ASTM_D_1827_-_92_2002.pdf

Designation:D 1827 92(Reapproved 2002)Standard Test Method forGas Content(Nonacidic)of Insulating Liquids byDisplacement with Carbon Dioxide1This standard is issued under the fixed designation D 1827;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method describes the determination of the gascontent of electrical insulating liquids with a viscosity of 216cSt or less at 100C.Any gas that is nonreactive with a strongcaustic solution may be determined.NOTE1The test method has a bias for samples containing gases otherthan oxygen and nitrogen in atmospheric ratios due to differentialsolubility effects.Gases which react with KOH such as carbon dioxidewill not be measured.Unsaturated hydrocarbons such as acetylene,ifpresent,will react with KOH to a small degree and will result in anunderestimation of the total gas present.1.2 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:D 831 Test Method for Gas Content of Cable and CapacitorOils2D 923 Practices for Sampling Electrical Insulating Liquids2D 1193 Specification of Reagent Water3D 3613 Practice for Insulating Liquids for GasAnalysis andDetermination of Water Content23.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 gas content by volumeof an insulating liquid,thevolume of gas contained in a given volume of liquid.It isusually expressed as a percentage at standard atmosphericconditions of 760 mm Hg pressure and 0C temperature.3.1.2 gas content by weightthe weight of gas contained ina given weight of liquid,usually expressed in parts per million.4.Summary of Test Method4.1 This test method consists essentially of purging dis-solved gases from a small liquid test specimen with purecarbon dioxide gas.The dissolved gases are then carried into agraduated buret(precision nitrometer)filled with a potassiumhydroxide solution for a precise measurement.The carbondioxide is completely absorbed by the potassium hydroxideand the volume of other gases is measured.5.Significance and Use5.1 Electrical insulating liquids,in many applications,re-quire low gas content.This is the case with capacitors andcertain types of cable,for example.This test is used as afactory control test and as a control and functional test ininstallation and maintenance work by utilities.This test re-quires care in manipulation and trained,careful personnel.6.Apparatus(see Fig.1)6.1 Precision Nitrometer(azotometer),A,with a calibratedcapacity of 1.5 mL and calibrated in 0.01-mL divisions.Nitrometers shall have individual calibration correction tablesthat give the correct volume for each 0.01-mL point on thescale when a 40%aqueous potassium hydroxide solution isused.The gas inlet shall consist of a 12/2 socket joint.Thenitrometer shall be provided with a liquid leveling bulb,B,of125-mL capacity.Rubber stoppers,K,with a short piece ofglass capillary tubing,should be placed in the top of thenitrometer and the leveling bulb,B,to prevent spattering of theKOH solution.6.2 Permanent Magnet and Steel Wire,The small steel wire,suitably consisting of a38-in.(10-mm)length of paper clip,shall be placed inside the nitrometer for manipulation by thesmall external permanent magnet.6.3 Pregl-Type Micro Stopcock,C,to allow delivery of gasto nitrometer or venting the gas to the atmosphere.Thisstopcock shall be provided with a 12/2 ball joint at the exit sideand a 12/2 socket joint at the inlet side.1This test method is under the jurisdiction of ASTM Committee D27 onElectrical Insulating Liquids and Gasesand is the direct responsibility of Subcom-mittee D27.03on Physical Tests.Current edition approved Aug.15,1992.Published October 1992.Originallypublished as D 1827 61 T.Last previous edition D 1827 84.2Annual Book of ASTM Standards,Vol 10.03.3Annual Book of ASTM Standards,Vol 11.01.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.6.4 Elbow Adapter,D,consisting of a 12/2 ball joint andhaving a drawn-down tip suitable for insertion in a small holein the rubber stopper,E.6.5 Stopper,E,of oil-resistant rubber,cut to fit the sample-purging chamber,F,and provided with two small holes toallow tight fitting of the elbow adapter,D,and sample deliverytube,G.6.6 Sample-Purging Chamber,F,with a 10-mm diameterfritted-glass disk,L,of medium porosity and a capacity of 15mL above the disk for 10-mL test specimens,or with a 25-mmdiameter fritted glass disk of medium porosity and a capacityof 75 mL above the disk for 50-mL test specimens