ASTM D7959-15

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D7959 − 15 An American National Standard
Standard Test Method for
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Chloride Content Determination
This standard is issued under the fixed designation D7959; 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 Elevated chloride levels have caused corrosive and abrasive
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wear of aircraft fuel control systems leading to engine failure.
1.1 This test method covers a rapid means of determining
chloride content of aviation turbine fuel. This methodology is
5. Interferences
applicable for chloride concentrations between 0 mg⁄L to
5.1 Some pH 7 buffer solution can contain trace levels of
0.3 mg⁄L.
chloride compounds and therefore produce a false positive
1.2 The values stated in SI units are to be regarded as
reading on the chloride test strip. Prior to using a new batch of
standard. No other units of measurement are included in this
pH 7 buffer solution, a sample should be confirmed to produce
standard.
no reading on the chloride test strip.
1.3 This standard does not purport to address all of the
6. Apparatus
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
6.1 Magnetic Stir Plate and Stir Bar—The magnetic stir
priate safety and health practices and determine the applica-
plate shall be capable of producing the stirring energy de-
bility of regulatory limitations prior to use.
scribed in Section 11.11. A magnetic stir bar in the form of a
cross or “starburst” approximately 32 mm by 32 mm has
2. Referenced Documents
proven to be more stable than the traditional bar shape.The stir
bar shall have a chemically inert coating such as polytetrafluo-
2.1 ASTM Adjuncts:
2 roethylene (PTFE).
Distillate Fuel Bar Chart
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6.2 Distillate Fuel Bar Chart.
3. Summary of Test Method
7. Reagents and Materials
3.1 A 3 L sample of aviation turbine fuel is extracted with
7.1 Iso-octane (2,2,4–trimethylpentane, CAS #540-84-1)—
pH 7 buffer solution by a magnetic stir plate and stir bar. The
Minimum ACS reagent grade purity.
chloride in the aviation turbine fuel sample transfers to the
buffer solution. A portion of the aqueous extract solution is 7.2 pH 7 Buffer Solution—Some pH 7 buffer solution can
then removed and analyzed with a chloride test strip. Silver contain trace levels of chloride compounds and therefore
ions within the test strip combine with chloride ions in the produce a false positive reading on the chloride test strip. Prior
extract as it is drawn up by capillary action to form a white to using a new batch of pH 7 buffer solution, a sample should
column of silver chloride. The chloride concentration of the
be confirmed to produce no reading on the chloride test strip.
extract, determined by the height of the column, is then related
NOTE 1—Prior batches of Fisher Scientific pH 7 buffer solution, catalog
backtothechloridecontentoftheaviationturbinefuelsample.
number SB108, have produced no reading on the chloride test strips.
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7.3 Chloride Test Strips —The conversion of the dimen-
4. Significance and Use
sionless test strip value to chloride concentration in mg/L
4.1 Chloride present in aviation turbine fuel can originate
found on the test strip container varies slightly from one lot of
from refinery salt drier carryover or possibly from seawater
chloride test strips to the next.
contamination (for example, product transferred by barge).
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Guidelines for Sodium Chloride Contamination Troubleshooting and Decon-
tamination of Airframe and Engine Fuel Systems, International Air Transport
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This test method is under the jurisdiction of ASTM Committee D02 on Association, 2nd Ed., February 1998, pg. 1.
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Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of The sole source of supply of the apparatus (Hach Quantab® Low Range
Subcommittee D02.J0.05 on Fuel Cleanliness. (30-600mg/LCl-))knowntothecommitteeatthistimeisHachCompany,P.O.Box
Current edition approved March 15, 2015. Published April 2015. DOI: 10.1520/ 389, Loveland, Colorado 80539-0389, http://www.hach.com. If you are aware of
D7959-15. alternative suppliers, please provide this information to ASTM International
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Available from ASTM International Headquarters. Order Adjunct No. Headquarters.Your comments will receive careful consideration at a meeting of the
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ADJD417601. Original adjunct produced in 1991. responsible technical committee, which you may attend.
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D7959 − 15
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