A Preface
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The procedures used to develop this document as well as those used for further maintenance are described in Part 1 of the ISO/IEC Directive. In particular, attention should be paid to the different approval criteria required for different types of ISO documents. This document has been drafted in accordance with the editorial rules of Part 2 of the ISO/IEC Directive (see iso.org/directives).

Please note that certain contents of this document may be subject to patent rights. ISO is not responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the introduction and/or in the ISO list of patent claims received (see.iso.org/patents).

ISO 3104-2020: Methods of test for petroleum and its products – Petroleum products – Transparent and opaque liquids – Determination of kinematic viscosity

Any trade names used in this document are provided as information for the convenience of the user and do not constitute an endorsement.

Voluntary, related standards and conformity assessment related ISO specific and express the meaning of terminology as well as in relevant ISO technical barriers to trade (TBT) adhere to the principle of the world trade organization (WTO) information, please refer to the iso.org/iso/foreword.html.

This document is prepared by Technical Committee ISO/TC 28, Petroleum and related products, fuels and lubricants of natural or synthetic origin.

The third edition cancels and replaces the second edition of the technical revision (ISO 3104:1994).

Compared with the previous edition, the main changes are as follows:

– Accuracy data has been updated to all actual fuels in the market;

– Biodiesel (FAME) blends and paraffin diesel are included in the scope;

– Includes process description and permission for automation technology.

Any feedback or questions regarding this document should be directed to the user’s national standards body. A full list of these agencies can be found at iso.org/members.html.

ISO 3104-2020: Methods of test for petroleum and its products – Petroleum products – Transparent and opaque liquids – Determination of kinematic viscosity

Introduction
Many petroleum products and some non-petroleum materials are used as lubricants, and the proper operation of the equipment depends on the proper viscosity of the liquid used. In addition, the viscosity of many petroleum fuels is very important for estimating better storage, handling, and operating conditions. Therefore, the importance of accurate measurement of viscosity for many product specifications cannot be overstated.

Warnings This document is not intended to address all safety concerns, if any, associated with its use. It is the responsibility of the user of this document to take appropriate steps to ensure the safety and health of personnel and to determine the applicability of any other restrictions before applying this document.

1 Scope
This document specifies procedure A for the use of a manual glass visvisometer and procedure B for the use of a glass capillary visvisometer in an automated assembly to determine the kinematic viscosity ν of transparent and opaque liquid petroleum products by measuring the time of a given volume of liquid in a gravimetrically overcalibrated glass capillary visvisometer. The dynamic viscosity η is obtained by multiplying the measured kinematic viscosity by the density ρ of the liquid. The test method covers kinematic viscosity ranging from 0.2 mm2/s to 300 000 mm2/s over a temperature range from -20 °C to +150 °C.

Note that the results obtained from this document depend on the behavior of the sample and are intended to be applied to liquids where shear stress and shear rate are proportional (Newtonian flow behavior). However, if the viscosity varies significantly with the shear rate, different results can be obtained from viscometers with different capillary diameters. Program and precision values have been included for residual fuel oils, which in some cases exhibit non-Newtonian behavior.

ISO 3104-2020: Methods of test for petroleum and its products – Petroleum products – Transparent and opaque liquids – Determination of kinematic viscosity

2 Normative references
The following documents are referenced in the text in such a way that some or all of their contents constitute the requirements of this document. For dated references, only the cited version applies. For undated references, the new version of the reference (including any revisions) applies.

ISO 3105, glass capillary kinematic viscometers-Specifications and operating instructions

ISO 3696:1987, Analytical laboratory water use. Specifications and test methods

ASTM E1137, Standard specification for Industrial Platinum Resistance Thermometers

ASTM E2877, Standard Guide for Digital Contact Thermometers

ISO 3104-2020: Methods of test for petroleum and its products – Petroleum products – Transparent and opaque liquids – Determination of kinematic viscosity

3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminology databases for standardization at the following addresses:

– ISO online browsing platform: available at iso.org/obp

– IEC Electronic Encyclopedia: available at electropedia.org

3.1 Kinematic viscosity ν
The resistance of a fluid to flow under gravity

Remark 1: For a gravity flow at a given static pressure head, the pressure head of a liquid is proportional to its density ρ. For any particular viscometer, the flow time of a fixed volume of fluid is proportional to its kinematic viscosity, ν :

ν = η/ρ

Note 2: where η is the dynamic viscosity coefficient.

3.2 Dynamic viscosity
Dynamic viscosity coefficient

Viscosity η

ISO 3104-2020: Methods of test for petroleum and its products – Petroleum products – Transparent and opaque liquids – Determination of kinematic viscosity

The ratio between the applied shear stress and the shear rate of the liquid

Note 1: It is a measure of resistance to liquid flow or deformation.

Remark 2: The term dynamic viscosity is also used in different contexts to denote frequency-dependent quantities in which shear stress and shear rate have sinusoidal time dependence.

3.3 Density ρ
Mass per unit volume of material at a given temperature