ASTM D5705-20

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Designation: D5705 − 15 D5705 − 20
Standard Test Method for
Measurement of Hydrogen Sulfide in the Vapor Phase
Above Residual Fuel Oils
This standard is issued under the fixed designation D5705; 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*
1.1 This test method covers the field determination of hydrogen sulfide (H S) in the vapor phase (equilibrium headspace) of a
residual fuel oil sample.
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1.2 The test method is applicable to liquids with a viscosity range of 5.5 mm /s at 40°C40 °C to 50 mm /s at 100°C.100 °C. The
test method is applicable to fuels conforming to Specification D396 Grade Nos. 4, 5 (Heavy), and 6.
1.3 The applicable range is from 5 μmol ⁄mol to 4000 μmol ⁄mol (micromoles per mole) (5 ppm v ⁄v to 4000 ppm v/v (parts per
million by volume)).
1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D396 Specification for Fuel Oils
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4175 Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
D6021 Test Method for Measurement of Total Hydrogen Sulfide in Residual Fuels by Multiple Headspace Extraction and Sulfur
Specific Detection
D7621 Test Method for Determination of Hydrogen Sulfide in Fuel Oils by Rapid Liquid Phase Extraction
3. Terminology
3.1 Definitions:
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
D02.14 on Stability Stability, Cleanliness and CleanlinessCompatibility of Liquid Fuels.
Current edition approved April 1, 2015Oct. 1, 2020. Published July 2015October 2020. Originally approved in 1995. Last previous edition approved in 20142015 as
D5705 – 14.D5705 – 15. DOI: 10.1520/D5705-15.10.1520/D5705-20.
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 the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5705 − 20
3.1.1 For definitions of terms used in this test method, see Terminology D4175.
3.1.2 equilibrium headspace, n—the vapor space above the liquid in which all vapor components are in equilibrium with the liquid
components.
3.1.3 residual fuel oil, n—a fuel oil comprising a blend of viscous long, short, or cracked residue from a petroleum refining process
and lighter distillates blended to a fuel oil viscosity specification.
3.1.3.1 Discussion—
Under the conditions of this test (1:1 liquid/vapor ratio, temperature, and agitation) the H S in the vapor phase (sample’s
headspace) will be in equilibrium with the H S in the liquid phase.
4. Summary of Test Method
4.1 A 1 L H S-inert test container (glass test bottle) is filled to 50 % by volume with fuel oil from a filled H S-inert container (glass
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sample bottle) just prior to testing. In the test container, the vapor space above the fuel oil sample is purged with nitrogen to
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displace air. The test container with sample is heated in an oven to 60 °C, and agitated on an orbital shaker at 3.67 s 6 0.08 s
(220 r ⁄min 6 5 r ⁄min (revolutions per minute)) for 3 min.
4.2 A length-of-stain detector tube and hand-operated pump are used to measure the H S concentration in the vapor phase of the
test container. The length-of-stain detector tube should be close to but not in contact with the liquid surface.
5. Significance and Use
5.1 Residual fuel oils can contain H S in the liquid phase and this can result in hazardous vapor phase levels of H S in storage
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tank headspaces. The vapor phase levels can vary significantly according to the headspace volume, fuel temperature and agitation.
Measurement of H S levels in the liquid phase provides a useful indication of the residual fuel oil’s propensity to form high vapor
phase levels, and lower levels in the residual fuel oil will directly reduce risk of H S exposure. It is critical, however, that anyone
involved in handling fuel oil, such as vessel owners and operators, continue to maintain appropriate safety practices designed to
protect the crew, tank farm operators and others who can be exposed to H S.
5.1.1 The measurement of H S in the liquid phase is appropriate for product quality control, while the measurement of H S in the
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vapor phase is appropriate for health and safety purposes.
5.2 This test method was developed to provide refineries, fuel terminals and independent testing laboratories, which do not have
access to analytical instruments such as a gas chromatograph, with a simple and consistent field test method for the rapid
determination of H S in the vapor phase above residual fuel oils.
NOTE 1—D5705 is one of three test methods for quantitatively measuring H S in residual fuels:
1) Test Method D6021 is an analytical test method to determine H S levels in the liquid phase.
2) Test Method D7621 is a rapid test method to determine H S levels in the liquid phase.
NOTE 2—Because of the reactivity, absorptivity and volatility of H S, any measurement method only provides an H S concentration at a given moment
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in time.
