ASTM D7042-04
(Test Method)Standard Test Method for Dynamic Viscosity and Density of Liquids by Stabinger Viscometer (and the Calculation of Kinematic Viscosity)
Standard Test Method for Dynamic Viscosity and Density of Liquids by Stabinger Viscometer (and the Calculation of Kinematic Viscosity)
SIGNIFICANCE AND USE
Many petroleum products, and some non-petroleum materials, are used as lubricants and the correct operation of the equipment depends upon the appropriate viscosity of the liquid being used. In addition, the viscosity of many petroleum fuels is important for the estimation of optimum storage, handling, and operational conditions. Thus, the accurate determination of viscosity is essential to many product specifications.
Density is a fundamental physical property that can be used in conjunction with other properties to characterize both the light and heavy fractions of petroleum and petroleum products.
Determination of the density or relative density of petroleum and its products is necessary for the conversion of measured volumes to volumes at the standard temperature of 15°C.
SCOPE
1.1 This test method specifies a procedure for the concurrent measurement of both the dynamic viscosity, η, and the density, ρ, of liquid petroleum products and crude oils, both transparent and opaque. The kinematic viscosity, ny, can be obtained by dividing the dynamic viscosity, η, by the density, ρ, obtained at the same test temperature.
1.2 The result obtained from this test method is dependent upon the behavior of the sample and is intended for application to liquids for which primarily the shear stress and shear rate are proportional (Newtonian flow behavior).
1.3 While the precision has only been determined for base oils in the viscosity range from 2.05 to 456 mPas at 40°C and from 0.83 to 31.6 mPas at 100°C and in the density range from 0.82 to 0.92 g/mL at 15°C (see 15.4), the test method can be applied to a wider range of materials, viscosity, density, and temperature. For materials not listed in Precision and Bias (Section 15), the precision and bias may not be applicable.
1.4 The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard. The accepted units of measure for density are grams per millilitre (g/mL) or kilograms per cubic metre (kg/m3).
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 to determine the applicability of regulatory limitations prior to use.
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Standards Content (Sample)
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Designation:D7042–04
Standard Test Method for
Dynamic Viscosity and Density of Liquids by Stabinger
Viscometer (and the Calculation of Kinematic Viscosity)
This standard is issued under the fixed designation D7042; 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 and Viscosity Oil Standards
D2270 Practice for Calculating Viscosity Index from Kine-
1.1 Thistestmethodspecifiesaprocedurefortheconcurrent
matic Viscosity at 40 and 100°C
measurement of both the dynamic viscosity, h, and the density,
D4052 Test Method for Density, Relative Density, and API
r, of liquid petroleum products and crude oils, both transparent
Gravity of Liquids by Digital Density Meter
and opaque. The kinematic viscosity, n, can be obtained by
D6299 Practice for Applying Statistical Quality Assurance
dividingthedynamicviscosity, h,bythedensity, r,obtainedat
and Control Charting Techniques to Evaluate Analytical
the same test temperature.
Measurement System Performance
1.2 The result obtained from this test method is dependent
D6300 Practice for Determination of Precision and Bias
upon the behavior of the sample and is intended for application
Data for Use in Test Methods for Petroleum Products and
toliquidsforwhichprimarilytheshearstressandshearrateare
Lubricants
proportional (Newtonian flow behavior).
D6617 Practice for Laboratory Bias Detection Using Single
1.3 While the precision has only been determined for base
Test Result from Standard Material
oils in the viscosity range from 2.05 to 456 mPa·s at 40°C and
D6708 PracticeforStatisticalAssessmentandImprovement
from0.83to31.6mPa·sat100°Candinthedensityrangefrom
of Expected Agreement Between Two Test Methods that
0.82 to 0.92 g/mL at 15°C (see 15.4), the test method can be
Purport to Measure the Same Property of a Material
applied to a wider range of materials, viscosity, density, and
2.2 ISO Standards:
temperature. For materials not listed in Precision and Bias
ISO 5725 Accuracy (trueness and precision) of measure-
(Section 15), the precision and bias may not be applicable.
ment methods and results
1.4 The values stated in SI units are to be regarded as the
ISO/IEC 17025 General Requirements for the Competence
standard. No other units of measurement are included in this
of Testing and Calibration Laboratories
standard. The accepted units of measure for density are grams
2.3 Other Documents:
per millilitre (g/mL) or kilograms per cubic metre (kg/m ).
NIST Technical Note 1297 Guideline for Evaluating and
1.5 This standard does not purport to address all of the
Expressing the Uncertainty of NISTMeasurement Results
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
3. Terminology
priate safety and health practices and to determine the
3.1 Definitions:
applicability of regulatory limitations prior to use.
