ISO 12345:2021

INTERNATIONAL ISO
STANDARD 12345
Third edition
Diesel engines — Cleanliness
assessment of fuel injection
equipment
Moteurs diesels — Évaluation de propreté pour équipement
d'injection de combustible
PROOF/ÉPREUVE
Reference number
ISO 12345:2021(E)
©
ISO 2021

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ISO 12345:2021(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland
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ISO 12345:2021(E)

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Test apparatus . 2
4.1 Pressure source . 2
4.1.1 Fuel injection pump test bench . 2
4.1.2 Hand-lever-operated testing and setting apparatus . 2
4.1.3 High-pressure pulsating flow rig . 2
4.1.4 Verification low-pressure pump . 2
4.1.5 Verification high-pressure delivery pump . 3
4.1.6 Pressure vessel . 3
4.1.7 Flushing pump . 3
4.2 Verification high-pressure pipe assembly . 3
4.3 Verification test injector. 3
4.4 Collecting vessel . 3
4.5 Verification rail . 3
4.6 Equipment for contamination measurement . 3
4.6.1 Gravimetric analysis apparatus. 4
4.6.2 Microscopic analysis apparatus . 5
4.7 Test fluid . 5
4.7.1 Calibration fluid . 5
4.7.2 Solvent, aliphatic hydrocarbon . 5
4.7.3 Water, de-mineralised . 6
4.8 Clean-up filter . 6
4.9 Pressure gauge . 6
5 Procedure. 6
5.1 General . 6
5.2 High-pressure supply pumps (common rail fuel injection system) . 7
5.2.1 General. 7
5.2.2 Dynamic test with the test pump running . 7
5.2.3 Flushing test at low speed with the test pump running by hand . 8
5.3 Unit injectors . 8
5.3.1 General. 8
5.3.2 Equipment set up and verification of cleanliness . 8
5.3.3 Test procedure . 9
5.4 Fuel injection pumps . 9
5.4.1 General. 9
5.4.2 Equipment set up and verification of cleanliness . 9
5.4.3 Test procedure . 9
5.5 CR fuel injectors .10
5.5.1 General.10
5.5.2 Dynamic test .10
5.5.3 Continuous high-pressure flow test .11
5.6 Fuel injectors (nozzle holder assemblies) .12
5.6.1 General.12
5.6.2 Dynamic test .12
5.6.3 Syringe test (washing out injectors) .12
5.7 High-pressure fuel injection pipes .13
5.7.1 General.13
5.7.2 Dynamic test .13
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ISO 12345:2021(E)

5.7.3 High-pressure flushing test .14
5.7.4 Syringe (solvent dispenser) or hand flush test .14
5.8 Rails .15
5.8.1 General.15
5.8.2 Pressure vessel flushing test.15
5.8.3 Low-pressure flushing test .16
5.8.4 Syringe or hand flush test .18
5.9 Low-pressure systems .18
5.9.1 General.18
5.9.2 Equipment set up and verification of cleanliness .18
5.9.3 Test procedure .19
6 Sample analysis .19
6.1 General .19
6.2 Gravimetric analysis .19
6.3 Particle size distribution .19
7 Reporting of the inspection results .20
8 Designation of cleanliness requirements .20
Annex A (normative) Typical test equipment for measuring fuel injection equipment
cleanliness .21
Annex B (normative) Rail low-pressure flushing test .28
Annex C (normative) Procedure for verifying test equipment initial cleanliness .30
Annex D (normative) Determination of flushing parameters for rail pressure vessel
flushing test .33
Annex E (informative) Comparison of CCC (component cleanliness code, ISO 16232) to
FIECC (fuel injection equipment cleanliness code, ISO 12345:2013) .35
Bibliography .37
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ISO 12345:2021(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 of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC22, Road vehicles, Subcommittee SC 34,
Propulsion, powertrain, and powertrain fluids.
This third edition cancels and replaces the second edition (ISO 12345:2013), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— the reporting of the inspection results (Clause 7) changed from FIECC (fuel injection equipment
cleanliness code, as in ISO 12345:2013) to CCC (component cleanliness code, as in ISO 16232).
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
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ISO 12345:2021(E)

