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BULLETIN NO. IC/FF-38R-2 ______ (Revised August, 1976) TRANSFORMER * I ImpectiBi & MaamtemaaBce Guide in .................................--....................... .---------- ---------------------------------- TOWOLDMON0025618 WATER_PCB-00010087 TTaiM ff Crnfemfls SECTION A TRANSFORMER ASKARELS.........................................1 t. Introduction..................... 1 II. History of Trade Name Types............................ 1 Table I - The Composition of Transformer Askareis ........................................ 2 III. Interchangeability .......... 2 IV. Table II - Official Transformer Askarel Shipping Specifications......................................3 V. Ordering Instructions ........................................ 2 VI. Stability.............................................................. 2 VII. Precautions When Handling Drums, Tank Cars and When Opening Transformers....................... 2 A. Keep Dry During Handling ......................... 2 Table III -- Handling and Pumping Temperatures.................................4 B. Use Ordinary Personal Precautions ............. 4 C. Precautions on Opening an Askarel Transformer......................................5 VIII. Avoid Environmental Pollution......................... 5 1. Labeling Askarel Transformers.....................6 2. Disposal of Liquid and Solid Wastes ...........6 3. Conditioning of New or Recycled Askarel .6 4. Teardown of Transformers for Repair or Scrap ......................................7 5. Transformer Disposal....................................7 IX. Expected Service Life........................................ 7 X. General Characteristics of Transformer Askarel Fluid.......................................................7 XI. Sampling Transformer Askarel Fluid ................8 XII. Evaluation of Askarel Received in New Equipment.............................................8 XIII. Dielectric Breakdown Voltage -- Moisture Relationship........................................ 9 Table IV - Relation of Dielectric Breakdown Voltage to Amount of Dissolved Water in Askarel and Mineral Oil......................................9 Table V -- Approximate Solubility of Water In Transformer Askarel and M ineral OH .... 10 XIV. Turbidity .......................................................... 10 XV. Check Pointsfor Maintaining Adcarel Insulation ........................................... 10 A. General Considerations............................... 10 B. Modern Sealing Procedures ........................11 C. The Older Sealing Arrangements................ 12 XVI. Periodic Fluid Inspection and What Checkpoints Mean ................................. 12 A. Visual Inspection.........................................13 B. Dielectric Breakdown Voltage ...................13 XVII. Inspection Checklist.........................................13 XVIII. Contamination in Transformers.........................14 Table VI -- Effect of Common Insulation Materials on Power Factor and Dielectric Strength........................................... 14 Table VII - Effect of Common Insulation Materials on Volume Resistivity of Askarel.......................................................... 14 XIX. ASTM Method for Investigating the Compatibility of Transformer Insulation and Construction Materials in Askareis........... 15 XX. Refining Askarel for Re-Use.............................15 A. filtering Through Dry Blotter Paper to Remove Moisture and Extraneous Particles....................................15 XXI. XXII. Table VIII - Water Removal by Filtering Askarel Through a Paper Press ...................... 16 B. Disposal of Solid Wastes............................ 16 C. Solid Insulation Requiring Drying..............16 0. Earth Treatment for Maximum Improvement of Power Factor and Volume Resistivity ....................................16 Table IX - Effect of Power Factor and Volume Resistivity........................17 Cleaning Arced Transformers.......................... 17 Sampling Askarel..............................................17 SECTION B ASKAREL FILLED SWITCHES AND TERMINAL CHAMBERS ....................................19 I. Introduction..................................................... 19 II. Sources of Contamination ............................... 19 III. Sealing Switches and Terminal Chambers... 20 IV. Askarel Used Under Mild Arcing Conditions . 20 V. Maintenance for Askarel Filled Switches ... .20 VI. Askarel Under Excessive Temperature or Fault Conditions .........................................21 SECTION C TOXICITY AND SAFE HANDLING............................ 21 I. Inhalation.......................................................... 21 II. Skin Contact..................................................... 21 SECTION D ANALYTICAL SERVICES ON TRANSFORMER ASKAREL AVAILABLE FROM MONSANTO...............................22 Types of Analyses Available: .........................................22 1) Routine Maintenance Check....................................22 2) Complete Analysis.................................................. 22 3) Analysis After Earth Refinement ..........................22 SECTION E APPENDICES..................................................................23 Appendix A -- Askarel Stability and Composition of Arc Formed Gas................................. 23 Appendix B -- Solubility of Gas in Transformer Askareis .................................................. 23 Appendix C - Effect of Temperature on Dielectric Breakdown Voltage of Askarel .................. 23 Appendix D - Comparison of the Approximate Viscosity in Saybolt Universal Seconds of Transformer Askareis and Mineral Oil..........................24 Appendix E -- The Density of Inerteen 54201 KA 7336-9 and Transformer Pyranol A13B3B-3....................................................... 24 Appendix F - Thermal Conductivity Values of Transformer Pyranol A13B3B-3...............................24 Appendix G -- Heat Capacity........................................ 24 Appendix H -- Coefficient of Expansion....................... 24 Appendix I -- Fire Resistance........................................ 24 Appendix J -- Seals, Properties and Procurement ..........................................................25 Appendix K - Caution Label........................................ 25 NOTICE: "Nothing contained herein is to be construed as a recommendation to use any product in conflict with any patent. MONSANTO MAKESNO WARRANTIES AS TO THE FITNESS FOR A PARTICULAR PURPOSE OR MERCHANTABILITY OF ANY PRODUCT REFERRED TO, no guarantee of satisfactory results from reliance up on contained information or recommendations, and dis claims all liability for any resulting loss or damage." 0220919 | TOWOLDMON0025619 WATEFLPCB-00010088 I. Introduction The term "askarel" as defined by IEEE, ASTM and the National Electrical Code generally describes a broad class of fire-resistant' synthetic chlorinated hydrocarbon insulating liquids widely used in transformers, reactors and accessory equipment operated at power frequencies. Askarels of various compositional types are in use. (For the general properties and types see ASTM D-2283.) Under arcing conditions the gases produced, while consisting of predominantly non-combustible hydrogen chloride, can contain varying amounts of combustible gases depending upon the askarel type. This manual describes the operating characteristics of transformer askarel liquid insulation as manufactured by Monsanto and how it differs from mineral oil. Appropriate handling and disposal procedures for both scrap askarel liquid and impregnated solid materials are given in accordance with the guidelines recommended by the American National Standards Institute. The information is based on facts gathered by Monsanto over 40 years as a producer of askarel, plus knowledge gained from the experience of transformer manufacturers and users. This guide outlines the maintenance required for askarel fluid in "modern" transformers and offers suggestions for sealing and maintaining askarel in old units. By following this guide, we believe users will obtain maximum service from askarel Insulation with a reasonable minimum of maintenance. If questions arise relating to the designing and building of transformers, these should be referred to regular transformer suppliers. Monsanto gratefully acknowledges the assistance, guidance and the contributions of certain data by the following: Edward L Raab - General Electric Dr. T. K. Sloat -- Westinghouse Electric )l. History of Trade Name Types "Askarel" is the generic name for the fire-resistant liquid insulation and coolant first used by General Electric Company in 1932 for their Pyranol1 brand name fire-resistant transformers, Westinghouse Electric Corporation uses their brand name, Inerteen.2 Whatever the trademarked brand, the askarel contains chlorinated biphenyl -- one of the best liquid insulations developed by science. This inert material is chemically stable, fire-resistant, heat stable, non-corrosive, and has high dielectric strength under the operating conditions encountered in transformers. In addition to manufacturing Aroclor