ASTM D445-15 pdf free.Standard Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity).
ASTM D445 specifies a procedure for the determination of the kinematic viscosity, ν, 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, η, can be obtained by multiplying the kinematic viscosity, ν, by the density, ρ, of the liquid.
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.
4. Smumary of Test Method
4.1 The time is measured for a fixed volume of liquid to flow tinder gravity through the capillary of a calibrated viscometcr tinder 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 determined 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 determination of viscosity is essential to many product specifications.
6. Apparatus
6.1 Viscometers—Usc 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 A I . I. whose specifications meet those given in Specifications D446 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 A I . 1. Annex Al gives further guidance.
6. 1 .2 Auumiaied Viscoineiers—Automated apparatus may be used as long as they mimic the physical conditions, operations or processes of the manual apparatus. Any viscometer, temperature measuring device, temperature control, temperature 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 arc permitted, however,
8. Certified Viscosity Reference Standards
8.1 CertifIed viscosity reference standards shall he 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 1)2162.
8.2 The uncertainty of the certified viscosity reference standard shall be stated for each certified value (k = 2, 95 % confidence). Sec ISO 5725 or NIST 1297.
9. Calibration and Verification
9. 1 Viscoi,ieters—Use only calibrated viscometers, thermometers, and timers as described in Section 6.ASTM D445-15 pdf free download.