ASTM D7042-21a

Standard Test Method for Dynamic Viscosity and Density of Liquids by Stabinger Viscometer (and the Calculation of Kinematic Viscosity)

SIGNIFICANCE AND USE
5.1 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.  
5.2 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.  
5.3 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 covers and 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, ν, 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 The precision has only been determined for those materials, viscosity ranges, density ranges, and temperatures as indicated in Section 15 on Precision and Bias. The test method can be applied to a wider range of materials, viscosity, density, and temperature. For materials not listed in Section 15 on Precision and Bias, the precision and bias may not be applicable.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
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, health, and environmental practices and to 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.

General Information

• Status: Published
• Publication Date: 31-Oct-2021
• ICS: 17.060 - Measurement of volume, mass, density, viscosity
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.07 - Flow Properties

Relations

• Refers: ASTM D445-24 - Standard Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity)
• Effective Date: 01-Apr-2024
• Refers: ASTM D1655-24 - Standard Specification for Aviation Turbine Fuels
• Effective Date: 15-Mar-2024
• Refers: ASTM D7566-24a - Standard Specification for Aviation Turbine Fuel Containing Synthesized Hydrocarbons
• Effective Date: 15-Mar-2024
• Refers: ASTM D6300-24 - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 01-Mar-2024
• Refers: ASTM D6708-24 - Standard Practice for Statistical Assessment and Improvement of Expected Agreement Between Two Test Methods that Purport to Measure the Same Property of a Material
• Effective Date: 01-Mar-2024
• Refers: ASTM D7566-24 - Standard Specification for Aviation Turbine Fuel Containing Synthesized Hydrocarbons
• Effective Date: 01-Mar-2024
• Refers: ASTM D975-23a - Standard Specification for Diesel Fuel
• Effective Date: 15-Dec-2023
• Refers: ASTM D6299-23a - Standard Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measurement System Performance
• Effective Date: 01-Dec-2023
• Refers: ASTM D6300-23a - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 01-Dec-2023
• Refers: ASTM D445-23 - Standard Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity)
• Effective Date: 01-Nov-2023
• Refers: ASTM D7566-23b - Standard Specification for Aviation Turbine Fuel Containing Synthesized Hydrocarbons
• Effective Date: 01-Oct-2023
• Refers: ASTM D7467-23 - Standard Specification for Diesel Fuel Oil, Biodiesel Blend (B6 to B20)
• Effective Date: 01-Oct-2023
• Refers: ASTM D1655-23a - Standard Specification for Aviation Turbine Fuels
• Effective Date: 01-Oct-2023
• Refers: ASTM D7566-23a - Standard Specification for Aviation Turbine Fuel Containing Synthesized Hydrocarbons
• Effective Date: 01-Jul-2023
• Refers: ASTM D7566-23 - Standard Specification for Aviation Turbine Fuel Containing Synthesized Hydrocarbons
• Effective Date: 01-Jun-2023

Overview

ASTM D7042-21a: Standard Test Method for Dynamic Viscosity and Density of Liquids by Stabinger Viscometer (and the Calculation of Kinematic Viscosity) establishes a procedure for the precise and concurrent measurement of dynamic viscosity and density of liquid petroleum products, crude oils, and other fluids exhibiting Newtonian flow behavior. This international standard, published by ASTM, is highly relevant for laboratories and industries that demand accurate viscosity and density data for product specification, quality control, and operational optimization.

Viscosity and density are vital physical properties for lubricants, fuels, and chemical feedstocks. Accurate measurements inform key processes, from equipment lubrication to the storage and handling of liquids. This standard specifically supports petroleum and allied industries by establishing a consistent, reproducible test method using a Stabinger viscometer, enabling the calculation of kinematic viscosity as a derived property.

Key Topics

• Dynamic Viscosity Determination: Measures the liquid's resistance to flow under shear, fundamental for predicting performance in lubrication and fuel injection.
• Density Measurement: Determines mass per unit volume, crucial for product blending, volume correction, and quality assessment.
• Kinematic Viscosity Calculation: Provides the flow rate under gravity by dividing dynamic viscosity by density at the same temperature.
• Sample Preparation and Handling: Ensures homogeneity and stability of test specimens, even for challenging or waxy crude oils and residual fuels.
• Calibration and Quality Assurance: Mandates use of certified reference standards and regular calibration checks to maintain measurement accuracy.
• Applicability: While precision is established for specific viscosity, density, and temperature ranges, the method can be extended beyond these with appropriate caveats.

Applications

ASTM D7042-21a is widely used in:

• Petroleum Refineries: For characterizing crude oils, base oils, diesel, jet fuel, and biodiesel blends, ensuring regulatory and specification compliance.
• Lubricant Manufacturing: For formulating and qualifying lubricants where viscosity directly impacts machinery efficiency and longevity.
• Fuel Quality Testing: Precise determination of diesel and aviation turbine fuel properties for operational optimization and safety.
• Product Specification: Supports converting measured liquid volumes to standard volumes at 15°C, a central process in trade and inventory management.
• Research and Development: Facilitates the investigation of temperature-dependent behavior of fluids.

The standard is also essential for laboratories seeking certification or operating under ISO/IEC 17025 accreditation, as it provides a documented, consistent methodology for critical property measurement.

Related Standards

ASTM D7042-21a references and complements several important industry standards:

• ASTM D445: Test Method for Kinematic Viscosity of Transparent and Opaque Liquids
• ASTM D4052: Test Method for Density, Relative Density, and API Gravity of Liquids by Digital Density Meter
• ISO/IEC 17025: General Requirements for Competence of Testing and Calibration Laboratories
• ASTM D2162: Practice for Basic Calibration of Master Viscometers and Viscosity Oil Standards
• ASTM D2270: Practice for Calculating Viscosity Index from Kinematic Viscosity at 40°C and 100°C
• ISO 5725: Accuracy (Trueness and Precision) of Measurement Methods and Results

Using ASTM D7042 in conjunction with these documents enables comprehensive analysis and global comparability for viscosity and density measurements.

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Keywords: ASTM D7042, dynamic viscosity, density measurement, Stabinger viscometer, kinematic viscosity calculation, petroleum products, lubricants, Newtonian flow, fuel quality, standard test method.

