kSIST FprEN ISO 3104:2020

SLOVENSKI STANDARD
oSIST prEN ISO 3104:2018
01-januar-2018
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Petroleum products - Transparent and opaque liquids - Determination of kinematic
viscosity and calculation of dynamic viscosity (ISO/DIS 3104:2017)

Mineralölerzeugnisse - Durchsichtige und undurchsichtige Flüssigkeiten - Bestimmung

Produits pétroliers - Liquides opaques et transparents - Détermination de la viscosité

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

Produits pétroliers — Liquides opaques et transparents — Détermination de la viscosité cinématique et

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form

or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior

written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of

Introduction .....................................................................................................................................................................5

1 Scope ....................................................................................................................................................................6

2 Normative references ....................................................................................................................................6

3 Terms and definitions ....................................................................................................................................6

4 Principle ..............................................................................................................................................................7

5 Reagents and materials .................................................................................................................................7

6 Apparatus design and requirements ........................................................................................................7

7 Verification ..................................................................................................................................................... 11

8 Re-calibration ................................................................................................................................................ 12

9 Quality control ............................................................................................................................................... 12

10 Sample preparation ..................................................................................................................................... 12

11 Procedure A – Manual equipment .......................................................................................................... 13

12 Procedure B –Automated equipment .................................................................................................... 15

13 Cleaning of the viscometer tube .............................................................................................................. 16

14 Calculation....................................................................................................................................................... 16

15 Expression of results ................................................................................................................................... 18

16 Precision of Procedure A ........................................................................................................................... 18

17 Precision of Procedure B ........................................................................................................................... 20

18 Test report ...................................................................................................................................................... 20

(normative) Viscometer types, calibration and verification .................................................... 21

(normative) Thermometers for kinematic viscosity test .......................................................... 22

(normative) Conditioning of samples prior to manual or automated analysis ................. 26

conformance with a certified reference material ............................................................................. 27

ISO (the International Organization for Standardization) is a worldwide federation of national

standards bodies (ISO member bodies). The work of preparing International Standards is normally

carried out through ISO technical committees. Each member body interested in a subject for which a

technical committee has been established has the right to be represented on that committee.

International organizations, governmental and non-governmental, in liaison with ISO, also take part in

the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held 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

Any trade name used in this document is information given for the convenience of users and does not

For an explanation on the meaning of ISO specific terms and expressions related to conformity

assessment, as well as information about ISO's adherence to the World Trade Organization (WTO)

The committee responsible for this document is ISO/TC 28, Petroleum and related products, fuels and

This third edition cancels and replaces the second edition (ISO 3104:1994), of which it constitutes a

technical revision. Major change is that the precision data are updated to all actual fuels on the market;

biodiesel (FAME) blends and paraffinic diesel have been included in the scope. Another important

change is that the procedure description and allowance of automated techniques have been included.

Many petroleum products, and some non-petroleum materials, are used as lubricants, and the correct

operation of 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 measurement of viscosity is essential to many product

This International Standard specifies a Procedure A using manual glass viscometers and a Procedure B

using glass capillary viscometers in an automated assembly, 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, is obtained by multiplying the measured kinematic viscosity by the density, ρ, of the liquid.

The range of kinematic viscosities covered in this test method is from (0,2 to 300 000) mm s over the

NOTE The result obtained from this International Standard is dependent upon the behaviour of the sample

and is intended for application to liquids for which primarily the shear stress and shear rates are proportional

(Newtonian flow behaviour). 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 behaviour, have been included.

WARNING — The use of this Standard can involve hazardous materials, operations and

equipment. This Standard does not purport to address all of the safety problems associated with

its use. It is the responsibility of users of this standard to take appropriate measures to ensure

the safety and health of personnel prior to the application of the standard, and fulfil statutory

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. For dated references, only the edition cited applies. For undated

references, the latest edition of the referenced document (including any amendments) applies.

ISO 3105:1994, Glass capillary kinematic viscometers — Specifications and operating instructions

ISO 3696:1987, Water for analytical laboratory use — Specification and test methods

ASTM E1137, Standard Specification for Industrial Platinum Resistance Thermometers

Note 1 to entry: For gravity flow under a given hydrostatic head, the pressure head of a liquid is proportional to

its density, ρ. For any particular viscometer, the time of flow of a fixed volume of fluid is directly proportional to

its kinematic viscosity, ν, where ν = η/ρ. and where η is the dynamic viscosity coefficient.

ratio between the applied shear stress and rate of shear of a liquid, sometimes called the coefficient of

dynamic viscosity, or simply viscosity; it is a measure of the resistance to flow or deformation of a liquid

Note 1 to entry: The term dynamic viscosity is also used in a different context to denote a frequency-dependent

