Document k9zyqMjRzK7w3MEqRNOYdxLLB

2P0r0in0t-ed-CmH.U . SU. A . 1-C ACHL.. VRFA..KWDUSSMNLSCAOALRNL.N, .PTEUSEAASGt1ONUEKMMTATRRT 'i POUNDED ISSA J fy x & T tn a - N o t fc rp u tfi* SPONSOREDY National toar 0FJRir nertoribrs 2 0 7 EAST OHIO STREET. CHICAGO HCAENNWI C FYARO6A0R,NKHC,*OI0ISB7CBt AIOI.N.I IBOTOHHMIOEAVBBET*... Miscellaneous Hazard 2561 Application No. 36C1794 February 18, 1937 REPORT on LIQUID DIELECTRIC AND COOLING- MEDIUM ADMIRED WITH SHALL AMOUNTS OF TRANSFORMER OIL General Electric Co., Schenectady, N.Y. INTRODUCTION In converting oil-filled transformers into Pyranol-filled transformers, the manufacturer has found that it is very difficult, if not impossible, to remove all traces of oil from the transformer with the practical methods available at the present time. The small quantity of oil remaining in the transformer becomes mixed with the Pyranol upon its addition to the transformer and it is, therefore, important to reduoe such contamination by residual transformer oil to point where the fire and explosion hazard of the Pyranol is not appreciably increased. Accordingly, this investigation was undertaken in order to obtain data as to the effect of the presence of small amounts of transformer oil on the fire and explosion hazards of Pyranol. ' Our reports, Miscellaneous Hazard 2581, dated September 29, 1934 and April 14/ 1936, respec tively, describe the fire and explosion hazards of the liquid dielectric and cooling mediums known as Pyranol Nos, 1476, 1480, 1485, 1488, 1490, and 1491 MH25S1 -2-- description PRODUCTS COVEHEP BY THIS REPORT: Liquid dielectric and cooling medium, "Pyranol No. 1488" admixed with, small amounts of transformer oil. P L A N OF I N V E S T I G A T I O N The-object of this investigation was to deter mine the fire and explosion hazard of Pyranol admixed with small amounts of transformer oil as compared with that of Pyranol containing no transformer oil. In planning the investigation, consideration was given to the effect of the added transformer oil upon the flash point, fire point, ignition temperature and explosibility. The tests included flash point tests, fire tests, ignition temperature tests, and tests for flammability using-specially-designed apparatus. e x a m i n a t i o n a n d t e s t re c o e d DESCRIPTION OF SAMPLES The manufacturer furnished a 10-gal sample of "Pyranol No. 1488" and a 1-gal sample of 10-C transformer oil. Samples of Pyranol-oil mixtures for the tests were made up containing 2, 3, and 5 per cent by volume of the transformer oil. SPECIFIC GRAVITY TESTS: METHOD The specific gravity was determined by means of a pycnometer. RESULTS The specific gravity of "Pyranol No. 1488" was 1.5606 at 15.6c(60F) 15.6C(60S) The specific gravity of 10-C transformer oil was 0.8845 at 15.6c(60F), 15.6c (6o f ) MH2581 -3- FLASH POINT TESTS: METHOD The flash point was determined with the Pensky-Martens closed tester according to the method (D93-32) of the American Society for Testing Materials RESULTS The results of the flash point tests are as follows: Sample Flash Point Pyranol No. 1488 Pyranol-oil mixture containing 2 per cent by volume transformer oil Pyranol-oil mixture containing 5 per cent by volume transformer oil Transformer oil 118.3C (245F) 118.3C (245F) 118.3C (245F) 126.7C {20F) FIRE TESTS: METHOD The fire tests were made with the Cleveland open cup according to the method (D92-33) of the American Society for Testing Materials. RESULTS Pyranol-oil mixtures containing 3 and 5 per cent by volume transformer oil gave negative (2) re sults in the fire tests (3). (310F) The transformer oil had a fire point of 154.4C (1) In this connection, see note 3 (2) Intermittent flashes were obtained but the mixture did not continue to burn. The sample was'heated to boiling point; *the test was then discontinued. (3) In view of the negative results obtained in the fire tests, it is clear that the flash point cannot be depended upon to give a true measure of the fire hazard of these mixtures. It was therefore neces sary to conduct tests of the explosibility of the vapors of the mixtures in specially designed ap paratus. See pages 6 and 7 MH2581 -4- IGNITION TEMPERATURE TESTS: METHOD The apparatus consists essentially of a com bustion chamber surrounded by a solder bath, which is heated at a constant temperature during the test by a bunsen burner. The temperature of the solder bath is measured by means of a calibrated thermocouple provided with a quartz tube to protect the hot junction. The combustion chamber consists of a quartz or glass flask of conical form with flat bottom, 4-1/2 in. (11.4 cm.) in height, 2-3/8 in. (6*0 cm.) in diameter at bottom, and 1-1/8 in. (2.8 cm.) in diameter at top. It is of about 160 cc capacity (rated capacity 125 cc) hav ing a ratio of surface area to volume of about 1.1, Measured test samples in the liquid phase are introduced into the heated combustion chamber by means of a micro pipette. Different amounts of the sample are admitted to the chamber in successive tests in order to determine the minimum temperature at which the vapor of the liquid in any proportion with air will ignite. The residual vapors or gases in the combustion chamber are completely displaced by a stream of air in the interval between tests. Ignition temperature tests were also conducted using a horizontal iron plate 10 in. square and 1/4 in, in thickness, heated by a gas burner. Flames and hot gases from the burner are deflected from the upper surface of the iron plate by a strip of sheet iron extending 10 in. beyond each side of the plate. The deflector is bolted to-the edges of the plate, asbestos gaskets being provided at the joint, A calibrated chrome1-alumel thermocouple (No. 14 Awg) connected with a potentiometer is used to measure the temperature of the plate, the hot junotion of the thermocouple being brazed to the center of the upper surface of the plate. Check measure ments of the temperatures of the plate are also made employing an optical pyrometer of the disappearing filament type. In conducting^tests, measured samples (up to 10 cc) were dropped on the center of the heated plate. A slow stream of air was applied to the evaporating sample in some of the tests. The minimum ignition temperature was determined by successive trial tests, during which the iron plate was maintained at progres sively lower temperatures. Miscellaneous Hazard Ho# 2581 Application Ho. 33C2060 September 29v 1934. REPORT on LIQUID DIELECTRIC AHD COOLING MEDIUMS General Electric Co., Schenectady, N. Y. PRODUCTS COVERED BY THIS REPORT: Liquid dieleotrio and cooling mediuma, "Pyranol No b . 