Diesel engines -- Fuel filters -- Method for evaluating fuel/water separation efficiency

ISO 16332:2018 specifies a fuel/water separator comparison test under defined and simplified laboratory conditions. This test is intended for pressure side fuel/water separators as well as for suction side fuel/water separators. Pressure side fuel/water separators are tested with fine droplets and suction side filters are tested with coarse droplets using the same test rig layout. The rated flow (in litres per hour) is intended for the range between 50 l/h and 1 500 l/h. By agreement between customer and fuel/water separator manufacturer, and with some modifications, the procedures can be used for fuel/water separators with higher or lower flow rates.

Moteurs diesel -- Filtres à carburant -- Méthode d'évaluation de l'efficacité de séparation carburant-eau

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Status
Published
Publication Date
04-Apr-2018
Current Stage
6060 - International Standard published
Start Date
06-Mar-2018
Completion Date
05-Apr-2018
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INTERNATIONAL ISO
STANDARD 16332
First edition
2018-04
Diesel engines — Fuel filters —
Method for evaluating fuel/water
separation efficiency
Moteurs diesel — Filtres à carburant — Méthode d'évaluation de
l'efficacité de séparation carburant-eau
Reference number
ISO 16332:2018(E)
ISO 2018
---------------------- Page: 1 ----------------------
ISO 16332:2018(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2018

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

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below or ISO’s member body in the country of the requester.
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Published in Switzerland
ii © ISO 2018 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 16332:2018(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Symbols .......................................................................................................................................................................................................................... 3

5 Test equipment....................................................................................................................................................................................................... 3

5.1 Test fluids ..................................................................................................................................................................................................... 3

5.1.1 Test fuels ................................................................................................................................................................................. 3

5.1.2 Test water ...................................................................... ......................................................................................................... 4

5.2 Laboratory equipment ..................................................................................................................................................................... 5

5.2.1 General...................................................................................................................................................................................... 5

5.2.2 Sampling bottles and glassware ......................................................................................................................... 5

5.2.3 Water detection system ............................................................................................................................................. 5

5.2.4 Equipment for determination of IFT .............................................................................................................. 5

5.3 Test stand ..................................................................................................................................................................................................... 5

5.3.1 General...................................................................................................................................................................................... 5

5.3.2 Fuel/water separator test circuit ...................................................................................................................... 5

6 Test conditions ....................................................................................................................................................................................................10

6.1 Volume of test fuel V ....................................................................................................................................................................10

6.2 Test fuel temperature T ...............................................................................................................................................................10

6.3 Test flow rate Q ................................................................................................................................................................................10

6.4 Upstream undissolved water concentration c ................................................................................................10

U,up

6.4.1 General...................................................................................................................................................................................10

6.4.2 Water injection flow rate Q ............................................................................................................................11

6.5 Back pressure ........................................................................................................................................................................................11

6.6 Sampling ....................................................................................................................................................................................................11

6.7 Droplet size distribution DSD .................................................................................................................................................11

6.8 Test duration t ..............................................................................................................................................................................11

test

7 Accuracy of measuring instruments and test conditions ........................................................................................11

8 Validation procedures..................................................................................................................................................................................12

8.1 General ........................................................................................................................................................................................................12

8.2 Water detection system ................................................................................................................................................................12

8.2.1 Inline water concentration measurement device (optional) .................................................12

8.2.2 Karl Fischer titration sytem ................................................................................................................................12

8.3 Emulsifying device ............................................................................................................................................................................13

8.4 Filter test circuit and water injection system ............................................................................................................13

8.4.1 General...................................................................................................................................................................................13

8.4.2 Validation preparation .............................................................................................................................................13

8.4.3 Preconditioning cycle ...............................................................................................................................................14

8.4.4 Validation cycle ..............................................................................................................................................................14

9 Simplified laboratory test ........................................................................................................................................................................15

9.1 Test procedure ......................................................................................................................................................................................15

9.1.1 General...................................................................................................................................................................................15

9.1.2 Pre-test preparation...................................................................................................................................................15

9.1.3 Preconditioning cycle ...............................................................................................................................................15

9.1.4 Efficiency measurement .........................................................................................................................................16

9.2 Calculation of water separation efficiency and reporting of test results ...........................................17

10 Test report ................................................................................................................................................................................................................18

Annex A (normative) Fuel treatment to obtain test fuel F2 .......................................................................................................19

© ISO 2018 – All rights reserved iii
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ISO 16332:2018(E)

Annex B (normative) Water emulsifying device ....................................................................................................................................21

Annex C (normative) Conditions and parameters for the determination of the interfacial

tension according to ISO 9101, drop volume method .................................................................................................28

