ASTM D 445-06

Designation: D 445 – 06 Designation: 71/1/97 An American National Standard British Standard 2000: Part 71:1990 Standard Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity)1 This standard is issued under the fixed designation D 445; 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 (e) indicates an editorial change since the last revision or reapproval. This standard has been approved for use by agencies of the Department of Defense. 1. Scope* 1.1 This test method specifies a procedure for the determi- nation of the kinematic viscosity, n, of liquid petroleum products, both transparent and opaque, by measuring the time for a volume of liquid to flow under gravity through a calibrated glass capillary viscometer. The dynamic viscosity, h, can be obtained by multiplying the kinematic viscosity, n, by the density, r, of the liquid. NOTE 1—For the measurement of the kinematic viscosity and viscosity of bitumens, see also Test Methods D 2170 and D 2171. NOTE 2—ISO 3104 corresponds to Test Method D 445. 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 rates are proportional (Newtonian flow behavior). If, however, the viscosity varies significantly with the rate of shear, different results may be obtained from viscometers of different capillary diameters. The procedure and precision values for residual fuel oils, which under some conditions exhibit non-Newtonian behavior, have been included. 1.3 The range of kinematic viscosities covered by this test method is from 0.2 to 300 000 mm2/s (see Table A1.1) at all temperatures (see 6.3 and 6.4). The precision has only been determined for those materials, kinematic viscosity ranges and temperatures as shown in the footnotes to the precision section. 1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 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 appro- priate safety and health practices and determine the applica- bility of regulatory limitations prior to use. 2. Referenced Documents 2.1 ASTM Standards: 2 D 446 Specifications and Operating Instructions for Glass Capillary Kinematic Viscometers D 1193 Specification for Reagent Water D 1217 Test Method for Density and Relative Density (Specific Gravity) of Liquids by Bingham Pycnometer D 1480 Test Method for Density and Relative Density (Specific Gravity) of Viscous Materials by Bingham Pyc- nometer D 1481 Test Method for Density and Relative Density (Specific Gravity) of Viscous Materials by Lipkin Bicap- illary Pycnometer D 2162 Practice for Basic Calibration of Master Viscom- eters and Viscosity Oil Standards D 2170 Test Method for Kinematic Viscosity of Asphalts (Bitumens) D 2171 Test Method for Viscosity of Asphalts by Vacuum Capillary Viscometer D 6071 Test Method for Low Level Sodium in High Purity Water by Graphite Furnace Atomic Absorption Spectros- copy D 6074 Guide for Characterizing Hydrocarbon Lubricant Base Oils D 6617 Practice for Laboratory Bias Detection Using Single Test Result from Standard Material E 1 Specification for ASTM Liquid-in-Glass Thermometers E 77 Test Method for Inspection and Verification of Ther- mometers 2.2 ISO Standards:3 1 This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.07 on Flow Properties. Current edition approved May 15, 2006. Published June 2006. Originally approved in 1937. Last previous edition approved in 2004 as D 445–04e2. In the IP, this test method is under the jurisdiction of the Standardization Committee. 2 For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards volume information, refer to the standard’s Document Summary page on the ASTM website. 3 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036. 1 *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. Copyright ASTM International Provided by IHS under license with ASTM Licensee=North Carolina DOT/5959838001 Not for Resale, 07/22/2007 01:10:05 MDTNo reproduction or networking permitted without license from IHS - - ` ` ` , ` ` , ` , , ` ` , ` ` ` ` ` ` ` , ` ` ` , ` ` ` - ` - ` , , ` , , ` , ` , , ` - - - ISO 3104 Petroleum Products—Transparent and Opaque Liquids—Determination of Kinematic Viscosity and Cal- culation of Dynamic Viscosity ISO 3105 Glass Capillary Kinematic Viscometers— Specification and Operating Instructions ISO 3696 Water for Analytical Laboratory Use— Specification and Test Methods ISO 5725 Accuracy (trueness and precision) of measure- ment methods and results. ISO 9000 Quality Management and Quality Assurance Standards—Guidelines for Selection and Use ISO 17025 General Requirements for the Competence of Testing and Calibration Laboratories 2.3 NIST Standards:4 NIST Technical Note 1297, Guideline for Evaluating and Expressing the Uncertainty of NIST Measurement Results NIST GMP 11 NIST Special Publication 819 3. Terminology 3.1 Definitions of Terms Specific to This Standard: 3.1.1 automated viscometer, n—apparatus which, in part or in whole, has mechanized one or more of the procedural steps indicated in Section 11 or 12 without changing the principle or technique of the basic manual apparatus. The essential ele- ments of the apparatus in respect to dimensions, design, and operational characteristics are the same as those of the manual method. 