SIST EN ISO 12956:2012

SLOVENSKI STANDARD
SIST EN ISO 12956:2012
01-januar-2012
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SIST EN ISO 12956:1999
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Geotextiles and geotextile-related products - Determination of the characteristic opening
size (ISO 12956:2010)
Geotextilien und geotextilverwandte Produkte - Bestimmung der charakteristischen
Öffnungsweite (ISO 12956:2010)
Géotextiles et produits apparentés - Détermination de l'ouverture de filtration
caractéristique (ISO 12956:2010)
Ta slovenski standard je istoveten z: EN ISO 12956:2010
ICS:
59.080.70 Geotekstilije Geotextiles
SIST EN ISO 12956:2012 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 12956:2012

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SIST EN ISO 12956:2012


EUROPEAN STANDARD
EN ISO 12956

NORME EUROPÉENNE

EUROPÄISCHE NORM
April 2010
ICS 59.080.70 Supersedes EN ISO 12956:1999
English Version
Geotextiles and geotextile-related products - Determination of
the characteristic opening size (ISO 12956:2010)
Géotextiles et produits apparentés - Détermination de Geotextilien und geotextilverwandte Produkte -
l'ouverture de filtration caractéristique (ISO 12956:2010) Bestimmung der charakteristischen Öffnungsweite (ISO
12956:2010)
This European Standard was approved by CEN on 22 March 2010.

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 CEN 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 CEN Management Centre has the same status as the
official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.






EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2010 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 12956:2010: E
worldwide for CEN national Members.

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SIST EN ISO 12956:2012
EN ISO 12956:2010 (E)
Contents Page
Foreword .3

2

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SIST EN ISO 12956:2012
EN ISO 12956:2010 (E)
Foreword
This document (EN ISO 12956:2010) has been prepared by Technical Committee ISO/TC 221
"Geosynthetics" in collaboration with Technical Committee CEN/TC 189 “Geosynthetics”, the secretariat of
which is held by NBN.
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 October 2010, and conflicting national standards shall be withdrawn at
the latest by October 2010.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 12956:1999.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association, and supports essential requirements of EU Directive(s).
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 12956:2010 has been approved by CEN as a EN ISO 12956:2010 without any modification.


3

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SIST EN ISO 12956:2012

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SIST EN ISO 12956:2012

INTERNATIONAL ISO
STANDARD 12956
Second edition
2010-04-15

Geotextiles and geotextile-related
products — Determination of the
characteristic opening size
Géotextiles et produits apparentés — Détermination de l'ouverture de
filtration caractéristique




Reference number
ISO 12956:2010(E)
©
ISO 2010

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SIST EN ISO 12956:2012
ISO 12956:2010(E)
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ii © ISO 2010 – All rights reserved

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SIST EN ISO 12956:2012
ISO 12956:2010(E)
Contents Page
Foreword .iv
1 Scope.1
2 Normative references.1
3 Symbols.1
4 Principle.1
5 Apparatus and materials.2
6 Test specimens.3
6.1 Handling .3
6.2 Selection.3
6.3 Number and dimensions.3
6.4 Specimen condition .3
7 Procedure.3
8 Calculation and expression of results .4
9 Test report.4
Annex A (normative) Mesh sizes.7
Annex B (informative) Example of the determination of the characteristic opening size.8

© ISO 2010 – All rights reserved iii

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SIST EN ISO 12956:2012
ISO 12956:2010(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 12956 was prepared by Technical Committee ISO/TC 221, Geosynthetics.
This second edition cancels and replaces the first edition (ISO 12956:1999), which has been technically
revised.

iv © ISO 2010 – All rights reserved

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SIST EN ISO 12956:2012
INTERNATIONAL STANDARD ISO 12956:2010(E)

Geotextiles and geotextile-related products — Determination of
the characteristic opening size
1 Scope
This International Standard specifies a method for the determination of the characteristic size of the openings
of a single layer of a geotextile or geotextile-related product using the wet-sieving principle.
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 9862, Geosynthetics — Sampling and preparation of test specimens
ISO 10320, Geotextiles and geotextile-related products — Identification on site
ISO 565, Test sieves — Metal wire cloth, perforated metal plate and electroformed sheet — Nominal sizes of
openings
ISO 2591-1, Test sieving — Part 1: Methods using test sieves of woven wire cloth and perforated metal plate
3 Symbols
For the purposes of this document, the following symbols apply.
3.1
d
n
particle size for which n % mass fraction is smaller than the mass of measured particles
3.2
O
90
size of opening which is equal to the particle of size d of the granular material which passes through the
90
geotextile or geotextile-related product
3.3
C
u
coefficient of uniformity, defined as d /d
60 10
4 Principle
The particle size distribution of a graded granular material (usually soil) is determined after washing through a
single layer of the geotextile or geotextile-related product used as a sieve, without load. The characteristic
opening size corresponds to a specified size of the granular material passed.
© ISO 2010 – All rights reserved 1

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SIST EN ISO 12956:2012
ISO 12956:2010(E)
5 Apparatus and materials
5.1 Sieving apparatus, composed of the following elements.
5.1.1 Sieving unit, allowing for the testing of a specimen with an exposed sieving area corresponding to a
minimum diameter of 130 mm, complying with the following requirements:
a) sieving device, with a frequency of 50 Hz to 60 Hz;
b) predominantly vertical sieve motion capable of maintaining a 1,5 mm amplitude (3 mm swing height) over
the period of test.
5.1.2 Water supply system.
5.1.3 Spray nozzle(s), to ensure even wetting of the test specimen, enclosed in a transparent cylinder or
covering cap to avoid soil or granular material loss;
It is recommended that the nozzle(s) be capable of a water discharge of approximately 0,5 l/min at a working
pressure of about 300 kPa.
5.1.4 Specimen clamping device.
5.1.5 Pan, affixed to the sieving apparatus, with a tube connection to the device for collection of the water
and granular material
...