1476, 1480, 1485, and 1488." GENERAL CHARACTER AND USE: \ The produota whioh are the subject of thla report are mixturea of chlorinated hydrocarbons in different pro portions. % they are pale, yellow liquids differing markedly In respect to viscosity. They are Intended for use as di eleotrio and ooollng mediums in electrical apparatus. "Pyranol No. 1476" Is intended for u b s in cables and oapaoitors. Pyranol Nos.v1480, 1485, and 1488 are in tended for use in transformers, Nos. 1480 and 1465 repre senting two extremes in the proportions of the chlorinated hydrocarbons and No. 1488 being the average. -V . ME2581 2- MARKING: ''Pyranol No a. 147 6, 1480, 148 5, or 1488" stenailad - on containers. C L A I M S M A D S FOR THE P R O D U C T S The manufacturer claims that the products are a distinct Improvement in liquid dielectric and cooling media, are nonflammable at ordinary temperatures, and evolve nonexolosive gaseous mixtures when deoomoosed by the electric arc. The following claims are quoted verbatim: "Pyranol is the trade name of the General Electric Comoany covering liquid dielectric-and cooling media which are non-inflammable and non-explosive at ordinary temperatures and which even when decomposed by heat or the electric arc evolve only non-inflammable and non-explosive mixtures. The use, of these improved liquid dielftotribs effectively removes the danger from fire and explosion heretofore Inevitably as sociated with the use of the inflammable and explosive oils in electric design. n "The Pyranols are chemically stable, non-aoidforming, non-sludging and of excellent dielectric properties. Being characterized by high dielectric strength and high di electric constant, they are admirably suited for use in elec trical apparatus. The dielectric constant of the Pyranols, being essentially of the same value as that of the solid insulation, insures a more equitable stress distribution when liquid ducts and solid Insulation are arranged in series. The dielectric constant, being more than twice that of miner al oil, also insures a minimum of physical size per micro farad in capacitor design. T h e Pyranols have been in successful commercial Service in Increasing amounts during the past three years. The value of these liquids as non-inflammable and non explosive dielectric and cooling media has been demonstrated. "The first oommereial use of the Pyranols in capac itor design was made in January, 1931. Commercial application of Pyranol oapaoitors has included the use of Pyranoi in all types of service, including a-o power factor oorreotion, use on direct current and high frequency circuits and other special applications well-suited to demonstrate the reliability and efficiency of the Pyranol capacitor. In the larger capacitor sizes a total of more than 8500 Pyranol-filled units with a r `\ HB2581 -3- capacity in exoess of 75,000 kva. have been manufactured and shipped in addition to a total of more than 250,000 small leva, Pyranol-filled oapaoitors for motor starting and motor running. "The manufacture of Pyranol-filled transformers began in liaroh, 1932 and has shown a steadily increasing volume. To date, more than 150 Pyranol-filled transformers have been shipped, totaling in excess of 27,000 kva. "In the period during which commercial application of the Pyranols has been made, clear evidence has been ob tained of their non-inflammable and non-explosive character, together with the advantages accruing therefrom. As ex amples, the following service experiences are cited, one illustration being taken from oapaoitor, and the other from transformer, experience "A 720 leva., 460 volt Pyraaol capacitor was in stalled in a grain elevator. Dust accumulation between ter minals of the oontrolllng air oirouit breaker eventually caused a severe aroover of considerable duration on the line side. Seven capacitor oases were melted open by the heat of the external aro. In twenty other oases the oapaoitor fill ing plug was melted off. In all oases the Pyranol was ex posed to the high temperature and decomposition effects of the eleotrio aro under the most favorable conditions for conflagration. In contrast to the behavior normally ex pected with mineral oil under similar conditions, the Pyranol did not burn nor evolve explosive gases. "Experience has shown that an aro at the surface of the oil in an oil-filled transformer represents the most serious condition favoring fire and explosion. Routine ex amination of a service operating Pyranol-filled subway trans former showed clear evidence of such an arc having been pres ent, yet not only had the transformer not exploded with re sulting flrer but the transformer was still operating satis factorily up to the time of the routine examination. The aro had burned completely away the Insulation on the incoming oable terminal, the burning ooourrlng at the surface of the Pyranol liquid, without affooting the service operation of the unit. "The remarkable oheiploal and electrical stability of the Pyranols aa evidenced by