chlorinated biphenyl , Monsanto also mixes this dielectric fluid with chlorobenzenes to produce the presently used Inerteen and Pyranol blends described in Table I. *"NOTE: Materials designated 'fire resistant* generally are more difficult to ignite, or once ignited, burn ai a slower rate than corresponding conventional materials. This term docs not mean that fire resistant materials will not burn. However, when properly used, Monsanto's fire resistant ASKAREL FLUIDS are useful in helping customers meet their fire safety requirements." ^Trademark of General Electric Company ^Tradcroaik of Westinghouse Electric Corporation ^Registered trademark of Monsanto Company 0220920 TOWOLDMON0025620 WATER_PCB-00010089 Tabic I The Composition of Typical Transformer Askarels Mothod_ASTM O2283.. Type E Type G Trade Names Inerteen 70-30 Inerteen 10042 Pyranol A13B3B3 Ingredients (% by wl.) Aroclor & 1254, chlorinated biphenyl (54fa chlorine by weight) 70 Aroclor 1242, chlorinated biphenyl (42*ochlorine by weight) Triclilorobenzene 30 Phenoxypropone oxide scavenger 0.18 to 0.22 Diepoxide scavenger - - 100 0.18 to 0.22 - 60 40 _ o.ii5 to o.i: ASTM Method D-2283, titled "Chlorinated Aromatic Hydrocarbons IAskarels) For Transformers", also lists the composition of all transformer askarels used at various times since 1932. Monsanto manufactures similar transformer askare! fluids in England where the trade name Pyroclor is used. III. Interchangeability In general all transformer askarels are interchangeable. However, it is suggested that the transformer manufacturer be consulted prior to mixing in significant proportions or total substitution. IV. Transformer Askarel Specifications Specifications for the three modern transformer askarel fluids, are shown in Table II. V. Ordering Instructions Monsanto's current policy is to sell askarel transformer fluids only to transformer manufacturers. Others interested in these fluids should contact the manufacturers of askarel transformers and not Monsanto. The transformer name plate indicates the transformer maker and usually gives sufficient data to identify the specific askarel fluids used. VI. Contamination Askarel insulation must never be mixed with mineral oil. Over two percent of mineral oil by volume in askarel begins to lower its fire resistance. In modern transformers, the principal "enemy" of askarel is contamination by water. Keeping askarel water-free will insure long time service. Askarel is heavier than water. If water gets into askarel insulation, only a urty amount (approximately 12S ppm) dissolves -- the rest floats on top. Askarel is very insoluble in water, only about 200 parts per billion of askarel dissolve in water. at normal temperatures. VII. Precautions When Handling Drums, Tank Cars, and When Opening Transformers Ine l.rbowmg are significant precautions: A. Kri-p Dry During Handling: in handling, storing, sampling and inspecting askarel -- and in 02209*1 | TOWOLDMON0025621 WATER_PCB-00010090 Table II Transformer Askarel Specifications (New Fluid) Specification Properties1 General Electric Co. Transformer Pyranol A13B3B-3 ASTM D2283 Type G Westinghouse Transformer Inerteen 70-30* ASTM D2283 Type D Westinghouse Transformer Inerteen 100-42* ASTM D2233 Type E Coiof, APHA Cu<'<i'tion W*?* compnt, ppm (ASTM 01533-60) Ac(iMv. mg KOH g (ASTM 0974-55) Strength. 25 C. 0.1 in. gap 'ASTM DB77 49) DH'teclric Constant, 100t'C. 60 H? (ASTM 0924 49) 150 max. Clear 30 max. 0.014 max. 35 KV, min. 4.2 to 4.6 150 max. Clear 30 max. 0.014 max. 35 KV, min. 4.2 to 4.5 60 max. Clear 35 max. 0.01 max. 35 K V, min, 4.7 to 4.9 Volume Resistivity, 100 C, 500 volts DC 0.1 inch gap, 10 ohm cm 100 100 100 (ASTM D11G9) Inornanti; chlorides, pprn (ASTM D1821 and G.E, Method E4C41B) 0.10 max. 0.10 max. 0.05 max. Refractive index. 25 C (ASTM D1807) Viscosity at 37.8'C (ASTM D88-56) Saybolt Universal Seconds 1.6110 to 1.6120 44 to 48 1.6153 to 1.6173 56 to 61 1.6240 to 1.6260 82 to 92 Pour Point 'C (ASTM D 97-57) -38 or lower -30 or lower 17 or lower Specific gravity 25'15.5JC (ASTM D1810) But n pomt (ASTM D92) 1.495 to 1.510 None to boiling 1.518 to 1.528 None to boiling . 1.381 to 1.392 None to boiling Distillation range (ASTM 020-56) corrected 1st drop 20CTC min. 1st drop 200*0 min. 10% 325JC min. f for stem and barometric pressure { i 40% max. below 270C 90% 379 to 394 35% below 270X 90% 379 to 394 90% 360 max. i i Fixed chlorine 56.4+0.5% 55.6% min. 43 + 0.5% Cot rosion test Color. APHA Acidity, mg KOH'g Inorganic chlorides ppm Condition Scavenger content Typical Properties3 After beating with aluminum for 6 hrs. at 200 to 220'C. the aluminum must not be corroded on either visual or weight inspection and the askarel should meet the following specifications: 200 max. 200 max. 200 max. 0.014 max. 0.014 max. 0.01 max. 0.15 max. 2.0 max. 0.15 max. Clear Clear Clear 0.115 to 0.135% 0.18 to 0.22% 0.18 to 0.22% Diepoxide phenoxypropene oxide phenoxypropene oxide Coefficient of Thermal Expansion (ASTM D1903), cm?/cm2/C Arc formed gases 0.0007 0.0007 0.00068 Askaiels ol various compositional types are used. Under arcing conditions the gases produced, while consisting predominantly ot non combustible hydrogen chlonde. can include varying amounts of consbustihiu ga>,?\ di*p--n<hng upon the askarel type Insulation systems incorporating these askarels and ccllulosic or other organic nia'-mob maT_ *We$tinghouse uses their private number inerteen 54267KA tor tnerteen 70-30 and their private number Inerteen 54201 CM foi Inerteen 100-42. when arced, produce gaseous mixtures which are modcately flammable. As a precaution, such gases should be removed from the askarel by bubbling dry nitrogen through the ask are! and flushing the gas space with dry rwtfoyw before any work is perfoimed on the apparatus. 3 These quantities ere final sales spire<l"rations only to the exien: that they coincide wilh Monsanto's published specifications. *Thi$ data is based upon samples tested m the laboratory and is not guaranteed for all samples. Write us for complete sales specifications for Askarel fluids. TOWOLDMON0025622 WATER_PCB-00010091 operating askarel transformers - take every precaution to guard the askarel insulation from exposure to high humidity and moisture contamination. Keep 5 or 55 gallon drums of askarel dry; lay stored drums on their sides with the bung at the highest point from floor to keep water off the drum head (which can be sucked into the askarel by the drum "breathing''). This precaution is not necessary when drums are stored indoors, which is the preferred place for storage. To avoid leakage the drums used for askarel are of heavy construction. Sixteen g3uge metal is used, with special rim seal and bung construction. The drums should be drained as completely as possible and then flushed twice with kerosene type solvent to remove all of the askarel. Accumulated liquids and washings should be collected and should be incinerated at high temperatures, e.g., about 2000SF, to destroy the polychlorinated biphenyls (PCBs). See Section A, VIII. Tank cars used to transport askarels are in exclusive service and not used interchangeably for other products. Alt cars must be unloaded through the top (dome fitting) either by pumping or with controlled pressure using dry air or dry nitrogen. If nitrogen has been used for unloading it is necessary to advise the shipper so that when the car returns the nitrogen can be replaced with dry air before any one may enter the car. If the car is to be unloaded by pumping it will be necessary to use a dryer on the air intake line to remove moisture. All tank cars are fitted with steam coils, which are available for unloading under extreme low temperature conditions. Convenient handling and pumping temperatures are given in Table III. B. Use Ordinary Personal Precautions: Transformer askarel has been made, handled, and used for over 40 years. It can be handled safely with recommended precautions. If accidentally spilled on hands, no serious skin irritation will occur. However, liquid askarel has a solvent action (similar to paint Tabic III Handling and Pumping Temperatures Product Unloading, Handling and Pumping Temperature C Pyranol A13B3B-3 (nerteen 70*30 Inerteen 100-42 20-55 20-55 35-75 thinner) on the fats and oils of the skin and prolonged contact may lead to drying and chapping of the skin. In case of contact, wash the skin with soap and water; remove and destroy saturated clothing. Clean up spills with rags, sawdust and al.uoflront clay. Segregate these items for proper disposal. (See p.ij1- 6, "Disposal of Liquid and Solid Wastes".) Eye contact may n sult in painful irritation but no permanent damage to tissues. If vl qi'ts in tiie eyes, flush with large amounts of water. As with a'l rye lust j.d, refer to a physician. To relieve irritotion, physir have used an opthalmic anesthetic solution as well as opthalm;c cortisone acetate solution. In'itxun-nt exposure to askarel vapors will not cause ill effects. However, prolonged exposure to high vapor concentrations should ivO'dril. it hot askarel must be handled in a closed or confined provide the area with mechanical exhaust ventilation - or 0220923 J TOWOLDMON0025623 WATER_PCB-00010092 wear an