ^ransparent spots called "shiners" in the insulation where the conductor can be seen. Although these transparent spots are usually as thick as the remainder of the insulation and as good electrics1ly, visually it appears as though there is no insulation at these spots. For this reason, treating compounds used for thin-walled asbestos wire insulation, usually contain finely ground pigments to minimize the incidence of these "shiners". 3. Fungus Resistance While asbestos fibers are fungus resistant, cotton or rayon carrier fibers * and reinforcing strands, if present, are subject to fungus attack. Such insul ations may be made fungus resistant by incorporating a fungicide in treating ** Handbook of Asbestos Textiles Third Edition, page 33 LAQ-WV. 10/93001858 10 0003647 .-pounds or by the use of cellulose acetate, nylon or polyester carrier fibers ir.. ar.y of these plus glass as reinforcing strands. .---sent Uses of Asbestos Textiles as Electrical Insulation Wire and Cable Insulation 3y far the largest users of asbestos textiles for electrical insulation are the wire and cable manufacturers. This industry uses almost, if not all, of the asbestos lap produced; a large percentage of the roving (either as roving or as fillers) and large quantities of yarn. In addition to these textiles, the industry uses a large portion of the non-voven asbestos tapes. Lap is the asbestos textile used in the Largest poundage. This product, either alone or in combination with other insulating materials, is used as the insulation for a vide variety of vires and cables. The lap is carded onto vires up to approximately one inch in diameter from sample carding machines in the form of an asbestos felt. After vrapping around the vire, the felt may be treated vith a vide variety of compounds, depending on the end use of the vire. A list of the standard vires, vhich account for the large majority of lap being used, vith the insulating materials and treating compounds used, the maximum temperature and voltage ratings, and principle uses are given in 1 Table V. Tvo nonstandard vires are also Included in this table. 10/93 001859 11 <<** - b 1 ii 15 00 0 w* I 00 w u 0I J t. i0 s -- 0 s0 0i n 000 b 4 9 10 j b0 00 9 01 1 0y3 100 i* 5 c i--.J w 04 -- s !S 0 0-- :> ) bW 0 "8 !: i* n A i j u ___1 t t i J 0b :i i it. i 3o 111 i: l 1 00 b0 00 40 0 0 0 J 40 b si i 0 : i0 3ii:.J 13 n b1 0 40 * b0 11 0b 0 0 :s 13 00e 9 z3 2 9 90 3 2 b W 0 i 3 ub057 90 4: n1 44 3 I 00 S 0J0 5i 1? 1 4 140 00 -1 a i j c !* iil 3* >1! > i & ft ! Si ill Ii ! ! tu a, i ** . 8ft 1 a Ift' k o ok k k w2 e e \ 1 me Mj se 0 c " v iy i 9 e C T M ? t!o 10 0 10 to 0b j Jt S' 00 aI :70 S0SJi 41 & "2 * 2ab ! 0*? .J !i to .00 55 .* 00 b* Is*^ ' C 5 " I--00 ^00 -1 1i s* !i 05 Ji 0t *8 it000o t 1? 0 t 2c :S *i j 10 si * *r 4 *T .* cl 0t t >1 0 is ? 2 05 2S -1 1] * <* 111 iii --4*0U 5*-* 30=-- i-0Cbi-b3t-05 -9 n j0i:i :=i SI SS? 0 0 s 40 c00L 0 0! S0 * 4 s w ., LAQ-WV 10/93 00186a _ i ' >> -12- 00 u 0S W O0 4 Ti- 23S s*1i:= i0Cs0' bi3 --0 f009 i ili s * a" * 04 0-0VC :';sss -;-J2s9 04 1 _J 0 08 u0 4 J5 0S020l 0^0 V 0 3^ 3 0 0.s : 5*5 = 11 lii 1 0 * c 0 1 0 rj J^ ;e w. :4 bs;1 4 4* 00 0 ej! * * %" w I. r1. b j 0f i 3 - 9w3 ;V 5b Si i 1 -i * t + ^ ` C303S49 The wires produced in the largest amounts are the Type A7 and Type AI wires. These account for aloost as much lap usage as all of the other types of wire combined. Two or more conductor cords and cables are made from many of the above vires, often employing asbestos fillers and braids. A cord which uses a considerable amount of lap is the so called "heater cord" Type HPD. In this cord, untreated lap or roving is used over either a cured or uncured rubber insulation to physically separate the twisted single conductors and as a thermal insulation where the cord is joined to an electrically heated appliance. On single vires with diameters in excess of approximately one inch (usually referred to as cables) where lap cannot be used, asbestos roving and asbestos paper tapes are used, either alone or in combination with other insulating materials. The wires produced in the large sizes are usually Type AVA or Type AVL cables. Notice that for the standard wires, the highest temperature rating is 200*C, although low voltage thermocouple wires are used in excess of 800*C. Other Insulations Competing With Asbestos Now let us look at the insulating materials which have or are replacing asbestos wire and cable insulations. Most of these wires have Underwriters' Laboratories, Inc., approval, or are made to military specifications. The most important single wires and cables in this class are listed in Table VI. With the exception of the high-temperature aircraft, wires are arranged roughly in chronological order with respect to the dates when commercially introduced, beginning in the early 19^0*s. AQ-WV 10/93 001861 - 13 - Q0036SO WIRE AND CABLE REPFACING ASBESTQ6-IM5UIATF.D TtfPK r. 1ft lit in si? : i: ii ' -- 8 e i a w \1 rt ft gt .4 9 3[ 21 * 1 3 3 8 a.1 H H:a * -- >a a t:WeW:eW.: III it i: it a4 4f5t ia CC I` 1 ! i11 uuu 82 9 9 111!! uug uu 2 2! 