their successful commercial application In electrical design, together with the noninflammable and non-explosive behavior of Pyranol-fllled equipment under the most favorable conditions for fire and explosion, thoroughly substantiates the ten years' develop ment and research program of which these produots are the culmination." MH2581 -4- PI AN OF I N V E S T I G A T I O N The object of this Investigation was to determine the fire and explosion hazard of the produot's. In planning the investigation consideration was given to the General Nature of the produots, their Fire and Toxio Hazard, Corrosive Action, Stability, and Uniformity* The method of investigation of eaoh of these phases is given below. Information as to the general nature of the prod uots was obtained by means of Identification Testa.. The fire hazard of. the produots was investigated in respect to flammability, explosibility, ignition tem perature, and decomposition temperature. The products of decomposition were investigated in respect to flammability and explosibility. Consideration was also given to the toxicity of the fumes produced on contact with hot metal surfaces and electric arcs. The tests included Flash Point Tests, Decomposition Temperature Tests, Ignition Temperature Tests, Tests for Flammability using specially designed appa ratus, Explosive Range Tests, Analytical Tests of Decompo sition Products in the presence of hot iron surfaces and electric arcs, and Teats of Transformers to Destruction. Corrosion TeatB of the produots on metals commonly used in electrical apparatus were conducted. Information bearing on the stability of the prod uots was obtained from Decomposition Temperature Zests, Corrosion Tests, and consideration of the ohemioal proper ties of the produots. The prooess for manufacturing the produots is subject to definite oontrol, and a detailed investigation of factory prooess was not therefore considered neoessary, 2 2 2 H I 2 2 2 I 2 22 2 2 2 2 22 2 DESCRIPTION OF SAMPLES The manufacturer furnished 5-gal. samples of the following produots: Pyranol Nos. 1476, 1480, 1485, and 1488. MH2581 5- - IDSKTIFICATIOK TESTS: METHODS Speolflo Gravity - The specifics gravity was deter mined by means of a pycnometer. Vlsooslty - The viscosity of Pyranol No. 1476 at 50 C{122 F) was determined by means of the Saybolt-Furol Viscosimeter using the method (D88-33) of the American Society for Testing Materials. The viscosity of Pyranol Kos. 1480, 1485, and 1488 at 37,8 0(100 ?) was determined by means of the SayboltUniveraal Viscosimeter using the method (D88-33) of the American Society for Testing Materials. Distillation Teat - A 100-g. sample was distilled using the method '020-3QJ of the Anerioan Society for Testlog Materials. Acidity - Acidity was determined by mixing a 20-g. sample with 50 oo. of neutral ethyl alcohol and titrating with K/50 potassium hydroxide solution using phenolphthaleln as an indicator. The acidity was calculated as per cent hydrochloric acid by weight. Free Chlorides - A 50-co. sample was agitated with 10 cc, of water in a separatory funnel. The aqueous extract was treated with aqueous silver nitrate solution and dilute nitric acid, the presence of chloride ions being indicated by the formation of a white precipitate of silver chloride. Determination of Chlorine - The peroentage by weight of combined or.iorlne was determined by the method of Carlus. RESULTS The results of the identification testa are re corded in Table I. FLASH POIHT TESTS: METHOD \ The flash point was determined with the PensfcyMartens closed tester using the method (D93-32) of the American Society for Testing Materials. J Soeolflo Gravity at 15.6 G(60 Fj r5.6"i(6'0"Fr TABLE I RESULTS OF IDENTIFICATION TESTS Pyranol No. 1476 Pyranol No. 1480 Pyranol No. 1485 1.5481 1.5492 1.5817 Pyranol No. 1488 1.5644 7iaooslty: Saybolt-Furol at 50 C(122 F) 51.2 - -- Saybolt-Unlversai at 37.8 C(100 F) - 43.3 97.7 53.9 Distillation Teat: Initial Boiling Point 352.2 C (666 F) 206.6 C(404 F) 207.7 C(406 F) 206.1 C (403 F) Temperature Below 235 0(455 F) 235 C (455 F) to 270 C(510 F) 270 0(518 FJ to 365.5 0(690 F) Above 365.5 0(690 F) amount distilled amount distilled amount distilled amount distilled 43.7$ by weight 18.7$ by weight 31.0$ by weight 5.1# " " 10.0$ " " 9.7$ " " 72,1$ by weight 0.14# " 24.0$ " 46.6 # " " 0.5$ " 65.9$ " 0.4$ " 54.8$ " End Point Residue Distillation Loss 374.4 0(706 F) 3.5$ by weight 0.4$ 11 " 394.4 G (742 F) 3.0$ by weight 1.2$ " " 395.0 C(743 F) 4.0# by weight 0.9# " " 396.1 C(745 F) 3.5$ by weight 0.6$ n Acidity as HCl.Per Gent by Weight 0.0017 0.0018 0.0018 0.0011 Free Chlorides Chlorine absent (1) presen t absent (1) present absent (i) present absent U) present (1) The percentage by weight of combined chlorine corresponds closely to data furnished by the manufacturer and held as confidential. tMo CoeJi i o* i MH2581 7 RESULTS The results of the flash point tests are as follows: (2 ) Sample No. Flash Point 1476 . 