ﺍﻟﻌﺭﺒﻴﺔ ﺍﻟﺨﻠﻴﺞ ﻟﺩﻭل ﺍﻟﺘﻌﺎﻭﻥ ﻤﺠﻠﺱ ﻟﺩﻭل ﺍﻟﺘﻘﻴﻴﺱ  ﻫﻴﺌﺔ 
GCC STANDARDIZATION ORGANIZATION (GSO) 
 
 
 
 
 
 ﻤﺸﺭﻭﻉ : ﻨﻬﺎﺌﻲ  
 
   
GSO2/FDS/ ISO 4020:2011 
ISO 4020:2001 
 
 
 
 
 ﺍﻟﻁﺭﻕ ﻤﺭﻜﺒﺎﺕ – ﺍﻟﺩﻴﺯل ﻟﻤﺤﺭﻜﺎﺕ  ﺍﻟﻭﻗﻭﺩ ﻤﺭﺸﺤﺎﺕ–  ﺍﻻﺨﺘﺒﺎﺭ  ﻁﺭﻕ   
  
Road vehicles – Fuel filters for diesel engines – Test methods  
 
 
 
 إﻋﺪاد 
 ﺍﻟﻤﺭﻜﺒﺎﺕ  ﻤﻭﺍﺼﻔﺎﺕ  ﻟﻘﻁﺎﻉ ﺍﻟﻔﺭﻋﻴﺔ  ﺍﻟﺨﻠﻴﺠﻴﺔ  ﺍﻟﻔﻨﻴﺔ ﻭﺍﻹﻁﺎﺭﺍﺕﺍﻟﻠﺠﻨﺔ    
    
 ﻟﺫﻟﻙ ﺒﺸﺄﻨﻬﺎ، ﻭﺍﻟﻤﻼﺤﻅﺎﺕ  ﺍﻟﺭﺃﻱ ﻹﺒﺩﺍﺀ ﺘﻭﺯﻴﻌﻬﺎ  ﺘﻡ ﺨﻠﻴﺠﻴﺔ ﻗﻴﺎﺴﻴﺔ ﻟﻤﻭﺍﺼﻔﺔ  ﻤﺸﺭﻭﻉ  ﺍﻟﻭﺜﻴﻘﺔ ﻫﺫﻩ
ﺨ ﻗﻴﺎﺴﻴﺔ ﻜﻤﻭﺍﺼﻔﺔ  ﺇﻟﻴﻬﺎ ﺍﻟﺭﺠﻭﻉ  ﻴﺠﻭﺯ ﻭﻻ ﻭﺍﻟﺘﺒﺩﻴل،  ﻟﻠﺘﻐﻴﻴﺭ ﻋﺭﻀﺔ ﻓﺈﻨﻬﺎ  ﻤﻥ ﺍﻋﺘﻤﺎﺩﻫﺎ  ﺒﻌﺩ ﺇﻻ ﻠﻴﺠﻴﺔ
ﺍﻟﺨﻠﻴﺠﻴﺔ  ﺍﻟﻬﻴﺌﺔ ﺇﺩﺍﺭﺓ ﻤﺠﻠﺱ. 
  ﺁﻭ ﺇﺱ ﺠﻲ/ ﺁﻴﺯﻭ٠٢٠٤ : ١١٠٢  ﻗﻴ ﺧﻠﻴﺠﻴﺔﻣﻮاﺻﻔﺔ  ﺎﺳﻴﺔ
GSO STANDARD GSO/ISO 4020:2011  
 