22 ft i : i si i! Ej %! : w 8? I * e *4 * ]; 1 nb 1]1 1.5 3 9 XX l ll >1 u w 88b 87b 88b Wa W Wa 28 i 3 ii w w 3 8 W w *b w 13 : II I ii : 3= w =18"1s ?s i; i: ii a i sJ 8w wfc a 0 * . iu w * 3 18 * 8w - wo 2 a . 2 4. 8 w a ! 11 j i ii* * * i * i - 5 w i; LAQ-WV . 10/93001862 . :i i if. - : - `|S 5 15 - rS ,St s Wci.>:. J -. z s : ;i m ;r - Hi - -t: i v<ni * ^07n5 i The first material to challenge asbestos as a high-temperature insulating material was fiberjjlass. By the early 19^0's, continuous filament fiberglass yarns were used for the manufacture of thin cloth and tapes which could be used in place of asbestos cloth and tapes. It was next used as exterior braids over high-temperature wire and cable Insulations as asbestos or silicone rubber. In some cases, varnished glass braids replaced asbestos braids formerly used. Next cane fiberglass-insulated magnet wire. This double wrapped fiberglass insulation has almost completely replaced asbestos-insulated magnet wire. Although untreated fiberglass has almost no abrasion resistance, this deficiency has been overcome to a considerable extent by treating the fiber glass insulating materials with tough high-temperature varnishes. While not normally considered a high-temperature insulation, the next material to make an inroad on asbestos wire insulation was neoprene. This material was approved by Underwriters' Laboratories, Inc., as the insulation for a new type of "heater cord" designated as type HPN. This is a parallel cord, insulated with neoprene or Rypalon, which has and will continue to be used in place of the HPD cord containing asbestos. It has the same ratings as HPD cord, 90*C and 300 volts. It is now being used on most small electrically heated appliances where there is no excessive heat at the appliance terminals, such as: toasters, warming trays, coffee makers, etc. HPN cord has the added advantage of being less expensive than the HPD cord. Two other high-temperature insulating materials introduced in the late 1 9^0's were polytetrafluoroethylene (PTFE), also known by the trade name of Teflon, and silicone rubber. - 15 - 10/93 001863 AT" (X)03652 4m introduced in the early 19^*0's, as a skived tape, has good electrical . excellent moisture resistance and is good for continuous use up to 25: I*. was first used in combination with both asbestos and fiberglass. La*.- r-*..*.od of extruding it directly on conductors was developed. Extruded, ur.f-:-: '..ires, which could be wrapped on wire, and then fused, were also made ava.. insulated with PTFE found immediate use as special high-temperature hoi.-.-.r. aircraft, thermocouple wires, coaxial cables, and control cables. Its inherent high cost has limited its use for wires and cables. It is, however, still ceir.g used in combination with asbestos and fiberglass for high-temperature aircraft, thermocouple and appliance lead wires. Introduced at about the same time as PTFE was another high-temperature wire dnd cable insulation - silicone rubber. Its growth in this field, has also been slow because of its high cost. During the 1950's, Underwriters Laboratories, Inc., listed several types of silicone rubber fixture and appliance wires, i.e., Type SF fixture wire. As the price of silicone rubber decreases, its use will increase. It is now being usedJ.n many places where asbestos insulated wires were formerly used, because of its superior electrical properties, especially at high humidities. The approval by Underwriters Laboratories, Inc., of Type IBS Switchboard wire in 1956 was the next important inroad on asbestos wire insulations. As can be seen from Table VI, the insulation of this wire is quite similar to Type TA Switchboard wire, with one important difference, there is no asbestos between the primary 001864 - 16 extruded insulation and the cotton braid. It has the sane ratings as Type TA -ire, yO*C and 600 volts. As would be expected, customers started using this -ire at the expense of type TA wire. In 1953, the General Electric Co., introduced a new wire and cable insuiaticn - Vulkene- a chemically cross-linked polyethylene. The cross-linking changes the polyethylene from a thermoplastic material which becomes soft and finally melts with increasing temperatures, to a thermosetting material which does not melt at elevated temperatures. This material has the excellent insulating qualities of polyethylene combined with higher temperature service ability. Its excellent insulating properties are maintained under conditions of high relative humidities at elevated temperatures. Since its introduction, many types of Vulkene insulated wires have been approved by the Underwriters' Laboratories, Inc. Several of these wires will further curtail the use of asbestos insulations. 