ASTM D2945-90(2003)e2

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
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Designation:D2945–90(Reapproved 2003)
Standard Test Method for
Gas Content of Insulating Oils
This standard is issued under the fixed designation D2945; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
´ NOTE—The metric value for the inside diameter of vinyl tubing in Fig. 1 was corrected editorially in December 2003.
´ NOTE—The mercury warning was editorially added in April 2009.
1. Scope Analysis and Determination of Water Content
1.1 This test method covers the determination of the gas
3. Summary of Test Method
content of electrical insulating oils of low and medium
3.1 This test method consists essentially of allowing oil to
viscosities in the general range of 100 SUS and below at 100°F
flow into an evacuated chamber as a thin film so that the oil is
(37.8°C), and is suitable for field or laboratory use.
thoroughly exposed to the vacuum, allowing free volatilization
NOTE 1—Fortestinginsulatingoilswithviscositiesabove100SUS,see
of the gaseous component. The system is brought back to
Test Method D831. For individual gas concentrations, see Method D3612.
atmospheric pressure, and the evolved gases measured. From
1.2 Warning—Mercury has been designated by EPA and
the volume of oil degassed in the chamber and the volume of
many state agencies as a hazardous material that can cause
released gas, the percent gas content may be estimated. The
central nervous system, kidney, and liver damage. Mercury, or
apparatus used produces the necessary vacuum without resort-
its vapor, may be hazardous to health and corrosive to
ing to use of a vacuum pump. This test method partially
materials. Caution should be taken when handling mercury and
degases the oil. The degree of degasification varies with the
mercury-containing products. See the applicable product Ma-
solubility of each gas in the oil.
terial Safety Data Sheet (MSDS) for details and EPA’s website
4. Significance and Use
(http://www.epa.gov/mercury/faq.htm) for additional informa-
tion. Users should be aware that selling mercury or mercury-
4.1 In filling electrical apparatus, it is desirable to use low
containingproducts,orboth,inyourstatemaybeprohibitedby gas content transformer oil in order to prevent foaming and to
state law.
avoid air pockets that might result in gaseous ionization. This
1.3 This standard does not purport to address all of the procedureprovidesasimplemethodtomeasurethegascontent
safety concerns, if any, associated with its use. It is the of the oil, and may be used as a factory-control test and as a
responsibility of the user of this standard to establish appro-
control or functional test in installation and maintenance work
priate safety and health practices and determine the applica- by utilities.
bility of regulatory limitations prior to use.
5. Apparatus
2. Referenced Documents
5.1 Dissolved Gas Content Analyser—Fig. 1 shows the
2.1 ASTM Standards:
assembled instrument, not drawn to scale, to permit magnifi-
D831 Test Method for Gas Content of Cable and Capacitor cation of small details. A borosilicate glass gas buret, 100-mL
Oils
capacity, graduated in ⁄5-mL divisions, serves as a vacuum
D3612 Test Method for Analysis of Gases Dissolved in chamber. A three-way stopcock, 120° bore with TFE-
Electrical Insulating Oil by Gas Chromatography
fluorocarbon plug, 3 stem, 2-mm bore is fused to the buret or
D3613 Practice for Sampling Insulating Liquids for Gas joined by a vinyl sleeve so that the joint is vacuum tight.
5.1.1 Rubber Vacuum Tubing—About 1200 mm of 8-mm
rubber vacuum tubing is securely fastened with a 20-mm
Hoffman pinch clamp to the lower tip of the buret, while the
This test method is under the jurisdiction of ASTM Committee D27 on
other end is secured to a 250-mL capacity leveling bulb.
Electrical Insulating Liquids and Gases and is the direct responsibility of Subcom-
mittee D27.03 on Analytical Tests.
5.1.2 Stubs 20 Gage Needle—Ashort section, about 40 mm
Current edition approved Feb. 23, 1990. Published April 1990. Originally
long, is cut and cemented to the three-way stopcock, Fig. 2.
published as D2945 – 71. Last previous edition D2945 – 84. DOI: 10.1520/D2945-
This serves to accommodate the vinyl tubing attached to the
90R03E02.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Withdrawn. The last approved version of this historical standard is referenced
the ASTM website. on www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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D2945–90 (2003)
1 gas buret, capacity 100 mL, graduated in ⁄5-mL divisions
1 stopcock, 120° bore with TFE fluorocarbon plug, 3 stems, 2-mm bore
1 leveling bulb, capacity 250 mL
1 beaker, capacity 250 mL
1200 mm (4 ft) vacuum rubber tubing, 8-mm ( ⁄16-in.) inside diameter
2 rubber tubing clamps, adjustable, cadmium-plated steel
2-pinch clamps, Hoffman swivel jaw, screw compressor, ⁄4 by 1 in. for vinyl tubing for 5 and 50-mL syringes
1 pinch clamp, Hoffman screw compressor for rubber tubing, ⁄4by1in.
6 clamps, wall type with wood screw to support buret, stopcock, and rod
1 leveling bulb support, adjustable, Fisher-Castaloy-R, self-locking
1 rod, diameter 12 mm ( ⁄2 in.), length 1500 mm (58 in.)
1 syringe, Luer, resistance glass, 50 mL, subdivisions 5 mL
1 syringe, Luer, resistance glass, 5 mL, subdivisions ⁄5 mL
1 1
Vinyl tubing, 1.6-mm ( ⁄16-in.) inside diameter, wall thickness 1.3 mm ( ⁄32 in.), length 150 mm (6 in.)
4.5 kg (10 lb) mercury
1 needle, 50 mm long, Stubbs gage 20
1 wooden board 1500 by 700 by 20 mm (58 by 28 by ⁄8 in.)
Components for Gas-Content Apparatus
FIG. 1 Dissolved Gas Content Analyser
FIG. 2 Detail of Needle Inlet
syringe.Alltheglasswareshouldbeclampedtoasuitable1500 5.1.3 Metal Rod, 12 mm, 1500 mm long, fitted with an
by 700 by 20-mm mounting board with rubber-covered wall- adjustable leveling bulb support is fastened to the wooden
type clamps. apparatus mounting board as in 5.1.2.
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D2945–90 (2003)
5.2 Syringe Assembly (see Fig. 3)—A 50-mL Luer syringe syringe. When full, release the drain tubing and allow the
with 5-mL subdivisions or a 5-mL Luer syringe with ⁄5-mL syringe to empty itself into the tee. This is repeated several
subdivisions is fitted with a 150-mm length of 0.8-mm inside times with the syringe in vertical position to expel any possible
diameter capillary vinyl tubing. An upper and lower collar of air bubbles from the syringe and inspect visually.After the last
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