ASTM D1298-12b(2017)e1
(Test Method)Standard Test Method for Density, Relative Density, or API Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method
Standard Test Method for Density, Relative Density, or API Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method
SIGNIFICANCE AND USE
5.1 Accurate determination of the density, relative density (specific gravity), or API gravity of petroleum and its products is necessary for the conversion of measured volumes to volumes or masses, or both, at the standard reference temperatures of 15 °C or 60 °F during custody transfer.
5.2 This procedure is most suitable for determining the density, relative density (specific gravity), or API gravity of low viscosity transparent liquids. This procedure can also be used for viscous liquids by allowing sufficient time for the hydrometer to reach temperature equilibrium, and for opaque liquids by employing a suitable meniscus correction. Additionally for both transparent and opaque fluids the readings shall be corrected for the thermal glass expansion effect and alternative calibration temperature effects before correcting to the reference temperature.
5.3 When used in connection with bulk oil measurements, volume correction errors are minimized by observing the hydrometer reading at a temperature close to that of the bulk oil temperature.
5.4 Density, relative density, or API gravity is a factor governing the quality and pricing of crude petroleum. However, this property of petroleum is an uncertain indication of its quality unless correlated with other properties.
5.5 Density is an important quality indicator for automotive, aviation and marine fuels, where it affects storage, handling and combustion.
SCOPE
1.1 This test method covers the laboratory determination using a glass hydrometer in conjunction with a series of calculations, of the density, relative density, or API gravity of crude petroleum, petroleum products, or mixtures of petroleum and nonpetroleum products normally handled as liquids, and having a Reid vapor pressure of 101.325 kPa (14.696 psi) or less. Values are determined at existing temperatures and corrected to 15 °C or 60 °F by means of a series of calculations and international standard tables.
1.2 The initial hydrometer readings obtained are uncorrected hydrometer readings and not density measurements. Readings are measured on a hydrometer at either the reference temperature or at another convenient temperature, and readings are corrected for the meniscus effect, the thermal glass expansion effect, alternative calibration temperature effects and to the reference temperature by means of the Petroleum Measurement Tables; values obtained at other than the reference temperature being hydrometer readings and not density measurements.
1.3 Readings determined as density, relative density, or API gravity can be converted to equivalent values in the other units or alternative reference temperatures by means of Interconversion Procedures (API MPMS Chapter 11.5), or Adjunct to D1250 Guide for Petroleum Measurement Tables (API MPMS Chapter 11.1), or both, or tables, as applicable.
1.4 The initial hydrometer readings determined in the laboratory shall be recorded before performing any calculations. The calculations required in Section 10 shall be applied to the initial hydrometer reading with observations and results reported as required by Section 11 prior to use in a subsequent calculation procedure (ticket calculation, meter factor calculation, or base prover volume determination).
1.5 Annex A1 contains a procedure for verifying or certifying the equipment for this test method.
1.6 The values stated in SI units are to be regarded as standard.
1.6.1 Exception—The values given in parentheses are provided for information only.
1.7 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 and health practices and determine the applicability of regulatory limitations prior to use.
1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in th...
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Standards Content (Sample)
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.
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Designation: D1298 − 12b (Reapproved 2017)
Manual of Petroleum Measurement Standards (MPMS), Chapter 9.1
Standard Test Method for
Density, Relative Density, or API Gravity of Crude Petroleum
and Liquid Petroleum Products by Hydrometer Method
This standard is issued under the fixed designation D1298; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
ε NOTE—Editorially corrected adjunct information in March 2023.
1. Scope The calculations required in Section 10 shall be applied to the
initial hydrometer reading with observations and results re-
1.1 This test method covers the laboratory determination
ported as required by Section 11 prior to use in a subsequent
using a glass hydrometer in conjunction with a series of
calculation procedure (ticket calculation, meter factor
calculations, of the density, relative density, or API gravity of
calculation, or base prover volume determination).
crude petroleum, petroleum products, or mixtures of petroleum
and nonpetroleum products normally handled as liquids, and 1.5 Annex A1 contains a procedure for verifying or certify-
having a Reid vapor pressure of 101.325 kPa (14.696 psi) or ing the equipment for this test method.
less. Values are determined at existing temperatures and
1.6 The values stated in SI units are to be regarded as
corrected to 15 °C or 60 °F by means of a series of calculations
standard.
and international standard tables.