3.1.1.1 Discussion—Automated viscometers have the capa- bility to mimic some operation of the test method while reducing or removing the need for manual intervention or interpretation. Apparatus which determine kinematic viscosity by physical techniques that are different than those used in this test method are not considered to be Automated Viscometers. 3.1.2 density, n—the mass per unit volume of a substance at a given temperature. 3.1.3 dynamic viscosity, n—the ratio between the applied shear stress and rate of shear of a liquid. 3.1.3.1 Discussion—It is sometimes called the coefficient of dynamic viscosity or, simply, viscosity. Thus dynamic viscos- ity is a measure of the resistance to flow or deformation of a liquid. 3.1.3.2 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 sinusodial time dependence. 3.1.4 kinematic viscosity, n—the resistance to flow of a fluid under gravity. 3.1.4.1 Discussion—For gravity flow under a given hydro- static head, the pressure head of a liquid is proportional to its density, r. For any particular viscometer, the time of flow of a fixed volume of fluid is directly proportional to its kinematic viscosity, n, where n = h/r, and h is the dynamic viscosity coefficient. 4. Summary of Test Method 4.1 The time is measured for a fixed volume of liquid to flow under gravity through the capillary of a calibrated viscometer under a reproducible driving head and at a closely controlled and known temperature. The kinematic viscosity (determined value) is the product of the measured flow time and the calibration constant of the viscometer. Two such determinations are needed from which to calculate a kinematic viscosity result that is the average of two acceptable deter- mined values. 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 deter- mination of viscosity is essential to many product specifica- tions. 6. Apparatus 6.1 Viscometers—Use only calibrated viscometers of the glass capillary type, capable of being used to determine kinematic viscosity within the limits of the precision given in the precision section. 6.1.1 Viscometers listed in Table A1.1, whose specifications meet those given in Specifications D 446 and in ISO 3105 meet these requirements. It is not intended to restrict this test method to the use of only those viscometers listed in Table A1.1. Annex A1 gives further guidance. 6.1.2 Automated Viscometers—Automated apparatus may be used as long as they mimic the physical conditions, operations or processes of the manual apparatus. Any viscom- eter, temperature measuring device, temperature control, tem- perature controlled bath or timing device incorporated in the automated apparatus shall conform to the specification for these components as stated in Section 6 of this test method. Flow times of less than 200 s are permitted, however, a kinetic energy correction shall be applied in accordance with Section 7 on Kinematic Viscosity Calculation of Specifications D 446. The kinetic energy correction shall not exceed 3.0 % of the measured viscosity. The automated apparatus shall be capable of determining kinematic viscosity of a certified viscosity reference standard within the limits stated in 9.2.1 and Section 17. The precision shall be of statistical equivalence to, or better (has less variability) than the manual apparatus. NOTE 3—Precision and bias of kinematic viscosity measurements for flow times of less than 200 s has not been determined. The precision stated in Section 17 is not know to be valid for kinematic viscosity measure- ments with flow times less than 200 s. 6.2 Viscometer Holders—Use viscometer holders to enable all viscometers which have the upper meniscus directly above the lower meniscus to be suspended vertically within 1° in all directions. Those viscometers whose upper meniscus is offset from directly above the lower meniscus shall be suspended vertically within 0.3° in all directions (see Specifications D 446 and ISO 3105). 