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.
Designation: D7042 − 21a
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* 2. Referenced Documents
1.1 Thistestmethodcoversandspecifiesaprocedureforthe
2.1 ASTM Standards:
concurrent measurement of both the dynamic viscosity, η, and
D341 Practice for Viscosity-Temperature Equations and
thedensity, ρ,ofliquidpetroleumproductsandcrudeoils,both
Charts for Liquid Petroleum or Hydrocarbon Products
transparent and opaque. The kinematic viscosity, ν, can be
D396 Specification for Fuel Oils
obtained by dividing the dynamic viscosity, η, by the density,
D445 Test Method for Kinematic Viscosity of Transparent
ρ, obtained at the same test temperature.
and Opaque Liquids (and Calculation of Dynamic Viscos-
ity)
1.2 The result obtained from this test method is dependent
D975 Specification for Diesel Fuel
upon the behavior of the sample and is intended for application
D1655 Specification for Aviation Turbine Fuels
toliquidsforwhichprimarilytheshearstressandshearrateare
D2162 Practice for Basic Calibration of Master Viscometers
proportional (Newtonian flow behavior).
and Viscosity Oil Standards
1.3 The precision has only been determined for those
D2270 Practice for Calculating Viscosity Index from Kine-
materials, viscosity ranges,densityranges,andtemperaturesas
matic Viscosity at 40 °C and 100 °C
indicated in Section 15 on Precision and Bias. The test method
D4052 Test Method for Density, Relative Density, and API
can be applied to a wider range of materials, viscosity, density,
Gravity of Liquids by Digital Density Meter
and temperature. For materials not listed in Section 15 on
D6299 Practice for Applying Statistical Quality Assurance
Precision and Bias, the precision and bias may not be appli-
and Control Charting Techniques to Evaluate Analytical
cable.
Measurement System Performance
D6300 Practice for Determination of Precision and Bias
1.4 The values stated in SI units are to be regarded as
Data for Use in Test Methods for Petroleum Products,
standard. No other units of measurement are included in this
Liquid Fuels, and Lubricants
standard.
D6617 Practice for Laboratory Bias Detection Using Single
1.5 This standard does not purport to address all of the
Test Result from Standard Material
safety concerns, if any, associated with its use. It is the
D6708 Practice for StatisticalAssessment and Improvement
responsibility of the user of this standard to establish appro-
of Expected Agreement Between Two Test Methods that
priate safety, health, and environmental practices and to
Purport to Measure the Same Property of a Material
determine the applicability of regulatory limitations prior to
D6751 Specification for Biodiesel Fuel Blend Stock (B100)
use.
for Middle Distillate Fuels
1.6 This international standard was developed in accor-
D7467 Specification for Diesel Fuel Oil, Biodiesel Blend
dance with internationally recognized principles on standard-
(B6 to B20)
ization established in the Decision on Principles for the
D7566 Specification for Aviation Turbine Fuel Containing
Development of International Standards, Guides and Recom-
Synthesized Hydrocarbons
mendations issued by the World Trade Organization Technical
D7915 Practice for Application of Generalized Extreme
Barriers to Trade (TBT) Committee.
Studentized Deviate (GESD) Technique to Simultane-
ously Identify Multiple Outliers in a Data Set
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 D02.07 on Flow Properties. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Nov. 1, 2021. Published December 2021. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 2004. Last previous edition approved in 2021 as D7042 – 21. Standards volume information, refer to the standard’s Document Summary page on
DOI:10.1520/D7042-21A. 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
D7042 − 21a
2.2 ISO Standards: cylinder under the influence of the shear stress of the test
ISO 5725 Accuracy (Trueness and Precision) of Measure- specimen and an eddy current brake in conjunction with
ment Methods and Results adjustment data. The density is determined by the oscillation
ISO 8217 Petroleum products – Fuels (class F) frequency of the U-tube in conjunction with adjustment data.
ISO/IEC 17025 General Requirements for the Competence The kinematic viscosity is calculated by dividing the dynamic
of Testing and Calibration Laboratories viscosity by the density.
2.3 Other Documents:
NIST Technical Note 1297 Guideline for Evaluating and 5. Significance and Use
Expressing the Uncertainty of NISTMeasurement Results
5.1 Many petroleum products, and some non-petroleum
DEF STAN 91-091 Turbine Fuel, Kerosene Type, Jet A-1
materials, are used as lubricants and the correct operation of
the equipment depends upon the appropriate viscosity of the
3. Terminology
liquid being used. In addition, the viscosity of many petroleum
3.1 Definitions:
fuels is important for the estimation of optimum storage,
3.1.1 density, n—mass per unit volume.
handling, and operational conditions. Thus, the accurate deter-
mination of viscosity is essential to many product specifica-
3.1.2 dynamic viscosity [η], n—the ratio between the ap-
plied shear stress and rate of shear of a liquid at a given tions.
temperature.
5.2 Density is a fundamental physical property that can be
3.1.2.1 Discussion—It is sometimes called the coefficient of
used in conjunction with other properties to characterize both
dynamic viscosity or, simply, viscosity. Thus, dynamic viscos-
the light and heavy fractions of petroleum and petroleum
ity is a measure of the resistance to flow or to deformation of
products.
a liquid under external shear forces.
5.3 Determination of the density or relative density of
3.1.2.2 Discussion—Thetermdynamicviscositycanalsobe
petroleum and its products is necessary for the conversion of
used in a different context to denote a frequency-dependent
measured volumes to volumes at the standard temperature of
quantity in which shear stress and shear rate have a sinusoidal
15 °C.
time dependence.
3.1.3 kinematic viscosity, n—the ratio of the dynamic vis-
6. Apparatus
cosity (η) to the density (ρ) of a liquid at a given temperature.
6,7
6.1 Stabinger Viscometer
3.1.3.1 Discussion—For gravity flow under a given hydro-
6.1.1 Viscosity Measurement—The Stabinger viscometer
static head, the pressure head of a liquid is proportional to its
uses a rotational coaxial cylinder measuring system. The outer
density (ρ). Therefore, the kinematic viscosity (ν) is a measure
cylinder (tube) is driven by a motor at a constant and known
of the resistance to flow of a liquid under gravity.
rotational speed. The low-density inner cylinder (rotor) is held
3.1.4 relative density (also called specific gravity (SG)),
in the axis of rotation by the centrifugal forces of the higher
n—the ratio of the density of a material at a stated temperature
density sample and in its longitudinal position by the magnet
to the density of a reference material (usually water) at a stated
and the soft iron ring. Consequently, the system works free of
temperature.
bearing friction as found in rotational viscometers. A perma-
3.2 Definitions of Terms Specific to This Standard:
nent magnet in the inner cylinder induces eddy currents in the
3.2.1 Tat12mm /s, °C, n—the temperature at which the
surrounding copper casing. The rotational speed of the inner
material has a kinematic viscosity of 12 mm /s.
cylinder establishes itself as the result of the equilibrium
3.2.1.1 Discussion—Term mostly is associated with jet fuel
between the driving torque of the viscous forces and the
where 12 mm /s is considered a critical viscosity value. The
retarding eddy current torque. This rotational speed is mea-
temperature is determined using Practice D341 interpolation or
sured by an electronic system (Hall effect sensor) by counting
extrapolation calculations from two kinematic viscosity data
the frequency of the rotating magnetic field (seeFig. 1 and Fig.
points.Othercriticalviscositydatacansimilarlybedetermined
2, No. 2).