organic cartridge respirator approved by the U.S. Bureau of Mines. C. Precautions On Opening an Askarel Transformer: Askarels of various compositional types are used. Under arcing conditions the gases produced, while consisting of predominantly non-combustible hydrogen chloride, can yield varying amounts of combustible gases depending upon the askarel type. Insulation systems incorporating these askarels and cellulosic or other organic materials may, when arced, produce gaseous mixtures which are moderately flammable. As a precaution, such gases should be removed from the askarel by bubbling dry nitrogen through the askarel and flushing the gas space with dry nitrogen before any work is performed on the apparatus. The American Institute of Electrical and Electronic Engineers Guide IEEE Std. 76*1974 gives more detailed instructions and guidance "For Acceptance and Maintenance of Transformer Askarel in Equip ment". This guide is published by the Institute of Electrical & Elec tronics Engineers, Inc., 345 East 47th Street, New York, New York 10017. We recommend that users of askarel transformers refer to this IEEE document. VIII. Avoid Environmental Pollution Transformer askarels contain polychlorinated biphenyls (PCBs) which have been used in the United States and elsewhere over the past 40 years for many industrial and consumer applications. During the past several years evidence has accumulated to indicate that PCBs are widely dispersed throughout the environment and that they can have adverse ecological and toxicological effects. The United States Government's Interdepartmental Task Force on PCBs, Com-72-10419, in their March 20, 1972 report titled, "Polychlorinated Biphenyls and die Environment", reoommended restricting PCBs to use in capacitors and transformers. This report is distributed by the National Technical Information Service, U.S. Department of Commerce, Springfield, Virginia 22151. A document titled, "Guidelines for Handling and Disposal of Capacitor and Transformer Grade Askareis, Containing Polychlorinated Biphenyls", has been prepared and is available from the American National Standards Institute, Committee Cl 07, 1430 Broadway, New York, New York 10018. Document number is ANSI Cl 07-1-1974. (This guideline is being revised during 1976. The new edition should be available 1976^77). The scope, objectives and the composition of this committee are: ANSI Committee C107 Scope: Procedures and guides for safe use, maintenance and disposal of askarel and askarei-soaked materials used in electrical equipment. Objectives: 1. Source of technical information and advice for Federal, State, local authorities and all others concerned. 2. Encourage development of suitable disposal facilities and keep all concerned informed. 3. Serve as the advisory group for United States participation in international organizations: CEE, IEC, CIGRE. Composition: Organizations active in or represented by this ANSI committee include: National Electrical Manufacturers Association, Electronic Industries Association, Institute of Electrical and Electronic Engineers, American Society for Testing and Materials; Electric Light and Power Association; Certified Ballast Manufactuieis Association; Environmental Prolection Agency; OHice of Environmental Affairs; General Services Administration; National TOWOLDMON0025624 WATER_PCB-00010093 Buteau of Standards; Department of the Army; Rural E U c11 location Administration; Division of Environmental Roerich, TVA; American Public Power Association, Water Portion Coniio! Federation; Food and Drug Administration; National Fire Protection Association; Underwriters Laboratories; and several sections of the U.S. Department of Interior. The following are pertinent excerpts taken from the ANSI Guidelines for askarel transformers: 1. LABELING ASKAREL TRANSFORMERS (Pg. 16) 4.22.1 Now Transformers. AH new transformers' that contain PCBs shall have a label oi adequate durability, permanent1/ and prominently attached to the tank by the manufacturer, given adequate warning and instructions. A suggested label includes the following: CAUTION: The insulating liquid in this transformer contains polychlorinated biphenyls (PCBs). Care should be taken to prevent entry into the environment. In case of malfunction or leaks, consult the instruction manual or the manufacturer. 4.2.2.2 fn Service Transformers. The transformer manu facturer should make available suitable labels with a similar warning as shown in 4.2.2.1 for use on existing transformers. 2. DISPOSAL OF LIQUID AND SOLID WASTES (Pg. 15) 4.1.6.5.1 General. Disposal of askarels and askarel-soaked materials sliould be accomplished by means in which there is no significant release of askaref to the environment. At present, disposal is accomplished by carefully controlled incineration of liquids and soaked software, and by con trolled landfill burial of apparatus and other hardware from which askarel has been previously drained and washed. Present knowledge indicates that proper incineration must involve a suitable balance between dwell time and temperature in the incineration plus oxygen availability and, finally, suitable scrubbers to remove the HCi that will be formed; for example, 2-second dwell time at 200CPF and 3c excess oxygen in stack gas, or 1.5-second dwell time at 270CPF and 2% oxygen in stack gas. These facilities should meet the applicable requirements of the state in which they are located and should control effluents within the limits set forth in this standard. Controlled landfill or deep-well disposal can be used where permitted by federal, state, and local regulations. The ANSI Guide lists the locations of facilities that conform with the above requirements. Monsanto has such an incin erator at the W. G. Krummrich Plant, Department 831, Sauget, Illinois 62201, where arrangements can be made for scrap askarel liquid disposal for a modest fee. For disposal of solid scup a controlled dry land-fill can be used where permitted by Federal, State and local regulations. 3. CONDITIONING OF NEW OR RECYCLED ASKAREL (Pg. 16) 4.2.1.3.1. Askarel Conditioning Equipment. The condi tioning umt sliould be located cither in the storage tank area or in the main transformer manufacturing area for filling with askarel. 4.2.1.3 2 Fuller's Earth. Conditioning of new askarel or rtxyclcd usk.t'd requires fuller's earth treatment. The spent fuller's earth in cartridges or lugs, when replaced, shouldbe allowed to d'ain thoroughly over drip pans to remove as much liquid askarel as possible. The cartrulgc units of steel mesh construction should lx? placed in the "STEEL CONTAMINA TCP WITH ASKAPE L" container for disposition. Cloth txHjs filled with fuller's earth should be placed in the `SCRAP BURNABLE ASKAREL WASTE" container for disposition. . ^ 0220925 I TOWOLDMON0025625 WATER_PCB-00010094 4. TEARDOWN OF TRANSFORMERS FOR REPAIR OR SCRAP (Pg. 16) 4.2.1.4.1 Drain all askarei from the unit cither into a holding tank or reuse or into the drum labeled "SCRAP ASKARE L" for disposition, and then allow sufficient time for all of the askarei to drain from the core and coils. 4.2.1.4.2 Remove the core and coil assembly horn the transformer. Sufficient absorbent materiaI should be niaced on the floor to absorb any askarei fluid that still drips from the transformer. 4.2.1.4.3 Place all materials in the appropriate salvage containers during the dismantling for later disposition. 4.2.1.4.4 All used materials, including rags, sawdust, tape, etc, regardless of quantity. shall be put into the appropriate containers for disposition. 6. TRANSFORMER DISPOSAL (Pg. 17) 4.2.3.6 The ultimate disposal of an askarel-filled trans former may be accomplished in either of fivo ways' (1) Complete drainage and dismantling with the proper disposal of the askarei and askarel-soaked components as described in 4.1.6. (2) Disposition of askarei transformers by means of junk or scrap dealers. This should be avoided unless a transformer is first drained, followed by soaking the interior with a suitable solvent. Accumulated liquids and washings are to be disposed of as described in 4.1.6. IX. Expected Service Life Manufacturers indicate that properly designed and installed askarei transformers are expected to give trouble-free service for at least 30 years. Since their introduction in 1932, the manufacturers report finding the overall failure rate to be less than 0.5% for all units under test and service conditions. The Edison Electric Institute's report (1956-1958) on their member utilities publishes the failure rate for askarei transformers as 0.13 per hundred banks per year. Mr. Frank M. Clark, who invented transformer askarels at the General Electric Company in the early 1930s, made the highly pertinent comment based on his many years of experience with G.E. Pyranol (askarei type) transformers that - "The important thing is to keep them dry - otherwise leave them alone". These words of wisdom became especially applicable in more recent years when welding shut rather than gasketing became the main method of sealing askarei transformers. These units are sbld with the understanding that the liquid is in a normally hermetically closed system. X. General Characteristics of Transformer Askarei Fluid Appreciation of the following characteristics, as given in the IEEE Guide, leads to understanding the reasons for selecting dielectric breakdown voltage and moisture as the prime practical tests to judge the quality of transformer askarei fluid. Also, due to these characteristics the power factor of transformer askarei will bo normally much higher than the corresponding values for mineral oil. In comparison to mineral insulating oil, askarei is a relatively polar material; i.e., its molecules are dipoles, free to rotate around their axes and responsive to orientation by electrical forces. Askarei also exhibits a much higher dielectric constant and capacitance than insulating oil, and these differences must be kept in mind when interpreting electrical test data. Because it is relatively {tolar, and possesses high solvency power, askarei is much more electrically sensitive than mineral oil to traces of extraneous soluble {tolar materials, and consequently the choice of 0220926 TOWOLDMON0025626 WATER_PCB-00010095 comtfuctioti.il materials destined for use tn askarel is very critical. This scmif.vify n rcrlL'cff.'d in the power factor and resistivity (specific resistance) of the askarel. 