Annex D (normative) Validation of the sampling procedure for Karl Fischer titration and

centrifuge ..................................................................................................................................................................................................................29

Annex E (normative) Determination of the concentration c of dissolved water in saturated fuel .30

Annex F (informative) Typical fuel/water separator test report .........................................................................................31

Annex G (informative) Report round robin ................................................................................................................................................33

Annex H (informative) Effect of KF-titration on the precision of water separation efficiency

measurements .....................................................................................................................................................................................................42

Bibliography .............................................................................................................................................................................................................................44

iv © ISO 2018 – All rights reserved
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ISO 16332:2018(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 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 the following

URL: www .iso .org/iso/foreword .html

This document was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 34,

Vehicle propulsion, powertrain, and powertrain fluids.

This document cancels and replaces the first edition ISO/TS 16332:2006 which has been technically

revised. The main changes compared to the previous edition are as follows:
— test fuel definition;
— change of IFT measurement standard and interface age;
— droplet size distribution;
— test duration;
— additional preconditioning cycle; and

— validation of test procedure by conduction of two round robin tests (see Annex G).

© ISO 2018 – All rights reserved v
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ISO 16332:2018(E)
Introduction

Modern fuel injection systems, installed in passenger cars, as well as in heavy duty or off-road

applications, require high and stable separation efficiencies for all insoluble contaminants in the fuel to

ensure a prolonged life. Beside solid contamination, undissolved water, in finely or coarsely emulsified

form, can also reduce the lifetime of injection systems. Suitable fuel/water separators, having a high

level water separation efficiency, are an absolute necessity for system longevity.

Factors found to affect the separation efficiency of undissolved water in the field are mainly due to the

fuel quality, which can differ widely in different regions of the world and which can also differ when

biogenic components are added to the fuel. Additionally the separation efficiency is strongly influenced

by fuel composition.
Separation efficiency tests can be applied mainly for two purposes:
— To evaluate the field performance of a fuel/water separator

To evaluate the performance of a fuel/water separator close to field conditions, the usage of

commercially, untreated fuel as test fluid is necessary.
— To compare fuel/water separators under repeatable test conditions

For a fuel/water separator comparison in the laboratory, fuel conditioning is necessary to achieve

constant and repeatable test conditions. Water separation efficiency results obtained with treated

fuel can be significantly different from those with commercially available, untreated fuel.

Tests performed with new fuel/water separators can lead to considerably higher water separation

efficiencies.

NOTE Ageing of the fuel/water separator due to operational conditions can strongly affect the water

separation function of a fuel/water separator. To test a fuel/water separator in an “end of life” state, it can be aged

in advance. It is proposed to do this by a standardized ageing procedure, to get comparable “end of life” states.

However, it is not a part of this document nor any other ISO standard. This procedure may be explored in future.

vi © ISO 2018 – All rights reserved
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INTERNATIONAL STANDARD ISO 16332:2018(E)
Diesel engines — Fuel filters — Method for evaluating fuel/
water separation efficiency
1 Scope

This document specifies a fuel/water separator comparison test under defined and simplified

laboratory conditions.

This test is intended for pressure side fuel/water separators as well as for suction side fuel/water

separators. Pressure side fuel/water separators are tested with fine droplets and suction side filters

are tested with coarse droplets using the same test rig layout.

The rated flow (in litres per hour) is intended for the range between 50 l/h and 1 500 l/h. By agreement

between customer and fuel/water separator manufacturer, and with some modifications, the

procedures can be used for fuel/water separators with higher or lower flow rates.

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 1219-1, Fluid power systems and components — Graphical symbols and circuit diagrams — Part 1:

Graphical symbols for conventional use and data-processing applications

ISO 9101, Surface active agents — Determination of interfacial tension — Drop volume method

ISO 6889, Surface active agents — Determination of interfacial tension by drawing up liquid films

ISO 12937, Petroleum products — Determination of water — Coulometric Karl Fischer titration method

ISO 13320, Particle size analysis — Laser diffraction methods

ASTM D4176–04 (2009), Standard Test Method for Free Water and Particulate Contamination in Distillate

Fuels (Visual Inspection Procedures)
3 Terms and definitions
For the purpose of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— IEC Electropedia: available at http: //www .electropedia .org/
— ISO Online browsing platform: available at https: //www .iso .org/obp
3.1
interfacial tension
IFT

work which is required to increase the interface of the liquid by one surface area unit

Note 1 to entry: In case of additivated liquids, the IFT-value has a significant time dependency. Therefore the

default value for the interface age within ISO 16332-usage is defined at 10 s.