1480 148 5 1488 232.2 C(450 F) 115.6 C (240 F) 118.3 C (245 F) 115.6 C (240 F) FIRE TESTS: METHODS The fire tests were made with the Cleveland open cup, using the method (D92-33) of the American Society for Testing Materials. RESULTS t e s t a .Sample Nos. 1476, 1480, 1485, and 1488 gave negative^) results in the fire (4) IGNITION TEMPERATURE TESTS: METHOD The apparatus consists essentially of a combus tion chamber surrounded by a solder bath, which is heated at a constant temperature during the test by a bunsen burner. The temperature of the solder bath is measured by means of a calibrated thermocouple provided with a quartz tube to protect the hot Junction. (2) In this connection, see Note 4. (3) Intermittent flashes were obtained but the product did not continue to b u m . The sample was heated to boiling point; the test was then discontinued. (4) In view of the negative results obtained in the Fire Tests, it is clear that the flash point test cannot be depended upon to give a true measure of the fire hazard of these products. It was therefore neces sary to conduct tests of the explosibillty of the vapors of the produots in specially-designed appar atus. See page 10, et.seq. MH2581 -8- The aombuation ohamber consists of a quartz flask of oonical form with flat bottom, 4-1/2 in. (11.4 om.) in height, 2-3/8 in. (6.0 om.) in diameter at bottom, and l-l/8 in. (2.8 om.) in diameter at top. It is of about 160 OQ. capacity (rated capacity 125 oc.) having a ratio of surface area to volume of about 1.1 Measured test samples in the liquid phase are in troduced into the heated combustion ohamber by means of a micro pipette. Different amounts of the sample are admitted to the ohamber in successive tests in order to determine the minimum temperature at which the vapor of the liquid 'in any proportion with air will ignite. The residual vapors or gases in the combustion chamber are completely displaced by a stream of air in the interval between tests. Ignition temperature tests were also conducted using a horizontal iron plate 10 in. square and l/4 in. in thickness, heated by a gas burner. Flames and hot gases from the burner are deflected from the upper surface of the iron plate by a strip of sheet iron extending 10 in. beyond each side of the plate. The deflector is bolted to the edges of the plate, asbestos gaskets being provided at the Joint. A calibrated ohromel-alumel thermocouple (Ho. 14 Awg) connected with a potentiometer is used to measure the tem perature of the plate, the hot Junction of the thermocouple being brazed to the oenter of the upper surface of the plate. Cheok measurements of the temperatures of the plate are also made employing an optioal pyrometer of the disappearing filament type. In conducting teats, measured samples (up to 10 oo.) were dropped on the oenter of the heated plate. A alow stream of air was applied to the evaporating sample in some of the tests. The minimum ignition temperature was deter mined by suooessive trial teats, during which the iron plate was maintained at progressively lower temperatures. HH2581 -9- RESULTS The results of the ignition temperature tests are tabulated below: (5) Ignition Temperature Samnle No. Q.uartz Flask Iron Plate . 1476 : Col : m 571 C (1059 8 F) lag 3-4 see. 754 C(1389.7 p) 1480 553 0(1027.4 P) " " " 714 0(1317.2 F) 1485 539 0(1002.2 F) " " " 714 0(1317.2 F) 1488 553 0(1027.4 P) " " " 716 0(1320.8 F) In the ignition tests using the heated iron plate the aombustion was very weak and did not show any tendency to propagate beyond the vicinity of the heated Iron surface. It will be noted that there was no con finement of the vapors in 'the tests with the heated iron elate. (5) The main value of the ignition test is to determine the minimum temperature required to produce igni tion under the most favorable conditions in the ab sence of a flame or spark, including ratio of vapor to air and ratio of heated surface to volume of vapor-air mixture. Under less favorable conditions as when the liquid is applied to a hot plate a higher temperature for ignition is required. A limitation of the ignition test in a small vessel is that it does not show whether flame propagation for any material distanoe will occur. After deter mining the ignition temperature therefore it is necessary to obtain additional data having a bear ing on flame propagation. These data- are given by testa with hot plate and by flammability tests with specially-designed apparatus. (6) The term "lag" is used to denote the time interval between the introduction of the sample and the appearance of flame. (7) Within experimental error the optical pyrometer and the thermocouple gave the Bame values for the tem perature of the iron plate. MH2581 10 FLAMKA3IIITY T5STS IN SFSOIALLY-DFSIGNTD APPARATUS: METHOD The apparatus consists of a cylindrical steel vessel 6 in. in diameter (internal} and 26 in. long. It is provided with a snail mioa window and an outlet to the atmosphere. The apparatus is heated externally'by gas burners. Openings* are provided half way between the ends of the vessel to admit eleotrode terminals connected to an induction coil. The eleotrode terminals are spaced to give a spark gap of l/4 in. An iron-oonstantan thermocouple connected to a potentiometer is used for rough measurements of the tem perature of the vapor inside of the vessel. Samples ranging in- volume from 20 to 90 oc. were introduced into the cylinder whioh had previously been heated to a predetermined temperature. The outlet of the cylinder was closed with a loose asbestos plug. Sparks were passed between the electrode terminals at intervals of l/2 min. Residual gases and vapors were displaced from the cylinder.by a stream of air in the interval between tests. SSSULTS Sample No. 1475 - No propagation of flame oc curred at tempera mires up to 204 0(399.2 F). Flame propa gation with weak pressure affoots (Just sufficient to push asbestos plug from outlet of cylinder) occurred at 208'C (406.4 F). Moderate pressure effects (asbestos plug thrown about 3 to 4 ft. horizontally from outlet of cylinder) were obtained at temperatures somewhat above 208 C(406.4 F). Sample No. 1480 - No propagation of flame oc curred, at temperatures up to 108 0(226,4 F). Flame propa gation with weak pressure effects occurred at 112 0(233.6 F). Moderate pressure effects were obtained at temperatures somewhat above 112 0(233.6 F). Sample No. 1485 - ^No propagation of flame 00- * curred at temperatures up to 110 0(230.0 F). Flame propa gation with weak pressure effeots occurred at 113 0(235 F). Moderate pressure effeots were obtained at temperatures somewhat above 113 0(235.4 F). MH2581 11 Sample No, 1488 - Ho