The time is measured for a fixed volume of liquid to flow under gravity through the glass capillary of a

calibrated viscometer under a reproducible driving head and at a known and closely controlled

temperature. The kinematic viscosity is the product of the measured flow time and the calibration

5.1 Cleaning solution, strongly-oxidizing cleaning solution or alkaline cleaning solutions can be

NOTE 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

5.4 Water, deionized or distilled, conforming to Grade 3 of ISO 3696. Filter before use.

5.5 Certified viscosity reference standards, (CRM) – data provided by an accredited calibration

laboratory - traceable to the international agreed value of distilled water (1,003 4 mm /s at 20 °C) as

specified in ISO/TR 3666 and calibrated in accordance with a standard practice for the basic calibration

6.1 Drying tubes, consisting of a desiccant drying system, consisting of either externally mounted

drying tubes or an integrated desiccant drying system designed to remove ambient moisture from the

capillary tube Ensure that they are packed loosely and that the silica gel is not saturated with water.

6.2 Sample filter, micron screen or fretted (sintered) glass filter, no more than 75 µm.

6.3 Reagent filter, micron screen or fretted (sintered) glass filter, no more than 11 µm.

6.4 Ultrasonic bath, unheated – with an operating frequency between 25 kHz to 60 kHz and a

typical power output of ≤100 W, of suitable dimensions to hold container(s) placed inside of bath, for

use in effectively dissipating and removing air or gas bubbles that can be entrained in viscous sample

types prior to analysis. It is permissible to use ultra- sonic baths with operating frequencies and power

outputs outside this range; however it is the responsibility of the laboratory to conduct a data

comparison study to confirm that results determined with and without the use of such ultrasonic

The viscometer shall have a certificate of calibration provided by an accredited laboratory.

The calibration constant, C, is dependent upon the gravitational acceleration at the place of calibration

and this shall therefore be supplied by the viscometer calibration laboratory, together with the

instrument constant. The variation in the value of g across the earth’s surface is about 0,5 % due to

latitude plus approx. 0,003 % per 100 m altitude. Apply a gravity correction to the viscometer

calibration constant if the acceleration of gravity of the testing laboratory differs by more than 0,1% of

where the subscripts 1 and 2 indicate, respectively, the calibration laboratory and the testing

NOTE Calculation of acceleration of gravity values can be found at www.NPL.co.uk.

IMPORTANT — Viscometers used for silicone fluids, fluorocarbons and other liquids, which are

difficult to remove by the use of a cleaning agent, shall be reserved for the exclusive use of those

fluids, except during their calibration. Subject such viscometers to calibration checks at frequent

intervals. The solvent washings from these viscometers shall not be used for the cleaning of other

viscometers. If the viscometer is cleaned using the material in 5.1 then the user shall verify the

6.5.2 Viscometer holder or mounting device within the temperature controlled bath, enabling

the glass viscometer to be suspended so that the upper meniscus is directly above the lower meniscus

Those viscometers whose upper meniscus is offset from directly above the lower meniscus shall be

The proper alignment of vertical parts may be confirmed by using a plumb line, but for rectangular baths

6.5.3 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

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

6.5.3.1 Adjust and maintain the viscometer bath at the required test temperature within the limits

given in 6.5.3, taking account of the conditions given in Annex B and of the corrections supplied on the

certificates of calibration for the thermometers. Maintain the bath temperature at the test temperature

using the readings of the temperature measuring device with the corrections supplied by the certificate

Thermometers shall be held in an upright position under the same conditions of immersion as when

calibrated. In order to obtain the most reliable temperature measurement, it is recommended that two

thermometers with valid calibration certificates be used. They should be viewed with a lens assembly

giving approximately 5x magnification and be arranged to eliminate parallax errors.

a) a calibrated liquid-in-glass thermometer, (Annex B) with a calibration and measurement capability

b) a digital contact thermometer as described in 6.5.6.1 with equal or better CMC.

The calibration data should be traceable to a calibration or metrology standards body and meet the

uncertainty of measurement required. The calibration certificate shall include data covering the series of

temperature test points which are appropriate for its intended use. When two thermometers are used

in the same bath in this range, they shall agree within 0,04 °C. See Annex B for the list of complying

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 (Annex B) or a digital contact

thermometer as described in 6.5.4.1 with a calibration and measurement capability (CMC) of ± 0,05 °C

or better shall be used, and when two thermometers are used in the same bath they shall agree within ±

When using liquid-in-glass thermometers, 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. It is recommended that thermometer readings (and any

corrections supplied on the certificates of calibrations for the thermometers) be recorded on a periodic

NOTE The resulting uncertainty of calibration may be dependent upon the immersion depth

