ASTM D2284-11

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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
Designation:D2284 −11
Standard Test Method for
1
Acidity of Sulfur Hexafluoride
This standard is issued under the fixed designation D2284; 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.
1. Scope 5.3 Wet Test Meter.
1.1 This test method covers the determination of the acidic NOTE 1—The meter is used to measure the volume of dry gas in liters
and hence the weight of SF samples. The density of sulfur hexafluoride
fluorides of sulfur hexafluoride (SF ).
6
6
at 0°C and 1 atm. of pressure (STP) is 6.52 g/L. The density of sulfur
1.2 The values stated in SI units are to be regarded as
hexafluoride at 25°C and 1 atm. of pressure (normal temperature and
standard. No other units of measurement are included in this pressure) is 5.97 g/L.Alternatively, the sample weight may be determined
by weighing the sample cylinder before and after sampling.
standard.
1.3 This standard does not purport to address all of the 6. Reagents
safety concerns, if any, associated with its use. It is the
6.1 Purity of Reagents—Use reagent grade chemicals in all
responsibility of the user of this standard to establish appro-
tests. Unless otherwise indicated, it is intended that all reagents
priate safety and health practices and determine the applica-
shall conform to the specifications of the Committee on
bility of regulatory limitations prior to use.
Analytical Reagents of theAmerican Chemical Society, where
3
such specifications are available. Other grades may be used,
2. Referenced Documents
provided it is first ascertained that the reagent is of sufficiently
2
2.1 ASTM Standards:
high purity to permit its use without lessening the accuracy of
D1193 Specification for Reagent Water
the determination.
6.2 Purity of Water—Unless otherwise indicated, references
3. Summary of Test Method
to water shall be understood to mean reagent grade water
3.1 Acidic constituents of the sample are absorbed in
conforming to Specification D1193.
slightly alkaline water containing an indicator and the excess
6.3 Phenolphthalein Indicator Solution (10 g/L)—Dissolve
base titrated with a standard acid solution.The resultant acidity
1 g of phenolphthalein in 100 mL of ethanol (95 %).
is expressed as equivalents of hydrofluoric acid (HF).
6.4 Sodium Hydroxide Solution (0.01 N)—Dissolve 0.4 6
4. Significance and Use
0.01 g of sodium hydroxide (NaOH) in water and dilute to 1 L.
Prepare a fresh solution weekly. Standardize by titrating
4.1 Acidic fluorides are undesirable in SF used as an
6
against a weighed amount of potassium acid phthalate.
electrical insulating gas in that they may contribute to corro-
sion or constitute dielectric hazard.
6.5 Sulfuric Acid (0.01 N)—Add 0.25 mL of concentrated
sulfuric acid (H SO , sp gr 1.84) to water and dilute to 1 L.
4.2 This test method is valid for both new and used SF.In
2 4
6
Standardize against standard 0.01 N NaOH solution.
used SF , it will only measure those active species which are
6
hydrolyzable.
7. Sampling
7.1 Take the sample as a liquid from the cylinder to be
5. Apparatus
sampled.Thismaybedonebyinvertingthecylindersothatthe
5.1 Gas Washing Bottles, 500-mL capacity, two required.
outlet valve is at the bottom.
5.2 Microburet, graduated to 0.01 mL.
8. Preparation of Apparatus
8.1 Place the cylinder to be sampled as suggested in Section
1
This test method is under the jurisdiction of ASTM Committee D27 on
7andconnectaneedlevalvetothecylinderoutlet.Connectthe
Electrical Insulating Liquids and Gases and is the direct responsibility of Subcom-
mittee D27.06 on Chemical Test.
3
Current edition approved May 1, 2011. Published May 2011. Originally Reagent Chemicals, American Chemical Society Specifications, American
approved in 1964 as D2284 – 64T. Last previous edition approved in 2002 as Chemical Society, Washington, DC. For Suggestions on the testing of reagents not
D2284 – 95(2002) which was withdrawn January 2011 and reinstated in May 2011. listed by the American Chemical Society, see Annual Standards for Laboratory
DOI: 10.1520/D2284-11. Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
2
The boldface numbers in parentheses refer to a list of references at the end of and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
this standard. MD.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
D2284−11
inlet of one of the gas sampling bottles to the cylinder needle
D = density of SF gas, g/L,
6
valve and the outlet to the wet test meter. Flexible ru
...