1.6.1 Exception—The values given in parentheses are pro-
1.2 The initial hydrometer readings obtained are uncor- vided for information only.
rected hydrometer readings and not density measurements.
1.7 This standard does not purport to address all of the
Readings are measured on a hydrometer at either the reference
safety concerns, if any, associated with its use. It is the
temperature or at another convenient temperature, and readings
responsibility of the user of this standard to establish appro-
are corrected for the meniscus effect, the thermal glass expan-
priate safety and health practices and determine the applica-
sion effect, alternative calibration temperature effects and to the
bility of regulatory limitations prior to use.
reference temperature by means of the Petroleum Measurement
1.8 This international standard was developed in accor-
Tables; values obtained at other than the reference temperature
dance with internationally recognized principles on standard-
being hydrometer readings and not density measurements.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
1.3 Readings determined as density, relative density, or API
mendations issued by the World Trade Organization Technical
gravity can be converted to equivalent values in the other units
Barriers to Trade (TBT) Committee.
or alternative reference temperatures by means of Interconver-
sion Procedures (API MPMS Chapter 11.5), or Adjunct to
2. Referenced Documents
D1250 Guide for Petroleum Measurement Tables (API MPMS
Chapter 11.1), or both, or tables, as applicable.
2.1 ASTM Standards:
D1250 Guide for the Use of the Joint API and ASTM
1.4 The initial hydrometer readings determined in the labo-
Adjunct for Temperature and Pressure Volume Correction
ratory shall be recorded before performing any calculations.
Factors for Generalized Crude Oils, Refined Products, and
Lubricating Oils: API MPMS Chapter 11.1
This test method is under the jurisdiction of ASTM Committee D02 on
D4057 Practice for Manual Sampling of Petroleum and
Petroleum Products, Liquid Fuels, and Lubricants and the API Committee on
Petroleum Products
Petroleum Measurement, and is the direct responsibility of Subcommittee D02.02
/COMQ, the joint ASTM-API Committee on Hydrocarbon Measurement for
Custody Transfer (Joint ASTM-API). This test method has been approved by the
sponsoring committees and accepted by the Cooperating Societies in accordance
with established procedures. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved July 15, 2017. Published July 2017. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1953. Last previous edition approved in 2012 as D1298 – 12b. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D1298-12BR17E01. the ASTM website.
© Jointly copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, USA and the American Petroleum Institute (API), 1220 L Street NW, Washington DC 20005, USA
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D1298 − 12b (2017)
D4177 Practice for Automatic Sampling of Petroleum and 3.1.3.1 Discussion—Other reference temperatures, such as
Petroleum Products 20 °C, may be used for some products or in some locations.
D5854 Practice for Mixing and Handling of Liquid Samples Less preferred units of measurement (for example, kg/L or
of Petroleum and Petroleum Products g/mL) are still in use.
E1 Specification for ASTM Liquid-in-Glass Thermometers
3.1.4 hydrometer reading, n—the point on the hydrometer
E100 Specification for ASTM Hydrometers
scale at which the surface of the liquid cuts the scale.