propagation of flame oc curred at temperatures up to 110 C (230.0 F). Flame propagation with weak pressure effects occurred at 113 C ^235.4 FJ. Moderate pressure effects were obtained at temperatures somewhat above 113 0(235.4 F). S31QSIV3 RANGE TESTS: METHOD The apparatus consists essentially of a glass chamber equipped with a spark gap and a stirrer. The chamber la cylindrical with the lower and hemispherical and is approximately 3 in. in diameter by S in. in height; It has a net volume of 1000 oo. The apparatus is provided with a glass lid supporting the stirrer and the leads to the spark gap near the bottom of the chamber. An opening in the lid Is provided for introduction of the sample. The glass chamber ia immersed in a molten solder bath to a depth of 6 in. In oonduotlng tests the solder bath was maintained at a constant temperature of 400 0(752 F), a measured quan tity of the liquid to be tested was placed in the apparatus, and the vapors stirred. Sparks were then passed at the spark gap while observations were made for flame travel and pressure effects. Following the test the vapors were displaced by a slow stream of compressed air in preparation for the next test. RESULTS The results of the explosive range tests of Sample Nos. 1476 and 1480 in air at 400 0(752 F) are shown in Table II. DECOMPOSITION TEMPERATURE TESTS: METHOD The apparatus described in oonneotlon with Igni tion Temperature Tests was used In these tests. The vapors evolved on introducing samples into the heated chamber were . tested with moist blue litmus paper; a change in the color * of the paper from blue to red indicating decomposition of the product. The minimum temperature at which litmus paper ' showed an appreciable change in color within a short time (3 min.) was considered to be the decomposition temperature. /""'S MH258I TAJ3LE II RESULTS OF EXPLOSIVE RANGE TESTS Sample No. 1476 1480 Volume Used in Test CC. 0.038 0.042 Lower Limit Lb.Vaporized Liquid per 1000 Cu. Ft. of Air (Caloulated) 3.69 4.09 Per Gent by Volume (Galoula ted) 1.0 1.6 Volume Used in Test CC. 0.100 0.105 Upper Limit Lb. Vaporized Liquid per 1000 Cu. Ft. of Air (Caloulated) Per Cent by Volume (Caloulated) 9.67 2.7 10.18 3.9 Weak pressure effoots were obtained in these tests, as would be expeoted for mixtures near the llmltB of flammability. KH2581 - 13 RESULTS Results of the decomposition temperature tests are recorded in the following table* Samnia No. 1476 1480 1485 1488 Decomposition Temperature 300 0(572.0 F) 324 0(615.2 F) 340 0(644.0 F) 340 0(644.0 F) A N A i m C A L TESTS OF DECOMPOSITION PRODUCTS: METHOD Hot Iron Surfaces - The cylinder previously de scribed under fiammaOillty Teats In Cpecially-designed Apparatus was also used for exposing vapor-air mixtures to hot iron surfaces. Connections for withdrawing sample of the decomposition products for analysis were inserted in the outlet pipe. The cylinder wa9 externally heated to a temperature of 600 0(1112 ?) by gas burners. Samples of the product in the liquid phase were introduced into the heated cylinder at a uniform rate. Samples of the decomposition products were withdrawn from the outlet pipe and hydrochloric acid, free chlorine, phosgene, carbon dioxide, oxygen, carbon monoxide, gases absorbed by bromine, and methane and other paraffin hy drocarbon gases, were determined using the following methods. Hydrochloric acid was determined by absorption with water and subsequent titration with standard alkali solution using methyl orange as an indicator. A sevenliter sample was drawn by a calibrated aspirator bottle* through an absorption train consisting of three spiral form bubbling towers. Free chlorine interferes with the determination and la removed by mercury in contact with the water in the bubbling towers. Tests for free chlorine were made by liberation of iodine from aqueous potassium iodide solution and sub sequent titration with sodium thiosulphate solution using staroh solution as an indicator. A seven-liter cample was drawn by a calibrated aspirator bottle through a train oonaisting of two spiral form bubbling towers containing potassium iodide solution. r> 'N MH2581 - 14. Phosgene was determined by absorption in aqueous aniline solution. Phosgene reacts quantitatively with aniline to form diphenylurea, one molecule of phosgene being equivalent to one molecule of diphenylurea. A. 15-liter sample was drawn through a train of three bubbling towers containing freshly prepared aqueous aniline solution saturated with diphenylurea. Free chlorine interferes with the determination and was re moved by granulated antimony oontalned in a tube through whloh the sample passed before it entered the bubbling towers. The precipitate of diphenylurea was separated from the aniline solution by filtration, washed with cold water, dissolved in ethyl alcohol, reoryatallized, dried, and weighed. Carbon dioxide, oxygen, oarbon monoxide, gases absorbed by bromine, and methane, were determined in the Hoorehead form of gas analysis apparatus after treating the sample with silver nitrate solution to remove hydro- . chloric acid. Electric Arcs - The apparatus consists of a cy lindrical steel vessel 10 in. in diameter (internal) and 16 in. high. It la provided with a anall mica window and an outlet to the atmosphere. Openings are provided in the vessel to admit two eleatrode holders, one holder being fixed and the other movable. The electrodes' are cooper rods 1/2 in. In diameter; their aroing terminals are horizontal, A connection for withdrawing samples of decomposition products for analysis is Inserted in the wall of the vessel. A anall cylindrical settling ohamber for the removal of solid products of decomposition is at tached to the sampling connection. The electrodes are connected to a 230-volt, d-o. test olrouit, the current being controlled