for other materials as T at (xx) mm /s.
6.1.2 Density Measurement—The digital density analyzer
uses a U-shaped oscillating sample tube and a system for
4. Summary of Test Method
electronic excitation and frequency counting (see Fig. 2, No.
4.1 Thetestspecimenisintroducedintothemeasuringcells,
3).
which are at a closely controlled and known temperature. The
measuring cells consist of a pair of rotating concentric cylin-
ders and an oscillating U-tube. The dynamic viscosity is
The Stabinger viscometer is covered by a patent. Interested parties are invited
determined from the equilibrium rotational speed of the inner
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
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St., attend.
4th Floor, New York, NY 10036, http://www.ansi.org. The sole source of supply of the apparatus known to the committee at this time
Available from National Institute of Standards and Technology (NIST), 100 isAnton Paar GmbH,Anton-Paar-Str. 20,A-8054 Graz,Austria. If you are aware of
Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http://www.nist.gov. alternative suppliers, please provide this information to ASTM International
Available from IHS, 15 Inverness Way East, Englewood, CO 80112, http:// headquarters. Your comments will receive careful consideration at a meeting of the
www.global.ihs.com. responsible technical committee, which you may attend.
D7042 − 21a
suring cells either by pressure or by suction, provided that
sufficient care and control is used to avoid any bubble
formation in the test specimen. All construction materials for
adaptors shall be fully compatible with all sample liquids and
cleaning agents, which contact them.
6.4 Hot Filling Adapter, for use with manual syringe filling
for the purpose of preventing the precipitation of waxy
componentsdissolvedinsampleandloweringsampleviscosity
for easier sample introduction and cleaning routines.
6.5 Autosampler, for use in automated injection analyses.
Theautosamplershallbedesignedtoensuretheintegrityofthe
FIG. 1 Viscosity Cell
test specimen prior to and during the analysis and be equipped
to transfer a representative portion of test specimen into the
measuring cells. The autosampler shall transfer the test speci-
men from the sample vial to the measuring cells of the
apparatus without interfering with the integrity of the test
specimen. The autosampler shall be able to mimic the proce-
dure for sample handling as set forth in 11.1 and 11.2. The
autosampler may have heating capability as a means to prevent
the precipitation of waxy components dissolved in the sample
and lower the viscosity of the sample for filling the measuring
cells.
6.6 Screen, with an aperture of 75 µm, to remove particles
from the sample.
6.7 Magnet, strong enough to remove ferromagnetic mate-
rials from the sample. Magnetic stirring rods are suitable.
6.8 Ultrasonic Bath, Unheated (optional), with an operating
FIG. 2 Cell Block
frequency between 25 kHz to 60 kHz and a typical power
output of ≤100 W, of suitable dimensions to hold container(s)
6.1.3 Temperature Control—The copper block surrounds placed inside of bath, for use in effectively dissipating and
both the viscosity and the density measuring cell in a way that removing air or gas bubbles that can be entrained in viscous
both cells are held at the same temperature. A thermoelectric sample types prior to analysis. It is permissible to use ultra-
heating and cooling system (see Fig. 2, No. 1) ensures the sonic baths with operating frequencies and power outputs
temperature stability of the copper block within 60.005 °C outside this range, however it is the responsibility of the
from the set temperature at the position of the viscosity cell laboratory to conduct a data comparison study to confirm that
overthewholetemperaturerange.Theuncertainty(k=2;95 % results determined with and without the use of such ultrasonic
confidence level) of the temperature calibration shall be no baths does not materially impact results.
more than 60.03 °C over the range from 15 °C to 100 °C.
Outside this range the calibration uncertainty shall be no more
7. Reagents and Materials
than 60.05 °C.
7.1 Sample Solvent, completely miscible with the sample.
6.1.4 The thermal equilibration time depends on the heat
7.1.1 For most samples, a volatile petroleum spirit or
capacity and conductivity of the liquid and on the difference
naphtha is suitable. If the solvent dries up without residues in
between injection temperature and test temperature. Adequate
an applicable time frame, the use of a separate drying solvent
temperature equilibration of the test specimen is automatically
is not required.
determined when successive viscosity values are constant
7.1.2 For residual fuels, a prewash with an aromatic solvent
within 60.07 % over 1 min and successive density values are
3 suchastolueneorxylenemaybenecessarytoremoveasphaltic
constant within 60.00003 g/cm over 60 s.
material.
NOTE 1—The Stabinger Viscometer, manufactured by Anton Paar
7.2 Drying Solvent, a volatile solvent miscible with the
GmbH, fulfills the stated requirements when operated in the most precise
mode of operation. sample solvent (see 7.1).
7.2.1 Highly concentrated ethanol (96 % or higher),
6.2 Syringes, commercially available, at least 5 mL in
n-hexane or n-heptane is suitable.
volume, with a Luer tip.All construction materials for syringes
shall be fully compatible with all sample liquids and cleaning
7.3 Dry Air or Nitrogen, for blowing the measuring cells.
agents, which contact them.
7.3.1 If the measuring cell temperature is below or near the
6.3 Flow-Through or Pressure Adapter, for use as an alter- dew point temperature of the ambient air, the use of an
native means of introducing the test specimen into the mea- appropriate desiccator is required.
D7042 − 21a
8. Sampling, Test Specimens, and Test Units 8.2.4 Remove the stirring rod and inspect for sludge or wax
adhering to the rod. If there is sludge or wax adhering to the
8.1 General Considerations and Guidelines:
rod, continue stirring until the sample is homogeneous.
8.1.1 Sampling is defined as all the steps required to obtain
8.2.5 Recap each container tightly and shake vigorously for
an aliquot of the contents of any pipe, tank, or other system,
1 min. Then loosen the cap, retighten to finger tight, then back
and to place the sample into the laboratory test container. The
off ⁄4 to a full turn and place back into the sample preheat
laboratory test container and sample volume shall be of
apparatus.
sufficient capacity to mix the sample and obtain a homoge-
8.2.6 Upon completion of 8.2.5 for all samples in the batch,
neous sample for analysis.
increase the sample pre-heat apparatus temperature to between
8.1.2 For some sample types, such as viscous lube oils that
100 °C and 105 °C and heat for 30 min.
are prone to having entrained air or gas bubbles present in the
8.2.7 Remove each container from the sample pre-heat
sample, the use of an ultrasonic bath (see 6.8) without the
apparatus, close tightly, and shake vigorously for 60 s.
heater turned on (if so equipped), has been found effective in
8.2.8 If a heated auto sampler is used, follow instructions in
dissipating bubbles typically within 1 min.
8.2.8.1 below. If a sample handler is used, follow instructions
8.1.3 Particles—For samples that are likely to contain
in 8.2.8.2 below.
particles (for example, used oils or crude oils) pass the sample
8.2.8.1 Ensure the sample vial magazine is held at a
through a 75 µm screen to remove the particles. For the
temperature between 60 °C and 80 °C. Load each sample into
removal of ferromagnetic materials the use of a magnet is
its own preheated sample vial from 8.2.1, insert the vials into
appropriate. Waxy samples must be heated to dissolve the wax
thesamplevialmagazine,andwaitfor10 minto15 minbefore
crystals prior to filtration and a preheated filter shall be used.
commencing measurement.
8.1.4 Test Specimen—A portion or volume of sample ob-
8.2.8.2 Load a preheated sample vial from 8.2.1 with the