'Eiey are: 1. Type SIS Switchboard. This wire consists of a flame resistant extruded cross-linked polyethylene insulation which requires no braid. This wire has the same ratings as types TA and TBS Switch board wires and is replacing both of these products. 2. A cross-linked polyethylene insulated motor lead wire having ratings of 125*C and 600 volts. This wire is replacing asbestos- and fiberglass insulated wires. 001865 17 he wire that will probably cause the greatest replacement of asbestos us an insulating material is the recently Underwriters' Laboratories, Inc., approved 150*C - 300 volt appliance wire. This wire consists of a primary insulation of cross-linked polyethylene over which is applied a thin wall of felted asbestos saturated with a heat-, and flame resistant compound. Note that this wire is similar to asbestos-insulated type AI wire but has a temperature rating 25*C higher. While this wire has limited approval for specific applications, it will probably replace a considerable amount of the present type AI wire. In addition to these Vulkene insulated wires and cables, GE recently Introduced new Vulkaflex apparatus and motor lead cable. This cable has a rating of 130*C at oltages up to 5000 volts. This cable is insulated with EFR., one of the new heat fesistant synthetic rubbers. It will probably replace some of the type AVA wires. Other wire and cable manufacturers are now producing or will produce these types of wires within the next few years. Another class of recently Introduced wire insulations are the new aromatic polyamides and polyimides. They are being used as wire enamels and for making yarns, cloth, woven-tape, and film-tapes. In several respects the "hottest" high-temperature wire insulations at the present time are the polyimide-film tapes coated with the copolymer of "fluor- inated ethylene and propylene" (FEP). These tapes can be wrapped on a conductor and fused. The wire may then be finished with a color coating of FEP, applied from a suspension. - 13 - C /I 001866 r This insulation is used for the nevest type aircraft wire covered by MIL-w-31331. The wire is rated at 200*C and 600 volts. The insulation tbiclmess is either 7 or 12 nils, depending on the type. Wire made with these tapes has excellent electrical properties. While the above developments made serious dents..in-the asbestos used for wire and cable insulations, the use of these nfew wires tended to stabilize and * the increased production of Type AF, AI and several other types of wire during the early 1960's, led to complacency on the part of the asbestos processors. Statements to the effect that asbestos would always maintain or expand its position in the vlre and cable insulating field, were common. This complacency was partially Justified, for each year, the sale of asbestos lap6, rovings, yams and paper tapes to the wire and cable industry increased. However, if the relative rate of production of the HPN, SF and TBS Types of wire to the increase in production of the asbestos insulated wires were examined, it would have been noted that the production of the former types were increasing at a much faster rate than were the old stand-bys as Types AF, AI, TA; and HPD, and this trend is continuing. In 1961, asbestos Insulated wires accounted for 2.6$ of the total wire1 and cable sales dollar. In 1967, it accounted for only 1.9$ of the total sales dollar. Between 1961 and 1967, the total wire and cable sales dollar 10/93001867 ' - 1? - oi--s increased 90^, while the sale of asbestos-insulated wires increased only cr.iy half as much growth as the wire and cable industry as a whole. Now lets look at asbestos textiles used for electrical insulating purposes other than wire and cable. These are the tapes, cloth, and sleeving, ^e products used in the greatest quantities are the woven tapes, known in the asbestos industry as "decinal" tapes, as their thickness is measured in decimal portions of an inch as opposed to commercial tapes where thickness is measured in fractional portions of an inch. In the electrical industry they are known as listing. 