Note 2 to entry: The conditions and parameters for determination of IFT by the drop volume method according

to ISO 9101 are defined in Annex C.
© ISO 2018 – All rights reserved 1
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ISO 16332:2018(E)

Note 3 to entry: Interfacial tension is equivalent to the specific interfacial energy and is expressed in Millinewtons

per meter (mN/m). Alternative methods to determine the IFT (at 10 s) can be used, as long as the comparability

to ISO 9101 is ensured.
3.2
droplet size distribution
DSD
percentage of the droplet population in different size ranges
Note 1 to entry: For further information, see B.3.
3.3
water concentration at the saturation level of dissolved water

concentration of water in water saturated test fuel with the IFT adjusted by Monoolein

Note 1 to entry: The determination of c is defined in Annex E.
3.4
base water concentration

concentration of water in the test fuel, determined after the preconditioning cycle

Note 1 to entry: See 8.4.3 or 9.1.3.

Note 2 to entry: In case one of the c -values [determined in 9.1.4 c) and d)] is lower than c (determined in

T,down,i B
9.1.3) take the lowest value as c .
3.5
undissolved water concentration

concentration of free water, that is concentration above base water concentration

3.6
total water concentration
summation of base water concentration and undissolved water concentration
Note 1 to entry: c = c + c .
T U B
3.7
sample index
integer from 1 to n, where n equals the number of samples
3.8
instantaneous water separation efficiency
water separation efficiency, at test time t
3.9
average water separation efficiency

average water separation efficiency, calculated based on the average downstream water concentration

Note 1 to entry: Calculation according to 9.2 e).
2 © ISO 2018 – All rights reserved
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ISO 16332:2018(E)
3.10
calibration flow rate

fuel flow rate, which is adjusted for calibration purpose of the emulsifying device

Note 1 to entry: The calibration procedure is defined in B.4.
3.11
sampling point index
< up> reference to the upstream sampling point
3.12
sampling point index
< down> reference to the downstream sampling point
4 Symbols

Graphical symbols used in this document for fluid power system components are in accordance with

ISO 1219-1.
5 Test equipment
5.1 Test fluids
5.1.1 Test fuels

For the validation and for each filter test one of the following three kinds of fuels can be used as test fuel.

— F1 Unmodified service station fuel
— F2 Standard test fuels: Fuels, treated according to Annex A
Test fuel F2.1: High IFT test fuel

— IFT (10 s): 22 ± 2 mN/m, according to ISO 9101, parameterized according to Annex C

Alternatively IFT (60 s): 20 ± 2 mN/m, according to ISO 9101 or ISO 6889.
— Separability (ASTM D 1401): To be reported
Test fuel F2.2: Low IFT test fuel
— IFT (10 s): 13 ± 2 mN/m, according to ISO 9101
Alternatively IFT (60 s): 11 ± 2 mN/m, according to ISO 9101 or ISO 6889.
To describe the test fuel used, the following parameters shall be determined:
— IFT(10 s) and IFT(60 s);
— separability (ASTM D 1401);
— water saturation level according to Annex E;
— bio diesel content (optional);
— density (optional);
— kinematic viscosity (optional);
— CFPP (optional).
© ISO 2018 – All rights reserved 3
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ISO 16332:2018(E)
Key
t interface age (s)
IFT interfacial tension (mN/m)
1 F1 (B0 Premium field fuel)
2 F1 (B7 Premium field fuel)
3 F 2.1
4 F 2.2

Figure 1 — Time dependency of interfacial tension [IFT(t)] for F1 fuels, F2.1 and F2.2 fuel

Figure 1 is showing two typical IFT(t)-curves for commercially available F1 fuels and for F 2.1 and

F 2.2 fuel.

Depending on the F1-quality, the brand/product specific slope in IFT(t) does not allow to deduct the F1

IFT(10 s) value based on the measured F1 IFT(60 s) value.

The Monoolein specific slope in IFT(t) of F2 fuel is stable and reproducible, therefore the deduction of

the F2 IFT(10 s)value - based on the measured F2 IFT(60 s) value - is valid and proven.

The test fuel shall be stored in a sealed container, protected from humidity, dust and light.

For each filter test fresh fuel shall be used. In the case of F2 fuel, fresh fuel can be achieved by retreating

used fuel according to Annex A.
5.1.2 Test water

Clean, distilled or deionised water, with a surface tension of 70 mN/m -72 mN/m, measured at

20 °C ± 1,5 °C.
4 © ISO 2018 – All rights reserved
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ISO 16332:2018(E)
5.2 Laboratory equipment
5.2.1 General

All laboratory equipment and glassware, required to determine the water concentration, shall be

according to ISO 12937.
5.2.2 Sampling bottles and glassware

100 ml sampling bottles carefully cleaned and dried, free of any residuals from the cleaning process.