tained from the laboratory sample and delivered to the mea-
first sample to be tested in the batch and place the sample vial
suring cells. The test specimen is obtained as follows:
into the sampler handler that is held between 60 °C and 80 °C.
8.1.4.1 Mix the sample, if required, to homogenize. Mixing
Loosen the cap of the other containers, retighten to finger tight,
at room temperature in an open container can result in the loss
then back off ⁄4 to full turn and place the containers back into
of volatile material; mixing in closed, pressurized containers,
the sample preheat apparatus that is reset to hold temperature
or at sub-ambient temperatures is recommended.
between 60 °C and 80 °C.
8.1.4.2 Draw the test specimen from a properly mixed
8.2.9 Complete the measurements according to 11.1 or 11.3.
laboratory sample using an appropriate syringe. Alternatively,
Analysis of all samples in the batch must be completed within
if the proper attachments and connecting tubes are used, the
1 h from completion of 8.2.7.
test specimen may be delivered directly to the measuring cells
using a flow through or pressure adapter (see 6.3) or autosam-
9. Calibration and Verification
pler (see 6.5) from the mixing container. For waxy or other
9.1 Use only a calibrated apparatus as described in 6.1. The
samples with a high pour point, before drawing the test
calibration shall be checked periodically using certified refer-
specimen, heat the laboratory sample to the desired test
ence standards as described in 9.2 and 9.3. The recommended
temperature, which has to be high enough to dissolve the wax
interval for viscosity and density calibration is once a month,
crystals.
for temperature control once a year. For the calibration
8.2 Instructions for Residual Fuel Oils:
procedure follow the instructions of the manufacturer of the
8.2.1 (Warning—Exercise care as vigorous boil-over can
apparatus.
occur when opaque liquids which contain high levels of water
9.2 Certified Viscosity and Density Reference Standards—
are heated to high temperatures. Wear appropriate personal
These are for use as confirmatory checks on the procedure in
protective equipment for handling hot materials.) Place the
the laboratory. Certified viscosity and density reference stan-
required number of disposable syringes or samples vials to be
dards shall be certified by a laboratory, which has shown to
used for the batch analysis into a sample preheat apparatus
meet the requirements of ISO/IEC 17025 or a corresponding
(such as an oven, bath, or heating block) held between 60 °C
national standard by independent assessment. Viscosity stan-
and 65 °C. If using manual syringe filling, a hot filling adapter
dards shall be traceable to master viscometer procedures
must be installed on the apparatus and the injection adapters
described in Test Method D2162. Density standards shall have
must also be pre-warmed along with the syringes.
a certified uncertainty of the density values of 0.0001 g/cm .
8.2.2 Place the first batch of residual fuel samples to be
The uncertainty of the reference standards shall be stated for
analyzed for the day in their original containers in a sample
each certified value (k = 2; 95 % confidence level). See ISO
preheat apparatus that is between 60 °C and 65 °C for 1 h.
5725 or NIST Technical Note 1297.
Ensure the cap on each container is tightly closed. For samples
of a very waxy nature or oils of high kinematic viscosity, it 9.3 Thermometer—For calibration and adjustment of the
may be necessary to increase the heating temperature above
temperature control, a digital thermometer with a probe diam-
60 °C to achieve proper mixing. The sample should be suffi- eter of 6.25 mm and a maximal length of 80 mm shall be used.
ciently fluid for ease of stirring and shaking.
For smaller probes the use of an adapter is suitable. The
8.2.3 Vigorously stir each sample for approximately 20 s uncertainty (k = 2; 95 % confidence level) of this thermometer
with a glass or steel rod of sufficient length to reach the bottom must be no more than 60.01 °C and has to be certified by a
of the container. laboratory which has shown to meet the requirements of
D7042 − 21a
ISO/IEC 17025 or a corresponding national standard by structions. Wait for the instrument to indicate that the determi-
independent assessment. A suitable thermometer is available nation is valid and record the values.
from the manufacturer of the apparatus.
11.1.5 Inject a further 1 mL without taking off the syringe
and repeat the measurement.
9.4 Acceptable Tolerance—If the determined values of a
11.1.6 If the deviation between two consecutive determina-
calibration check measurement do not agree within the accept-
tions exceeds the determinability limits as stated in Table 1 for
able tolerance band of the certified values, as calculated from
this product, repeat step 11.1.5 until the deviation is within
Annex A1, recheck each step in the procedure, including the
these limits. Discard all previously determined values and
special cleaning procedure from 12.2, to locate the source of
report the values of the last determination as the result.
error.
11.1.6.1 For products not listed in the precision section, it is
NOTE 2—Values exceeding the acceptable tolerance are generally
the responsibility of the user of this standard to establish
attributable to deposits in the measuring cells that are not removed by the
reasonable determinability limits by a series of tests.
routine flushing procedure.
11.1.6.2 If the syringe is empty before obtaining a valid
10. Adjustment
determination,rinseanddrythemeasuringcellsasdescribedin
10.1 An adjustment has to be carried out when repeated 12.1andrepeatstep11.1.4.Ifitisnotpossibletoobtainavalid
result within an applicable number of repetitions, report the
calibration check measurements do not agree with theAccept-
able Tolerance Band as stated in 9.4 and the error cannot be robust mean value and the standard deviation (k = 2; 95 %
confidence level) together with a remark indicating that the
located elsewhere. For the adjustment procedure follow the
determinability exceeded the limits stated in 15.2.1 for this
instructions of the manufacturer of the apparatus.
product.
10.2 For an adjustment, use only certified viscosity and
11.1.7 Removethetestspecimenimmediately,rinseanddry
density reference standards that fulfill the requirements as
the measuring cells as described in 12.1.
stated in 9.2. The reference standards have to be within the
viscosity, density, and temperature range specified by the
11.2 Alternative Procedure (Sample Displacement)—For a
manufacturer of the apparatus.
series of samples that are mutually soluble (for example,
various diesel fuels). It is the responsibility of the user of this
10.3 After an adjustment procedure a calibration check
standard to determine the applicability of this procedure to
measurement shall be performed.
each class of samples.
11. Procedure
11.2.1 Set the internal temperature control to the desired
measuring temperature.
11.1 Standard procedure (rinsing and drying)
11.2.2 Set the determinability limits and temperature stabil-
11.1.1 Set the internal temperature control to the desired
ity criteria to the values stated in Table 1 for the specific
measuring temperature.
product.
11.1.2 Set the determinability limits and temperature stabil-
ity criteria to the values stated in Table 1 for the specific 11.2.3 Make sure that the measuring cells are clean and dry
as described in 12.1.
product.
11.1.3 Make sure that the measuring cells are clean and dry 11.2.4 Load a minimum of 5 mLof the test specimen to the
as described in 12.1. syringe;ifenoughsampleisavailableitisrecommendedtouse
11.1.4 Load a minimum of 5 mLof the test specimen to the a 10 mL or larger syringe and to fill the entire syringe. Pour
syringe; if enough sample is available it is recommended to fill slowly at least 3 mL of the test specimen into the measuring
the entire syringe. Pour at least 2 mL of the test specimen into cells.Aslow flow ensures that the new test specimen displaces