3.1.1 dynamic viscosity (h), n—the ratio between the ap-
2. Referenced Documents plied shear stress and rate of shear of a liquid.
2 3.1.1.1 Discussion—It is sometimes called the coefficient of
2.1 ASTM Standards:
dynamic viscosity or, simply, viscosity. Thus, dynamic viscos-
D445 Test Method for Kinematic Viscosity of Transparent
ity is a measure of the resistance to flow or to deformation of
and Opaque Liquids (and Calculation of Dynamic Viscos-
a liquid under external shear forces.
ity)
3.1.1.2 Discussion—The term dynamic viscosity can also
D2162 PracticeforBasicCalibrationofMasterViscometers
be used in a different context to denote a frequency-dependent
quantity in which shear stress and shear rate have a sinusoidal
time dependence.
This test method is under the jurisdiction of ASTM Committee D02 on
3.1.2 kinematic viscosity (n), n—the ratio of the dynamic
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
D02.07 on Flow Properties.
viscosity (h) to the density (r) of a liquid.
Current edition approved July 1, 2004. Published July 2004. DOI: 10.1520/
D7042-04.
2 3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM 4th Floor, New York, NY 10036.
Standards volume information, refer to the standard’s Document Summary page on Available from National Institute of Standards and Technology (NIST), 100
the ASTM website. Bureau Dr., Stop 3460, Gaithersburg, MD 20899-3460.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D7042–04
3.1.2.1 Discussion—For gravity flow under a given hydro- and the soft iron ring. Consequently, the system works free of
static head, the pressure head of a liquid is proportional to its bearing friction as found in rotational viscometers. A perma-
density (r). Therefore the kinematic viscosity (n) is a measure nent magnet in the inner cylinder induces eddy currents in the
of the resistance to flow of a liquid under gravity. surrounding copper casing. The rotational speed of the inner
3.1.3 density (r), n—mass per unit volume. cylinder establishes itself as the result of the equilibrium
3.1.4 Relative density (also called specific gravity (SG)), between the driving torque of the viscous forces and the
n—the ratio of the density of a material at a stated temperature retarding eddy current torque. This rotational speed is mea-
to the density of a reference material (usually water) at a stated sured by an electronic system (Hall effect sensor) by counting
temperature. thefrequencyoftherotatingmagneticfield(seeFig.1andFig.
2, No. 2).
4. Summary of Test Method
6.1.2 Density Measurement—The digital density analyzer
4.1 Thetestspecimenisintroducedintothemeasuringcells, uses a U-shaped oscillating sample tube and a system for
which are at a closely controlled and known temperature. The electronic excitation and frequency counting (see Fig. 2, No.
measuring cells consist of a pair of rotating concentric cylin- 3).
ders and an oscillating U-tube. The dynamic viscosity is 6.1.3 Temperature Control—The copper block surrounds
both the viscosity and the density measuring cell in a way that
determined from the equilibrium rotational speed of the inner
cylinder under the influence of the shear stress of the test both cells are held at the same temperature. A thermoelectric
heating and cooling system (see Fig. 2, No. 1) ensures the
specimen and an eddy current brake in conjunction with
adjustment data. The density is determined by the oscillation temperature stability of the copper block within 60.005°C
from the set temperature at the position of the viscosity cell
frequency of the U-tube in conjunction with adjustment data.
The kinematic viscosity is calculated by dividing the dynamic overthewholetemperaturerange.Theuncertainty(k=2;95 %
confidence level) of the temperature calibration shall be no
viscosity by the density.
more than 60.03°C over the range from 15 to 100°C. Outside
5. Significance and Use
this range the calibration uncertainty shall be no more than
5.1 Many petroleum products, and some non-petroleum 60.05°C.
6.1.4 The thermal equilibration time depends on the heat
materials, are used as lubricants and the correct operation of
the equipment depends upon the appropriate viscosity of the capacity and conductivity of the liquid and on the difference
between injection temperature and test temperature. Adequate
liquid being used. In addition, the viscosity of many petroleum
fuels is important for the estimation of optimum storage, temperature equilibration of the test specimen is automatically
determined when successive viscosity values are constant
handling, and operational conditions. Thus, the accurate deter-
mination of viscosity is essential to many product specifica- within 60.07 % over 1 min and successive density values are
constant within 60.00003 g/mL over 1 min.
tions.
5.2 Density is a fundamental physical property that can be 6.2 Syringes, commercially available, at least 5 mL in
used in conjunction with other properties to characterize both volume, with a Luer tip.All construction materials for syringes
shall be fully compatible with all sample liquids and cleaning
the light and heavy fractions of petroleum and petroleum
products. agents, which contact them.
6.3 Flow-Through or Pressure Adapter, for use as an
5.3 Determination of the density or relative density of
petroleum and its products is necessary for the conversion of alternative means of introducing the test specimen into the
measuring cells either by pressure or by suction, provided that
measured volumes to volumes at the standard temperature of
15°C. sufficient care and control is used to avoid any bubble
formation in the test specimen. All construction materials for
6. Apparatus
adaptors shall be fully compatible with all sample liquids and
5,6
cleaning agents, which contact them.