4 Available from National Institute of Standards and Technology (NIST), 100 Bureau Dr., Stop 3460, Gaithersburg, MD 20899-3460. D 445 – 06 2Copyright ASTM International Provided by IHS under license with ASTM Licensee=North Carolina DOT/5959838001 Not for Resale, 07/22/2007 01:10:05 MDTNo reproduction or networking permitted without license from IHS --```,``,`,,``,```````,```,```-`-`,,`,,`,`,,`--- 6.2.1 Viscometers shall be mounted in the constant tempera- ture bath in the same manner as when calibrated and stated on the certificate of calibration. See Specifications D 446, see Operating Instructions in Annexes A1–A3. For those viscom- eters which have Tube L (see Specifications D 446) held vertical, vertical alignment shall be confirmed by using (1) a holder ensured to hold Tube L vertical, or (2) a bubble level mounted on a rod designed to fit into Tube L, or (3) a plumb line suspended from the center of Tube L, or (4) other internal means of support provided in the constant temperature bath. 6.3 Temperature-Controlled Bath—Use a transparent liquid bath of sufficient depth such, that at no time during the measurement of flow time, any portion of the sample in the viscometer is less than 20 mm below the surface of the bath liquid or less than 20 mm above the bottom of the bath. 6.3.1 Temperature Control—For each series of flow time measurements, the temperature control of the bath liquid shall be such that within the range from 15 to 100°C, the tempera- ture of the bath medium does not vary by more than 60.02°C of the selected temperature over the length of the viscometer, or between the position of each viscometer, or at the location of the thermometer. For temperatures outside this range, the deviation from the desired temperature must not exceed 60.05°C. 6.4 Temperature Measuring Device in the Range from 0 to 100°C—Use either calibrated liquid-in-glass thermometers (Annex A2) of an accuracy after correction of 60.02°C or better, or any other thermometric device of equal or better accuracy. 6.4.1 If calibrated liquid-in-glass thermometers are used, the use of two thermometers is recommended. The two thermom- eters shall agree within 0.04°C. 6.4.2 Outside the range from 0 to 100°C, use either cali- brated liquid-in-glass thermometers of an accuracy after cor- rection of 60.05°C or better, or any other thermometric device of equal or better accuracy. When two temperature measuring devices are used in the same bath, they shall agree within 60.1°C. 6.4.3 When using liquid-in-glass thermometers, such as those in Table A2.1, use a magnifying device to read the thermometer to the nearest 1⁄5 division (for example, 0.01°C or 0.02°F) to ensure that the required test temperature and temperature control capabilities are met (see 10.1). It is recommended that thermometer readings (and any corrections supplied on the certificates of calibrations for the thermom- eters) be recorded on a periodic basis to demonstrate compli- ance with the test method requirements. This information can be quite useful, especially when investigating issues or causes relating to testing accuracy and precision. 6.5 Timing Device—Use any timing device that is capable of taking readings with a discrimination of 0.1 s or better and has an accuracy within 60.07 % (see Annex A3) of the reading when tested over the minimum and maximum intervals of expected flow times. 6.5.1 Electrical timing devices may be used if the current frequency is controlled to an accuracy of 0.05 % or better. Alternating currents, as provided by some public power sys- tems, are intermittently rather than continuously controlled. When used to actuate electrical timing devices, such control can cause large errors in kinematic viscosity flow time mea- surements. 7. Reagents and Materials 7.1 Chromic Acid Cleaning Solution, or a nonchromium- containing, strongly oxidizing acid cleaning solution. (Warning—Chromic acid is a health hazard. It is toxic, a recognized carcinogen, highly corrosive, and potentially haz- ardous in contact with organic materials. If used, wear a full face-shield and full-length protective clothing including suit- able gloves. Avoid breathing vapor. Dispose of used chromic acid carefully as it remains hazardous. Nonchromium- containing, strongly oxidizing acid cleaning solutions are also highly corrosive and potentially hazardous in contact with organic materials, but do not contain chromium which has special disposal problems.) 7.2 Sample Solvent, completely miscible with the sample. Filter before use. 7.2.1 For most samples a volatile petroleum spirit or naph- tha is suitable. For residual fuels, a prewash with an aromatic solvent such as toluene or xylene may be necessary to remove asphaltenic material. 