1 ﺘﻘﺩﻴﻡ  
 ﺍﻷﺠﻬﺯﺓ  ﻋﻀﻭﻴﺘﻬﺎ  ﻓﻲ ﺘﻀﻡ ﺇﻗﻠﻴﻤﻴﺔ ﻫﻴﺌﺔ ﺍﻟﻌﺭﺒﻴﺔ ﺍﻟﺨﻠﻴﺞ ﻟﺩﻭل ﺍﻟﺘﻌﺎﻭﻥ ﻤﺠﻠﺱ ﻟﺩﻭل ﺍﻟﺘﻘﻴﻴﺱ ﻫﻴﺌﺔ
 ﺍﻟﻘﻴﺎﺴﻴﺔ ﺍﻟﻤﻭﺍﺼﻔﺎﺕ  ﺇﻋﺩﺍﺩ ﺍﻟﻬﻴﺌﺔ ﻤﻬﺎﻡ ﻭﻤﻥ ، ﺍﻟﻌﺭﺒﻴﺔ ﺍﻟﺨﻠﻴﺞ ﺩﻭل ﻓﻲ ﻭﺍﻟﻤﻘﺎﻴﻴﺱ  ﻟﻠﻤﻭﺍﺼﻔﺎﺕ  ﺍﻟﻭﻁﻨﻴﺔ
ﺒﻭﺍﺴﻁ ﺍﻟﺨﻠﻴﺠﻴﺔ  ﻤﺘﺨﺼﺼﺔ  ﻓﻨﻴﺔ ﻟﺠﺎﻥ ﺔ  . 
 ﺍﻟﻔﻨﻴﺔ ﺍﻟﻠﺠﻨﺔ ﻋﻤل ﺒﺭﻨﺎﻤﺞ ﻀﻤﻥ ﺍﻟﻌﺭﺒﻴﺔ ﺍﻟﺨﻠﻴﺞ ﻟﺩﻭل ﺍﻟﺘﻌﺎﻭﻥ ﻤﺠﻠﺱ ﻟﺩﻭل ﺍﻟﺘﻘﻴﻴﺱ ﻫﻴﺌﺔ ﻗﺎﻤﺕ ﻭﻗﺩ  
 ٢ﺭﻗﻡ-١  " ﺍﻟﻤﺭﻜﺒﺎﺕ  ﻤﻭﺍﺼﻔﺎﺕ  ﻟﻘﻁﺎﻉ ﺍﻟﻔﺭﻋﻴﺔ ﺍﻟﺨﻠﻴﺠﻴﺔ  ﺍﻟﻔﻨﻴﺔ ﻭﺍﻹﻁﺎﺭﺍﺕﺍﻟﻠﺠﻨﺔ   "  ﺒﺘﺒﻨﻲ
 ﺁﻴﺯﻭ  ﺭﻗﻡ ﺍﻟﺩﻭﻟﻴﺔ ﺍﻟﻘﻴﺎﺴﻴﺔ ٠٢٠٤ﺍﻟﻤﻭﺍﺼﻔﺔ /١٠٠٢ " ﻤﺭﻜﺒﺎﺕ ﺍﻟﻁﺭﻕ -ﻤﺭﺸﺤﺎﺕ ﺍﻟﻭﻗﻭﺩ ﻟﻤﺤﺭﻜﺎﺕ 
ﺍﻟﺩﻴﺯل – ﻁﺭﻕ ﺍﻻﺨﺘﺒﺎﺭ“   – ﺃﺼﺩﺭﺘﻬﺎ  ﻭﺍﻟﺘﻲ" ﻟﻠﺘﻘﻴﻴﺱ ﺍﻟﺩﻭﻟﻴﺔ ﺍﻟﻤﻨﻅﻤﺔ "  ﺒﺎﻟﻠﻐﺔ ﺘﺭﺠﻤﺘﻬﺎ  ﻭﺘﻤﺕ
، ﺍﻟﻤﻤﻠﻜﺍﻟﻌﺭﺒﻴﺔ  ﻭﻗﺎﻤﺕ ﺍﻟﻤﻭﺍﺼﻔﺔﺔ  ﻫﺫﻩ ﻤﺸﺭﻭﻉ  ﺒﺈﻋﺩﺍﺩ ﺍﻟﺴﻌﻭﺩﻴﺔ  ﺍﻟﻌﺭﺒﻴﺔ  . 
 ﺍﻟﻤﻭﺍﺼﻔﺔ  ﻫﺫﻩ ﺍﻋﺘﻤﺩﺕ  ﻭﻗﺩ  ﻋﻠﻴﻬﺎ ﻓﻨﻴﺔ ﺘﻌﺩﻴﻼﺕ  ﺃﻴﺔ ﺇﺩﺨﺎل ﺩﻭﻥ ﺨﻠﻴﺠﻴﺔ ﻗﻴﺎﺴﻴﺔ ﻜﻤﻭﺍﺼﻔﺔ  ﻓﻲ ﻭﺫﻟﻙ
 ﺭﻗﻡ ﺍﻟﻬﻴﺌﺔ ﺇﺩﺍﺭﺓ ﻤﺠﻠﺱ ﺍﺠﺘﻤﺎﻉ      )          (  ﺒﺘﺎﺭﻴﺦ         ﻋﻘﺩ ﺍﻟﺫﻱ ، /      /       ، ﻫـ
      ﺍﻟﻤﻭﺍﻓﻕ/      /       ﻡ  .
  