by resistors. An ammeter is connected in the olrouit and a voltmeter is oonneoted across the electrode terminals. A sample of the produot, about 15 lb., was placed in the vessel, the arcing terminals of the electrodes being > partially immersed in the sample. The aroing terminals were located on the axis of the oyUnder, 3-1/2 in. above the bottom. A continuous arb (170 amperes) was maintained between the electrodes until destruction of the aroing terminals (5 min.). HH2581 15 - Samples of'the decomposition products were with drawn continuously during this period and tested for phosgene and chlorine using the methods previously de scribed* Samples of the deoomposition produota were also collected in evacuated glass sampllngj tubes at the conclusion of the test and the chief constituents de termined, employing the following methods* Eydrochlorlo acid was determined by absorption in water and titration with standard alkali solution* Carbon dioxide, carbon monoxide, oxygen, gases absorbed by bromine, and paraffin hydrocarbon gases were tested for,using the Moorehead apparatus after treating the sample with water to remove hydrochloric aaid* Tests were also conducted with the arcing ter minals of the electrodes 3-3/4 in* below the level of the sample in the vessel* A 31-lb* sample of the product was used in these tests. The arcing terminals were located on the axis of the cylinder, 2 in* from the bottom. A con tinuous arc (125 to 190 amperes) was maintained between the electrodes until destruction of the arcing terminals* Sam ples of the decomposition produota were withdrawn at inter vals during the test (See Table 7) and the chief constituents determined using the methods previously described* RESULTS Hot Iron Surfaces r The results of analytical tests of the decomposition products are shown in Table III. Eleotrio Arcs - The results of analytical testa of the decomposition products in the presence of an elec tric arc between terminals partially immersed in Sample Nos. 1476 and 1480 are shown in Table 17. The results of analytical tests of the decompo sition products in the presence of an eleotrio arc between terminals Immersed in Sample Nos. 1476 and 1480 are shown in Table 7. TESTS OF TRANSFORMERS TO DESTRUCTION: METHODS The following tests were conducted at the Pitts field, Massachusetts, plant of the General Eleotrio Company. KH2581 TABLE III RESULTS OF ANALYTICAL TESTS OF DECOMPOSITION PRODUCTS IN PRESENCE OF HOT IRON SURFACES Hydroohlorio Aold Per Cent by Volume Shlorln " "" " Phosgene n n " rt o o o Sample No. 1476 5 to 13 Uln. after Start of Test 11.2 0,,000 0. Sample No. 1480 5 to 13 Uln. after Start of Test 7.5 0.000 ().300 D Min.after 13 Min.after 5 Win.after 13 kiln.after , Start of Teat Start of Test Start of Test Start of Test Carbon Dioxide " " rt n 27.6 20.2 15.2 15.6 Carbon Monoxide " " rt " 13.2 8.0 17.0 11.4 Oxygen " "n " 1.0 1.0 2.0 0.4 Cases Absorbed by Bromine n rt " 0.0 0.0 0.0 o o Methane and Other Caaeous Paraffin Hydrooarbons " "" " 0.0 0.0 0.0 0.0 ----------------- .-- .....- .... . .. In addition to the above volatile deoompoaltlon produots some finely divided oarbon was formed. V MH2581 TABLE IV RESULTS OF ANALYTICAL TESTS OF DECOMPOSITION PRODUCTS IN THE PRESENCE OF Samolo No* 1476 6 iiin.after Start of Teat Hydroohlorlo .old Per Cent by Volume Carbon Dioxide " n " " 26.7 l.a Carbon Monoxide " " 11 " 7.7 Oxygen " "n " 7.7 Cases Absorbed by Bromine nun 0 .0 Methane and Other Gaseous Paraffin Hydrocarbons " "" " 0 .0 Chlorine Phosgene Start of Test to 5 Min.after Start of Test 0 .000 0 .0 0 0 oarbon was formed. (3) Less than 0.001 per oent by volume Sample No. 1480 > Min.after Start of Teat 34.0 0.7 4.3 10.0 0 .0 0 .0 tart of iest to 5 Min.after Start of Test 0 .0 0 0 <8> trace amount of finely divided I f TBffSHJt rsuira or rihjlly cix tests or Dscotcposxtioif Products ii or ntifili f tue prsseicc Electric arcs sbtrkehteruhais ivuerssd orsauples fyrihol 2* Uln. aftar Start of Taat Ryftroohlorlo iold Par Caot by Volume Carboa Dloxlda II * m m CarbonWonoxlde n m m Oxygen n nm m 36.5 0.0 O.fi 12.4 Oaaaa ibaorbad bj Broalna m VI m * 0.0 Uathane and Othar Saaooua ParafiIn Rydrooarbona n vt m 0.0 Saaple fio. 1476 5 Ilio. 6* Uln. aftar Start aftar Start of Taat of Taat 62.0 69.2 0.0 0.0 0.5 0.4 7.4 5.7 0.0 0.0 0.0 0.0 5 Uln. aftar Start of Taat 17.7 0.0 0.5 16.0 0.0 0.0 Chlorloa Phoagaoa n 1 m m mn m Start of Taat to 5| llln. aftar Start of Tast il.ODO traoo1) la tddltloD to tht abova volatila daoapoaitlon prodilotaa largo aaount of flnoly dlvlded oarbon aa formad. (91 Laaa than O.OOl par oant by voluaa, Samolo lo. 1400 7.5 Uin. 10 Uln. aftar Start aftar Start of Teot of Taat 6o0..a5 62.4 0.0 0.2 0.2 7.6 7.3 11 Uln. after Start of Taat 73.1 0.0 0.2 6.1 0.0 0.0 0.0 0.0 Start of Taat to 11 Uln. after Start of Taat 0.000 (9) traaa 0.0 0.0 MHS 551 19 Two transformers, rated 60 cycles, 5 kv-a., 2200110 volts, were employed, the interiors being designed for use in Pyranol. Taps were brought c it from the outer layer of the 123-volt winding, arranged in suoh a manner that an arc could be started between the coil and carbon blocks located on the core clamps. The carbon blocks were used so that the arc could be maintained more readily during the arcing test. Steel subway tanks were used for these test trans formers in order to provide 'sufficient strength to with stand the nressure generated during the transformer failure Pressure-tight covers were provided with glass pressur re lief diaphragms designed to break at not less than 10 to 12 lb. pressure per square inch. A visual pressure indicator was provided In the cover to show the pressure in the tank before the relief diaphragm was broken. Pyranol No. 1488 was used in these tests. Short Circuit Test - The first transformer was prepared with the arcing tips bent back