6.5.4.2 The DCT probe is to be immersed no less than the immersion depth stated on the calibration

NOTE With respect to DCT probe immersion depth, a procedure is available in ASTM E644, Section 7 [2], for

determining the minimum depth. With respect to an ice bath, ASTM E563 provides guidance on the preparation

of an ice bath however variance from the specific steps is permitted provided preparation is consistent as it is being

Response time less than or equal to 6 s, as defined in specification ASTM E1137/E1137M

Calibration report The DCT shall have a report of temperature calibration which should be traceable to a

national calibration or metrology standards body issued by a calibration laboratory

Calibration data The calibration report shall include at least 3 calibration temperatures including 0°C

An ISO/IEC 17025 accredited laboratory with temperature calibration in its accreditation scope and meets the stated

Automated viscometers, which use the technical principles of this standard, are acceptable provided

they meet the accuracy and precision of all the equipment listed in 6.5. In addition, if they are used to

measure kinematic viscosity in samples subject to conditioning using the steps in Annex C, a heated

sample tray shall be used if the sample is not analysed immediately after conditioning. This sample tray

(6.6.2) shall be heated to a temperature which will not allow the sample to fall below the testing

Flow times of less than 200 s are acceptable; however the kinetic energy correction must be calculated

and should not exceed 3 % of the measured viscosity. Where a value of greater than 3% is achieved the

Some automated equipment contains sample loading trays for analysis of multiple samples. When a

sample has been subjected to conditioning using the steps in Annex C, the sample shall not be allowed to

cool below the testing temperature on the loading tray as this will result in an increase in measured

viscosity as compared to the manual procedure. These trays shall be heated above the test temperature

to ensure the temperature of the sample does not fall below the test temperature by the time of testing.

If embedded, a temperature measuring device shall fully meet the requirements of 6.5.4 and be

removable for an external calibration. The embedded device will provide an independent reference

temperature read-out, allowing the temperature control of the automated apparatus to be adjusted at

6.7 Timing device, capable of taking readings with a discrimination of 0,1 s or better, and having

an uncertainty within ± 0,07 % of the reading when tested over intervals of 200 s and 1 000 s.

Time signals as broadcast by the National Institute of Standards and Technology are a convenient and

NOTE Many broadcast networks put out a standard frequency signal, as do many telephone networks. Such

signals are suitable for checking the timing devices used to an accuracy of 0,1 s.

Timing devices employed in automated viscometers may be an integral part of the apparatus and

typically are digital (using a precision crystal oscillator) with precision discriminations of 0,01 s or

better. As such, the timing devices may not be able to be individually verified once installed.

Documentation of the accuracy of the timing device over the intended measuring range of the viscometer

tube should therefore be provided by the manufacturer. Independent verification of timing devices

Electrical timing devices may be used if the current frequency is controlled to an uncertainty 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

Verify the calibration of the viscometer using a certified viscosity reference standard (5.5) following

Procedure A (manual, Clause 11) or Procedure B (automated, Clause 12). Acceptable tolerance bands

for this verification check are detailed in Annex D. If the measured kinematic viscosity does not fall

within this acceptable range recheck each step in the procedure, including thermometer and

viscometer calibrations and cleaning to locate the source of error. Table 1 in ISO 3105 gives details of

Alternatively verify working viscometers against a reference viscometer having a certificate of

calibration provided by an accredited calibration laboratory accredited to ISO 3105.

Verification is required at least prior to first use of the viscometer and whenever a physical change is

made to the apparatus e.g. re-calibrating the temperature set-point, after cleaning or investigating the

Verify the calibration of the liquid in glass thermometer on a periodic basis in line with B.2 at least at the

frequencies described and maintain records of such checks. A complete new recalibration of the

thermometer, while permitted, is not necessary in order to meet the accuracy ascribed to the design of

the thermometer until the ice point change from the last full calibration amounts to one scale division

Verify the calibration of the DCT at least annually. The probe shall be recalibrated, when the check value

Verification can be accomplished with the use of a water triple point cell or an ice bath.

ASTM Standard Practices E563 , E1750 , and E2593 may be used as reference regarding checking

Verify the accuracy of the timer, regularly check timers and maintain records of such checks.

NOTE Many broadcast networks put out a standard frequency signal, as do many telephone networks. Such

signals are suitable for checking the timing devices used to an accuracy of 0.1 s.

Glass capillary viscometer recalibration if required should be undertaken using the procedures in

CAUTION — Users are cautioned that recalibrating equipment in situ when a verification fails

will potentially calibrate in an error. The most common sources of error are caused by particles

of dust lodged in the capillary bore and temperature measurement errors. It should be

appreciated that a correct result obtained on standard oil does not preclude the possibility of a