ASTM D446-12(2017)
(Specification)Standard Specifications and Operating Instructions for Glass Capillary Kinematic Viscometers
Standard Specifications and Operating Instructions for Glass Capillary Kinematic Viscometers
SCOPE
1.1 These specifications cover operating instructions for glass capillary kinematic viscometers of all the types described in detail in Annex A1, Annex A2, and Annex A3 as follows:
Modified Ostwald viscometers, Annex A1
Suspended-level viscometers, Annex A2
Reverse-flow viscometers, Annex A3
1.2 The calibration of the viscometers is described in Section 6.
1.3 This standard covers some widely used viscometers suitable for use in accordance with Test Method D445. Other viscometers of the glass capillary type which are capable of measuring kinematic viscosity within the limits of precision given in Test Method D445 may be used.
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 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
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Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation:D446 −12 (Reapproved 2017)
Designation: 71/2/95
Standard Specifications and Operating Instructions for
Glass Capillary Kinematic Viscometers
This standard is issued under the fixed designation D446; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope and Viscosity Oil Standards
2.2 ISO Documents:
1.1 These specifications cover operating instructions for
ISO 3104Petroleum Products—Transparent and Opaque
glasscapillarykinematicviscometersofallthetypesdescribed
Liquids—Determination of Kinematic Viscosity and Cal-
in detail in Annex A1, Annex A2, and Annex A3 as follows:
culation of Dynamic Viscosity
Modified Ostwald viscometers, Annex A1
Suspended-level viscometers, Annex A2 ISO 3105 Glass Capillary Kinematic Viscometers—
Reverse-flow viscometers, Annex A3
Specifications and Operating Instructions
1.2 The calibration of the viscometers is described in ISO5725Basic Methods for the Determination of Repeat-
Section 6. ability and Reproducibility of a Standard Measurement
Method
1.3 This standard covers some widely used viscometers
ISO17025General Requirements for the Competence of
suitable for use in accordance with Test Method D445. Other
Testing and Calibration Laboratories
viscometers of the glass capillary type which are capable of
ISO Guide25General Requirements for the Calibration and
measuring kinematic viscosity within the limits of precision
Testing Laboratories
given in Test Method D445 may be used.
2.3 NIST Standards:
1.4 The values stated in SI units are to be regarded as
NIST1297Guidelines for Evaluating and Expressing the
standard. No other units of measurement are included in this
Uncertainty of NIST Measurement Results
standard.
1.5 This international standard was developed in accor-
3. Materials and Manufacture
dance with internationally recognized principles on standard-
3.1 Fully annealed, low-expansion borosilicate glass shall
ization established in the Decision on Principles for the
be used for the construction of all viscometers. The size
Development of International Standards, Guides and Recom-
number,serialnumber,andmanufacturer’sdesignationshallbe
mendations issued by the World Trade Organization Technical
permanently marked on each viscometer. All timing marks
Barriers to Trade (TBT) Committee.
shall be etched and filled with an opaque color, or otherwise
made a permanent part of the viscometer. See detailed descrip-
2. Referenced Documents
tion of each type of viscometer in Annex A1, Annex A2, and
2.1 ASTM Standards:
Annex A3.
D445Test Method for Kinematic Viscosity of Transparent
3.2 With the exception of the FitzSimons and Atlantic
and Opaque Liquids (and Calculation of DynamicViscos-
viscometers, all viscometers are designed to fit through a
ity)
51-mm hole in the lid of a constant-temperature bath having a
D2162Practice for Basic Calibration of MasterViscometers
liquid depth of at least 280 mm; and it is assumed that the
surfaceoftheliquidwillbenotmorethan45mmfromthetop
of the bath lid. For certain constant-temperature baths, espe-
These specifications and operating instructions are under the jurisdiction of
ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and cially at low or high temperatures, it may be necessary to
are the direct responsibility of Subcommittee D02.07 on Flow Properties.
constructtheviscometerswiththeuppermosttubeslongerthan
Current edition approved Dec. 1, 2017. Published December 2017. Originally
approvedin1966asD2515–66.RedesignatedD446in1977.Lastpreviousedition
approved in 2012 as D446–12. DOI: 10.1520/D0446-12R17.
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 1070, Gaithersburg, MD 20899-1070, http://www.nist.gov.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D446−12 (2017)
shown to ensure adequate immersion in the constant- 6.2 Reference Viscometers:
temperature bath. Viscometers so modified can be used to
6.2.1 Select a clear petroleum oil, free from solid particles
measure kinematic viscosity within the precision of the test
and possessing Newtonian flow characteristics, with a kine-
method.Thelengthsoftubesandbulbsonthefiguresshouldbe
matic viscosity within the range of both the reference viscom-
held within 610% or 610mm, whichever is less, such that
eter and the viscometer to be calibrated. The minimum flow
the calibration constant of the viscometer does not vary by
timeshallbegreaterthanthatspecifiedintheappropriatetable
more than 615% from the nominal value.
of the annex in both the reference viscometer and the viscom-
eter which is to be calibrated in order that the kinetic energy
4. Nomenclature for Figures
correction (see 7.1 and 7.2) may be less than 0.2%.