7.3 Drying Solvent, a volatile solvent miscible with the sample solvent (see 7.2) and water (see 7.4). Filter before use. 7.3.1 Acetone is suitable. (Warning—Extremely flam- mable.) 7.4 Water, deionized or distilled and conforming to Speci- fication D 1193 or Grade 3 of ISO 3696. Filter before use. 8. Certified Viscosity Reference Standards 8.1 Certified viscosity reference standards shall be certified by a laboratory that has been shown to meet the requirements of ISO 17025 by independent assessment. Viscosity standards shall be traceable to master viscometer procedures described in Test Method D 2162. 8.2 The uncertainty of the certified viscosity reference standard shall be stated for each certified value (k = 2, 95% confidence). See ISO 5725 or NIST 1297. 9. Calibration and Verification 9.1 Viscometers—Use only calibrated viscometers, ther- mometers, and timers as described in Section 6. 9.2 Certified Viscosity Reference Standards (Table A1.2)— These are for use as confirmatory checks on the procedure in the laboratory. 9.2.1 If the determined kinematic viscosity does not agree within the acceptable tolerance band, as calculated from Annex A4, of the certified value, recheck each step in the procedure, including thermometer and viscometer calibration, to locate the source of error. Annex A1 gives details of standards available. NOTE 4—In previous issues of Test Method D 445, limits of 60.35% of the certified value have been used. The data to support the limit of 60.35% cannot be verified. Annex A4 provides instructions on how to determine the tolerance band. The tolerance band combines both the uncertainty of the certified viscosity reference standard as well as the uncertainty of the laboratory using the certified viscosity reference standard. D 445 – 06 3Copyright ASTM International Provided by IHS under license with ASTM Licensee=North Carolina DOT/5959838001 Not for Resale, 07/22/2007 01:10:05 MDTNo reproduction or networking permitted without license from IHS - - ` ` ` , ` ` , ` , , ` ` , ` ` ` ` ` ` ` , ` ` ` , ` ` ` - ` - ` , , ` , , ` , ` , , ` - - - 9.2.1.1 As an alternative to the calculation in Annex A4, the approximate tolerance bands in Table 1 may be used. 9.2.2 The most common sources of error are caused by particles of dust lodged in the capillary bore and temperature measurement errors. It must be appreciated that a correct result obtained on a standard oil does not preclude the possibility of a counterbalancing combination of the possible sources of error. 9.3 The calibration constant, C, is dependent upon the gravitational acceleration at the place of calibration and this must, therefore, be supplied by the standardization laboratory together with the instrument constant. Where the acceleration of gravity, g, differs by more that 0.1 %, correct the calibration constant as follows: C2 5 ~g2/g1! 3 C1 (1) where the subscripts 1 and 2 indicate, respectively, the standardization laboratory and the testing laboratory. 10. General Procedure for Kinematic Viscosity 10.1 Adjust and maintain the viscometer bath at the required test temperature within the limits given in 6.3.1 taking account of the conditions given in Annex A2 and of the corrections supplied on the certificates of calibration for the thermometers. 10.1.1 Thermometers shall be held in an upright position under the same conditions of immersion as when calibrated. 10.1.2 In order to obtain the most reliable temperature measurement, it is recommended that two thermometers with valid calibration certificates be used (see 6.4). 10.1.3 They should be viewed with a lens assembly giving approximately five times magnification and be arranged to eliminate parallax errors. 10.2 Select a clean, dry, calibrated viscometer having a range covering the estimated kinematic viscosity (that is, a wide capillary for a very viscous liquid and a narrower capillary for a more fluid liquid). The flow time for manual viscometers shall not be less than 200 s or the longer time noted in Specifications D 446. Flow times of less than 200 s are permitted for automated viscometers, provided they meet the requirements of 6.1.2. 10.2.1 The specific details of operation vary for the different types of viscometers listed in Table A1.1. The operating instructions for the different types of viscometers are given in Specifications D 446. 10.2.2 When the test temperature is below the dew point, fill the viscometer in the normal manner as required in 11.1. To ensure that moisture does not condense or freeze on the walls of the capillary, draw the test portion into the working capillary and timi