2.2 API Standards:
3.1.4.1 Discussion—In practice for transparent fluids this
MPMS Chapter 8.1 Manual Sampling of Petroleum and
can be readily determined by aligning the surface of the liquid
Petroleum Products (ASTM Practice D4057)
on both sides of the hydrometer and reading the Hydrometer
MPMS Chapter 8.2 Automatic Sampling of Petroleum and
scale where these surface readings cut the scale (Hydrometer
Petroleum Products (ASTM Practice D4177)
Reading – Observed). For nontransparent fluids the point at
MPMS Chapter 8.3 Mixing and Handling of Liquid Samples
which the liquid surface cuts the Hydrometer scale cannot be
of Petroleum and Petroleum Products (ASTM Practice
determined directly and requires a correction (Meniscus Cor-
D5854)
rection). The value represented by the point (Meniscus Read-
MPMS Chapter 11.1 Temperature and Pressure Volume Cor-
ing) at which the liquid sample rises above the main surface of
rection Factors for Generalized Crude Oils, Refined Prod-
the liquid subtracted from the value represented by where the
ucts and Lubricating Oils (Adjunct to ASTM D1250)
main surface of the liquid cuts the Hydrometer scale is the
MPMS Chapter 11.5 Density/Weight/Volume Intraconver-
amount of the correction or Meniscus correction. This menis-
sion
cus correction is documented and then subtracted from the
2.3 Energy Institute Standards: value represented by the Meniscus Reading to yield the
Hydrometer Reading corrected for the Meniscus (Hydrometer
IP 389 Determination of wax appearance temperature
(WAT) of middle distillate fuels by differential thermal Reading – Observed, Meniscus Corrected).
analysis (DTA) or differential scanning calorimetry (DSC)
3.1.5 observed values, n—values observed at temperatures
IP Standard Methods Book, Appendix A, Specifications – IP
other than the specified reference temperature. These values are
Standard Thermometers
only hydrometer readings and not density, relative density
2.4 ISO Standards:
(specific gravity), or API gravity at that other temperature.
ISO 649-1 Laboratory glassware – Density hydrometers for
3.1.6 pour point, n—lowest temperature at which a test
general purpose – Part 1: Specification
portion of crude petroleum or petroleum product will continue
2.5 ASTM Adjuncts:
to flow when it is cooled under specified conditions.
Adjunct to D1250 Standard Guide for the Use of the Joint
3.1.7 relative density (specific gravity), n—the ratio of the
API and ASTM Adjunct for Temperature and Pressure
mass of a given volume of liquid at a specific temperature to
Volume Correction Factors for Generalized Crude Oils,
the mass of an equal volume of pure water at the same or
Refined Products, and Lubricant Oils: API MPMS Chapter
different temperature. Both reference temperatures shall be
11.1, Addenda 1 and 2
explicitly stated.
3.1.7.1 Discussion—Common reference temperatures in-
3. Terminology
clude 60/60 °F, 20 ⁄20 °C, 20/4 °C. The historic deprecated
3.1 Definitions of Terms Specific to This Standard:
term specific gravity may still be found.
3.1.1 API gravity, n—a special function of relative density
3.1.8 wax appearance temperature (WAT), n—temperature
(specific gravity) 60/60 °F, represented by:
at which waxy solids form when a crude petroleum or
°API 5 @141.5/ relative density 60/60 °F # 2 131.5 (1)
~ !
petroleum product is cooled under specified conditions.
3.1.1.1 Discussion—No statement of reference temperature
is required, as 60 °F is included in the definition.
4. Summary of Test Method
3.1.2 cloud point, n—temperature at which a cloud of wax
4.1 The sample is brought to a specified temperature and a
crystals first appears in a liquid when it is cooled under specific
test portion is transferred to a hydrometer cylinder that has
conditions.
been brought to approximately the same temperature. The
3.1.3 density, n—the mass of liquid per unit volume at 15 °C
appropriate hydrometer and thermometer, also at a similar
and 101.325 kPa with the standard unit of measurement being
temperature, are lowered into the test portion and allowed to
kilograms per cubic metre.
settle. After temperature equilibrium has been reached, the
hydrometer scale is read, and the temperature of the test
portion is taken. The observed hydrometer reading is corrected
Published as Manual of Petroleum Measurement Standards. Available from the
for the meniscus effect, the thermal glass expansion effect,
American Petroleum Institute (API), 1220 L St., NW, Washington, DC 20005-4070,
alternative calibration temperature effects and then reduced to
http://www.api.org.
the reference temperature by means of the volume correction
Available from Energy Institute, 61 New Cavendish St., London, W1G 7AR,
U.K., http://www.energyinst.org.
factors or tables as applicable by use of the appropriate Adjunct
Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
to D1250 Guide for Petroleum Measurement Tables (API
4th Floor, New York, NY 10036, http://www.ansi.org.