9 These tapes have a wide variety of uses. Type II tapes are used as the primary insulation for certain types of magnet wire and bus bar insulation. Type IV tapes have the highest and most diversified usage. Their principle uses re for secondary insulation, for end turns of large size magnet wire, and for oil wrapping Asbestos cloths, Types II and IV, are usually impregnated with varnishes, phenolic, eopxy, and silicone, and are used as high-temperature slot insulations for motors and generators. They are also used as high-temperature, abrasionresistant panel insulations for various uses. Although not an asbestos textile, the importance of asbestos paper as elec trical insulation should be mentioned. In tape form, impregnated with resinous materials, they are used as insulations for large-size cables and some magnet wire insulation for transformers. Its greatest use, however, is for laminated composite molded insulations, vigh-temperature (200#C) panel and molded insulations for various uses. LAQ-WV .10/93 20 ? 903657 What materials have or are replacing these asbestos products? Woven '.-rglass tapes and cloth have been used to sane extent, but due to the -.-r:or abrasion resistance of the asbestos materials, this has been limited. It. fact, in some instances where glass textiles were used, asbestos is again :-.r.g specified. Tapes and cloth, made with a combination of fiberglass and asbestos yarns, finding increased usage. Ihe advantage of this combination is the high strength of the glass and the abrasion resistance of the asbestos. Teflon in tape or sheet form may not be considered a competitive material for asbestos papers, but is a high temperature plastic which is widely used as electrical insulation. As with wire insulations, the new polyamide and polyiaide tapes, cloth, and particularly paper, are beginning to be used for specialized applications. While this paper is at present much more expensive than asbestos paper, it is finding specialized uses as turn, layer, and barrier insulation on dry-type transformers-? It can be bonded in place by pretreatment with a partially cured ("B" stage) polyimide coating. A similar paper is used for wrapping coils, thus eliminating a varnish treatment. Riese materials are rated up to 220*C. i Dollar values are not available for asbestos textiles used for electrical insulations other than wire and cable. It is believed that there has not been the sharp downward trend which has occured in that industry. LAQ-WV 10/93 001869 21 L j \j w Jt;fOi Now we have seen the insulating materials which are gradually but surely replacing asbestos insulation. What is being done about it? To survive, an industry must keep up with new developments. Table VI lists eighteen basic single-conductor vires and cables, developed roughly within the past 25 years. About half of these have been developed in the past ten years. Now look at Table V. How many new asbestos-insulated vires have been developed within the last 25 years? The answer is none, as all of these wire desi^is are over 30 years old. How many new products have been developed by the asbestos textile industry as new or improved electrical insulating materials during this time? How many products employing asbestos electrical insulation in place of other materials ave been introduced during this period? The answer is very few. During the 19^'s, thin asbestos papers and tapes were introduced, which have found considerable use as electrical insulations, but this is not a textile. The only really new development in this field is the very recently developed fine cut asbestos yarns. These will find many uses in the electrical insulating field. Can it replace fiberglass braids, cloth, and tape? Only if it is pursued in an aggressive manner. Not Just by showing the yarns, tapes, and cloth, but by making, or having made end-use products. Sho'v where and how it is better. Compare technical data. Show the end product to the processors, and also to the end-product users. Make him want it. Until you can sell the end-use product, you will not sell the yarn. 001870 22 C003659 After examining the many materials which are making Inroads on asbestos insulations, can the statement still be made that asbestos will at least maintain its present position as an electrical Insulation? It is entirely up to the asbestos processors. It will be true wily if they do "as best as" they know bow in two areas; development and marketing. 10/93 001871 23 .V" 0003660