6.1 Stabinger Viscometer
6.1.1 Viscosity measurement—The Stabinger viscometer
uses a rotational coaxial cylinder measuring system. The outer
cylinder (tube) is driven by a motor at a constant and known
rotational speed. The low-density inner cylinder (rotor) is held
in the axis of rotation by the centrifugal forces of the higher
density sample and in its longitudinal position by the magnet
The Stabinger viscometer is covered by a patent. Interested parties are invited
to submit information regarding the identification of an alternative to this patented
item to the ASTM International headquarters. Your comments will receive careful
consideration at a meeting of the responsible technical committee, which you may
attend.
The sole source of supply of the apparatus known to the committee at this time
isAnton Paar GmbH,Anton-Paar-Str. 20,A-8054 Graz,Austria. If you are aware of
alternative suppliers, please provide this information to ASTM International
headquarters. Your comments will receive careful consideration at a meeting of the
responsible technical committee, which you may attend. FIG. 1 Viscosity Cell
D7042–04
volatilematerial;mixinginclosed,pressurizedcontainers,orat
sub-ambient temperatures is recommended.
8.3.2 Draw the test specimen from a properly mixed labo-
ratorysampleusinganappropriatesyringe.Alternatively,ifthe
proper attachments and connecting tubes are used, the test
specimen can be delivered directly to the measuring cells from
the mixing container. For waxy or other samples with a high
pour point, before drawing the test specimen, heat the labora-
tory sample to the desired test temperature, which has to be
high enough to dissolve the wax crystals.
9. Calibration and Verification
9.1 Use only a calibrated apparatus as described in 6.1. The
calibration shall be checked periodically using certified refer-
ence standards as described in 9.2 and 9.3. The recommended
interval for viscosity and density calibration is once a month,
FIG. 2 Cell Block
for temperature control once a year. For the calibration
procedure follow the instructions of the manufacturer of the
apparatus.
6.4 Screen, with an aperture of 75 µm, to remove particles
9.2 Certified Viscosity and Density Reference Standards—
from the sample.
These are for use as confirmatory checks on the procedure in
6.5 Magnet, strong enough to remove iron fillings from the
the laboratory. Certified viscosity and density reference stan-
sample. Magnetic stirring rods are suitable.
dards shall be certified by a laboratory, which has shown to
7. Reagents and Materials
meet the requirements of ISO/IEC 17025 or a corresponding
national standard by independent assessment. Viscosity stan-
7.1 Sample Solvent, completely miscible with the sample.
7.1.1 For most samples, a volatile petroleum spirit or dards shall be traceable to master viscometer procedures
described in Test Method D2162. Density standards shall have
naphtha is suitable. If the solvent dries up without residues in
an applicable time frame, the use of a separate drying solvent a certified uncertainty of the density values of 0.0001 g/mL.
The uncertainty of the reference standards shall be stated for
is not required.
7.1.2 For residual fuels, a prewash with an aromatic solvent each certified value (k = 2; 95 % confidence level). See
ISO 5725 or NIST Technical Note 1297.
suchastolueneorxylenemaybenecessarytoremoveasphaltic
material. 9.3 Thermometer—For calibration and adjustment of the
temperature control, a digital thermometer with a probe diam-
7.2 Drying Solvent, a volatile solvent miscible with the
sample solvent (see 7.1). eter of 6.25 mm and a maximal length of 80 mm shall be used.
For smaller probes the use of an adapter is suitable. The
7.2.1 Highly concentrated ethanol (96 % or higher) is suit-
uncertainty (k = 2; 95 % confidence level) of this thermometer
able.
must be no more than 60.01°C and has to be certified by a
7.3 Dry Air or Nitrogen, for blowing the measuring cells.
laboratory which has shown to meet the requirements of
7.3.1 If the measuring cell temperature is below or near the
ISO/IEC 17025 or a corresponding national standard by
dew point temperature of the ambient air, the use of an
independent assessment. A suitable thermometer is available
appropriate desiccator is required.
from the manufacturer of the apparatus.
8. Sampling, Test Specimens, and Test Units
9.4 Acceptable Tolerance—If the determined values of a
8.1 Sampling is defined as all the steps required to obtain an calibration check measurement do not agree within the accept-
able tolerance band of the certified values, as calculated from
aliquot of the contents of any pipe, tank, or other system, and
to place the sample into the laboratory test container. The Annex A1, re-check each step in the procedure, including the
special cleaning procedure from 12.2, to locate the source of
laboratory test container and sample volume shall be of
sufficient capacity to mix the sample and obtain a homoge- error.
neous sample for analysis.
NOTE 1—Values exceeding the acceptable tolerance are generally
8.2 Particles—For samples that are likely to contain par-
attributable to deposits in the measuring cells that are not removed by the
ticles (for example, used oils or crude oils) pass the sample
routine flushing procedure.
through a 75-µm screen to remove the particles. For the
10. Adjustment
removalofironfilingstheuseofamagnetisappropriate.Waxy
samples must be heated to dissolve the wax crystals prior to 10.1 An adjustment has to be carried out when repeated
filtration and a preheated fi
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