the measuring cells. Leave the syringe in the inlet opening and theoldoneratherthanmergingwithit.Leavethesyringeinthe
start the motor and wait for about 10 s, then stop the motor inlet opening, start the motor and wait for about 10 s, then stop
again. Inject an additional 1 mL, leave the syringe in the inlet the motor. Inject an additional 1 mL, leave the syringe in the
opening, and start the measurement. Alternatively, the instru- inlet opening, and start the measurement. Alternatively, the
ment may be configured to perform pre-wetting automatically instrumentmaybeconfiguredtoperformpre-wettingautomati-
prior to starting the measurement. Follow manufacture’s in- cally prior to starting the measurement. Follow manufacture’s
TABLE 1 Determinability Limits and Temperature Stability Criteria
NOTE 1—X is the final determination.
RDV RDD Temperature Viscosity Density Stability Time Repeats Equilibra-
(Determinability, (Determinability, Stability Stability tion Time
dynamic viscos- density)
ity)
3 3
For ALL materials at ALL temperatures 0.10 % 0.0002 g/cm ±0.005 °C ±0.07 % 0.00003 g/cm 60 s 3 0 s
unless specifically listed below 0.001 X
3 3
Residual Fuel Oils at 50 °C and 100 °C 0.35 % 0.0003 g/cm ±0.010 °C ±0.10 % 0.00005 g/cm 40 s 3 30 s
0.0035 X
3 3
Jet fuel at –20 °C and –40 °C, Scanning 0.0011889 X 0.000113 g/cm ±0.005 °C ±0.07 % 0.0001 g/cm 60 s 0 0 s
procedure
D7042 − 21a
instructions. Wait for the instrument to indicate that the The apparatus reports measured density and dynamic viscosity
determination is valid and record the values. values as well as calculated kinematic viscosity and the
11.2.5 Inject slowly a further 2 mL without taking off the temperature for a pre-defined kinematic viscosity in accor-
syringe and repeat the measurement. dance with Practice D341, Standard Viscosity-Temperature
11.2.6 If the deviation between two consecutive determina- Charts for Liquid Petroleum Products. This procedure can be
tions exceeds the determinability limits as stated in Table 1 for applied with either sample filling procedure.
this product, repeat step 11.2.5 until the deviation is within 11.4.2 The temperature range of interest shall be defined as
these limits. Discard all previously determined values and well as the temperature points at which data shall be reported.
report the values of the last determination as the result. Ensure that the study material’s boiling and freezing points are
11.2.6.1 For products not listed in the precision section it is not exceeded by the defined temperature range. The tempera-
the responsibility of the user of this standard to establish turerangeanddatareportingtemperaturesshallbeenteredinto
reasonable determinability limits by a series of tests. the apparatus in either table format or defined as start, stop and
11.2.6.2 If the syringe is empty before obtaining a valid interval temperature.
determination repeat step 11.2.4. If it is not possible to obtain 11.4.3 When performing measurements at sub-zero tem-
a valid result within an applicable number of repetitions, report peratures it is essential that the risk of ice formation during
the robust mean value and the standard deviation (k = 2; 95 % drying routines and sample filling in the measuring cells is
confidence level) together with a remark indicating that the eliminated. This can be achieved by using dry air after cell
determinability exceeded the limits stated in 15.1.1 for this cleaning and selecting a sample filling temperature which is
product. well above 0 °C.
11.2.7 For the next sample of this series repeat the steps 11.4.4 When testing jet fuel in conformance with this test
11.2.4 – 11.2.6. method, the apparatus shall be equipped with an appropriate
11.2.8 After the last sample of a series perform a cleaning counter cooling system. The filling temperature shall be 15 °C
procedure as described in 12.1. or above, test temperatures shall be –20 °C, –40 °C with
duplicate determinations at –20 °C and –40 °C so that deter-
11.3 Procedure for Use with Autosampler:
minability can be verified.
11.3.1 Set the determinability and temperature stability
11.4.5 For conformance with stated precision on jet fuel
criteria to values in Table 1 for the corresponding testing
(see Tables 1-3) set the test stability criteria in accordance with
parameter(s) and temperature(s) of interest. Ensure that auto-
Table 1.
matic prewetting has been configured. See manufacture’s
instructions for details. Temperature control/stability require-
12. Cleaning of the Measuring Cells
ments at the test temperatures of interest are provided in 6.1.3.
12.1 Fill the measuring cells with at least 3 mL of the
For all other sample types, see 11.3.2 for guidance.
sample solvent (see 7.1). Check if the density cell is filled
11.3.2 For products not listed in the precision section, it is
completely by examining the displayed density value. Start the
the responsibility of the user of this test method to establish
motor for at least 10 s. For poorly soluble samples, extend this
reasonable determinabi
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D7042 − 21 D7042 − 21a
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*
1.1 This test method covers and 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, ν, 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 The precision has only been determined for those materials, viscosity ranges, density ranges, and temperatures as indicated
in Section 15 on Precision and Bias. The test method can be applied to a wider range of materials, viscosity, density, and
temperature. For materials not listed in Section 15 on Precision and Bias, the precision and bias may not be applicable.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
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, health, and environmental practices and to 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:
D341 Practice for Viscosity-Temperature Equations and Charts for Liquid Petroleum or Hydrocarbon Products
D396 Specification for Fuel Oils
D445 Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity)
D975 Specification for Diesel Fuel
D1655 Specification for Aviation Turbine Fuels
D2162 Practice for Basic Calibration of Master Viscometers and Viscosity Oil Standards
D2270 Practice for Calculating Viscosity Index from Kinematic Viscosity at 40 °C and 100 °C
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
D02.07 on Flow Properties.
Current edition approved Jan. 1, 2021Nov. 1, 2021. Published January 2021December 2021. Originally approved in 2004. Last previous edition approved in 20202021
as D7042 – 20.D7042 – 21. DOI:10.1520/D7042-21.DOI:10.1520/D7042-21A.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. 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
D7042 − 21a
D4052 Test Method for Density, Relative Density, and API Gravity of Liquids by Digital Density Meter
D6299 Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measure-
ment System Performance
D6300 Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products, Liquid Fuels, and
Lubricants
D6617 Practice for Laboratory Bias Detection Using Single Test Result from Standard Material
D6708 Practice for Statistical Assessment and Improvement of Expected Agreement Between Two Test Methods that Purport
to Measure the Same Property of a Material
D6751 Specification for Biodiesel Fuel Blend Stock (B100) for Middle Distillate Fuels
D7467 Specification for Diesel Fuel Oil, Biodiesel Blend (B6 to B20)
D7566 Specification for Aviation Turbine Fuel Containing Synthesized Hydrocarbons
D7915 Practice for Application of Generalized Extreme Studentized Deviate (GESD) Technique to Simultaneously Identify
Multiple Outliers in a Data Set
2.2 ISO Standards:
ISO 5725 Accuracy (Trueness and Precision) of Measurement Methods and Results
ISO 8217 Petroleum products – Fuels (class F)
ISO/IEC 17025 General Requirements for the Competence of Testing and Calibration Laboratories
2.3 Other Documents:
NIST Technical Note 1297 Guideline for Evaluating and Expressing the Uncertainty of NIST Measurement Results
