oSIST prEN ISO 12185:2023

SLOVENSKI STANDARD
oSIST prEN ISO 12185:2023
01-januar-2023
Surova nafta, naftni in sorodni proizvodi - Določanje gostote - Laboratorijski
merilnik gostote z nihajočim U cevnim senzorjem (ISO/DIS 12185:2022)
Crude petroleum, petroleum products and related products - Determination of density -
Laboratory density meter with an oscillating U tube sensor (ISO/DIS 12185:2022)
Rohöl und Mineralölerzeugnisse - Bestimmung der Dichte - U-Rohr-Oszillationsverfahren
(ISO/DIS 12185:2022)
Pétroles bruts, produits pétroliers et produits connexes - Détermination de la masse
volumique - Densimètre de laboratoire à capteur à tube en U oscillant (ISO/DIS
12185:2022)
Ta slovenski standard je istoveten z: prEN ISO 12185
ICS:
75.040 Surova nafta Crude petroleum
75.080 Naftni proizvodi na splošno Petroleum products in
general
oSIST prEN ISO 12185:2023 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN ISO 12185:2023

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oSIST prEN ISO 12185:2023
DRAFT INTERNATIONAL STANDARD
ISO/DIS 12185
ISO/TC 28/SC 2 Secretariat: BSI
Voting begins on: Voting terminates on:
2022-10-24 2023-01-16
Crude petroleum, petroleum products and related
products - Determination of density - Laboratory density
meter with an oscillating U tube sensor
Pétroles bruts et produits pétroliers — Détermination de la masse volumique — Méthode du tube en U
oscillant
ICS: 75.080
This document is circulated as received from the committee secretariat.
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
ISO/CEN PARALLEL PROCESSING
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 12185:2022(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION. © ISO 2022

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oSIST prEN ISO 12185:2023
ISO/DIS 12185:2022(E)
DRAFT INTERNATIONAL STANDARD
ISO/DIS 12185
ISO/TC 28/SC 2 Secretariat: BSI
Voting begins on: Voting terminates on:

Crude petroleum, petroleum products and related
products - Determination of density - Laboratory density
meter with an oscillating U tube sensor
Pétroles bruts et produits pétroliers — Détermination de la masse volumique — Méthode du tube en U
oscillant
ICS: 75.080
This document is circulated as received from the committee secretariat.
COPYRIGHT PROTECTED DOCUMENT
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
© ISO 2022
ISO/CEN PARALLEL PROCESSING
THEREFORE SUBJECT TO CHANGE AND MAY
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
NOT BE REFERRED TO AS AN INTERNATIONAL
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on STANDARD UNTIL PUBLISHED AS SUCH.
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
IN ADDITION TO THEIR EVALUATION AS
or ISO’s member body in the country of the requester. BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
ISO copyright office
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STANDARDS MAY ON OCCASION HAVE TO
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CH-1214 Vernier, Geneva
POTENTIAL TO BECOME STANDARDS TO
Phone: +41 22 749 01 11
WHICH REFERENCE MAY BE MADE IN
Reference number
Email: copyright@iso.org
NATIONAL REGULATIONS.