4.1 The figures in the annexes contain letters to designate
6.2.2 Select a calibrated viscometer of known viscometer
specific parts of each viscometer.These letters are also used in
constant C . This viscometer may be a reference viscometer
the text of the standard when reference to the viscometers is
(driving head at least 400mm) that has been calibrated by the
given. The more frequently used letters on the figures in the
step-up procedure using viscometers of successively larger
annexes are as follows:
capillary diameters, starting with distilled water as the basic
A lower reservoir
kinematic viscosity standard or a routine viscometer of the
B suspended level
same type that has been calibrated by comparison with a
bulb
C and J timing bulbs
reference viscometer. See Test Method D2162.
D upper reservoir
6.2.3 Mount the calibrated viscometer together with the
E, F, and I timing marks
G and H filling marks
viscometer to be calibrated in the same bath and determine the
K overflow tube
flow times of the oil in accordance with Test Method D445.
L mounting tube
M lower vent tube
6.2.3.1 The calibration of the reference viscometer should
N upper vent tube
only be carried out by a reputable laboratory meeting the
P connecting tube
requirements of, for example, ISO Guide25.
R working capillary
6.2.4 Calculate the viscometer constant C as follows:
5. Viscometer Holder and Alignment
C 5 t 3C /t (1)
~ !
1 2 2 1
5.1 All viscometers which have the upper meniscus directly
above the lower meniscus (Cannon-Fenske routine in Annex
where:
A1 and all in Annex A2) shall be mounted in a constant
C = the constant of the viscometer being calibrated,
temperature bath with tube L held within 1° of the vertical as
t = the flow time to the nearest 0.1s in the viscometer
observedwithaplumbboborotherequallyaccurateinspection
being calibrated,
means. A number of commercially available holders are so
C = the constant of the calibrated viscometer, and
designed that the tube L is held perpendicular to the lid of a t = the flow time to the nearest 0.1s in the calibrated
constant-temperaturebath;nevertheless,theviscometershould
viscometer.
be tested with a plumb line in order to ensure that the tube L
6.2.5 Repeat 6.2.1 – 6.2.3 with a second oil whose flow
is in a vertical position.
timesareatleast50%longerthanthefirstoil.Ifthetwovalues
5.1.1 Those viscometers whose upper meniscus is offset
of C differ by less than 0.2% for those viscometers listed in
fromdirectlyabovethelowermeniscus(allothersinAnnexA1
Annex A1 and Annex A2 and less than 0.3% for those
and all in Annex A3) shall be mounted in a constant-
viscometers listed in Annex A3, use the average. If the
temperature bath with tube L held within 0.3° of the vertical.
constants differ by more than this value, repeat the procedure
5.2 Roundmetaltops,designedtofitabovea51mmholein
taking care to examine all possible sources of errors.
thelidofthebath,arefrequentlycementedontotheZeitfuchs,
6.2.5.1 The calibration constant, C, is dependent upon the
Zeitfuchs cross-arm, and Lantz-Zeitfuchs viscometers which
gravitational acceleration at the place of calibration and this
then are permanently mounted on the lid of the bath. Also a
must, therefore, be supplied by the standardization laboratory
rectangular metal top, 25mm×59mm, is often cemented on
together with the instrument constant. Where the acceleration
to the Zeitfuchs cross-arm and Zeitfuchs viscometers.Viscom-
ofgravity, g,differsbymorethan0.1%,correctthecalibration
eters fitted with metal tops should also be set vertically in the
constant as follows:
constant-temperature bath with the aid of a plumb line.
C 5 g /g 3C (2)
~ !
2 2 1 1
5.3 In each figure, the numbers which follow the tube
designationindicatetheoutsidetubediameterinmillimetres.It
where subscripts 1 and 2 indicate respectively the standard-
is important to maintain these diameters and the designated
ization laboratory and the testing laboratory.
spacing to ensure that holders will be interchangeable.
6.3 Certified Viscosity Reference Standards:
6. Calibration of Viscometers
6.3.1 Certified viscosity reference standards shall be certi-
fied by a laboratory that has been shown to meet the require-
6.1 Procedures:
6.1.1 Calibrate the kinematic glass capillary viscometers ments of ISO17025 by independent assessment. Certified
viscosity reference standards shall be traceable to master
covered by this standard using the procedures described in
Annex A1, Annex A2, and Annex A3. viscometer procedures described in Practice D2162.