DEF STAN 91-091 Turbine Fuel, Kerosene Type, Jet A-1
3. Terminology
3.1 Definitions:
3.1.1 density, n—mass per unit volume.
3.1.2 dynamic viscosity [η], n—the ratio between the applied shear stress and rate of shear of a liquid at a given temperature.
3.1.2.1 Discussion—
It is sometimes called the coefficient of dynamic viscosity or, simply, viscosity. Thus, dynamic viscosity is a measure of the
resistance to flow or to deformation of a liquid under external shear forces.
3.1.2.2 Discussion—
The term dynamic viscosity can also be used in a different context to denote a frequency-dependent quantity in which shear stress
and shear rate have a sinusoidal time dependence.
3.1.3 kinematic viscosity, n—the ratio of the dynamic viscosity (η) to the density (ρ) of a liquid at a given temperature.
3.1.3.1 Discussion—
For gravity flow under a given hydrostatic head, the pressure head of a liquid is proportional to its density (ρ). Therefore, the
kinematic viscosity (ν) is a measure of the resistance to flow of a liquid under gravity.
3.1.4 relative density (also called specific gravity (SG)), n—the ratio of the density of a material at a stated temperature to the
density of a reference material (usually water) at a stated temperature.
3.2 Definitions of Terms Specific to This Standard:
2 2
3.2.1 T at 12 mm /s, °C, n—the temperature at which the material has a kinematic viscosity of 12 mm /s.
3.2.1.1 Discussion—
Term mostly is associated with jet fuel where 12 mm /s is considered a critical viscosity value. The temperature is determined using
Practice D341 interpolation or extrapolation calculations from two kinematic viscosity data points. Other critical viscosity data can
similarly be determined for other materials as T at (xx) mm /s.
4. Summary of Test Method
4.1 The test specimen is introduced into the measuring cells, which are at a closely controlled and known temperature. The
measuring cells consist of a pair of rotating concentric cylinders and an oscillating U-tube. The dynamic viscosity is determined
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
Available from National Institute of Standards and Technology (NIST), 100 Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http://www.nist.gov.
Available from IHS, 15 Inverness Way East, Englewood, CO 80112, http://www.global.ihs.com.
D7042 − 21a
from the equilibrium rotational speed of the inner cylinder under the influence of the shear stress of the test specimen and an eddy
current brake in conjunction with adjustment data. The density is determined by the oscillation frequency of the U-tube in
conjunction with adjustment data. The kinematic viscosity is calculated by dividing the dynamic viscosity by the density.
5. Significance and Use
5.1 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.
5.2 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.
5.3 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.15 °C.
6. Apparatus
6,7
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 and the soft iron ring.
Consequently, the system works free of bearing friction as found in rotational viscometers. A permanent magnet in the inner
cylinder induces eddy currents in the surrounding copper casing. The rotational speed of the inner cylinder establishes itself as the
result of the equilibrium between the driving torque of the viscous forces and the retarding eddy current torque. This rotational
speed is measured by an electronic system (Hall effect sensor) by counting the frequency of the rotating magnetic field (see Fig.
1 and Fig. 2, No. 2).
6.1.2 Density Measurement—The digital density analyzer uses a U-shaped oscillating sample tube and a system for electronic
excitation and frequency counting (see Fig. 2, No. 3).
6.1.3 Temperature Control—The copper block surrounds both the viscosity and the density measuring cell in a way that both cells
are held at the same temperature. A thermoelectric heating and cooling system (see Fig. 2, No. 1) ensures the temperature stability
of the copper block within 60.005 °C from the set temperature at the position of the viscosity cell over the whole temperature
range. The uncertainty (k = 2; 95 % confidence level) of the temperature calibration shall be no more than 60.03 °C over the range
from 15 °C to 100 °C. Outside this range the calibration uncertainty shall be no more than 60.05 °C.
FIG. 1 Viscosity Cell
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 is Anton 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.
D7042 − 21a
FIG. 2 Cell Block
6.1.4 The thermal equilibration time depends on the heat capacity and conductivity of the liquid and on the difference between
injection temperature and test temperature. Adequate temperature equilibration of the test specimen is automatically determined
when successive viscosity values are constant within 60.07 % over 1 min and successive density values are constant within
60.00003 g/cm over 60 s.
NOTE 1—The Stabinger Viscometer, manufactured by Anton Paar GmbH, fulfills the stated requirements when operated in the most precise mode of
operation.
6.2 Syringes, commercially available, at least 5 mL in volume, with a Luer tip. All construction materials for syringes shall be fully
compatible with all sample liquids and cleaning agents, which contact them.
6.3 Flow-Through or Pressure Adapter, for use as an alternative means of introducing the test specimen into the measuring cells
either by pressure or by suction, provided that sufficient care and control is used to avoid any bubble formation in the test specimen.
All construction materials for adaptors shall be fully compatible with all sample liquids and cleaning agents, which contact them.
6.4 Hot Filling Adapter, for use with manual syringe filling for the purpose of preventing the precipitation of waxy components
dissolved in sample and lowering sample viscosity for easier sample introduction and cleaning routines.
6.5 Autosampler, for use in automated injection analyses. The autosampler shall be designed to ensure the integrity of the test
specimen prior to and during the analysis and be equipped to transfer a representative portion of test specimen into the measuring
cells. The autosampler shall transfer the test specimen from the sample vial to the measuring cells of the apparatus without
interfering with the integrity of the test specimen. The autosampler shall be able to mimic the procedure for sample handling as
set forth in 11.1 and 11.2. The autosampler may have heating capability as a means to prevent the precipitation of waxy
components dissolved in the sample and lower the viscosity of the sample for filling the measuring cells.
6.6 Screen, with an aperture of 75 μm, to remove particles from the sample.
6.7 Magnet, strong enough to remove iron fillingsferromagnetic materials from the sample. Magnetic stirring rods are suitable.
6.8 Ultrasonic Bath, Unheated (optional), with an operating frequency between 25 kHz to 60 kHz and a typical power output of
≤100 W, of suitable dimensions to hold container(s) placed inside of bath, for use in effectively dissipating and removing air or
gas bubbles that can be entrained in viscous sample types prior to analysis. It is permissible to use ultrasonic baths with operating
frequencies and power outputs outside this range, however it is the responsibility of the laboratory to conduct a data comparison
study to confirm that results determined with and without the use of such ultrasonic baths does not materially impact results.
7. Reagents and Materials
7.1 Sample Solvent, completely miscible with the sample.
D7042 − 21a
7.1.1 For most samples, a volatile petroleum spirit or naphtha is suitable. If the solvent dries up without residues in an applicable
time frame, the use of a separate drying solvent is not required.
7.1.2 For residual fuels, a prewash with an aromatic solvent such as toluene or xylene may be necessary to remove asphaltic
material.
7.2 Drying Solvent, a volatile solvent miscible with the sample solvent (see 7.1).
