4.1 Many petroleum products and some non-petroleum products are used as lubricants in the equipment, and the correct operation of the equipment depends upon the appropriate viscosity of the lubricant being used. Additionally, 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.

4.2 The viscosity of used oils is a commonly determined parameter in the oil industry to assess the effect of engine wear on the lube oils used, as well as the degradation of the engine parts during operation.

4.3 The Houillon viscometer tube method offers automated determination of kinematic viscosity. Typically a sample volume of less than 1 mL is required for the analysis.

1.1 This test method covers the measurement of the kinematic viscosity of transparent and opaque liquids; such as base oils, formulated oils, diesel oil, biodiesel, biodiesel blends, and used lubricating oils using a Houillon viscometer in automated mode.

1.2 The range of kinematic viscosity capable of being measured by this test method is from 2 mm²/s to 1500 mm²/s (see Fig. 1). The range is dependent on the tube constant utilized. The temperature range that the apparatus is capable of achieving is between 20 °C and 150 °C, inclusive. However, the precision has only been determined for the viscosity range; 2 mm²/s to 478 mm²/s at 40 °C for base oils, formulated oils, diesel oil, biodiesel, and biodiesel blends; 3 mm²/s to 106 mm²/s at 100 °C for base oils and formulated oils; 25 mm²/s to 150 mm²/s at 40 °C and 5 mm²/s to 16 mm²/s at 100 °C for used lubricating oils. As indicated for the materials listed in the precision section.

Note 1: Viscosity range of a Houillon tube is based on most practical flow time of 30 s to 200 s.

1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.4 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 and health practices and determine the applicability of regulatory limitations prior to use. For specific warning statements, see Section 6.