D446−12 (2017)
6.3.1.1 The uncertainty of the certified viscosity reference where:
standard shall be stated for each certified value (k=2, 95%
ν = the kinematic viscosity, mm /s,
confidence). See ISO5725 or NIST 1297.
g = the acceleration due to gravity, m/s ,
D = the diameter of the capillary, m,
6.3.2 Select from Table 1 a certified viscosity reference
L = the length of the capillary, m,
standard with a kinematic viscosity at the calibration tempera-
H = the average distance between the upper and lower
ture within the kinematic viscosity range of the viscometer to
menisci, m,
be calibrated and a minimum flow time greater than that
V = the timed volume of liquids passing through the
specified in the appropriate table of the annex. Determine the 3
capillary, m (approximately the volume of the timing
flow time to the nearest 0.1s in accordance with Test Method
bulb),
D445 and calculate the viscometer constant, C, as follows:
E = the kinetic energy factor, mm ·s, and
t = the flow time, s.
C 5 ν/t (3)
7.1.2 Iftheviscometerisselectedsothattheminimumflow
where:
2 time shown in the tables of AnnexA1, AnnexA2, and Annex
ν = the kinematic viscosity, mm /s, for the certified viscos-
A3 are exceeded, the kinetic energy term, E/t , becomes
ity reference standard, and
insignificant and Eq 4 may be simplified by grouping the
t = the flow time, s.
non-variable terms into a constant, C, as follows:
6.3.3 Repeat with a second certified viscosity reference
ν 5 C·t (5)
standard whose flow times are at least 50% longer than the
7.2 Kinetic Energy Correction:
first certified viscosity reference standard. If the two values of
7.2.1 The viscometers described in the Annex A1, Annex
C differ by less than 0.2% for those viscometers listed in
A2, and Annex A3 are designed such that the kinetic energy
Annex A1 and Annex A2 and less than 0.3% for those
correctionterm, E/t ,isnegligibleiftheflowtimeismorethan
viscometers listed in Annex A3, use the average as the
200s. In the case of several sizes of viscometers for the
viscometer constant for the viscometer being calibrated. If the
measurement of low-kinematic viscosity liquids, a minimum
constants differ by more than this value, repeat the procedure
flowtimegreaterthan200sisrequiredinorderthatthekinetic
taking care to examine all possible sources of errors.
energycorrectionterm, E/ t ,shallbenegligible.Theminimum
6.4 Expression of Constant: flow times required are set out as footnotes to the appropriate
tablesofviscometerdimensionsgivenintheAnnexA1,Annex
6.4.1 Report the constant to the nearest 0.1% of the
A2, and Annex A3.
determinedvalue.Thisgenerallymeansfoursignificantfigures
2 2
N N
7.2.2 For viscometers whose constants are 0.05mm /s or
from 1×10 to 6.999×10 and three significant figures from
N N
less, a kinetic energy correction can be significant if the
7×10 to 9.99×10 .
minimum 200s flow is not observed. Where this is not
possible, Eq 5 takes on the following form:
7. Kinematic Viscosity Calculation
2 2
kinematicviscosity, mm /s 5 Ct 2 E/t (6)
7.1 Basic Formula:
where:
7.1.1 Kinematic viscosity, expressed in mm /s, can be
E = kinetic energy factor, mm ×s,
calculated from the viscometer dimensions as follows:
2 2
C = viscometer constant, mm /s ,
6 4 2
ν 5 10 πgD Ht/128 VL 2 E/t (4)
~ !
TABLE 1 Certified Viscosity Reference Standards
Approximate Kinematic Viscosity, mm /s
Designation
20 °C 25 °C 40 °C 50 °C 80 °C 100 °C
S3 4.6 4.0 2.9 . . 1.2
S6 11 8.9 5.7 . . 1.8
S20 44 34 18 . . 3.9
S60 170 120 54 . . 7.2
S200 640 450 180 . . 17
S600 2400 1600 520 280 67 32
S2000 8700 5600 1700 . . 75
S8000 37 000 23 000 6700 . . .
S30000 . 81 000 23 000 11 000 . .
D446−12 (2017)
tered is with a viscometer calibrated with water and used for
t = flow time, s.
oils. Generally, viscometers are calibrated and used with
7.2.3 Although the kinetic energy factor, E, is not a
hydrocarbons whose surface tensions are close enough for
constant, it may be approximated by means of the following
these corrections to be insignificant.
equation:
7.5 Effect of Temperature:
3/2 1/2
E 552.5 V /L Cd (7)
~ !
7.5.1 The viscometer constant, C, is independent of tem-
where:
perature for all those viscometers which have the volume of
(using the units given in Figs. A1.1-A3.4) sample adjusted at bath temperature and in the case of all
suspended-level viscometers.
V = volume of the timing bulb, mL,
7.5.2 The following viscometers, which have a fixed vol-
L = capillary working length, mm,
d = capillary working diameter, mm,
...
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