7.2.1 Highly concentrated ethanol (96 % or higher) higher), n-hexane or n-heptane is suitable.
7.3 Dry Air or Nitrogen, for blowing the measuring cells.
7.3.1 If the measuring cell temperature is below or near the dew point temperature of the ambient air, the use of an appropriate
desiccator is required.
8. Sampling, Test Specimens, and Test Units
8.1 General Considerations and Guidelines:
8.1.1 Sampling is defined as all the steps required to obtain an aliquot of the contents of any pipe, tank, or other system, and to
place the sample into the laboratory test container. The laboratory test container and sample volume shall be of sufficient capacity
to mix the sample and obtain a homogeneous sample for analysis.
8.1.2 For some sample types, such as viscous lube oils that are prone to having entrained air or gas bubbles present in the sample,
the use of an ultrasonic bath (see 6.8) without the heater turned on (if so equipped), has been found effective in dissipating bubbles
typically within 1 min.
8.1.3 Particles—For samples that are likely to contain particles (for example, used oils or crude oils) pass the sample through a
75 μm screen to remove the particles. For the removal of iron filingsferromagnetic materials the use of a magnet is appropriate.
Waxy samples must be heated to dissolve the wax crystals prior to filtration and a preheated filter shall be used.
8.1.4 Test Specimen—A portion or volume of sample obtained from the laboratory sample and delivered to the measuring cells.
The test specimen is obtained as follows:
8.1.4.1 Mix the sample, if required, to homogenize. Mixing at room temperature in an open container can result in the loss of
volatile material; mixing in closed, pressurized containers, or at sub-ambient temperatures is recommended.
8.1.4.2 Draw the test specimen from a properly mixed laboratory sample using an appropriate syringe. Alternatively, if the proper
attachments and connecting tubes are used, the test specimen may be delivered directly to the measuring cells using a flow through
or pressure adapter (see 6.3) or autosampler (see 6.5) from the mixing container. For waxy or other samples with a high pour point,
before drawing the test specimen, heat the laboratory sample to the desired test temperature, which has to be high enough to
dissolve the wax crystals.
8.2 Instructions for Residual Fuel Oils:
8.2.1 (Warning—Exercise care as vigorous boil-over can occur when opaque liquids which contain high levels of water are
heated to high temperatures. Wear appropriate personal protective equipment for handling hot materials.) Place the required
number of disposable syringes or samples vials to be used for the batch analysis into a sample preheat apparatus (such as an oven,
bath, or heating block) held between 60 °C and 65 °C. If using manual syringe filling, a hot filling adapter must be installed on
the apparatus and the injection adapters must also be pre-warmed along with the syringes.
8.2.2 Place the first batch of residual fuel samples to be analyzed for the day in their original containers in a sample preheat
apparatus that is between 60 °C and 65 °C for 1 h. Ensure the cap on each container is tightly closed. For samples of a very waxy
nature or oils of high kinematic viscosity, it may be necessary to increase the heating temperature above 60 °C to achieve proper
mixing. The sample should be sufficiently fluid for ease of stirring and shaking.
D7042 − 21a
8.2.3 Vigorously stir each sample for approximately 20 s with a glass or steel rod of sufficient length to reach the bottom of the
container.
8.2.4 Remove the stirring rod and inspect for sludge or wax adhering to the rod. If there is sludge or wax adhering to the rod,
continue stirring until the sample is homogene.homogeneous.
8.2.5 Recap each container tightly and shake vigorously for 1 min. Then loosen the cap, retighten to finger tight, then back off
⁄4 to a full turn and place back into the sample preheat apparatus.
8.2.6 Upon completion of 8.2.5 for all samples in the batch, increase the sample pre-heat apparatus temperature to between 100 °C
and 105 °C and heat for 30 min.
8.2.7 Remove each container from the sample pre-heat apparatus, close tightly, and shake vigorously for 60 s.
8.2.8 If a heated auto sampler is used, follow instructions in 8.2.8.1 below. If a sample handler is used, follow instructions in
8.2.8.2 below.
8.2.8.1 Ensure the sample vial magazine is held at a temperature between 60 °C and 80 °C. Load each sample into its own
preheated sample vial from 8.2.1, insert the vials into the sample vial magazine, and wait for 10 min to 15 min before commencing
measurement.
8.2.8.2 Load a preheated sample vial from 8.2.1 with the first sample to be tested in the batch and place the sample vial into the
sampler handler that is held between 60 °C and 80 °C. Loosen the cap of the other containers, retighten to finger tight, then back
off ⁄4 to full turn and place the containers back into the sample preheat apparatus that is reset to hold temperature between 60 °C
and 80 °C.
8.2.9 Complete the measurements according to 11.1 or 11.3. Analysis of all samples in the batch must be completed within 1 h
from completion of 8.2.7.
9. Calibration and Verification
9.1 Use only a calibrated apparatus as described in 6.1. The calibration shall be checked periodically using certified reference
standards as described in 9.2 and 9.3. The recommended interval for viscosity and density calibration is once a month, for
temperature control once a year. For the calibration procedure follow the instructions of the manufacturer of the apparatus.
9.2 Certified Viscosity and Density Reference Standards—These are for use as confirmatory checks on the procedure in the
laboratory. Certified viscosity and density reference standards shall be certified by a laboratory, which has shown to meet the
requirements of ISO/IEC 17025 or a corresponding national standard by independent assessment. Viscosity standards shall be
traceable to master viscometer procedures described in Test Method D2162. Density standards shall have a certified uncertainty
of the density values of 0.0001 g/cm . The uncertainty of the reference standards shall be stated for each certified value (k = 2;
95 % confidence level). See ISO 5725 or NIST Technical Note 1297.
9.3 Thermometer—For calibration and adjustment of the temperature control, a digital thermometer with a probe diameter 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 uncertainty (k = 2;
95 % confidence level) of this thermometer must be no more than 60.01 °C and has to be certified by a laboratory which has shown
to meet the requirements of ISO/IEC 17025 or a corresponding national standard by independent assessment. A suitable
thermometer is available from the manufacturer of the apparatus.
9.4 Acceptable Tolerance—If the determined values of a calibration check measurement do not agree within the acceptable
tolerance band of the certified values, as calculated from Annex A1, recheck each step in the procedure, including the special
cleaning procedure from 12.2, to locate the source of error.
NOTE 2—Values exceeding the acceptable tolerance are generally attributable to deposits in the measuring cells that are not removed by the routine
flushing procedure.
D7042 − 21a
10. Adjustment
10.1 An adjustment has to be carried out when repeated calibration check measurements do not agree with the Acceptable
Tolerance Band as stated in 9.4 and the error cannot be located elsewhere. For the adjustment procedure follow the instructions
of the manufacturer of the apparatus.
10.2 For an adjustment, use only certified viscosity and density reference standards that fulfill the requirements as stated in 9.2.
The reference standards have to be within the viscosity, density, and temperature range specified by the manufacturer of the
apparatus.
10.3 After an adjustment procedure a calibration check measurement shall be performed.
11. Procedure
11.1 Standard procedure (rinsing and drying)
11.1.1 Set the internal temperature control to the desired measuring temperature.