1: is imporuru to note that, with the exception of water, the dielectric b-I'j'-.down voltage of askarcl is not generally adversely affected by many of the soluble polar materials to which its power factor and iv> st-vify (specific resistance) are so sensitive. In fact, the dielectric breakdown voltage of askarcl is somewhat greater than that of insulating oil. Therefore, the values assigned these dielectric fluids in newly supplied transformers are 30 KV mm. and 26 KV min., respectively. As with insulating oil. askarel must be kept dcy. It can pick up moisture from exposure to humid atmosphere. Under similar conditions of exposure, askarel can pick up nearly twice as much moisture when measured on a parts per million weight basis. Xi. Sampling Transformer Askarel Fluid The following precautions about sampling are quoted from the IEEE Guide. "Representative samples, whether of the complete contents or only ports thereof, are extremely important from the standpoint of evaluation of the quality of the pioduct sampled. Obviously careless sampling procedure or contamination in the sampling equipment will result in a sample that is not truly representative. This generally leads to erroneous conclusions concerning quality and incurs loss of time, effort, and expense involved in securing, transporting, and testing the sample. It is strongly recommended that all of the procedures and precautions outlined in the latest revision of ASTM D 923 (Sampling Electrical Insulating Liquids) be followed. "Because of the high specific gravity (relative density) of askarel (greater than 1), water and some other impurities are most likely to be found at or near the surface. The top sample, therefore, is considered to represent the worst condition." XII. Evaluation of Askarel Received in New Equipment Some users of askarel equipment find it desirable to make "as received tests" on all equipment. It is quite common to use the dielectric breakdown voltage test and visual appearance as the most significant tests. If suitable equipment and trained personnel are available additional information may be obtained from the power factor, color, and moisture content tests. In sampling askarel contained in apparatus extreme care must be exercised in order to obtain a representative sample. ASTM Method D 923 should be followed. New equipment with askarel exhibiting the following characteristics is considered acceptable: Dielectric Breakdown Voltage Color Condition Visual Water Content Power Factor at 25* C 30KVmin. 300 max. (Straw color) Clear 35 ppm max. * ASTM Methods D 877 D2129 D 1702 D 1533 D 924, D 150 *Thc power factor of askarel taken from new transformers, reactors and accessory equipment can reflect the presence of moisture, dissolved polar compounds, or other contaminants and may vary with the type of equipment from which the sample was taken due to the different ratios of liquid to solid insulation and to the high solvency power of the askarel, Given an acceptable water content and dielectnc bieakdown voltage of the askarel as indicated above, a high posver factor seldom impairs the serviceuh'bty of the askaiel within rather broad limits and is 0229Z1 | TOWOLDMON0025627 WATER_PCB-00010096 indicative of the degree of uxtianfoos solub1-' pot at pi.-vnal* present. Recognizing tr . possibility of a wiilo rjrge of (' .\i:r fjrt. recorded for askiuel in new i-ijiupnu-nt, it is diltic.ilt to i st.iijiish a Single limit which v.ould be jcteptabi-.* to boiti s;.|'p'im j:.d users for all applications. However, as a bioad guide, ; ower factors up to about 10 a; ?G'Cand 63 cycles per second erU) do rot in general indicate any abnoimjl contamination providing that the Other criteria (water content, dielectric breakd ;nvn volt.i ;e. etc.) arc met. Much higher power factors may indicate excessive contamination or the misapplication of the sohcl materials used in manufacture in contact with the askarel and should be investigated. XIII. Dielectric Breakdown Voltage -- Moisture Relationship The dielectric breakdown voltage of askarel is highly sensitive to excess moisture; not sensitive to ordinary dissolved polar materials. While the dielectric breakdown voltage can also be lowered by severe aremg, askarel turns noticeably black or has particles of sooty carbon floating in it if arcing has occurred. Then the transformer should be repaired and the askarel replaced. If the dielectric breakdown voltage is checked periodically and decreases significantly - this indicates moisture pick-up, arcing, or both. When the dielectric breakdown voltage has dropped to 26 KV or less, an analysis for water is necessary. If water is found in excess of 40 ppm at room temperature, its source should be located and corrections made. When the moisture content approaches 125 ppm (saturation level at room temperature), the dielectric breakdown voltage of askarel drops below the value required for efficient insulating. The moisture content should not be allowed to rise over 70 ppm, sampled at operating temperature. If the moisture content is found to be in a satisfactory range and the dielectric breakdown voltage is low, the transformer manufacturer should be consulted. Table IV shows the relationship of dielectric breakdown voltage vs. moisture and Table V indicates the approximate water solubility limits in askarel and mineral oil. Table IV Relation of Dielectric Breakdown Voltage to Amount of Dissolved Water in Askarel and Mineral Oil Water Content (PPM) Breakdown Voltage jASTM D877) Askarel Mineral Oil 0 70 KV 50 KV 20 55 39 40 47 30 60 40 26 80 38 22 no 70 5 0220928 ^| TOWOLDMON0025628 WATER_PCB-00010097 T able V Approximate Solubility of Water in Transformer Askarel and Mineral Oil !L 30 22 20 A 10 14 0 32 10 50 20 68 30 86 40 104 Amount of Water (PPM) Dissolved Askarel Mineral Oil 88 16 10 28 13 41 20 65 33 94 58 128 85 170 130 XIV. Turbidity ., . may be the visual sign of undissolved water, or mav indicate dirt. Cloudiness may also result from cold precipitation of tin tetraphenyl "scavenger" that was used in the earlier Pyranot transformers. This scavenger begins to come out of solution around 15'F above zero. To redissolve it requires heating to 150-200^ and agitation. High dielectric breakdown voltage will quickly indicate that any turbidity present is not moisture; that the insulating efficiency of the askarel is still excellent. However, if the dielectric strength is below 26 KV, moisture should be determined, using the Karl Fischer method (ASTM D1533-60). The dielectric breakdown voltage test for askarel serves primarily as an indicator for moisture. It is by far the most important maintenance test for transformer askarel. XV. Check Points for Maintaining Askarel Insulation A. General Considerations: Modern askarel transformers with welded construction or silicone or Viton* gaskets (hand hole-cover, switch and terminal compartment covers) and with properly constructed bushings require little maintenance. With properly constructed trans formers, annual or semi-annual visual inspection and dielectric breakdown voltage test of the askarel fluid should suffice for routine maintenance checking over many years of service. However, many askarel units were installed in the early 1930s before the development of some of the better modern gasketing materials and before improved designs were developed for sealing out moisture. Such early units should be, and can be, modernized. Leaky or deteriorated gaskets should be replaced. If the askarel has become contaminated, it should be reconditioned. At the same time, a general clean-up of the unit and possible refinishing may be desirable. If it is not convenient to take an old transformer out of service for general repairs, leaky gaskets can be sealed temporarily by painting over the leaky area with epoxy cement. A survey of users indicates a good number of early-built askarel transformers {over 20 years old) are kept in continuous service in critirai installations by the following steps (instead of modernization). The operating units are equipped with compound pressure gauges for reading pressure above and below atmospheric. Positive *t ladruu'k of . I. DuPont DcNomouis & Company, Inc. TOWOLDMON0025629 WATER_PCB-00010098 pressure is maintained on the sMI by introducing nitrog-Mj jt ? to 3 pounds above atmospheric. Regular workmen in the .if.