ISO 9912-2:2013

INTERNATIONAL ISO
STANDARD 9912-2
Second edition
2013-11-01
Agricultural irrigation equipment —
Filters for microirrigation —
Part 2:
Strainer-type filters and disc filters
Matériel agricole d’irrigation — Filtres —
Partie 2: Filtres à tamis
Reference number
ISO 9912-2:2013(E)
©
ISO 2013

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ISO 9912-2:2013(E)

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© ISO 2013
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ISO 9912-2:2013(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Marking . 3
4.1 General . 3
5 Design and construction requirements . 4
5.1 General . 4
5.2 Filter housing . 4
5.3 Connections . 4
6 Mechanical and hydraulic tests . 5
6.1 General . 5
6.2 Resistance of the filter to internal hydrostatic pressure . . 5
6.3 Filter element tightness and resistance to buckling or tearing . 7
6.4 Clean pressure drop . 8
7 Information to be supplied by the manufacturer . 8
Bibliography .10
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ISO 9912-2:2013(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.
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
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
on the ISO list of patent declarations received. www.iso.org/patents
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
The committee responsible for this document is ISO/TC 23, Tractors and machinery for agriculture and
forestry, Subcommittee SC 18, Irrigation and drainage equipment and systems.
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 WTO principles in the Technical Barriers to Trade
(TBT) see the following URL: http://www.iso.org/iso/home/standards_development/resources-for-
technical-work/foreword.htm
This second edition cancels and replaces the first edition (ISO 9912-2:1992), of which it constitutes a
minor revision.
ISO 9912 consists of the following parts, under the general title Agricultural irrigation equipment —
Filters for microirrigation:
— Part 1: Terms, definitions and classification
— Part 2: Strainer-type filters and disc filters
— Part 3: Automatic flushing strainer-type filters and disc filters
A fourth part on granulated media filters is planned.
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INTERNATIONAL STANDARD ISO 9912-2:2013(E)
Agricultural irrigation equipment — Filters for
microirrigation —
Part 2:
Strainer-type filters and disc filters
1 Scope
This part of ISO 9912 specifies general construction requirements and test methods for strainer filters
and disc filters (hereinafter called filters) intended for operation in agricultural irrigation systems.
This part of ISO 9912 does not cover the aspects of filtration ability, efficiency, and capacity (like quality
of filtered water or time of operation before a filter becomes entirely clogged), nor does it deal with
structural requirements or tests of automatic flushing mechanism filters that are covered by ISO 9912-3.
NOTE The parameters of filtration ability, efficiency, and capacity, their definitions, and their test methods are
to be included in a separate ISO Technical Report. The test methods for comparing various filters under identical
operating conditions will be described in that Technical Report, using water as defined by the client, to characterize
the filter properties during operation with this water, or with water defined by the tester or the client.
2 Normative references
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 7-1, Pipe threads where pressure-tight joints are made on the threads — Part 1: Dimensions, tolerances
and designation
ISO 7005-1, Pipe flanges — Part 1: Steel flanges for industrial and general service piping systems
ISO 7005-2, Metallic flanges — Part 2: Cast iron flanges
ISO 9912-1:2004, Agricultural irrigation equipment — Filters for micro-irrigation — Part 1: Terms,
definitions and classification
3 Terms and definitions
For the purposes of this document, the terms and definitions in ISO 9912-1 and the following apply.
3.1
strainer filter
strainer
device containing one or more filter elements, such as a screen or a mesh, used for separating clogging
material from water flowing through the device by collecting it on the surface of the filter element or elements
[SOURCE: ISO 9912-1:2004, 2.8]
3.2
disc filter
filter in which the filter element is a disc filter element
Note 1 to entry: See also 3.4.
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ISO 9912-2:2013(E)

3.3
strainer filter element
filter element
component of a strainer filter consisting of a perforated plate, a screen, a mesh, or a combination of
these, intended to retain clogging materials larger than a specified size from the water flowing through
the component
[SOURCE: ISO 9912-1:2004, 2.25]
3.4
disc filter element
filter element
component of a filter composed of discs with grooved or textured faces arranged adjacent to the other
to form a stack
3.5
filter housing
component of a filter that houses or supports the filter element
[SOURCE: ISO 9912-1:2004, 2.34]
3.6
filter housing cover
removable cover permitting assembly, disassembly, inspection, and cleaning of the filter elements
3.7
drain valve
flush valve
valve normally installed at the bottom of a filter, intended for draining or flushing of contaminate from
the filter housing
3.8
nominal pressure
p
nom
numerical designation equal to the maximum working pressure specified by the manufacturer at which
a device will operate at a water temperature of 23 °C ± 3 °C
3.9
clean pressure drop
pressure drop in a clean filter, measured with a flow of clean water
3.10
safe maximum pressure drop
maximum allowable pressure difference, declared by the manufacturer, between inlet and outlet
pressures across a filter, when the filter element has become clogged to the extent of requiring cleaning
or replacement
3.11
critical pressure drop before failure
maximum allowable pressure difference, declared by the manufacturer, between inlet and outlet
pressures across each filtering element of the filter, which will not cause failure of the filter element
3.12
range of recommended flow rates
range of flow rates, declared by the manufacturer, for proper operation of a filter
3.13
nominal size
numerical designation used to refer to the size of the device end connection which is identical to the
numerical designation of the pipe or pipes to which the device is to be connected directly
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ISO 9912-2:2013(E)

3.14
aperture size
size, declared by the manufacturer, that expresses the ability of a filter to retain particles and
suspended matter
Note 1 to entry: The aperture size is expressed in microns.
3.15
filter connection length
overall length between the extremities of the connections of a filter, the face-to-face distance between
the connections, or the distance between centre-lines of the parallel inlet and outlet ports
3.16
contaminate
debris, suspended particles of organic or inorganic origin, or other contaminants removed from water
in the filtration process
[SOURCE: ISO 9912-1:2004, 2.9]
4 Marking
4.1 General
Each filter shall bear a readily visible, durable marking giving the particulars specified in 4.1.1 and 4.1.2.
4.1.1 Marking of filter housing
The marking of the filter housing shall include:
a) the name of manufacturer and/or registered trademark,
b) the model identification,
c) the nominal size,
d) the nominal pressure,
e) an arrow indicating the direction of water flow, and
f) the aperture size (optional marking, applicable when a filter is supplied with the filter element
already assembled).
The aperture size may be marked on an adhesive label affixed to the filter housing in a prominent position.
4.1.2 Marking of filter element
Th
...