11.1.2 Set the determinability limits and temperature stability criteria to the values stated in Table 1 for the specific product.
11.1.3 Make sure that the measuring cells are clean and dry as described in 12.1.
11.1.4 Load a minimum of 3 mL 5 mL of the test specimen to the syringesyringe; if enough sample is available it is recommended
to fill the entire syringe. Pour at least 2 mL of the test specimen into the measuring cells. Leave the syringe in the inlet opening
and start the measurement. motor and wait for about 10 s, then stop the motor again. Inject an additional 1 mL, leave the syringe
in the inlet opening, and start the measurement. Alternatively, the instrument may be configured to perform pre-wetting
automatically prior to starting the measurement. Follow manufacture’s instructions. Wait for the instrument to indicate that the
determination is valid and record the values.
11.1.5 Inject a further 1 mL without taking off the syringe and repeat the measurement.
11.1.6 If the deviation between two consecutive determinations exceeds the determinability limits as stated in Table 1 for this
product, repeat step 11.1.5 until the deviation is within these limits. Discard all previously determined values and report the values
of the last determination as the result.
11.1.6.1 For products not listed in the precision section, it is the responsibility of the user of this standard to establish reasonable
determinability limits by a series of tests.
11.1.6.2 If the syringe is empty before obtaining a valid determination, rinse and dry the measuring cells as described in 12.1 and
repeat step 11.1.4. If it is not possible to obtain a valid result within an applicable number of repetitions, report the robust mean
value and the standard deviation (k = 2; 95 % confidence level) together with a remark indicating that the determinability exceeded
the limits stated in 15.2.1 for this product.
11.1.7 Remove the test specimen immediately, rinse and dry the measuring cells as described in 12.1.
TABLE 1 Determinability Limits and Temperature Stability Criteria
NOTE 1—X is the final determination.
RDV RDD Temperature Viscosity Density Stability Time Repeats Equilibra-
(Determinability, (Determinability, Stability Stability tion Time
dynamic viscos- density)
ity)
3 3
For ALL materials at ALL temperatures 0.10 % 0.0002 g/cm ±0.005 °C ±0.07 % 0.00003 g/cm 60 s 3 0 s
unless specifically listed below 0.001 X
3 3
Residual Fuel Oils at 50 °C and 100 °C 0.35 % 0.0003 g/cm ±0.010 °C ±0.10 % 0.00005 g/cm 40 s 3 30 s
0.0035 X
3 3
Jet fuel at –20 °C and –40 °C, Scanning 0.0011889 X 0.000113 g/cm ±0.005 °C ±0.07 % 0.0001 g/cm 60 s 0 0 s
procedure
D7042 − 21a
11.2 Alternative Procedure (Sample Displacement)—For a series of samples that are mutually soluble (for example, various diesel
fuels). It is the responsibility of the user of this standard to determine the applicability of this procedure to each class of samples.
11.2.1 Set the internal temperature control to the desired measuring temperature.
11.2.2 Set the determinability limits and temperature stability criteria to the values stated in Table 1 for the specific product.
11.2.3 Make sure that the measuring cells are clean and dry as described in 12.1.
11.2.4 Load a minimum of 5 mL of the test specimen to the syringesyringe; if enough sample is available it is recommended to
use a 10 mL or larger syringe and to fill the entire syringe. Pour slowly at least 3 mL of the test specimen into the measuring cells.
A slow flow ensures that the new test specimen displaces the old one rather than merging with it. Leave the syringe in the inlet
opening and opening, start the motor and wait for about 10 s, then stop the motor. Inject an additional 1 mL, leave the syringe in
the inlet opening, and start the measurement. Alternatively, the instrument may be configured to perform pre-wetting automatically
prior to starting the measurement. Follow manufacture’s instructions. Wait for the instrument to indicate that the determination is
valid and record the values.
11.2.5 Inject slowly a further 2 mL without taking off the syringe and repeat the measurement.
11.2.6 If the deviation between two consecutive determinations exceeds the determinability limits as stated in Table 1 for this
product, repeat step 11.2.5 until the deviation is within these limits. Discard all previously determined values and report the values
of the last determination as the result.
11.2.6.1 For products not listed in the precision section it is the responsibility of the user of this standard to establish reasonable
determinability limits by a series of tests.
11.2.6.2 If the syringe is empty before obtaining a valid determination repeat step 11.2.4. If it is not possible to obtain a valid result
within an applicable number of repetitions, report the robust mean value and the standard deviation (k = 2; 95 % confidence level)
together with a remark indicating that the determinability exceeded the limits stated in 15.1.1 for this product.
11.2.7 For the next sample of this series repeat the steps 11.2.4 – 11.2.6.
11.2.8 After the last sample of a series perform a cleaning procedure as described in 12.1.
11.3 Procedure for Use with Autosampler:
11.3.1 Set the determinability and temperature stability criteria to values in Table 1 for the corresponding testing parameter(s) and
temperature(s) of interest. Ensure that automatic prewetting has been configured. See manufacture’s instructions for details.
Temperature control/stability requirements at the test temperatures of interest are provided in 6.1.3. For all other sample types, see
11.3.2 for guidance.
11.3.2 For products not listed in the precision section, it is the responsibility of the user of this test method to establish reasonable
determinability and temperature stability criteria by a series of tests.
11.3.3 Configure the cleaning and drying routines for the autosampler for sufficient cleaning efficiency of the product being tested.
NOTE 3—For specific information on proper configuration, follow the manufacturer’s instructions.
11.3.4 Configure the autosampler for a minimum of two consecutive determinations per sample.
11.3.5 Transfer a portion of the sample into the appropriate sample vial. Cap or cover the vials as necessary.
11.3.5.1 Load sample(s) vial onto vial tray or holder and analyze the test specimens.
The Stabinger Viscometer, manufactured by Anton Paar GmbH, uses the terms, “Repeat Deviation Viscosity, RDV” and “Repeat Deviation Density, RDD” in lieu of
“Determinability” in apparatus firmware and documentation.
D7042 − 21a
11.3.5.2 Evaluate the data. Rerun samples which exceed the determinability criteria established for the sample type being
analyzed. (See 11.3.1 and 11.3.2.)
11.4 Procedure for Temperature Scanning:
11.4.1 The Temperature Scan Procedure is used to study the test material’s temperature dependence over a pre-defined
temperature range and with pre-defined temperature intervals. The apparatus reports measured density and dynamic viscosity
values as well as calculated kinematic viscosity and the temperature for a pre-defined kinematic viscosity in accordance with
Practice D341, Standard Viscosity-Temperature Charts for Liquid Petroleum Products. This procedure can be applied with either
sample filling procedure.
11.4.2 The temperature range of interest shall be defined as well as the temperature points at which data shall be reported. Ensure
that the study material’s boiling and freezing points are not exceeded by the defined temperature range. The temperature range and
data reporting temperatures shall be entered into the apparatus in either table format or defined as start, stop and interval
temperature.
11.4.3 When performing measurements at sub-zero temperatures it is essential that the risk of ice formation during drying routines
and sample filling in the measuring cells is eliminated. This can be achieved by using dry air after cell cleaning and se
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