5.3 This test method does not necessarily simulate the vapor phase H S concentration in a fuel storage tank. It does, however,
provide a level of consistency so that the test result is only a function of the residual fuel oil sample and not the test method,
operator, or location. No general correlation can be established between this field test and actual vapor phase concentrations of H S
in residual fuel oil storage or transports. However, a facility that produces fuel oil from the same crude source under essentially
constant conditions might be able to develop a correlation for its individual case.
6. Interferences
6.1 Typically, sulfur dioxide and mercaptans may cause positive interferences. In some cases, nitrogen dioxide can cause a
negative interference. Most detector tubes will have a precleanse layer designed to remove certain interferences up to some
maximum interferant level. Consult the manufacturer’s instructions for specific interference information.
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7. Apparatus
7.1 Shaker, a bench-top orbital shaker and platform equipped with a four-prong clamp to hold 1 L Boston round-bottom glass
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bottles and capable of operation at 3.67 s 6 0.08 s (220 r ⁄min 6 5 r ⁄min (revolutions per minute)).
NOTE 3—An orbital shaker with an orbit of 19 mm has been found to be suitable.
7.2 Timer, capable of measuring from 1 s to 30 min at second intervals.
7.3 Stopper with Temperature Measuring Device, a No. 2 cork stopper with a temperature measuring devices inserted through it
that is capable of accurately measuring the temperature of the sample at 60 °C 6 1 °C as required in the procedure and extending
at least 25 mm into the residual fuel but no closer than 25 mm from the bottom of a test bottle (see Fig. 1(a)). A dial thermometer
having a range of –18 °C to 82 °C and a 200 mm stem has been found suitable to use.
7.4 Oven or Water Bath, capable of heating the fuel oil samples to 60 °C 6 1 °C.
3 3 3
7.5 Detector Tube Pump, a hand-operated piston or bellows-type (Fig. 1(b)) pump with a capacity of 100 cm 6 5 cm per stroke.
It must be specifically designed for use with detector tubes. (Warning—A detector tube and pump together form a unit and must
be used as such. Each manufacturer calibrates detector tubes to match the flow characteristics of its specific pump. Crossing brands
of pumps and tubes is not permitted, as considerable loss of system accuracy is likely to occur.)
FIG. 1 Measurement of H S in the Vapor Phase of Residual Fuel Oil
Direct Reading Colorimetric Indicator Tubes Manual, First Edition, American Industrial Hygiene Association, Akron, OH 44311, 1976.
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8. Reagents and Materials
8.1 Containers—Both sample and test containers are composed of H S-inert material such as 1 L size (clear Boston round-bottom)
glass bottles with screw caps. The bottles are clean and dry. Mark test containers at the 50 % volume level by using a ruler.
(Warning—Hydrogen sulfide reacts with metal surfaces and is easily oxidized, which depletes its concentration and gives false
low test results. Containers such as epoxy-lacquered cans are suitable for sample collection. Alternative containers must give
equivalent results to those obtained by using glass.)
8.2 Length-of-Stain Detector Tube and Calibration Scale, a sealed glass tube with breakoff tips sized to fit the tube holder of the
detector tube pump. The reagent layer inside the tube, typically a silica gel substrate coated with the active chemicals, must be
specific for hydrogen sulfide and must produce a distinct color change when exposed to a sample of gas containing hydrogen
sulfide. Any substances known to interfere must be listed in the instructions accompanying the tubes. A calibration scale should
be marked directly on the tube, or other markings that provide for easy interpretation (reading) of hydrogen sulfide content from
a separate calibration scale should be supplied with the tubes. The calibration scale shall correlate H S concentration to the length
of the color stain. Annex A1 provides additional information. Shelf life of the detector tubes must be a minimum of two years from
the date of manufacture, when stored according to the manufacturer’s recommendations.
9. Sampling
9.1 The sampling of residual fuel oils is done according to Practice D4057 for the sampling of storage tanks, ships, or barges.
Composite sampling or running samples can be taken; spot samples should be taken from the midpoint or below midpoint of the
fuel oil in a storage tank by first sufficiently purging sample transfer lines and then taking single samples where each sample
comprises one and only one test. (Warning—Samples taken for this test method shall be dedicated to a single H S determination
and not used for any other purpose, as any additional handling can lead to loss of H S and thus low results.)
NOTE 4—Liquid samples taken well into the fuel oil have had less H S lost by degassing as compared with a fuel oil’s surface. Samples taken from well
within the fuel oil storage provide material that represents the greatest potential for H S exposure during fuel oil movements. Hydrogen sulfide is lost
by
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