ISO 14085-6:2015

INTERNATIONAL ISO
STANDARD 14085-6
First edition
2015-03-01
Aerospace series — Hydraulic filter
elements — Test methods —
Part 6:
Initial cleanliness level
Série aérospatiale — Eléments filtrants hydrauliques — Méthode
d’essais —
Partie 6: Niveau de propreté
Reference number
ISO 14085-6:2015(E)
©
ISO 2015

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ISO 14085-6:2015(E)

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ISO 14085-6:2015(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Summary of test method . 1
5 Materials and equipment . 1
6 Procedure. 2
7 Contaminant analysis . 3
7.1 Method of analysis . 3
7.2 Reporting of results . 3
8 Criterion for acceptance . 3
9 Identification statement . 3
Annex A (informative) Contaminant analysis methods . 4
Annex B (informative) Filter element cleanliness test data report form . 6
Bibliography . 7
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ISO 14085-6:2015(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 (see 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 (see 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.
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: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 20, Aircraft and space vehicles, Subcommittee
SC 10, Aerospace fluid systems and components.
ISO 14085 consists of the following parts, under the general title Aerospace series — Hydraulic Filter
elements — Test methods:
— Part 1: Test sequence
— Part 2: Conditioning
— Part 3: Filtration efficiency and retention capacity
— Part 4: Verification of collapse/burst pressure rating
— Part 5: Resistance to flow fatigue
— Part 6: Initial cleanliness level
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ISO 14085-6:2015(E)

Introduction
In aerospace hydraulic fluid power systems, power is transmitted and controlled through a liquid
under pressure. The liquid is both a lubricant and power-transmitting medium. The presence of solid
contaminant particles in the liquid interferes with the ability of the hydraulic fluid to lubricate and
causes wear and malfunction of the components. The extent of contamination in the fluid has a direct
bearing in the performance, reliability, and safety of the system, and needs to be controlled to levels that
are considered appropriate for the system concerned.
Filters are used to control the contamination level of the fluid by removing solid contaminant particles,
typically consisting of a filter element enclosed in a filter housing. The filter element is the porous device
that performs the actual process of filtration. The complete assembly is designated as a filter.
Hydraulic fluid circuits require high levels of cleanliness which are not to be degraded by the filter
element itself when installed into the circuit. This procedure defined a test method to determine the
initial cleanliness level of a new hydraulic filter element.
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INTERNATIONAL STANDARD ISO 14085-6:2015(E)
Aerospace series — Hydraulic filter elements — Test
methods —
Part 6:
Initial cleanliness level
1 Scope
This part of ISO 14085 defines a reference method for determining the level of cleanliness of new filter
elements for use in aircraft hydraulic systems, after production prior to shipment, or prior to installation
in the circuit.
It applies to filter elements used on systems requiring fluid cleanliness conditions defined in the
particular specification.
The tests data resulting from application of this part of ISO 14085 can be used to compare the cleanliness
of aerospace hydraulic filter elements.
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 3722, Hydraulic fluid power — Fluid sample containers — Qualifying and controlling cleaning methods
ISO 4405, Hydraulic fluid power — Fluid contamination — Determination of particulate contamination by
the gravimetric method
ISO 5598, Fluid power systems and components — Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 5598 and the following apply.
3.1
extraction liquid
test liquid extracted from the filter housing in which the filter element is installed during agitation
4 Summary of test method
The test consists of inserting the test filter element into a pre-cleaned filter housing and adding a solvent.
The filter assembly shall then be agitated to flush and collect built-in contaminant from a new filter
element. Multiple extraction liquid samples shall be used to achieve maximum contaminant removal.
The collected contaminant shall then be analysed using particle counting or gravimetric techniques,
and the amount of contamination shall be reported.
5 Materials and equipment
2
5.1 Test liquid: Use a suitable solvent with a viscosity less than 5 mm /s at test temperature. The test
liquid shall be compatible with all materials used in the filter, as well as with the functional liquid of the
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ISO 14085-6:2015(E)

system in which the filter will be applied. The test liquid should be compatible with all test apparatus,
including seals and filters, and filtered to the agreed initial cleanliness level.
The supplier and purchaser should agree upon the test liquid to be used in the collection process, and its
required initial cleanliness level, prior to the test. The contamination contained in the entire test liquid
volume to be used shall be less than 1 % of the presumed or allowable contamination level of the filter
element or class 1 per ISO 11218, so that it does not significantly influence the measured contamination
level. If the expected contamination level is unknown, a maximum contamination level of three particles
larger than or equal to 6 µm(c), or equivalent, per millilitre of container volume is considered appropriate.
WARNING — Exercise care when using test liquids with low flash points.
5.2 Test filter housing: Use a test filter housing (recommended by the filter manufacturer). Preferably
the housing type to be used in service can be utilized
...