  
 
Foreword 
 
GCC Standardization Organization (GSO ) is a regional Organization which 
consists of the National Standards B odies of GCC member  States. One of 
GSO main functions is to issue Gulf Standards through specialized technical 
committees (TCs). GSO through the technical program of  committee TC No.2-1: " The Gulf 
technical Subcommittee for vehicles an d tyres standards” has adopted the 
International Standard No . : ISO 4020:2001  “Road vehi cles – Fuel filters for 
diesel engines – Test methods " issu ed by International Organization for 
Standardization which has been translat ed into Arabic. The Draft Standard 
has been prepared by Kingdom of Saudi Arabia This standard has been approved as Gulf Standard without any technical 
modifications by GSO Board of Director s in its meeting No..../....  …….held 
on    /    /   /  H ,   /    /   G  
 
  
  
  
   
 Reference numbe r
ISO 4020:2001(E)
© ISO 2001
  
 
 INTERNATIONAL 
STANDARD  ISO
4020
First edition
2001-12-15
Road vehicles — Fuel filters for diesel 
engines — Test methods 
Véhicules routiers — Filtres à combustible pour moteurs diesels — 
Méthodes d'essai 
 ISO 4020:2001(E) 
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ii  © ISO 2001 – All rights reserved
  ISO 4020:2001(E) 
© ISO 2001 – All rights reserved   iii
 Contents Page 
Foreword....................................................................................................................... ..............................................iv  
1 Scope .......................................................................................................................... ....................................1  
2 Normative references........................................................................................................... .........................1  
3 Terms and definitions .......................................................................................................... .........................2  
4 Flow rates ..................................................................................................................... ..................................4  
5 Test materials................................................................................................................. ................................4  
5.1 Test liquid.................................................................................................................... ...................................4  
5.2 Test contaminants for tests to determine instantaneous filtration efficiency and filter life..................4  
5.3 Test installation, general..................................................................................................... ..........................5  
6 Tests.......................................................................................................................... ......................................5  
6.1 Test for cleanliness of new filters............................................................................................ ....................5  
6.2 Fabrication integrity test..................................................................................................... ..........................6  
6.3 Test for differential pressure of new filters.................................................................................. ...............6  
6.4 Test for instantaneous filtration efficiency and filter life ................................................................... .......7  
6.5 Test for water separation efficiency ........................................................................................... ...............14  
6.6 Collapse/burst test of the filter element...................................................................................... ..............16  
6.7 Burst test of complete filters................................................................................................. .....................17  
6.8 Pulsating pressure fatigue test ................................................................................................ ..................18  
6.9 Vibration resistance fatigue test .............................................................................................. ..................20  
Annex A (normative)   Test liquid for fuel filter test ............................................................................................. ...21 
Annex B (normative)   Test installations ........................................................................................................... .......22  
Annex C (normative)   Organic contaminant.......................................................................................................... ..37 
Annex D (normative)   Specification for carbon black powder used for the organic contaminant 
concentrate .................................................................................................................... ..............................40  
Annex E (normative)   Supplementary details for water separation test ..............................................................42  
Annex F (normative)   Determination of the insoluble content ..............................................................................44  
Annex G (normative)   Diagram for showing instantaneous filtration efficiency and differential pressure 
versus choking time............................................................................................................ ........................47  
Bibliography................................................................................................................... ...........................................48  
 
