ISO 3104 Petroleum products - Transparent and opaque liquids - Determination of kinematic viscosity and calculation of dynamic viscosity
5 Reagents and materials
5.1 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 hazardous in contact with organic materials. If used, wear a full face-shield and full-length protective clothing including suitable gloves. Avoid breathing vapour. 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.
5.2 Sample solvent, completely miscible with the sample. Filter before use.
NOTE 4 For most samples a volatile petroleum spirit or naphtha is suitable. For residual fuels, a prewash with an aromatic solvent such as toluene or xylene may be necessary to remove asphaltenic material.
5.3 Drying solvent, volatile and miscible with both the sample solvent (5.2) and water (5.4). Filter before use.
NOTE 5 Acetone is suitable.
5.4 Water, deionized or distilled, conforming to Grade 3 of ISO 3696. Filter before use.
5.5 Certified viscosity reference standards, for use as confirmatory checks on the procedure in the laboratory.
6 Apparatus
6.1 Viscometer, calibrated, of the glass capillary type, capable of measuring kinematic viscosity within the limits of precision given in clause 14 (see annex A).
NOTE 6 Viscometers listed in tableA.1, whose specifications meet those given 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.1; annex A gives further guidance.
Automated viscometers, which have been shown to measure kinematic viscosity within the limits of precision given in clause 14, are acceptable alternatives. Apply a kinetic energy correction (see ISO 3105) to kinematic viscosities less than 10 mm2/s and flow times less than 200 s.
6.2 Viscometer holder, enabling 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 ISO 3105).
NOTE 7 The proper alignment of vertical parts may be confirmed by using a plumb line, but for rectangular baths with opaque ends this may not be wholly satisfactory.
6.3 Temperature-controlled bath, containing a transparent liquid of sufficient depth such that at no time during the measurement is any portion of the sample in the viscometer less than 20 mm below the surface of the bath liquid or less than 20 mm above the bottom of the bath.
Temperature control of the bath liquid shall be such that, for each series of flow-time measurements, within the range of 15°C to 100°C the temperature of the bath medium does not vary by more than +/- 0.02 °C from 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 shall not exceed +/- 0.05°C.
6.4 Temperature-measuring device, for the range 0°C to 100°C, either calibrated liquid-in-glass thermometer (annex B) of an accuracy after correction of +/- 0.02°C or better, or any other thermometric device of equal or better accuracy. When two thermometers are used in the same bath, they shall agree within 0.04°C.
NOTE 8 If calibrated liquid-in-glass thermometers are used, the use of two thermometers is recommended. Outside the range 0°C to 100°C, a calibrated liquid-in-glass thermometer of an accuracy after correction of +/- 0.05°C or better shall be used, and when two thermometers are used in the same bath they shall agree within +/- 0.1°C.
6.5 Timing device, capable of taking readings with a discrimination of 0.1 s or better, and having an accuracy within +/- 0.07 % (see annex C) of the reading when tested over intervals of 200 s and 900 s.
NOTE 9 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 systems, are intermittently rather than continuously controlled. When used to actuate electrical timing devices, such control can cause large errors in viscosity flow measurements.
