Crude petroleum and petroleum products - Determination of density - Oscillating U-tube method (ISO 12185:1996)

Gives a method for the determination, using an oscillation U-tube densitometer, of the density of crude petroleum and related products within the range 600 kg/m^3 to 1 100 kg/m^3 which can be handled as single-phase liquids at the test temperature and pressure.

Rohöl und Mineralölerzeugnisse - Bestimmung der Dichte - U-Rohr-OSZillationsverfahren (ISO 12185:1996)

Pétroles bruts et produits pétroliers - Détermination de la masse volumique - Méthode du tube en U oscillant (ISO 12185:1996)

La présente Norme internationale prescrit une méthode pour la détermination, au moyen d'un densimètre à tube en U oscillant, de la masse volumique des pétroles bruts et produits pétroliers qui sont des liquides monophasés à la température et à la pression d'essai dans le domaine de masse volumique compris entre 600 kg/m3 et 1 100 kg/m3. La présente Norme internationale est applicable aux liquides de n'importe quelle tension de vapeur, dans la mesure où des précautions appropriées sont prises pour s'assurer que ces liquides restent à l'état monophasé sans perte des fractions légères et changement consécutif de la composition et de la masse volumique au cours de la manipulation de l'échantillon et au cours du mesurage de sa masse volumique.
NOTE 1 Si la masse volumique déterminée est à convertir en une masse volumique à une température de référence, en utilisant des tables de mesure du pétrole, il convient d'effectuer la détermination à une température aussi proche que possible de la température de référence, afin de minimiser les incertitudes liées à l'utilisation de tables généralisées. La présente méthode n'est pas applicable aux densimètres en ligne.

Surova nafta in naftni proizvodi - Določanje gostote - Metoda z oscilirajočo U-cevjo (ISO 12185:1996)

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SIST EN ISO 12185:1998



Crude petroleum and petroleum products - Determination of density - Oscillating U-tube

method (ISO 12185:1996)
Rohöl und Mineralölerzeugnisse - Bestimmung der Dichte - U-Rohr-
OSZillationsverfahren (ISO 12185:1996)

Pétroles bruts et produits pétroliers - Détermination de la masse volumique - Méthode du

tube en U oscillant (ISO 12185:1996)
Ta slovenski standard je istoveten z: EN ISO 12185:1996
75.040 Surova nafta Crude petroleum
75.080 Naftni proizvodi na splošno Petroleum products in
SIST EN ISO 12185:1998 en

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

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SIST EN ISO 12185:1998
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SIST EN ISO 12185:1998
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SIST EN ISO 12185:1998
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SIST EN ISO 12185:1998
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SIST EN ISO 12185:1998
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SIST EN ISO 12185:1998
First edition
Crude Petroleum and Petroleum
- Determination of density -
Oscillating Umtube method
P&roles bruts et produits petroliers - Determination de Ia masse
volumique - Methode du tube en U oscillant
Reference number
ISO 12185:1996(E)
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SIST EN ISO 12185:1998
ISO 12185:1996(E)
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. Esch 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 electrotechnical standardization.
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/TC 28, Petroleum products and lubricants, Subcommittee SC 3,
Static Petroleum measurement.
Ann ex A forms an integral part of this International Standard. Annex B is
for i nformation only.
0 ISO 1996

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced

or utilized in any form or by any means, electronie or mechanical, including photocopyrng and

microfilm, without Permission in writing from the publisher.
International Organrzation for Standardization
Case Postale 56 l CH-l 211 Geneve 20 l Switzerland
Printed in Switzerland
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SIST EN ISO 12185:1998
Crude Petroleum and Petroleum products -
Determination of density - Oscillating U-tube method

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. lt 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.