 ISO 4020:2001(E) 
iv  © ISO 2001 – All rights reserved
 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 3. 
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 International Standard may be the subject of 
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. 
International Standard ISO 4020 was prepared by Technical Committee ISO/TC 22, Road vehicles , Subcommittee 
SC 7, Injection equipment and filters for use on road vehicles . 
This first edition cancels and replaces ISO 4020-1:1979, which has been technically revised. The former Part 2 has 
been withdrawn. 
Annexes A to G form a normative part of this International Standard. INTERNATIONAL STANDARD ISO 4020:2001(E)
 
© ISO 2001 – All rights reserved   1
 Road vehicles — Fuel filters for diesel engines — Test methods  
1 Scope 
This International Standard specifies the types of test for fuel filters in accordance with their application. 
This International Standard applies to fuel filters provided for road vehicles with diesel engines and for test 
installations for fuel injection equipment. 
The test described may be used for fuel filters located either on the pressure side or on the suction side of the fuel 
supply pump. 
This International Standard is intended for filters having a rated flow of up to 200 l ⋅h−1. 
By agreement, the tests, with some modifications, may be used for filters with higher rates of flow. 
2 Normative references 
The following normative documents contain provisions which, through reference in this text, constitute provisions of 
this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to 
investigate the possibility of applying the most recent editions of the normative documents indicated below. For 
undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. 
ISO 565:1990, Test sieves — Metal wire cloth, perforated metal plate and electroformed sheet — Nominal sizes of 
openings  
ISO 760:1978, Determination of water — Karl Fischer method (General method)  
ISO 2719:—
1), Determination of flash point — Pensky-Martens closed cup method  
ISO 2942:1994, Hydraulic fluid power — Filter elements — Verification of fabrication integrity and determination of 
the first bubble point  
ISO 3016:1994, Petroleum products — Determination of pour point  
ISO 3104:1994, Petroleum products — Transparent and opaque liquids — Determination of kinematic viscosity and 
calculation of dynamic viscosity  
ISO 3405:2000, Petroleum products — Determination of distillation characteristics at atmospheric pressure  
ISO 3675:1998, Crude petroleum and liquid petroleum products — Laboratory determination of density — 
Hydrometer method  
                                                      
