EN ISO 20844:2004

SLOVENSKI STANDARD
01-september-2004
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Petroleum and related products - Determination of the shear stability of polymer-
containing oils using a diesel injector nozzle (ISO 20844:2004)
Mineralölerzeugnisse und verwandte Produkte - Bestimmung der Scherstabilität von
polymerhaltigen Ölen mit Hilfe einer Diesel-Einspritzdüse (ISO 20844:2004)
Pétrole et produits connexes - Détermination de la stabilité au cisaillement de fluides
contenant des polymeres au moyen d'un injecteur pour moteur diesel (ISO 20844:2004
Ta slovenski standard je istoveten z: EN ISO 20844:2004
ICS:
75.080 Naftni proizvodi na splošno Petroleum products in
general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 20844
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2004
ICS 75.080
English version
Petroleum and related products - Determination of the shear
stability of polymer-containing oils using a diesel injector nozzle
(ISO 20844:2004)
Pétrole et produits connexes - Détermination de la stabilité Mineralölerzeugnisse und verwandte Produkte -
au cisaillement de fluides contenant des polymères au Bestimmung der Scherstabilität von polymerhaltigen Ölen
moyen d'un injecteur pour moteur diesel (ISO 20844:2004) mit Hilfe einer Diesel-Einspritzdüse (ISO 20844:2004)
This European Standard was approved by CEN on 1 March 2004.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2004 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 20844:2004 E
worldwide for CEN national Members.

Foreword
This document (EN ISO 20844:2004) has been prepared by Technical Committee ISO/TC 28
"Petroleum products and lubricants" in collaboration with Technical Committee CEN/TC 19
"Petroleum products, lubricants and related products", the secretariat of which is held by NEN.
This European Standard shall be given the status of a national standard, either by publication of
an identical text or by endorsement, at the latest by September 2004, and conflicting national
standards shall be withdrawn at the latest by September 2004.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary,
Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
Endorsement notice
The text of ISO 20844:2004 has been approved by CEN as EN ISO 20844:2004 without any
modifications.
INTERNATIONAL ISO
STANDARD 20844
First edition
2004-03-15
Petroleum and related products —
Determination of the shear stability of
polymer-containing oils using a diesel
injector nozzle
Pétrole et produits connexes — Détermination de la stabilité au
cisaillement de fluides contenant des polymères au moyen d'un
injecteur pour moteur diesel
Reference number
ISO 20844:2004(E)
©
ISO 2004
ISO 20844:2004(E)
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ii © ISO 2004 – All rights reserved

ISO 20844:2004(E)
Contents Page
Foreword. iv
1 Scope. 1
2 Normative references . 1
3 Terms and definitions. 1
4 Principle . 2
5 Reagents and materials. 2
6 Apparatus. 2
7 Samples and sampling . 3
8 Preparation of test rig. 3
9 Calibration. 3
10 Procedure. 4
11 Calculation. 4
12 Expression of results. 4
13 Precision . 5
14 Test report. 5
Annex A (normative) Test rig . 6
Bibliography . 9

ISO 20844:2004(E)
Foreword
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 matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. 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.
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.
ISO 20844 was prepared by Technical Committee ISO/TC 28, Petroleum products and lubricants.

iv © ISO 2004 – All rights reserved

INTERNATIONAL STANDARD ISO 20844:2004(E)

Petroleum and related products — Determination of the shear
stability of polymer-containing oils using a diesel injector
nozzle
WARNING —The use of this International Standard may involve hazardous materials, operations and
equipment. This International Standard does not purport to address all of the safety problems
associated with its use. It is the responsibility of the user of this International 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 to assess the resistance to shear stresses applied to mineral
oils, synthetic oils and other fluids containing polymers, when passed through a specified diesel injector
nozzle. The shear stability is measured by the change in viscosity of the fluid under test, brought about by the
polymer degradation during stress. Under normal circumstances, this International Standard is applied to
hydraulic fluids of categories HR and HV as defined in ISO 6743-4 ([1] in the Bibliography) and specified in
ISO 11158 ([2] in the Bibliography), but it may also be applied to fire-resistant hydraulic fluids within categories
HFA, HFB, HFC and HFD, with modified conditions as specified in ISO 12922 ([3] in the Bibliography).
No formal correlation has been established between the viscosity loss, or the absence of viscosity loss,
obtained using the procedures described in this International Standard and that of oils and fluids in actual
service. However, it provides standardized conditions for the evaluation of polymer stability under minimized
thermal and oxidative stresses. It is normally used by manufacturers of fluids and additives, and users, as a
means of ranking existing and potential formulations.
NOTE Changes to properties other than viscosity are specified in some specifications, but these are not covered by
the procedures specified in this International Standard.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 3104:1994, Petroleum products — Transparent and opaque liquids — Determination of kinematic
viscosity and calculation of dynamic viscosity
ISO 3170:2004, Petroleum liquids — Manual sampling
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO 20844:2004(E)
3.1
shear stability
percentage loss in viscosity at 40 °C of an oil or fluid subjected to the mechanical shear stresses specified in
this International Standard
NOTE Viscosity measurements at other temperatures may be specified by some users.
3.2
calibration pressure
recorded gauge pressure when the specified calibration fluid is within a viscosity loss range of 2,7 mm /s to
3,0 mm /s at 100 °C
4 Principle
A test portion of the oil or fluid under test is pumped through a diesel injector nozzle by means of a diesel fuel
pump, at high pressure to exert shear stresses. After a specified number of passes, the viscosity of the
stressed oil or fluid is measured and compared to that of the unstressed oil or fluid. The percentage loss in
viscosity, corrected by a factor to account for the calibration procedure, is the shear stability of the material
under test.
5 Reagents and materials
1)
5.1 Calibration fluid, of calibration oil grade RL 34 .
5.2 Diesel fuel, of commercial grade, if required for adjustment of the injector nozzle valve opening
pressure (see 8.1).
NOTE Precalibrated injector nozzles are normally used.
6 Apparatus
6.1 Test rig
2)
The test rig is described in Annex A . It shall be located in a position where the ambient temperature is
between 20 °C and 25 °C, and shall be supplied with a supply of circulating cooling water regulated for flow.
6.2 Viscosity measuring apparatus
Viscometers and baths shall conform to ISO 3104. Bath temperatures of at least 40 °C and 100 °C are
required.
...