5.2.3 Water detection system
5.2.3.1 Karl Fischer (KF) titrator
As commercially available.

For biodiesel and biodiesel containing fuels the direct Karl Fischer method is recommended.

Humidity is probably the largest source of error during the titration process. Special precautions shall

be taken during setup and testing. The amount of water per sample should be ≥50 µg to reach a good

relation between titration time and accuracy.
5.2.3.2 Centrifuge

For higher water concentration as specified in 6.4.1, 20 000 ppm water concentration, a centrifuge

according to D.2 can be used. The measurement accuracy according to Table 1 shall be confirmed.

5.2.4 Equipment for determination of IFT

The equipment for determination of the interfacial tension shall be according to ISO 9101.

5.3 Test stand
5.3.1 General

The test stand, shown diagrammatically in Figure 2, shall comprise a fuel/water separator test circuit

as described in 5.3.2.
All parts in contact with fuel, should be made of stainless steel.
5.3.2 Fuel/water separator test circuit
5.3.2.1 Fuel sump (1)

The container with a conical bottom should be made of stainless steel. The fuel outlet shall be located

at the lowest point of bottom. The container shall be able to contain the volume as specified in 6.1. The

fuel sump shall be covered with a non-transparent cover to protect the fuel from light. The fuel sump

shall contain a suitable device to maintain homogeneity of its content.
5.3.2.2 Water sump (6)

The container should be made of stainless steel or corrosion resistant material with appropriate volume.

NOTE Instead of the container, a continuous water supply unit can be used.
© ISO 2018 – All rights reserved 5
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ISO 16332:2018(E)
5.3.2.3 Heat exchanger (3)

The heat exchanger shall be able to maintain the test fuel temperature T within the tolerances given in

Table 1.

Alternative to the position of the heat exchanger depicted in Figure 2, the heat exchanger can as well be

positioned downstream the back pressure gauge (16).
5.3.2.4 Test pump (2)

A pump type shall be chosen, which does not exhibit pressure pulsation with an amplitude greater than

10 % of the average pressure at the inlet of the water emulsifying device.
5.3.2.5 Water injection pump (7)

The pump type shall be adjustable to enable a water concentration in the test circuit between 1 500 ppm

and 20 000 ppm over the complete flow rate of test fluid.
5.3.2.6 Fuel flow meter (5a)

The equipment shall be suitable for the complete range of the flow rate of test fluid with an accuracy as

specified in Table 1.
5.3.2.7 Water flow meter (5b)

The equipment shall be suitable for the complete range of the required injection range with an accuracy

as specified in Table 1.
5.3.2.8 Injection device (8)

The concept shall allow a continuous water injection. The resulting DSD at the injection point shall be

validated. The validation criterion is defined by:
d shall be greater or equal to the d value chosen according to 6.7
3,50 3,50
5.3.2.9 Water emulsifying device (9)

The concept shall be able to generate a DSD as specified according to 6.7. Jet emulsification - as described

in Annex B is recommended to be applied.

For each combination of emulsifying device, test fuel, flow rate and temperature a calibration curve is

mandatory

In case the jet emulsification concept in accordance with Annex B is used, the calibration procedure is

described in B.4.
5.3.2.10 Operating pressure gauge (10)

The operating pressure is defined at the up-stream side of the test fuel water separator (14). The

required accuracy is specified in Table 1.
5.3.2.11 Differential pressure gauges (11)
The required accuracy is specified in Table 1.
5.3.2.12 Upstream sampling point (12)
The upstream sampling point shall be designed as illustrated in Figure 4.
6 © ISO 2018 – All rights reserved
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ISO 16332:2018(E)
5.3.2.13 Temperature indicator (13)
The required accuracy is specified in Table 1.
5.3.2.14 Water drainage system (15)

Realized as a graduated and transparent collector (e.g. laboratory measuring cylinder), located directly

below the test fuel/water separator (14). The internal diameter of the connecting pipe between the test

fuel/water separator (14) and the graduated water drainage system (15) shall be of at least 10 mm an

unconstrained removal of water. It shall be realized with pressure-tight fittings. The collector volume

shall be drainable at its lowest point.

The collector volume shall be adjusted to the total amount of water injected, with a maximum of 5 % of

the volume of test fuel V (according to 6.1).

In case the collected amount of water is reaching 80 % of the collector volume, the water shall be drained

out of the collector within approx. 1 min. The collector outlet valve shall be adjusted adequately. Care

should be taken, not to take samples during or immediately after the water draining.

5.3.2.15 Back pressure gauge (16)
For determination of back pressure with an accuracy as specified in Table 1.
5.3.2.16 Back pressure control valve (17) (optional equipment)

The backpressure control valve is to ease test fuel/water separator venting, to adjus

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