based on this International Standard are encouraged
1 Scope
to investigate the possibility of applying the most re-
cent editions of the Standards indicated below.
This International Standard specifies a method for the
Members of IEC and ISO maintain registers of cur-
determination, using an oscillating U-tube density
rently valid International Standards.
meter, of the density of crude Petroleum and related
products within the range 600 kg/m3 to 1 100 kg/m3
ISO 91-1 :1992, Petroleum measurement tables -
which tan be handled as Single-Phase liquids at the
Part 1: Tables based on reference temperatures of
test temperature and pressure.
15 “C and 60 degrees F.
This International Standard is applicable to liquids of
ISO 91-2: 1991, Petroleum measuremen t tables -
any vapour pressure as long as suitable precautions
Part 2: Tables based on a reference temperature of
are taken to ensure that they remain in Single Phase
20 “C.
with no loss of light ends and subsequent changes in
composition and density during both the Sample
ISO 3015:1992, Petroleum products - Determination
handling and the density determination.
of cloud Point.
NOTE 1 If the determined density is to be converted to
ISO 3016:1994, Petroleum products - Determination
a density at some reference temperature using Petroleum
of pour Point.
measurement tables, the determination should be carried
out at a temperature as close as possible to the reference

temperature in Order to minimize uncertainties due to the ISO 3170:1988, Petroleum liquids - Manual

use of generalized tables.
This method is not intended for use in calibrating on-
ISO 3171 :1988, Petroleum liquids - Automatic pipe-
line density meters.
line sampling.
ISO 3696:1987, Water for analytical laboratory use -
Specification and fest methods.
ISO 3838: 1983, Crude Petroleum and liquid or solid
2 Normative references
Petroleum products - Determination of density or
relative density - Capillary-s toppered pyknome ter
The following Standards contain provisions which,
and gradua ted bicapillary pyknome ter me thods.
through reference in this text, constitute provisions
of this International Standard. At the time of publi-
cation, the editions indicated were valid. All Standards
are subject to revision, and Parties to agreements
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SIST EN ISO 12185:1998
ISO 12185:1996(E)
be minimized by using certified calibration Standards of
IPl) 389193 Determination of wax appearance tem-
Chemical characteristics and viscosity similar to that of the
persture 0; middle distillate fuels by differential ther-
Sample under test [3].
mal analysk or differential scanning calorimetry.
5 Problems have been experienced with certain density
IP 1995, Standard methods for analysis and testing
meters due to condensation gathering on the cell Sensors
of Petroleum and related products, Appendix G Den-
and electronics when the cell temperature is held below the
sity of water; Appendix H Density of ambient air.
dew-Point of the ambient air. If there is risk of this occurring,
the surrounding air should be kept dry.
BIPM2) Tables, Density of water and Density of ambi-
ent air, to replace, when published, the corresponding
5.2 Circulating constant-temperature bath, if re-
I P tables.
quired (see 9.1.2), capable of maintaining the tem-
perature of the circulating liquid to within + 0,05 “C
of the required temperature.
3 Definitions
For the purposes of this International Standard, the
5.3 Calibrated temperature Sensor, capable of
following definitions apply.
measuring the temperature of the cell to an accuracy
of at least + 0,lO “C.
3.1 density: Mass of the substance, expressed in
The rate of energy transfer across the cell is low and
kilograms, divided by its volume, expressed in cubic
therefore care should be taken to use Sensors with
very fine leads in Order to minimize heat transfer in
or out of the cell along the leads.
3.2 reference temperature: Temperature at which
the Sample density is to be reported.
5.4 Homogenizer, suitable for the Sample and
NOTE 2 This temperature should be either 15 “C or
Sample Container, and capable of producing hom-
20 “C.
ogeneous subsamples for test (see clause 8); a high
Speed shear or static mixer, or other type as appro-
4 Principle
A small (typically less than 1 ml) Portion of the test
6 Reagents
Sample is introduced into a temperature-controlled
Sample cell. The oscillation frequency is noted, and
Unless otherwise stated, use only reagents of recog-
the density of the test Sample calculated using cell
nized analytical grade.
constants previously determined by measuring the
oscillation frequencies when the cell is filled with
6.1 Flushing solvent.
calibration fluids of known density.
NOTE 6 Any solvent may be used provided that it
is capable of producing a clean dry cell.
5 Apparatus
6.2 Ammonium peroxydisulfate, Solution in con-
5.1 Density meter, capable, once calibrated, of de-
centrated sulfuric acid, 8 g/l.
termining density with a resolution of + 0,l kg/m3 or
WARNING - Ammonium peroxydisulfate is a
strong oxidizing agent.
3 Meters commonly display two forms of digital result,
6.3 Calibration fluids.
either a density value or the period of oscillation from which
density tan be calculated.
A minimum of two calibration fluids are needed to
calibrate the cell. They shall be Chosen so that their
4 Research has shown that the density meter may show
densities bracket the density of the Sample under
a bias of up to 1 kg/m3 due to viscosity effects. Users
test. The density of the calibration fluids shall be
should ascertain whether a viscosity correction is required
traceable to recognized national Standards or based
by checking the result using a pyknometer method such as
on internationally accepted values.
that given in ISO 3838. Alternatively, viscosity effects tan
1) Institute of Petroleum, 61 New Cavendish Street, London Wl M 8AR, UK.