*3 daily record the temperature and pressure. If a sudden pressure drop is noted more nitrocien r$ introduced and the gjjkvts ate chi rk.id for leaks with soap solution. Leaks are scaled by applying epoxy cement. Modern Sealing Procedures: Transformer purchasers should specify the following modern techniques for scaling: 1. Welding Construction: Covers, radiator connections, switch and terminal housings, instrument connections, etc. should be welded. 2. Bushing Connections: A number of bushings have been developed to obtain a proper seal for the electrical connection through the tank wall. They are classified as follows: 1) Welded Type (Bushing flange welded to tank wall) a. Cast resin bushing with a molded seal to the bushing stud and external stainless steel or copper flanges. b. Rolled flange bushing with the metal to porcelain seal at the cap and flange made by being rolled into grooves in the porcelain over silicone rubber rings. The seal between the cap and stud is made by welding. c. Porcelain or glass bushings with metal to glass or metal to porcelain seals. 2) Bolted Type * (Bolted to tank wall) a. Cast resin bushings with either cast or metal flanges containing recessed gasket grooves. b. Porcelain or glass bushings with flanges containing recessed grooves or gasket stop. The gaskets may be either of rectangular or circular cross-section, usually % inch thick. Bushings with recessed grooves are suitable to use with cork, cork-nitrile rubber combinations or nitrile rubber as well as gasket materials such as silicone or Viton. 3. Small Size Connections: When not possible to weld, small size connection seals should be made with Flexitaflic* stainless steel rings. The surfaces must be machined and parallel. The filler between the steel laminations of the Flexilallic ring should be either silicone or Viton. 4. Gaskets for Hand-Hole Covers: Modern design specified silicone gaskets. Such gaskets must be retained in a groove. The groove preferably is machined into the flange or cover. However, it can also be formed by welding concentric steel strips to the flange or the cover. Generally the gaskets should be 5/16 to 1/2 in. thick for covers, depending on the depth of the groove or stop. A rectangular cross-section n usually used. The silicone materia) should be Dow Corning No. 50 Silastic4* or equivalent. This is a low compulsion set material. For best sealing 20-25\. compression is recommended, with ample clearance in tin* groove oi stop to allow for this compression. No cement is requited. With reasonable care the gasket-is removable without damage and is reuseable. Silastic 50 is slightly swelled by askarel which contnlut s to the tightness of the seat. It is not detenor .itt.J by jA .i. I fluid or vapors. It resists weathering and ii is tln.imully MjIiU- and Tuiirmark ot F lon'tcillic Gasket Company * * Tuilomar k ot Dow Coming 0220930 jlj' | TOWOLDMON0025630 WATER_PCB-00010099 flexible at all operating temperatures. It is an excellent moisture barner. NOTE; Dow Corning, Midland, Michigan will supply a list ol Silastic 50 gasket fabricators to at! transformer manufacturers or users. They will also furnish technical data. See Appendix J: Seals, Properties and Procurements. C. The Older Sealing Arrangements: The older type gaskets consist of either cork or cork-nitrile rubber combinations or straight nitrile rubber. . 1. Cork-Nitrile Combinations: Covers for the main tank, hand-holes, switch and terminal chambers, relief diaphrams, etc., are held in place by studs welded to the flange or by bolts. The gaskets are cut with openings and placed over the bolts. Often Shellac (Westinghouse Style No. 1150419, or General Electric Company's Glyptal* 12761 U used to cement the cork to the flanges. The following is recommended for sealing with the cork -- nitrile rubber combinations: Use Armstrong NC-757 cork-nitrile material or equivalent. The gasket can be cut from a single sheet or by scarfing strips of the material. A convenient method for joining strips is to make a Keystone Type joint. For this purpose, Westinghouse, Sharon, Pennsylvania, offers their gasket cutter Style No. 326 6614 G01, (about $15). The joints -- and also the gasket -- should be cemented to the flange, using one of the above cements. Excess cement should not be allowed to reach the interior of the transformer. After installation and bolting, the outside edge of the gasket should be coated thoroughly with epoxy cement to increase weather resistance. This epoxy cement is a paste to which a curing catalyst is added immediately before use. Typical are: a. Epoxy Patch Kit #1*C Hysol Corporation, Olean, New York b. Scotchcast** Resin #4 Minnesota Mining & Manufacturing Company St. Paul, Minnesota c. Adhesive A-1 and Activator Type B Armstrong Products Company Argonne Road, Warsaw, Indiana d. Adhesive 9860 1, Synthetics Organic Company, Cleveland, Ohio, used with activator diethylene triamine (Carbide and Carbon Chemical Company) 2. Straight Nitrile Rubber: When straight nitrile rubber was originally used, invariably the gasket was recessed in a groove. Thi? was to prevent gasket flow and to protect the material against excessive compression. Although this type seal was not cemented, the nitrile rubber gasket is not reuseable. Since grooves or stops have already been provided for the nitrile rubber seal, Silastic 50 can be easily substituted and is recommended. This conforms with modern practice. XVI. Periodic Fluid Inspection and What Checkpoints Mean On a regular schedule - at six, nine, or twelve-month intervals - make a simp' visu.il inspection of your askarot insulation and run a dielectric breakdown voltage check. Trai1tm.uk ol General Electric Comnany ` * T i Jdt m.iik of Minnesota Mining & Manufacturing Company TOWOLDMON0025631 WATER_PCB-00010100 A. Visual Inspection: Askarel is a clear, faint-yellow liquid. After long term use this color may gradually intensity to light brown. The fluid should remain clear and free fiom turbidity or cloudiness. Any color change - such as to a green, red or blue cast - indicates extraction of impurities (color materials) from the solid insulation. If a distinct foreign color pick up is noted, check the complete range of electrical characteristics and notify the transformer maker. Blackening of the askarel may indicate an arcing condition. Other color changes alone are not danger signals since the dielectric breakdown voltage is not likely to be impaired. B. Dielectric Breakdown Voltage If the dielectric breakdown voltage has decreased significantly from the last inspection, or if it has gradually decreased below 26 KV range (at 25nC) - RUN A CHECK FOR MOISTURE. Use ASTM D1533 (Karl Fischer Method). The dielectric breakdown voltage of askarel is the major indicator to the operating efficiency of your liquid insulation, Besides the visual inspection tests, dielectric breakdown voltage is the only test necessary to run on a routine basis. Well-seated askarel transformers have service records of 25 to 30 years on the original askarel. XVII. Inspection Checklist 1. If askarel is clear -- even though darkened to tight brown, has no sediment or turbidity, has dielectric breakdown voltage over 26 KV -- give it the inspection "OK". 2. If askarel is clear, but has foreign color of blue, green, red ... it is "extracting color" from internal materials. This is not, of itself, an operating hazard when the dielectric breakdown voltage stays over 26 KV and moisture remains low. However, this rare occurrence calls for checking into the condition of the interior construction and consulting the transformer maker. However, when sampling the fluid care should be taken to avoid getting color into the askarel from paint that may be inside or outside of the sample valve. 3. If the moisture content is found to be above 70 ppm at operating temperature, then sampling should be done at more frequent intervals to establish a possible trend, particularly on outdoor installations. 4. If askarel is clear, but dielectric breakdown voltage drops to 22 or lower KV, and moisture rises over 80 ppm when sampled at operating temperature ... the askarel is ready for simple "refining". If the moisture is near the saturation level (about 125 ppm at room temperature) a thorough inspection should be made for water droplets in the transformer tank, and even for "globules" of water floating on the askarel surface. If found, the transformer manufacturer should be consulted for reconditioning both the transformer and the fluid. 5. If askarel is dark brown to black, if black particles of carbon are seen, and dielectric strength is low .. . the askarel has been broken down by arcing. It cannot be refined and should be removed and incinerated under proper conditions. (See ANSI C107.1-1974, Section 4.1.6). If any of these five simple inspection tests appear out of the otdmaty or the relationship between appearance and test values is abnormal, contact your transformer supplier for a complete analysis. Whenever a sample is to be shipped to Monsanto, please follow the directions shown under: "SAMPLING ASKAREL". 