Introduction
Modern fuel injection systems contain many closely controlled clearances and rely on the fuel-flowing
characteristics of small orifices; thus they require the close control of sources of contamination in
order to maintain the operational performance demanded of them throughout their design life. To this
end, such systems are designed with integral fuel-filtration equipment, which reduces the amount of
potentially damaging debris that could enter the system from external sources.
However, contamination of the fuel injection system can also occur internally, from system use or
wear, from equipment servicing, or as a result of the original supplier’s manufacturing and assembly
processes. The focus of this document is on the latter source of contamination, and is thus concerned
with the assessment of the cleanliness of the fuel injection equipment as originally supplied to the
engine manufacturer.
Fuel injection systems comprise a number of components. Traditional systems contain low-pressure
elements (fuel tank, pipe work, filters, lift pump, etc.), a fuel injection pump, high-pressure pipes and
fuel injectors, located within the engine cylinder head.
During the preparation of this document, the importance of care in the handling and measurement
of contamination samples was clearly recognized. Moreover, the low levels of contaminant with fuel
injection equipment make this a particularly difficult task. For this document to be used meaningfully
- as an indicator of component cleanliness and a driver towards higher-quality standards - extreme
attention to detail is recommended for the user. Therefore, verification requirements for the used test
equipment are emphasized in detail.
It is not always clear what level and type of cleanliness would be beneficial for improved performance
and life on a cost-effective basis. The actual quantitative levels can only be set in relation to other
parameters, agreed between the manufacturer, supplier and user. This document provides a set of
procedures for evaluating the cleanliness of fuel-injection equipment and a framework for a common
measurement and reporting.
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INTERNATIONAL STANDARD ISO 12345:2021(E)
Diesel engines — Cleanliness assessment of fuel injection
equipment
1 Scope
This document specifies cleanliness assessment procedures for evaluating the amount of debris found
within the clean side of diesel fuel injection assemblies, which could lead to a reduction in the system’s
operational effectiveness.
While other International Standards, e.g. ISO 16232, relate to cleanliness of components used in road
vehicle fluid circuits, this document is focused on diesel fuel injection assemblies as supplied to diesel
engine manufacturers or the service market.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 4008-1, Road vehicles — Fuel injection pump testing — Part 1: Dynamic conditions
ISO 4113, Road vehicles — Calibration fluids for diesel injection equipment
ISO 4788, Laboratory glassware — Graduated measuring cylinders
ISO 7440-1, Road vehicles — Fuel injection equipment testing — Part 1: Calibrating nozzle and holder
assemblies
ISO 8535-1, Diesel engines — Steel tubes for high-pressure fuel injection pipes — Part 1: Requirements for
seamless cold-drawn single-wall tubes
ISO 8984-1, Diesel engines — Testing of fuel injectors — Part 1: Hand-lever-operated testing and setting
apparatus
ISO 14644-1, Cleanrooms and associated controlled environments — Part 1: Classification of air cleanliness
by particle concentration
ISO 16232:2018, Road vehicles — Cleanliness of components and systems
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 16232 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
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ISO 12345:2021(E)

3.1
Reynolds number
Re
dimensionless parameter expressing the ratio between the inertia and viscous forces in a flowing fluid,
given by the formula
Ul×
R =
e
v
where,
R is the Reynolds number (Re);
e
U is the mean axial fluid velocity across the defined area, expressed in millimetres per seconds;
l is the characteristic dimension of the system over which the flow occurs, expressed in millimetres;
 [for pipes l = d (pipe bore diameter)]
ν is the kinematic viscosity of the fluid, expressed in square millimetres per second (centistokes).
4 Test apparatus
Typical test equipment recommended for measuring fuel-injection equipment cleanliness is described
in Annex A. In 4.1 to 4.9 are details of specific apparatus that shall be used, unless a suitable alternative
can be demonstrated.
4.1 Pressure source
Pressure source is test dependent as described in 4.1.1 to 4.1.7.
4.1.1 Fuel injection pump test bench
A test bench as specified in ISO 4008-1 with a single cylinder pump or one cylinder of an inline pump.
4.1.2 Hand-lever-operated testing and setting apparatus
A testing apparatus as described in ISO 8984-1.
4.1.3 High-pressure pulsating flow rig
A pressuse source capable of achieving:
a) a flow rate which will generate a turbulent flow in the pipes (Re > 4 000) for a period of 30 s ± 1 s,
while pulsating the flow between zero and this value at a frequency of 0,2 Hz to 1 Hz, followed by
b) a flush at 1,4 MPa ± 0,1 MPa constant pressure for 15 s ± 1 s.
4.1.4 Verification low-pressure pump
A plunger or diaphragm-type pump, having a flow rate of approximately twice the rated value for the
component under test at a pressure of at least 2 MPa. The verification low-pressure pump has to be
cleaned to the cleanliness level CL in accordance with Annex C. It has to be carefully stored with a
proper cover in a clean environment.
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ISO 12345:2021(E)