2) Bureau International des Poids et Mesures, Pavillon de Breteuil, F-92312 Sevres Cedex, France.

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SIST EN ISO 12185:1998
ISO 12185:1996(E)

When water and/or air are used, the requirements of receiver (whether it is pressurized or not) could result

6.3.1 and 6.3.2 shall be met. in Iight-end loss from the material being sampled,
thereby affecting the density measurement.
6.3.1 Water, conforming to ISO 3696 grade 2 or
When drawing samples using variable-volume re-
ceivers, the sampling pressure and temperature of
the Sample Source should be noted on the receiver
Prior to use, pass the water through a 0,45 Pm filter,
and remove dissolved air by first boiling and then
cooling. Once de-aired, handle the water carefully so
lt is essential that the Portion of the Sample to be
as to minimize the amount of air redissolved.
tested is representative of the bulk Sample, and sam-
ple mixing is
sometimes necessary to ensure
Obtain the water density from the table given in Ap-
homogenization Prior to subsampling.
pendix G of IP “Standard methods for analysis and
testing of Petroleum and related products”. On publi-
cation of the BIPM tables (see clause 2), the values
8 Sample preparation
for density of water given therein shall be used.
NOTE 7 The density of water at various temperatures
8.1 General
given in Appendix G has been prepared by the Institute of
Petroleum, in Order to provide a Source for the density of
Samples shall be handled in such a manner that:
water based on the International Temperature Scale 1990,
whilst the work to produce new water-density tables, based
light-end loss is minimized;
on new water data, is carried out by BIPM?
the temperature of the Sample does not drop be-
6.3.2 Air.
low .
Use the values of the density of air given in
1) its cloud Point, when determined in accord-
Appendix H of IP “Standard methods for analysis and
ante with ISO 3015;
testing of Petroleum and related products”. On publi-
cation of the BIPM tables (see clause 2), the values
2) or its wax appearance temperature (WAT),
for density of ambient air given therein shall be used.
when determined in accordance with
I P 389/93;
NOTE 8 The density of ambient air at various tempera-
tures given in Appendix H has been prepared by the lnsti-
3) or 20 “C above its pour Point, when deter-
tute of Petroleum, in Order to provide a Source for the
mined in accordance with ISO 3016.
density of ambient air based on the International Tempera-
ture Scale 1990, whilst work to produce new density of
NOTE 9 lt should be recognized that loss of light ends
ambient air tables is carried out by BIPM.
during homogenization or heating, necessary when
Sediment, water or undissolved wax are present in samples
of volatile crude Petroleum or Petroleum products, tan
6.4 Water, conforming to ISO 3696 Grade 3.
Cause errors in the determined density value.
7 Sampling 8.2 Petroleum products which are free
of water and/or Sediments and which are
Unless otherwise specified in a commodity specifi-
sufficiently mobile
cation, samples shall be taken as described in
ISO 3170 or ISO 3171, and/or in accordance with the
Mix by gentle shaking.
requirements of national Standards or regulations.
Special care should be taken to prevent any loss of
8.3 Crude Petroleum and Petroleum
volatile components from the Sample. Wherever
products containing water and/or Sediments
possible samples should be drawn, transported a

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