0220932 TOWOLDMON0025632 WATER_PCB-00010101 XVIII. Contamination in Transformers Moisture, paniculate matter and arced decomposition products are known to be serious contaminating influences on transformer askaief. The power factor test normally used for the detection of contamination in mineral oil filled vansformert is of little use for this purpose in askarel filled transformers, due to the extreme effect of extraneous soluble polar materials. This increase in power factor as illustrated in Table VI has no adverse effect on dielectric breakdown voltage. Table VI . Effect of Common Insulation Materials on Power Factor and Dielectric Strength (Heat Aged 96 Hours in Askaref at 100*C.) Material Immersed Askarel After Exposure Power Factor, Dielectric Percent at 60 eye., 10CTC Strength 25*C. None (control) Black varnished cloth Copper Pressboard Manila paper Phenol formaldehyde resins Shellac Iron Synthetic rubber 1.0 85.0 1.5 2.0 1.5 1.6 6.0 5.0 70.0 35 KV 42 40 3739 41 36 39 39 Similarly, trace contaminants from commonly used construction materials can lower the volume-resistivity of askarel, without'affecting its dielectric breakdown voltage. This is shown in Table VII. Table VII Effect of Common Insulation Materials on Volume Resistivity of Askarel Sample Volume Resistivity x 109 ohm-cm (at 100C.( 500 Volts DC., 0.1" gap) 1. New askarel before heat aging 2. New askarel after heat aging 96 hours at 100eC 3. After heat aging with 1 sq. inch specimens of: a. Phenolic resin tap changer material b. Paper c. Grade A pressboard (tan) d. Grade A pressboard (gray) e. Grade A pressboard, laminated strip f. Cotton wrapping Q. Glyptal 1276 cement, cured 48 hrs. at 1 lO^C 2,000 1,900 1,200 750 500 500 400 300 100 While trace contamination easily lowers volume resistivity from high levels, it is important to note that heavy contamination (as when arced) does not lower the resistivity below the order of 109 ohm-cm. at 100C. The different behavior of askarel vs. mineral oil in these respects can be summarized as follows: High powoi factor and low volume resistivity in transformer mmoial oils ate commonly regarded as 'danger signals" that the oil has di terioraled and broken down chemically or excessive moisture is present. This is NOT TRUL of askarel liquid insulation unless the dielectric bu'akdnwn soilage is losv oi the moistuie content is high. \ 0220433 | TOWOLDMON0025633 WATER_PCB-00010102 Manufacturers of askarel typo transformers jwm rut that t s n.nu well known tl'3t askarel transformers with mit.dl ,.} the askarel fluid in excess of 50 j at room temp-ratu'C a-.I PQ H/ .r-- t v r>g satisfactory service life. However, dve rxv.H to Uc j wrjnce !" ' Moth dielectric breakdown voltage and moisture are at sot factory u-.c's and do not show adverse trends. XIX. ASTM D3255 Method For Investigating The Compat ibility of Transformer Insulation and Construction Materials in Askarels This method uses the change of electrical and,'Or chemical characteristics of transformer askarel resulting from its controlled exposure to insulation and construction materials, in order to evo'uate their immediate major "contamination" effect on the askarel fluid. Delayed or long time contamination effects may not be detected. The method also utilizes various physical tests on the insulation and construction materials after controlled exposure to the askarel to determine the compatibility of these materials with transformer askarel. Properly proportioned specimens of the insulation or structural materials are immersed in refined askarel for 168 hours at 100 1"C in a forced draft oven. Changes in electrical and chemical properties of the transformer askarel are compared against a control sample of the askarel treated in the same manner, in absence of the test specimens. Dissipation factor (ASTM D 924) change is one of the criteria used. The askarel fluid is refined by absorptive treatment to a dissipation factor level of 0.05 max. at 100'C and 60 Hz and 0.01 max. at 25`C and 60 Hz. Corresponding values of the askarel fluid after heating 168 hours at 100C in absence of a test specimen are 0.075 and 0.02 respectively. The maximum dissipation factor levels suggested for the askarel after heating in presence of the test specimen are 0.20 at 100*0 and 60 Hz and 0.04 at 25C and 60 Hz. XX. Refining Askarel for Reuse A. Filtering Through Dry Blotter Paper to Remove Moisture and Extraneous Particles: Most operators prefer portable refining apparatus, such as a plate press fitted with a dolly, available from Sparkler, Mundelein, Illinois or General Electric Company, Pittsfield, Massachusetts; or the earthen cartridge filter type available from Industrial Filter Corporation, Lebanon, Indiana. Filter paper liners for the plate press are available from Carl Schleicher and Schuell Company, Keane, New Hampshire and manufacturers of filter presses listed above. ' The filter paper must be dried immediately before use. For best results, spread the paper for maximum surface exposure in a hot air circulating oven and heat it for 4 to 6 hours at 110C. Circulate the askarel hot (but not over 4(7*0 through the filter fitted with the dry paper liners. After filtration the dielectric breakdown voltage of the askarel should be 35 KV minimum. PRECAUTIONS: 1. Filtering should not be done when the relative humidity exceeds 75%. 2. Any flexible hoses and gaskets on the refining equipment should be lined with or made of materials that will not be softened by contact with askarel fluid. (Materials lined with Silicone, Viton or Teflon* or flexible metal materials are suitable.) Trademark of E. I. DuPont DeNcmour* & Company. Inc. 0220934 TOWOLDMON0025634 WATER_PCB-00010103 TABLE VIM Guide to Rate of Dissolved Water Removal By Filtering Askarel Through a Paper Press Passes Through Papet Press Water in Askarel PPM 0 115 1 35 2 22 3 - 18 4 12 6 10 6 10 TOWOLDMON0025635 WATER_PCB-00010104 B. Make sure that the askarel is at least as watm as the surrounding air. (Cold liquids can condense moisture from humid air.} C. When sampling askarel from transformers, it is best to take the sample when the unit is warm and operating at average or maximum load, especially for a check on moisture as reflected by a dielectric breakdown voltage test. Sampling the warm askarel more truly represents its condition during operation. Experience shows that water will migrate from a transformer's solid insulation to the askarel liquid and vice versa, depending on temperature. Therefore, when the transformer is hot, the moisture is most likely to be found in the liquid. This accounts largely for periodic variations in dielectric breakdown voltage. For example, a relatively high dielectric breakdown voltage may be found during winter months and a relatively low dielectric breakdown voltage during the summer months on samples taken from the same unit. When testing has been completed, the remainder of the fluid sample should be destroyed by high temperature incineration described in Section VIII. TOWOLDMON0025636 WATER_PCB-00010105 I. Introduction High voltage leads are usually connected to askarel or mineral oil-filled network transformers and power centers through terminal chambers and* switches. In some cases terminal chambers are not used, and the high voltage leads are connected directly to the switch terminals. They may be filled with either askarel or mineral oil. Switches are usually rotary or drum type fitted with a revolving block and porcelain unit as the principal element arranged for three-phase service. Askarel transformers with attached switches have been in use for about 30 years. When they were first introduced, the availability of insulating and gasketing materials was rather limited and even the best materials at the time had no service history. As a result, inadequate gasketing materials such as cork, nitrile rubber, and nitrile rubber-and-cork particles were used. While satisfactory for a limited period of time, these materials cannot be depended upon for the expected long life of the equipment. The terminal chamber is usually above or below the switch compartment and separated by a steel wall through which the bushings are inserted. When bushings are properly selected and correctly installed, there is no leakage from one compartment to the other. With poor bushing seals, and the terminal chamber above the switch, potting compounds or cable oil can seep into the askarel. When the terminal chamber is below the switch, askarel can drain into the terminal chamber. II. Sources of Contamination There are three possible sources of contamination for askarel in switches and terminal chambers; they rank in this order of frequency: (1) water entering through poor gaskets; (2) decomposition products from arcing when switch is used to break magnetizing current; (3) entrance of pothead or cable compounds through leaky bushing seals. Unlike an askarel transformer where the amount of contaminant is likely to be very small (probably only