Website: www.iso.org ISO/DIS 12185:2022(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
Published in Switzerland
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
ii
  © ISO 2022 – All rights reserved
PROVIDE SUPPORTING DOCUMENTATION. © ISO 2022

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oSIST prEN ISO 12185:2023
ISO/DIS 12185:2022(E)
Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Definitions . 2
3.1 Density . 2
3.2 Displayed density . 2
3.3 Reference temperature . 2
3.4 Test temperature . 2
3.5 Adjustment . 2
3.6 Calibration . 2
3.7 Liquid density standard . 3
4 Principle . 3
5 Apparatus . 3
5.1 Density meter . 3
5.2 Calibrated temperature sensor . 4
5.3 Homogenizer . 4
5.4 Adjustment liquids . 4
5.5 Calibration liquids . 5
6 Sampling . 5
7 Sample preparation .5
7.1 General . 5
7.2 Petroleum products which are free of water and sediment and which are
sufficiently mobile . 6
7.3 Crude petroleum and petroleum products containing water and / or sediments . 6
7.4 Waxy crude petroleum . 6
7.5 Waxy samples . 6
7.6 Fuel oils . 6
8 Apparatus preparation .6
8.1 Test temperature . 6
8.2 Cell cleaning . 7
9 Meter adjustment . 7
10 Meter calibration . 7
10.1 Calibration of displayed density . 7
10.2 Calibration of displayed temperature . 7
11 Test procedure .8
11.1  . 8
11.2  . 9
11.3  . 9
11.4  . 9
11.5  . 9
11.6  . 9
11.7  . 10
11.8  . 10
12 Calculation .10
12.1  . 10
13 Test report .10
14 Precision .11
14.1 General . 11
14.2 Repeatability and reproducibility for all samples other than gasolines . 11
iii
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oSIST prEN ISO 12185:2023
ISO/DIS 12185:2022(E)
Annex A Gasoline repeatability and reproducibility .13
Bibliography .14
iv
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oSIST prEN ISO 12185:2023
ISO/DIS 12185:2022(E)
Foreword
ISO (the International Organisation for Standardisation) 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 matters of electro-
technical standardization.
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
editorial rules of the ISO/IEC Directives, Part 2. www.iso.org/directives Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
International Standard ISO 12185 was prepared by Technical Committee ISO TC28, Petroleum products
and lubricants, Subcommittee SC2 Measurement of Petroleum& Related Products
This second edition cancels and replaces the first edition (ISO 12185:1996), which has been technically
revised. The main changes compared to the previous edition are as follows:
More specific requirements for the traceable calibration of laboratory density meters;
Rewording of the methodology when using density meters to take account of the wide variety of models
now available.
The committee responsible for this document is ISO/TC 28/SC2/WG12.
The first edition of this standard, (ISO 12185:1996) was written at a time when there were relatively
few models of laboratory density meter on the market, and the effect of sample viscosity on displayed
density had only recently been reported.
There are now a considerable number of different manufacturers and models of laboratory density
meter available worldwide. This edition of the standard has been written to encompass this wider
range of instruments, many of which use different methodologies or algorithms to cope with the effect
of viscosity on displayed density.
Most laboratory density meters in use today indicate a measured density. However, there are still a few
meters in use which display oscillation frequency or period. The principles laid down in this standard
can still be applied to these meters, but the calculations for adjustment, calibration, and determination
of sample density will have to be carried out on the indicated frequency, using the manufacturer’s
equations
v
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oSIST prEN ISO 12185:2023

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oSIST prEN ISO 12185:2023
DRAFT INTERNATIONAL STANDARD ISO/DIS 12185:2022(E)
Crude petroleum, petroleum products and related
products - Determination of density - Laboratory density
meter with an oscillating U tube sensor
WARNING — The use of this International Standard may 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 the user of this standard to establish appropriate safety
and health practices and determine the applicability of regulatory limitations prior to use.
1 Scope
This International Standard specifies a method for the determination, using an oscillating U-tube
3
density meter, of the density of crude petroleum and related products within the range 600 kg/m to
3
1 100 kg/m which can be handled as single-phase liquids at the test temperature and pressure.
This International Standard is applicable to liquids of any vapour pressure as long as suitable
precautions are taken to ensure that they remain in single phase. Loss of light components will lead to
changes in density during both the sample handling and the density determination.
This method is not intended for use with in-line density meters.
2 Normative references
The following documents contain provisions which, through reference in this text, constitute
provisions of this International Standard. At the time of publication, the additions indicated were valid.
All standards are subject to revision, and parties to agreements based on this International Standard
are encouraged to investigate the possibility of applying the most recent editions of the standards
indicated below. Members of IEC and ISO maintain registers of currently valid International Standards.