clear of the core and was connected for test as shown in Fig. 1. The secon dary winding was ahort-oiroulted externally and the pri mary winding was connected across a 12,000 kv-a. generator at 1500 volts. Arolng Test with Arc from Coil ~.o Core - The seoond transformer was prepared with the arcing tips bent so that they made light contact with the carbon arcing blocks and waB connected for test, as shown in Fig. 2, with the primary and secondary windings in series. The oore, tank, and the other high voltage lead were connected to ground. The 12,000 kv-a. generator was connected so as to apply 7500 volts between the ungrounded 122-volt lead and ground. The transformers before test are shown in Figs. 3 and 4. RESULTS Short Circuit Test - No aopreoiable change in pressure within the tank was noted for approximately 2 min. after current waa supplied to the transformer. The pressure increased fairly rapidly from thereon, and ap proximately 15 seo. later the pressure relief diaphragm ruptured at a pressure of about 12 lb. per sq. in. Cur rent was applied to the transformer for approximately l/2 min. after the diaphragm ruptured. S e c / v O A /? y AO /2 2 y & r W V /V S Q /,V G *f ^ P * * sfA f l y <% * > ^ 2 2 G C 10*34.7% W S /V & //V < 5 *< sl . , /roo y 'f y 22.00 SCiTSS/ O //*SO FIGZ FIGa 3 r I FlGT 4 MH2561 20 - A large volume of gases was liberated during the test. These gases did not Ignite upon application of a test flame. Upon examination of the transformers after the test, the noils were found to be severely burned. Arcing Teat with Arc from Coll to Core - No ap preciable change in pressure within the tank was noted for approximately 2 min.'after current was supplied to the transformer. From then on the pressure increased slowly to about 8 lb. per sq. in. and then increased rapidly to about 16 lb. per sq. in. before the pressure relief diaphragn ruptured. The arcing stopped'shortly after the diaphragm ruptured. Current was supplied to the trans former for about l/2 min. after the diaphragm ruptured. A large volume of gases was liberated during the test. These gases did not ignite upon application of a test flame. Upon examination of the transformer after the test, it was found that aros had been established betweenthe aralng tips and the oore. There was no evidence of arcing along the face of the coil. CORROSION TESTS: METHOD The metals used in the corrosion tests were copper, yellow brass, iron, tin-lead solder, copper and tin-lead solder, and copper and iron coupled.. Test speci mens, 3/4 in. wide and 6 in., long were cut from sheets of the metals. The specimens were buffed, measured, oleansed with soap and water, washed with ethyl aloohol and ethyl ether, dried, and weighed. Eaah specimen was Immersed for half its length in a sample of the product contained in a glass tube provided with a cork stopper. The tubes were heated to a temperature of 90 C in an eleotrioally-heated oven oontrolled by a ther mostat. The samples were examined visually at weekly in tervals during the test for eVidenoes of corrosion. At the conclusion of the test, the specimens were cleansed, dried, weighed and the change in weight per square centi meter of surface area calculated. MH2581 - 21 RESULTS When heated in glass tubes containing Sample No. 1476, 1480, 1485, or 1488 of the products at 90 C for 1608 hr., specimens of copp.er, yellow brass, copper and tin-lead solder, and oopper coupled with iron Bhowed no visible evidence of corrosion except for a slight dis coloration of the surfaces above the liquid. Specimens of iron, iron coupled with oopper, and tin-lead solder showed no change in appearance. The change in weight of the speci mens was very small (less than 0.1 mg.per sq.om.) R E C O R D Iff S E R V I C E These materials have been in commercial service In increasing amounts during the past three years. The value of these liquids as dielectric and cooling media has been demonstrated. THE S U 3 K I T T 0 8 The manufacturer, the General Electric Company, Schenectady, New York, is experienced in the manufacture of electrical apparatus and related products, many of their products being listed by Underwriters' Laboratories. SUPERVISION OF PRODUCTS BY UNDERWRITERS' LABORATORIES: The products will be placed under Reexamination Service. MH2581 r^ V,, 22 conclusions SSNSRAL NATJR5: These, produces are mixtures of chlorinated aro matic hydrocarbons The results of the Identification Tests indicate that the products are mixtures containing oombined chlorine in amounts corresponding closely to those stated by the manufacturer FIHE AND TOXIC HAZARD: These products are nonflammable at ordinary tem peratures. They are capable of forming moderately com bustible and explosive mixtures with air uwder laboratory test conditions at higher temperatures, beginning at a temperature level of 112 C(233.6 F) to 113 C(235.4 F ) , in the case of Pyranol Nos 1480, 1485, and 1488, and 208 C (4064 F) in the case of Pyr&nol No 1476, but under prac tical conditions formation of combustible or explosive mixtures is regarded as extremely unlikely The fire hazard is very small. It will be noted that the flash points of the products are comparatively high, and that a so-called "fire pointrtwae not obtained While Intermittent flashes oc curred in this test, the products did not oontinue to burn The flash point and so-called "fire point" testa, partic ularly the latter, in the case of chlorinated hydrocarbons are of limited value as a measure of fire hazard but are useful for purposes of identification The practical significance of the above tdsts In the case of the products in question is that their fire hazard is of a low order (\ MH2581 - 23 y y As shown by the results of Flammability Teats In Specially-designed Apparatus vapors of Pyranol So. 1476 failed to ignite or explode in