trace amounts) in relation to the volume of askarel fluid ~ in switches or terminal chambers with faulty seals, the amount of contamination can be relatively large. Experience has shown that, based on the number of installed eskaret-switch units, the percentage of failures is extremely small. When investigated, it has been found that most failures originate in the switch chamber. Water is the chief source of contamination. However, heavy contamination of askarel with petrolatum and asphalt material, due to leakage, have caused a few failures. Petrolatum is used frequently for filling terminal chambers. When either cable oil or petrolatum seeps into askarel, no great harm results. The fire resistance wilt be somewhat decreased and power factor of the askarel will increase with an accompanying drop in resistivity. While highly undesirable, it is doubtful that failure of the unit results. Where asphaltic compounds are used in place of petrolatum, the danger is increased somewhat because asphaltic contamination may cause excessively high dielectric losses in the askarel. When the terminal chamber is below the switch chamber, the potting compound can bo contaminated by askarel if the bushing s<als are leaky. This is undesirable because the askarel will increase the power factor and conductivity of the potting compound or cable oil and develop heat from dielectric loss, if this mixture is drawn into the cable TOWOLDMON0025637 WATER_PCB-00010106 Inuilmion, a cable failure is likely. This again emphasizes the imporijnce of tight bushing assemblies. III. Scaling Switches and Terminal Chambers Prop'.1' bushing construction, use of Silastic seals and welding wherever posvble is highly desirable (as covered in Section A). Where an elastomeric seal is to be used in contact with both askarel and petroleum oil, DuPont's Viton is suggested. For new equipment the user should specify these modern sealing arrangements to keep out contaminants and minimize maintenance. IV. Askarel Used Under Mild Arcing Conditions . The IEEE Guide for Transformer Askarel calls attention to the following: . "* "Askarel is used, to some extent, in apparatus where it is subjected to light intermittent arcing, such as in self-contained induction regulators, where operating switches are continually producing slight arcs, in transformer de-energizing switches, etc., Under normal conditions, deterioration of the askarel is very slight. However, improperly adjusted or defective switches in this type of apparatus can produce excessive and prolonged arcing and accelerated deterioration of the askarel. It is recommended that when askarel is used under these conditions, checks of the liquid, especially for moisture and dielectric breakdown voltage made more frequently than when it is used only as a cooling and insulating fluid. Deterioration of this type is indicated by a blackening of the liquid. It can usually be reconditioned as previously described. Special attention should be given to maintaining the scavenger at the appropriate concentration." V. Maintenance for Askarel Filled Switches A. Switches used for grounding after power source has been de-energized wilt not undergo arcing. B. Switches interrupting magnetizing current will be subject to arcing; the amount of decomposition will depend on power interrupted, time and frequency of operation. As a general rule, the liquid should be checked after 5 to 10 operations. 1. On newly installed switches, check the askarel at 3,6 and 12 month intervals; if found satisfactory, check once annually thereafter. With proper attention to the gasketing of covers and bushings, experience will probably indicate that less frequent inspection is warranted. . 2. Check askarel for: a. Dielectric breakdown voltage (ASTM D877): It should be 26 KV minimum. If dielectric breakdown voltage is low, confirm presence of water by Karl Fischer method ASTM D-1533, Filter to remove moisture. Dielectric itrength should then be 30 KV minimum. b. Presence of carbon from arcing: Fluid should be relatively free of carbon. If badly arced and very black, replace fluid. If only minute amounts of carbon are present, filtration is recommended. Check power factor of liquid (should not be over 5% at 25C and 60 cycles). Flush out switch chamber with several gallons of fresh askarel before refilling. 3. If there is discoloration, high power factor, detectable change in specific gravity or refractive index, or if fluid flashes below 250*F, there is a possibility of seepage of potting compound into the switch compartment, In this case, correct any leaky bushing seals with proper replacements and fill with new askarel. 4. If terminal chamber is below switch, chTcit potting compound for presence of askarel (can usually be detected by odor or by an increase m specific gravity!. If askarel is present, correct any leaky bustling seals with proper replacements, and rencsv compounds. 6. Examine cover gaskets visually. Deterioration can be detected 02209 38 TOWOLDMON0025638 WATER_PCB-00010 by swhmg ond c.ukrg of the exposed edge. In casus of s.'^ -r i.-ffc,* l.quid s*.-.>page is usually present. 6. C' K U.IT It iK.o- at p.using gland of switching shaft. If li-k. .3 ftPuck rt.th a S.la.t.c ring type gasket. VI. Askarel Under Excessive Temperature or Fault Conditions The IEEE Gw Jt abo points out that. < "CMotob- nrenes used in transformer askarels begin to boil at temp rc'urus of about ?QSi>C. under atmospheric conditions. If the material is hi'jtrd o such high temperature in a sealed system, prcssuti. de.' *ops. Procure will also develop in the system if the askarel is diced sufficiently to generate copious hydrogen chloride gas. "Therefore. it is recommended that wherever possible, sealed askarel-filied equipment be provided with pressure relief devices. These devices must be large enough to provide immediate relief at a definite pressure, and to prevent further build up of pressure if decomposition continues. It must be remembered that the presence of devices of this sort does not necessarily preclude the rupturing of containing vessels, since pressure build up can be extremely rapid under violent arcing conditions." Safe f r t*' yc / .... ......... . fj'v !) Jilt I t. Inhalation At ordinary temperatures the chlorinated biphenyls in Askarel have not presented industrial toxicological problems. The hazard of potential toxic exposure varies with their volatility: the lower-chlorinated, morevolatile ones present more of a potential problem from the standpoint of both inhalation and skin contact. When Askarel fluids are used at elevated temperatures, engineering controls must be applied, either by the use of closed systems or by effective local-exhaust ventilation together with general workroom exhaust. Vapors of Askarel at room temperature should not be breathed in a confined space, and no vapor of any fluid evolved at elevated temperatures should be allowed to be dispersed into the general workroom. Inhalation tests on animals indicate that the maximum safe concentra tion of vapor is in the range of from 0.5 to 1.0 milligram per cubic meter of air. The threshold limit value (maximum allowable concen tration of an 8-hour working day) set by the American Conference of Government Hygienists are 1.0 milligram of the lower-chlorinated biphenyl compounds per cubic meter of air and 0.5 milligram of the more-highly-chlorinated compounds, per cubic meter of air. II. Skin Contact Prolonged or repeated skin contact with the Askarel fluids must be avoided by the use of gloves and protective garments, because of the possible occurrence of a condition called chloracne. Although reports of this condition caused by Askarel are rare, it can be produced by excessive skin contact. If the fluid is spilled on the skin the slkin should be washed in the usual manner with a soap solution. A burn caused by contact with a hot Askarel should be treated like any ordinary burn. For disposal instructions of Askarel fluids, see Section A VIII, p.'pc G. 0220939 TOWOLDMON0025639 WATER_PCB-00010108 L y 4. Tt (C*, a.