ISO 91-1, Petroleum measurement tables - Part 1: Tables based on reference temperatures of 15 °C and
60 °F
ISO 91-2, Petroleum measurement tables - Part 2: Tables based on a reference temperature of 20 °C
ISO 3015, Petroleum and related products from natural or synthetic sources — Determination of cloud
point
ISO 3170, Petroleum liquids — Manual sampling
ISO 3171, Petroleum liquids — Automatic pipeline sampling
ISO 3696, Water for analytical laboratory use — Specification and test methods
ISO 4259, Petroleum products - Determination and application of precision data in relation to methods of
test
ISO 17025, General requirements for the competence of testing and calibration laboratories.
IP 389 Determination of wax appearance temperature of middle distillate fuels by differential thermal
analysis or differential scanning calorimetry.
Tanaka M., Girard G., Davis R., Peuto A., Bignell N., Recommended table for the density of water
between 0 °C and 40 °C based on recent experimental reports. Metrologia, 38, 301-309 (2001)
Wagner W., Pruss A., The IAPWS Formulation 1995 for the Thermodynamic Properties of Ordinary
Water Substance for General and Scientific Use. J. Phys. Chem. Ref. Data, 31, 387-535 (2002)
1
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oSIST prEN ISO 12185:2023
ISO/DIS 12185:2022(E)
Picard A, Davis R S, Gläser M, Fujii K, Revised formula for the density of moist air (CIPM-2007)
Metrologia 45 149–155 (2008)
3 Definitions
For the purposes of this International Standard, the following definitions apply.
3.1 Density
The mass of liquid per unit volume at a specified temperature. This is usually the mass of liquid
expressed in kilograms, divided by its volume, expressed in cubic metres. The unit of measurement can
3 3
be displayed as either kgm- or kg/m . When quoting liquid density, the temperature at which it has
3
been measured shall also be quoted. (Example 840,0 kg/m at 20,1 °C)
3 3
Note The SI unit of density is kg/m ; the derived unit of measure g/cm is commonly used in some
industries.
3.2 Displayed density
The density of the sample as displayed by the density meter.
May either be the density measured at the temperature that the meter has been set to, or a density at
another temperature, which has been calculated by the meter using an algorithm chosen by the meter
user. To avoid confusion when reporting the displayed density, the temperature to which this density
refers should also be quoted.
3.3 Reference temperature
Temperature at which the sample density needs to be reported. This temperature will normally be one
of 15 °C, 20 °C, or 25 °C, or the Celsius equivalent of 60 °F. Such a reference temperature is normally
stipulated by the National Authorities or commercial agreement.
3.4 Test temperature
Temperature of the sample in the density meter cell.
Note Choose a temperature at which the sample is a single-phase liquid, and the sample viscosity is within
the meter’s specification.
3.5 Adjustment
A set of operations carried out on a density meter to bring it into a state of performance suitable for use.
NOTE Most, but not all, laboratory density meters can be adjusted using water and either air or another
liquid.
Adjustment of a density meter should not be confused with calibration. After a meter has been adjusted
it must be calibrated to find the error in the displayed density.
3.6 Calibration
The operation that establishes, under specified conditions, the relationship between the value indicated
by the density meter and the certified value of the liquid density standard. When taken in association
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oSIST prEN ISO 12185:2023
ISO/DIS 12185:2022(E)
with the associated measurement uncertainties, this process provides a method for obtaining a density
measurement result from an instrument indication.
Note A meter must be calibrated after it has been adjusted. One or more traceable liquid density standards
should be injected, and the displayed result compared with the certified density. This will give the calibration
offset for the meter.
Some meters have the facility to store the calibration offset, and automatically correct any subsequent
indicated density. Where this is not the case, all subsequent readings will need to be corrected for this
offset by applying the appropriate correction manually.
Note 1 to entry Some models of density meter may call the calibration step “secondary adjustment”.
3.7 Liquid density standard
A liquid whose density has been determined using a method giving results which are traceable to the
SI system of units. It must be accompanied by a certificate that provides the value of the density at one
or more temperatures, the associated uncertainty, and a statement of metrological traceability. Ideally,
such a certificate should be issued by an ISO17025 accredited laboratory.
