ASTM D7961-15
(Practice)Standard Practice for Calibrating U-tube Density Cells over Large Ranges of Temperature and Pressure
Standard Practice for Calibrating U-tube Density Cells over Large Ranges of Temperature and Pressure
SIGNIFICANCE AND USE
5.1 This practice covers a series of methods offered to aid users in calibrating U-tube density meters to provide a measure of density and an associated expanded uncertainty. The reference density, as obtained from either an equation of state (EOS) or CRM has an uncertainty that arises from the uncertainty of the measurements of temperature, pressure, and also the chemical purity of the substance studied (origin) or for that matter of the certified reference material. This uncertainty results in an additional uncertainty for the density of these samples. Because the measurements made with U-tube density meters are not absolute, the uncertainty with which the instrument calibration is determined is directly related to the uncertainty of the density obtained.
SCOPE
1.1 This practice outlines procedures for the calibration of U-tube density cells. It is applicable to instruments capable of determining fluid density at temperatures in the range –10 °C to 200 °C and pressures from just greater than the saturation pressure to 140 MPa. The practice refers to density cells as they are utilized to make measurements of fluids primarily in the compressed-liquid state. Examples of substances for which the density can be determined with a calibrated U-tube density meter include: crude oils, gasoline and gasoline-oxygenate blends, diesel and jet fuels, hydraulic fluids, and lubricating oils.
1.2 This practice specifies a procedure for the determination of the expanded uncertainty of the density measurement.
1.3 This practice pertains to fluids with viscosities
1.4 4 The values listed in SI units are regarded as the standard, unless otherwise stated. The SI unit for mass density is kilograms per cubic metre (kg·m-3) and can be given as grams per cubic centimetre (g·cm-3).
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 and health practices and determine the applicability of regulatory limitations prior to use.
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Standards Content (Sample)
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Designation: D7961 − 15
Standard Practice for
Calibrating U-tube Density Cells over Large Ranges of
1
Temperature and Pressure
This standard is issued under the fixed designation D7961; 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 Crude Oils by Digital Density Analyzer
D6792 Practice for Quality System in Petroleum Products
1.1 This practice outlines procedures for the calibration of
and Lubricants Testing Laboratories
U-tube density cells. It is applicable to instruments capable of
D7483 TestMethodforDeterminationofDynamicViscosity
determining fluid density at temperatures in the range –10 °C
and Derived Kinematic Viscosity of Liquids by Oscillat-
to 200 °C and pressures from just greater than the saturation
ing Piston Viscometer
pressure to 140 MPa. The practice refers to density cells as
D7578 Guide for Calibration Requirements for Elemental
they are utilized to make measurements of fluids primarily in
Analysis of Petroleum Products and Lubricants
the compressed-liquid state. Examples of substances for which
D7740 Practice for Optimization, Calibration, and Valida-
the density can be determined with a calibrated U-tube density
tion ofAtomicAbsorption Spectrometry for MetalAnaly-
meter include: crude oils, gasoline and gasoline-oxygenate
sis of Petroleum Products and Lubricants
blends, diesel and jet fuels, hydraulic fluids, and lubricating
oils.
3. Terminology
1.2 This practice specifies a procedure for the determination
3.1 Definitions:
of the expanded uncertainty of the density measurement.
3.1.1 calibration, n—set of operations that establishes the
1.3 This practice pertains to fluids with viscosities < 1 Pa·s relationship between the reference density of standards and the
(1000 centipoise) at ambient conditions. corresponding density reading of the instrument. D4052
3.1.2 certified reference material (CRM), n—reference ma-
1.4 4 The values listed in SI units are regarded as the
terial one or more of whose property values are certified by a
standard, unless otherwise stated. The SI unit for mass density
-3
technically valid procedure, accompanied by a traceable cer-
is kilograms per cubic metre (kg·m ) and can be given as
-3
tificate or other documentation that is issued by a certifying
grams per cubic centimetre (g·cm ).
body. [D02.94] D6792, [D02.03] D7578
1.5 This standard does not purport to address all of the
3.1.3 density (ρ), n—mass per unit volume at a specified
safety concerns, if any, associated with its use. It is the
temperature. [D02.07] D7483
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
3.1.4 standard reference material (SRM), n—trademark for
bility of regulatory limitations prior to use.
reference materials certified by NIST. [D02.03] D7740
2. Referenced Documents 4. Summary of Practice
2
2.1 ASTM Standards: 4.1 This practice details the considerations and procedures
D1193 Specification for Reagent Water necessaryinordertocompleteacalibrationofaU-tubedensity
D4052 Test Method for Density, Relative Density, and API meter and an associated uncertainty analysis. The principal
Gravity of Liquids by Digital Density Meter
objectiveofthispracticeistoprovidetheuserwithinformation
D5002 Test Method for Density and Relative Density of as to how different aspects of the calibration procedure
contribute to the overall uncertainty of related density mea-
surements obtained with a U-tube density meter.
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This practice is under the jurisdiction ofASTM Committee D02 on Petroleum
Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcom-
5. Significance and Use
mittee D02.04 on Hydrocarbon Analysis.
5.1 This practice covers a series of methods offered to aid
Current edition approved Dec. 1, 2015. Published February 2016. DOI: 10.1520/
D7961-15.
usersincalibratingU-tubedensitymeterstoprovideameasure
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
of density and an associated expanded uncertainty. The refer-
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
ence density, as obtained from either an equation of state
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. (EOS) or CRM has an uncertainty that arises from the
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D7961 − 15
uncertainty of the measurements of temperature, pressure, and NIST Standard Reference Database 23 or
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