^>. L.. |n~;^V'r D c: i r-. n` T*-**--* ,..L ii iV.. --"V - -r*. *94 **' - - Arf / \ r>! f <-r\*'*n I - iL.. j -VC--- iJ. Ljv-ti r ^ Ayr -`'Ti i.4 iU -i vV -i*L ia ` Transformer users not wishing to make their own fluid analyses can obtain the service from Monsanto. Simply contact Monsanto and specify what analyses are wanted. You will be sent the proper-sized, clean sample container, fitted with a proper label, When you receive this, carefully take your sample (following the procedure for sampling in this guide). Send the container to Monsanto's laboratory. Charges listed include sample container and laboratory costs. The charges are those in effect August 6, 1976, and are subject to change. * Types of Analyses Available Analysis 1} ROUTINE MAINTENANCE CHECK " Total Charge: $35.00 Per Sample To determine the general condition of the fluid and find whether further analysis is necessary, (one-quart sample required) Properties Tested Dielectric Breakdown Voltage Color and Condition Moisture You will be notified of the results of this test. If further testing is indicated, and you want a complete analysis, you will be sent a five-pint sample container. This sample will be used for the following series of tests: Analysis 2) COMPLETE ANALYSIS . Total Charge: $165.00Per Sample (1) To determine the extent of fluid contamination, (2) earth refinement to determine what degree of restoration of electrical and Insulating properties is possible, (3) check test to see how the fluid responded to earth treatment. a) Complete Analysis: to determine the extent of contamination Properties Tested Free Chlorides Color and Condition Acidity Specific Gravity Dielectric Breakdown Voltage Refractive Index Power Factor, Dielectric Constant, and Resistivity Water b) Earth Refinement Response: Consists of treatment for 2.5 hours at 50-60C. with 0.1 to 0.2 percent by weight of properly conditioned Attapulgus clay and then filtration through dry filter paper. c) Analysis After Laboratory Earth Refinement: Properties Tested Acidity Refractive Index Dielectric Breakdown Voltage Water Power Factor, Dielectric Constant, and Resistivity Free Chlorides You wifi be notified of the results of this test series on your sample. Then after refining your entire transformer fluid fill you can check on the results by requesting the following analysis: Analysis 3) ANALYSIS AFTER EARTH REFINEMENT Total Charge: $70.00 Per Sample (This charge will not apply when analyses 1 and 2 have already been made.) To determine whether the entire lot of the askarel fill responded to the same extent as the laboratory sample, (five-pint sample required) Properties Tested Free Chlorides Color and Condition Acidity Refractive Index Dielectric BreakdownVoltage Water Power Factor, Dielectric Constant, and Resistivity To arrange for the tests described above write to the following address: David Wood Monsanto Industrial Chemicals Company 800 North Linclliorgh Blvd. St. Louis, Missomi G31C6 Samples to tv' tested should be clearly marked for identification and sent directly to: Mniisanto Company VV. G. Kiumtiineii Laboratory r*Ki(Ji!t, IIIkUMS Uri/01 Attention J. A. Gloeckner 0220940 TOWOLDMON0025640 WATER_PCB-00010109 APPENDIX A Aska'd Su:L'<litv and Composition of Arc Formed Gas: Askarel insulation is one of the most inert, chemically-stable heat rr-snot, non-corrosive liquids known. It will rot break down, oxidize or sludge when exposed to air and high temperatures, 150C. or even somewhat higher. Arcing, however, will break down the compound to liberate some hydrogen chloride and small amounts of Carbon. APPROXIMATE COMPOSITION ARC-FORMED GAS FROM TRANSFORMER ASKAREL BLENDS ASTM TYFES D AND G (JNERTEEN 70-30 AND PYRANOL A1333B-3, RESPECTIVELY) Gas carbon monoxide carbon dioxide oxygen inert gases hydrogen chloride (note the absence of phosgene) Amount 0.3% 0.3% 0.6% 1.5% 97.3% This arc-formed gas from ASTM Type D and Type F transformer askarels is non-flammable and non-combustible. For all practical purposes, the amount of gas liberated from askarel under a given set of arcing conditions is about 100 cubic centimeters per kilowatt-second. APPENDIX B_____________________________________________________________________ SOLUBILITY OF GAS IN TRANSFORMER ASKARELS ASTM TYPES D AND G Carbon dioxide Air Nitrogen Hydrogen chloride1 1 In absence of scavenger Percent of Gas By Volume Corrected to: 25C 760 mm____ 0C. 760 mm 25cC 100*0 25*C 100C 71% 5.7 6.0 37.8 47% 4.9 4.8 50.9 - 5.8 5.0 5.5 4.4 -- APPENDIX C EFFECT OF TEMPERATURE ON DIELECTRIC BREAKDOWN VOLTAGE OF ASKAREL Temperature C -60 -40 -20 0 20 40 CO 80 Dielectric Breakdown Voltage ASTM D877 67 KV 63 57 55 50 50 48 45 r*.... 1 TOWOLDMON0025641 WATER_PCB-00010110  APPENDIX D COMPARISON OF THE APPROXIMATE VISCOSITY IN SAYBOLT UNIVERSAL SECONDS OF TRANSFORMER ASKARELS AND MINERAL OIL Temp. *C -20 0 20 40 60 80 100 Pyranol A13333-3 1,000 100 70 45 39 34 . 30 10-C Mineral Oil 1,000 150 85 49 40 34 30 Inerteen 70-30 2,800 195 85 50 40 36 33 APPENDIX E THE DENSITY OF INERTEEN 70-30 AND TRANSFORMER PYRANOL A13B3B* Approx. Density gm/cc. Temp. *C 0 20 40 60 60 Inerteen 70-30 1.574 1.552 1.529 1.507 1.485 Pyranol A13B38-3 1.577 1.555 1.532 1.510 1.488 APPENDIX F__________________________________________________________________________________ The thermal conductivity values of transformer Pyranol A13B3B-3 at 27*C and 58C are 26.2 and 25.8 x 10*5 calories centimeters-*, degrees centigrade-1, second-1, respectively. Or, approximately 0.06 BTU per (hr.) (sq. ft.) (#F.) per foot. This same approximation applies to Inerteen 70-30. APPENDIX G_________________________________________________________________________________________ Heat Capacity Over the temperature range of 25* to 125*C the specific heat of transformer askarel is close to 0.30 calories per gram per degree. APPENDIX H_________________________________________________________________________________________ Coefficient of Expansion The average coefficient of expansion of transformer askarel over the temperature range20 to 100*C is0.0007 cc/cc/"C.One gallon would increase to 1.056 gallons or) heating from 20 to 100*0. APPENDIX I Fire Resistance Askarels of various compositional types are used. Under arcing conditions the gases produced, while consisting`of predominantly non-combustible hydrogen chloride can yield varying amounts of combustible gases depending upon the askarel type. Insulation systems incorporating these askarels and cellulosic or other organic materials may, when arced, produce gaseous mixtures which are moderately flammable. As a precaution, such gases should be removed from the askarel by bubbling dry nitrogen through the askarel and flushing the gas space with dry nitrogen before any work is performed on the apparatus. 4 02209*2 TOWOLDMONOQ25642 WATEFLPCB-00010111 APPENDIX J Seals. Properties and Procurement Dow Corning Corporation, Midland. Michigan with Districts at Atlanta, Boston, Chicago, Cleveland, Dallas, Los Angeles, New York City, Washington, D.C. and Toronto has available Bulletin 09-019, August 1962 entitled "Silastic Design Data". This lists the gasket fabricators throughout the country from whom the "Silastic 50' gasketing can be purchased in sheet. extrusions or molded shapes. Generally, Silastic 50 sheet goods are stocked by local die cutters, hence, could be generally purchased locally. Usually small Quantities of gaskets are die cut. If larger quantities are needed, tools are made of the same type used to cut other elastomers. Where the gasket is extruded for fitting into a machined groove or between gasket stops, Dow Corning advises use of a starved joint. This joint is then cemented using Dow Coming's Silastic 140 (clear) or their RTV 731 (white) materials, which air cure. Dow Coming points out that the local "rubber" fabricators purchase the Silastic 50 in billet form. This is worked on a roll mill in preparation for sheeting or extrusion. Then to obtain the desired physical properties the fabricator must oven cure the Silastic 50 for 24 hours at 480*F. SPECIFICATIONS* ASTM D676 ASTM D412 ASTM D412 ASTM D395 Color Specific Gravity at 77*F Hardness, Shore A. Scale Tensile Strength, psi, min Elongation, percent, min Compression Set after 22 hr; at 300*F, percent, max White 1.20 + 0.02 45 to 60 800 250 30 *AII physical properties measured on 0.075 inch thick samples molded 5 minutes at 240F, and oven cured 24 hours at 480T. APPENDIX K Caution Label Tha following or equivalent caution statements should be fixed on all containers of transformer askarels and the trans formers themselves: This product contains Polychlorinated Biphenyls (PCBs). Care should be taken to prevent entry into the environment through spills, leakage, use, vaporization, or disposal of liquid or containers. Avoid prolonged breathing of vapors or mists. Avoid contact with eyes or prolonged contact with skin. If skin contact occurs, remove by washing with soap and water. Following eye contact, flush with water. In case of spillage onto clothing, the clothing should be removed as *oon as practical and the skin washed. Dispose of any contaminated materials as suggested in the American National Standards Institute document Cl 07.1, "Guidelines for Handling and Disposal of Capacitor and Transformer Grade Atkarefs, Containing Polychlorinated Biphenyls". MONSANTO INDUSTRIAL CHEMICALS COMPANY FUNCTIONAL PRODUCTS GROUP 800N. LINDBERGH BLVD. ST. LOUIS, MISSOURI 63166 The information herein regarding obtaining optimum results from askarel fluids in your transformer has been accumulated by Monsanto for over 40 years from the experience of makers and users of askarel transformers and it is believed will be helpful. Nothing herein shall be construed as applying to other than askarel insulation. Data and maintenance suggestions herein do not apply to the other components of the transformer. All operating and maintenance suggestions recommended by the manufac turer of the transformer should also be carefully followed. Because these maintenance directions apply only to the askarel insulation, Monsanto disclaims any liability for damage to property or injury to persons arising from transformer operation. 02209*3 TOWOLDMON0025643 WATER_PCB-00010112 US CUSTOMER SERVICE CENTERS AKRON, OHIO 44313 260 SpringtiJ* Onv* Bom 5444 Montrose Development Park Ttl. 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