4 Principle
The test sample is introduced into the cell of a density meter which has previously been adjusted
and calibrated. The density of the sample is calculated from the indicated density, by applying such
corrections as have been determined during the calibration stage.
The cell oscillates constantly at its characteristic resonant frequency. This frequency is a function of
the mass of the cell. The mass of the cell is a function of the density of its contents. This means that the
liquid in the cell must be free of gas bubbles . The higher the sample density, the lower the oscillation
frequency. Sample density is calculated from the frequency.
Accurate temperature control of the cell is important as density changes with temperature.
5 Apparatus
5.1 Density meter
Meters can often be programmed to indicate two or more forms of density results, which may or may
not be “corrected” for viscosity. If a meter can indicate a “viscosity corrected” density, this value should
3
always be used. Note: Research has shown that the “viscosity correction” can be greater than 1 kg/m
for very viscous samples in certain models of meter.
Most modern density meters have integral thermostats to maintain cell temperature. Older models
may need a circulating constant-temperature bath, capable of maintaining the temperature of the
circulating liquid to within ±0,05 °C of the required temperature.
Note 2 to entry Problems have been experienced with certain density meters due to condensation gathering on
the cell sensors and electronics when the cell temperature is held below the dew-point of the ambient air. If there
is risk of this occurring, the surrounding air should be kept dry.
Many laboratory density meters are equipped with autosamplers to allow for automatic operation.
Any autosampler fitted must be designed to ensure the integrity of the test sample prior to and during
analysis. The autosampler must be designed so as to ensure that a representative sub-sample is injected
into the density meter. Autosampler behaviour should be monitored on a regular basis, especially if the
samples contain dissolved gases or other lighter boiling components.
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oSIST prEN ISO 12185:2023
ISO/DIS 12185:2022(E)
5.2 Calibrated temperature sensor
Capable of measuring the temperature of the cell to an accuracy of at least ±0,05 °C. Should this ±0,02 °C?
3
For a liquid of nominal density of 750 kg/m , an error of temperature in 0,05 °C, equates to a change in
3
density of 0,03 kg/m .
Most modern meters have integral thermometers, which shall be calibrated. Depending on the model of
the meter, these may be either PRTs or thermocouples.
Note Ideally, any temperature measuring device should be able to be removed from the meter, to allow it
to be recalibrated at some time after the factory calibration. Most manufacturers have designed their meters so
that this is not possible. Users should be aware that most temperature measurement devices do drift with time.
Some meters can have a very small diameter thermometer carefully inserted into the cell, to check the
indicated cell temperature, using a liquid such as dodecane as a light lubricant. In this case, the energy
transfer rate across the cell is low. Therefore, care should be taken to use thermometers with very fine
leads to minimize heat transfer in or out of the cell along the leads.
5.3 Homogenizer
This should be suitable for the sample and sample container, and capable of producing homogeneous
subsamples for test (see Section 8). Such a device may be required for fluids that are essentially non-
homogeneous, for example water in crude oil and where required they should be suitable for the sample
and sample container. Care should be taken not to reduce the sample integrity by overmixing, in some
cases this will cause the loss of light ends, in others the creation of an emulsion for which secondary
properties such as water in crude oil may be harder to determine.). Use a high-speed shear mixer.
Flushing solvent
Any liquid may be used provided that it is capable of producing a clean dry cell.
Note 1 to entry If the cell is heavily contaminated, it might need to be soaked with proprietary laboratory
detergent. If this is the case the cell temperature can be increased to accelerate the reaction.
5.4 Adjustment liquids
A minimum of two fluids are needed to adjust the cell. They shall be chosen so that their densities
bracket the density of the sample under test. For many meters, manufacturers suggest that air and
water are acceptable adjustment fluids.
The water should conform to ISO 3696 grade 2 or better.
Cooled water from a distillation unit is ideal; otherwise, it may be necessary to pass the water through
a
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