MPMS Chapter 11.1) and observed temperature from the
Available from ASTM International Headquarters. Order Adjunct No.
ADJD1250-A1A2-E-PDF. Original adjunct produced in 1983. thermometer.
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D1298 − 12b (2017)
4.2 If necessary, the hydrometer cylinder and its contents native calibration temperature effects shall be applied to the
are placed in a constant temperature bath to avoid excessive observed readings prior to corrections. Instruments that satisfy
temperature variation during the test. the requirements of this test method, but are not provided with
a recognized calibration certificate, are classed as uncertified.
5. Significance and Use
6.2 Thermometers, having range, graduation intervals and
5.1 Accurate determination of the density, relative density
maximum permitted scale error shown in Table 2 and conform-
(specific gravity), or API gravity of petroleum and its products
ing to Specification E1 or IP Appendix A.
is necessary for the conversion of measured volumes to
6.2.1 Alternative measuring devices or systems may be
volumes or masses, or both, at the standard reference tempera-
used, provided that the total uncertainty of the calibrated
tures of 15 °C or 60 °F during custody transfer.
system is no greater than that specified in 6.2. The stated
repeatability and reproducibility values are not applicable if
5.2 This procedure is most suitable for determining the
alternative fluids are used in the liquid-in-glass thermometers.
density, relative density (specific gravity), or API gravity of
low viscosity transparent liquids. This procedure can also be
6.3 Hydrometer Cylinder, clear glass, or plastic (see 6.3.1).
used for viscous liquids by allowing sufficient time for the
The inside diameter of the cylinder shall be at least 25 mm
hydrometer to reach temperature equilibrium, and for opaque
greater than the outside diameter of the hydrometer and the
liquids by employing a suitable meniscus correction. Addition-
height shall be such that the appropriate hydrometer floats in
ally for both transparent and opaque fluids the readings shall be
the sample test portion with at least 25 mm clearance between
corrected for the thermal glass expansion effect and alternative
the bottom of the hydrometer and the bottom of the cylinder.
calibration temperature effects before correcting to the refer-
6.3.1 Hydrometer cylinders constructed of plastic materials
ence temperature.
shall be resistant to discoloration or attack by oil samples and
shall not affect the material being tested. They shall not become
5.3 When used in connection with bulk oil measurements,
opaque under prolonged exposure to sunlight.
volume correction errors are minimized by observing the
hydrometer reading at a temperature close to that of the bulk oil
6.4 Constant-Temperature Bath, if required, of dimensions
temperature.
such that it can accommodate the hydrometer cylinder with the
test portion fully immersed below the test portion liquid
5.4 Density, relative density, or API gravity is a factor
surface, and a temperature control system capable of maintain-
governing the quality and pricing of crude petroleum.
ing the bath temperature within 0.25 °C of the test temperature
However, this property of petroleum is an uncertain indication
throughout the duration of the test.
of its quality unless correlated with other properties.
6.5 Stirring Rod, optional, of glass or plastic, approximately
5.5 Density is an important quality indicator for automotive,
400 mm in length.
aviation and marine fuels, where it affects storage, handling
and combustion.
7. Sampling
6. Apparatus
7.1 Unless otherwise specified, samples of non-volatile
petroleum and petroleum products shall be taken by the
6.1 Hydrometers, of glass, graduated in units of density,
procedures described in Practice D4057 (API MPMS Chapter
relative density, or API gravity as required, conforming to
8.1) and D4177 (API MPMS Chapter 8.2).
Specification E100 or ISO 649-1, and the requirements given
in Table 1.
7.2 Samples of volatile crude petroleum or petroleum prod-
6.1.1 The user should ascertain that the instruments used for
ucts are p
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