4.1.5 Verification high-pressure delivery pump
For testing of high-pressure pipes with open ends, having a flow rate capable of generating a Reynolds
number in the pipes of Re > 4 000. A pressure capability of 3 MPa ± 0,1 MPa is considered suitable.
The verification high-pressure delivery pump shall be cleaned to the cleanliness level CL in accordance
with Annex C. It shall be carefully stored with a proper cover in a clean environment.
4.1.6 Pressure vessel
Used as pressure source. It shall be able to supply a testing pressure of at least 0,5 Mpa (= 5 bar) and to
produce a turbulent flow inside the rail (recommended flow rate at least 2,5 l/min).
4.1.7 Flushing pump
Used for testing of rails with open ends, having a flow rate of at least 0,1 l/min. For this pump a pressure
capability of up to 0,1 MPa ± 0,01 MPa is considered suitable.
4.2 Verification high-pressure pipe assembly
600 mm long of tube ISO 8535-1 S-2-6-2 1 P 0, as specified in ISO 8535-1, and suitable for the component
under test.
Stainless steel tubing should be used because of its resistance to rust and corrosion contamination. The
verification high-pressure pipe assembly shall be cleaned to the cleanliness level CL in accordance with
Annex C. It shall be carefully stored with proper cover in a clean environment.
4.3 Verification test injector
In accordance with ISO 7440-1, fitted with an orifice plate of orifice diameter 2,5 mm. The inlet edge
filter shall be removed to improve the particle passage.
+0,3
The nozzle opening pressure shall be set to 20, 7 MPa.
   0
4.4 Collecting vessel
It may be necessary for collecting test fluid downstream from the tested equipment at a flow rate
different from that passing through the particle counter, the contamination monitor or the membrane
filter.
The collecting vessel may be used for storing test fluid before transfer fluid samples to laboratory
for analysis. A cylindrical stainless steel or glass reservoir with a conical bottom should be used for
facilitating further particle collection.
4.5 Verification rail
Needed to establish the cleanliness level CL for the whole rail cleanliness test apparatus.
For the verification the verification rail shall be cleaned to the blank value in accordance with Annex C
and carefully stored with proper cover in a clean environment.
4.6 Equipment for contamination measurement
Involving the application of two specific techniques for evaluating the level of contamination:
— gravimetric analysis;
— microscopic examination.
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ISO 12345:2021(E)

Each requires the specific laboratory apparatus as given in 4.6.1 and 4.6.2.
4.6.1 Gravimetric analysis apparatus
See ISO 16232:2018, 9.2.2.
4.6.1.1 Non-ventilated drying oven
Capable of maintaining a temperature of 80 °C ± 2 °C.
4.6.1.2 Filter holder
Comprising:
— glass funnel of at least 300 ml capacity with suitably calibrated volumetric graduations (e.g.
25 ml ± 2 ml),
— suitable cover for the funnel (e.g. petri dish),
— clamping device,
— suitable base to support the membrane filter, and
— a means of dissipating any static electricity generated during the filtering process.
4.6.1.3 Vacuum flask
Suitable for the filter holder and of capacity enabling it to hold the entire volume of sample liquid
without refilling.
4.6.1.4 Vacuum device
Able to generate a vacuum of 86,6 kPa (gauge).
4.6.1.5 Solvent dispenser (syringe)
A pressurized vessel that discharges solvent through an in-line filter membrane with a pore size of not
greater than 1 µm.
4.6.1.6 Tweezers
Flat-bladed (non-serrated, blunt tips), and of stainless steel.
4.6.1.7 Graduated cylinders
For measuring out the volume of test liquid, the accuracy of which shall be in accordance with ISO 4788,
unless a suitable alternative can be demonstrated (with a minimum accuracy of ±2 %).
4.6.1.8 Sample bottles
Of 250 ml nominal capacity, preferably flat-bottomed and wide-mouthed, with a screw cap containing a
suitable internal polymeric seal.
4.6.1.9 Plastic film
0,05 mm thick × 50 mm × 50 mm, placed between the sample bottle cap and neck if the cap does not
have an internal seal. The film shall be compatible with both the cleaning and sample liquids.
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ISO 12345:2021(E)

4.6.1.10 Filter membranes
Preferred 25 mm or 47 mm in diameter, white, without grids, and compatible with the fluid to be
analysed and with the rinsing chemicals. Reference membranes shall have a recommended pore size of
between 5 µm to 8 µm. The pore size used shall be stated.
4.6.1.11 Petri dishes
Of glass and 150 mm diameter.
4.6.1.12 Analytical balance
Of at least 0,05 mg accuracy.
4.6.1.13 Alpha-ray ionizer
To be used to prevent collection of dust during the weighing operation placed under the balance scale
incorporating the filter and projecting from beneath it.
4.6.1.14 Air dryer
4.6.1.15 Collecting vessel
A vessel with a vacuum device connecting, to be used to collect test fluid.
4.6.2 Microscopic analysis apparatus
See ISO 16232:2018, 9.2.3 and 9.3.1.
4.6.2.1 Filter membrane
Compatible with the sample liquid and any solvents or chemicals used in the processes. Normally,
the membrane shall be of 25 mm or 47 mm diameter
...