ASTM D6849-22

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Designation: D6849 − 13 (Reapproved 2021) D6849 − 22
Standard Practice for
Storage and Use of Liquefied Petroleum Gases (LPG) in
Sample Cylinders for LPG Test Methods
This standard is issued under the fixed designation D6849; 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 Scope*
1.1 This practice covers information for the storage and use of LPG samples in standard cylinders of the type used in sampling
method, Practice D1265 and floating piston cylinders used in sampling method, Practice D3700.
1.2 This practice is especially applicable when the LPG sample is used as a quality control (QC) reference material for LPG test
methods, such as gas chromatography (GC) analysis (Test Method D2163) or vapor pressure (Test Method D6897) that use only
a few mL per test, since relatively small portable Department of Transportation (DOT) cylinders (for example, 20 lb common
barbecue cylinders, or common Mower/Forklift cylinders) can be used. This practice can be applied to other test methods.
However, test methods that require a large amount of sample per test (for example, manual vapor pressure Test Method D1267)
will require QC volumes in excess of 1000 L if stored in standard DOT cylinders or American Society of Mechanical Engineers
(ASME) vessels.
1.2.1 Modification of the pressure relief (QCC1) valve on single access port cylinders may prohibit the collection or transport of
cylinders outside of permitted facilities such as refineries, gas plants or pipeline stations. No modification is generally required for
multi-port mower/forklift cylinders that have a separate access port for pressure relief and additional access ports for filling,
liquid/vapor withdrawal or liquid level indication. Consult the Authority having Jurisdiction for detailed regional regulatory
requirements for transport of LPG in pressurized cylinders.
1.3 This practice can be applied to other test methods. However, test methods that require a large amount of sample per test (for
example, manual vapor pressure Test Method D1267) will require QC volumes in excess of 1000 L if stored in standard DOT
cylinders or American Society of Mechanical Engineers (ASME) vessels.
1.3.1 Test methods for trace materials that may be sensitive to vessel surfaces (for example H O, H S/sulfur, or trace residues)
2 2
could preferably use aluminum, stainless steel or internally coated vessels to minimize surface absorption/reaction or larger vessels
to minimize surface/volume ratio.
1.4 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.
This practice is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
D02.08 on Volatility.
Current edition approved Dec. 1, 2021May 1, 2022. Published December 2021July 2022. Originally approved in 2002. Last previous edition approved in 20132021 as
D6849 – 13.D6849 – 13 (2021). DOI: 10.1520/D6849-13R21.10.1520/D6849-22.
*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
D6849 − 22
2. Referenced Documents
2.1 ASTM Standards:
D1265 Practice for Sampling Liquefied Petroleum (LP) Gases, Manual Method
D1267 Test Method for Gauge Vapor Pressure of Liquefied Petroleum (LP) Gases (LP-Gas Method)
D2163 Test Method for Determination of Hydrocarbons in Liquefied Petroleum (LP) Gases and Propane/Propene Mixtures by
Gas Chromatography
D3700 Practice for Obtaining LPG Samples Using a Floating Piston Cylinder
D6299 Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measure-
ment System Performance
D6897 Test Method for Vapor Pressure of Liquefied Petroleum Gases (LPG) (Expansion Method)
3. Terminology
3.1 Definitions:
3.1.1 floating piston cylinder (FPC), n—high-pressure sample container with a free-floating internal piston that effectively divides
the container into two separate compartments.
3.1.1.1 Discussion—
A floating piston cylinder is used to collect a sample of liquid under pressure without the formation of a gaseous phase which can
result in changes in the composition of the liquid sample.
3.1.2 high-pressure sample cylinder, n—a container used for storage and transportation of a sample obtained at pressures above
atmospheric pressure.
3.1.2.1 Discussion—
This type of sample cylinder, sometimes called a ‘standard 80 % fill cylinder’, when used for LPG typically contains both liquid
and vapor phase material.
3.1.3 liquefied petroleum gas, (LP Gas, LPG), n—a narrow boiling range mixture of hydrocarbons consisting of propane,
propylene, butanes and butylenes, individually or in specified combinations, with limited amounts of other hydrocarbons and
naturally occurring non-hydrocarbons.
3.1.3.1 Discussion—
LPG is typically maintained in a liquid state by containing it within a closed container or storage tank that can withstand the vapor
pressure of the LPG at ambient temperature, or at a low temperature in refrigerated storage.
3.1.4 maximum fill volume (reduced fill volume), n—the volume of a container that may be safely occupied by the liquid sample,
usually expressed as a percentage of the total capacity.
3.1.4.1 Discussion—
Some regulatory agencies use the expressions ‘maximum fill density’ and ‘reduced fill density.’
4. Summary of Practice
4.1 This practice provides information for the design and operation of LPG sample storage cylinders taking into account properties
of LPG and types of cylinders in common use for storage of LPG.
4.2 This practice provides additional guidelines to Practice D6299 to determine the minimum volume of LPG sample material
required, when used as a QC reference material.
5. Significance and Use
5.1 LPG samples can change composition during storage and use from preferential vaporization of lighter (lower molecular
weight) hydrocarbon components, dissolved inert gases (N , Ar, He, and so forth) and other dissolved gases/liquids (NH , CO ,
2 3 2
H S, H O, etc.). Careful selection of cylinder type, cylinder volume, and use of inert gas for pressurizing cylinders is required to
2 2
ensure that composition changes are small enough to maintain the integrity of LPG when used as a QC reference material for
various LPG test methods.
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volume information, refer to the standard’s Document Summary page on the ASTM website.
D6849 − 22
5.2 Monitoring of ongoing precision and bias on QC materials using control chart techniques in accordance with Practice D6299
can be used to establish the need for calibration or maintenance.
6. Reference Materials
6.1 The LPG QC reference material should have a vapor pressure and composition in the range of the samples regularly tested
by the equipment. This is particularly important for LPG/natural gas liquid (NGL) mixtures near the critical temperature, as these
liquids have large thermal and pressure expansion coefficients.
6.2 LPG QC reference materials should be stored in an environment suitable for long term storage without significant sample
degradation for the test(s) being performed.
NOTE 1—As an example, evidence of a long term shift or bias in the LPG QC reference material results obtained relative to the established statistical
control limits and average value determined for the test initially, may indicate that the composition of the LPG QC reference material has significantly
degraded or changed over time. An investigation should be conducted to determine if the long term stability of the QC reference material is the cause
for the out-of-control situation.
7. Use of Floating Piston Cylinders for LPG Samples
7.1 Minimum LPG sample volume can be determined in accordance with Practice D6299.
NOTE 2—Estimating the minimum LPG sample volume needed includes such things as the sample volume needed to conduct the appropriate test(s) and
the number of analytical measurements that are expected to be made over the intended period of use.
7.2 Floating piston cylinders (see Fig. 1) are preferred for LPG sample materials for tests involving accurate determination of light
gases.
7.3 Excessive inert gas pressure should be avoided for long term storage of vapor pressure QC or calibrant materials in floating
piston cylinders. Leakage of inert
...