tests at 204 C(399.2 F) but weak combustion occurred in testa at 208 0(406.4 F). Vapors of Pyranol Nos. 1430, 1485, and 1488 failed to ignite or, explode in tests at 108 to 110 C(226.4 F to 230.0 F) but weak combustion ooourred in tests at 112 to 113 0(233.6 F to 235.4 F). Moderate explosions were ob tained.in tests at temperatures somewhat above these minimum values. At a temperature of 400 0(752 F) the lower limits of flammability (upward propagation) of the vapors of Pyranol Nos. 1476 and 1480 were'found to be 1.0 per cent and 1.6 per cent by volume in air respectively and the cor responding upper limits of flammability (upward propagation) were found to be 2.7 per oent and 3,9 oer bent by volume. It will be noted that*these are comparatively narrow ex plosive ranges. The minimum ignition temperatures of the products were found to be 571 0(1059.8 F), 553 0(1027.4 F ), 539. C( 1002.2 F), and 553 0(1027.4 F) for Pyranol Nos. 1476, 1480, 1485, and 1488 respectively as recorded in the results of Ignition Temperature Tssts. In the ignition tests using the heated iron no ignition ooourred at plate temperatures below 714 0. At higher temperatures the combustion was very weak and did not propagate beyond the vicinity of the heated iron surface. In the tests with electric arcs the gases liber ated, carbon monoxide and hydrochloric acid, were in such proportions as to be nonflammable alone or mixed with air. It will be noted that in the case of mineral oil under similar condition, highly explosive gases would be formed. In the Ts9ts of Transformers to Destruction under both short-circuit and arcing conditions, with Pyranol No. 1488 as the dielectric medium, the gases liberated were practically nonflammable. The gases or fumes produced by burning or de composition of the products by hot metal surfaoes or eleotrib arcs include hydrochloric acid, carbon monoxide, and in some oases a small amount of phosgene. This will ordi narily constitute a r.oxic hazard only where the conditions are suoh as to aause confinement of the fumes as in a closed room in which combustion or decomposition of the products i8 maintained by fire, highly heated surfaces, or eleatric aros. HH2561 24 It Is to be noted in this oonnection that oils in common use at present as the dielectric medium for elec trical apparatus are readily combustible and when burning under conditions of restricted air suooly form carbon mon oxide in dangerous concentrations While phosgene is poisonous, our data indioate that the concentrations likely to result in the failure of a transformer or other electrical apparatus containing these products are not liable to endanger life. The resulting concentration of hydrochloric acid In air when failure of a transformer or other electrical apparatus containing these products occurs will depend largely upon the conditions. It will constitute a toxic hazard only where the conditions are such as to cause a high concentration of the fumes as in a closed room. The exceedingly unpleasant and Irritating fumes from the decomposition of these products even in ooncenr trations of a very low order act not only to give warning of their presence but to prevent dangerous exposure of persons. While carbon monoxide is odorless and toxic its formation from these products is always accompanied, by the simultaneous formation of hydrochloric acid gas which gives adequate warning of its presence as brought out above. - It will be noted that combustion and decomposition of the products was maintained by heated surfaces (600 C, 1112 F)'or by an electric arc in carrying out the analytical tests of the decomposition products. As shown by the results of the Decomposition Temperature Tests, the oroduots were not aDpreolably decomposed at temperatures below 300 C(572 7). CORROSIVE ACTION: The produots do not oorrode the metals commonly used in electrical apparatus. No corrosion occurred in the tests conducted on representative metals and alloys as recorded under Corrosion Teats* It will be noted from the results of Analytical Tests of Decomposition Products that appreciable amounts of hydrochloric acid are formed on combustion or decompo sition of the products in the presenoe of hot metal surfaces or electric arcs. MH2581 - 25 - STABILITY*: The products are reasonably stable and in use are unlikely to undergo decomposition resulting in an in crease in fire hazard. In the Decomposition Temperature Tests the prod ucts did not undergo appreciable decomposition at tem peratures below 300 C(572 F)* Considerations of the 'Chemical structure and properties of the products also indicate that they are reasonably stable* UNIFORMITY: Considering the general process of manufacture, it appears to be practicable to maintain a high standard of uniformity on a commercial scale* r^. `n ' f` RECOMMENDATION TO THE EXEC TNICAL AND FIRE COUNCILS OF UNDERWRITERS* LABORATORIES; We re^-immend promulgation of the following notice to subscribers and the action indicated thereby: Guide No. 540 14 September 29, 1934 - Laboratories1 File MH2581 General Electric Co*, Mfr*, 1 River Road, Schenectady, N. T. Dielectric Mediums Synthetic liquids intended for use as dielectric and cooling mediums in eleotrioal apparatus, particularly transformers, oables, and capacitors. Nonflammable and nonexolosive at ordinary temperatures* Marking; "Ryranol Nos. 1476, 1480, I486, or 1488." Listed by Report - Further information is contained in a re tort dated September 29, 1934, copy of which may be ob tained either from the manufacturer or from Underwriters* Laboratories. Listed - Reexamination Servioe. See deBcrlptir-i of Reexamination Servioe on guide card. Teats by: A. H. Nuckolls R. E. Dufour C. C. Clogston Report by: Reviewed by: Asgo.Cheo.Engr. Chemlpal Engineer. Thp foregoing Recommendation has been accepted RED:BIS