1) To be published. (Revision of ISO 2719:1988) ISO 4020:2001(E) 
2  © ISO 2001 – All rights reserved
 ISO 4548-7:1990, Methods of test for full-flow lubricating oil filters for internal combustion engines — Part 7: 
Vibration fatigue test  
ISO 8213:1986, Chemical products for industrial use — Sampling techniques — Solid chemical products in the 
form of particles varying from powders to coarse lumps 
ISO 11841-1:2000, Road vehicles and internal combustion engines — Filter vocabulary — Part 1: Definitions of 
filters and filter components  
ISO 11841-2:2000, Road vehicles and internal combustion engines — Filter vocabulary — Part 2: Definitions of 
characteristics of filters and their components  
ISO 12103-2:1997, Road vehicles — Test dust for filter evaluation — Part 2: Aluminium oxide test dust  
ASTM-D 971-99a, Standard Test Method for Interfacial Tension of Oil Against Water by the Ring Method  
ASTM-D 2784-98, Standard Test Method for Sulfur in Liquefied Petroleum Gases (Oxy-Hydrogen Burner or Lamp) 
3 Terms and definitions 
For the purposes of this International Standard the terms and definitions given in ISO 11841-1, ISO 11841-2 and 
the following apply. 
NOTE Pressures are indicated in kPa (instead of bar) or in Pa (instead of mbar); to obtain them in bar or mbar, divide them 
by 102⋅(100 kPa = 1 bar; 100 Pa = 1 mbar) 
3.1 
sedimentor 
separator in which contaminant is removed by density difference 
3.2 
instantaneous filtration efficiency 
h 
ratio between the test contaminant retained versus that added, expressed as a percentage 
12
1100dd
dh-=  
where 
d1 is the concentration of test contaminant at filter inlet; 
d2 is the concentration of test contaminant at filter outlet. 
3.3 
filter life 
t or V 
service interval of a filter or filter element until maintenance or replacement, expressed in minutes or until final 
differential pressure is reached, expressed in litres 
3.4 
pressure difference 
pstat 
difference in static pressure between upstream and downstream of a filter, expressed in pascals ISO 4020:2001(E) 
© ISO 2001 – All rights reserved   3
 3.5 
rated flow q
v 
normal operating flow at which liquid is passed through a filter, expressed in litres per hour or litres per minute 
NOTE The flow can be that specified by the manufacturer or as agreed between manufacturer and user. 
3.6 contaminant, organic 
suspension of finely divided carbon black in test liquid, formulated to provide similar filter choking characteristics to 
those of normal diesel fuel 
3.7 
contaminant, inorganic 
fused aluminium oxide dust of closely controlled particle size 
NOTE It is the incombustible constituent that is added to the organic contaminant for the purpose of revealing the 
instantaneous filtration efficiency property of a filter. 
3.8 
collapse/burst pressure of filter element 
pdiff 
differential pressure at which a choked filter element suffers structural failure, expressed in kilopascals 
3.9 
burst pressure of complete filter 
p 
internal pressure at which the filter housing suffers structural failure, expressed in kilopascals 
3.10 
fabrication integrity test 
test to indicate quality standard of filter element by measurement of volume of air escaping through filter medium or 
joints in unit time, when immersed in liquid at specified depth and internal pressure 
NOTE The volume is measured in millilitres per minute and is given the symbol VB. 
3.11 
test of cleanliness 
test to enables the degree of cleanliness of new filters to be determined and reveal the amount of impurities flushed 
from the clean side of the filter under specified test conditions 
NOTE The amount is measured in milligrams and is given the symbol W. 
3.12 
test flow rate q
t 
rate at which test liquid flows through the filter during a specific test, expressed in litres per hour or litres per minute 
NOTE It may be different from the rated flow qv. 
3.13 
undissolved water 
water dispersed in test liquid 
NOTE This means diesel fuel containing water which can be separated by physical means, e. g. by centrifuging. ISO 4020:2001(E) 
4  © ISO 2001 – All rights reserved
 4 Flow rates 
The test flow rate shall reflect service conditions and shall be one of the following values: 
10 l⋅h−1, 25 l⋅h−1, 50 l⋅h−1, 75 l⋅h−1, 100  l⋅h−1, 125  l⋅h−1, 150  l⋅h−1, 175  l⋅h−1, 200  l⋅h−1 
or as agreed between filter manufacturer and user. 
5 Test materials 
5.1 Test liquid 
The test liquid used for all tests, except the water separation test (see 6.5) and collapse/burst test of the filter 
element (see 6.6), shall be a straight mineral oil2) with properties as shown in annex A. 
Except in tests 6.1 and 6.2, this liquid shall be used at such a temperature that the kinematic viscosity of the liquid 
lies between 4 mm2/s and 6 mm2/s. Alternatively, the liquid shall be blended with refined spindle oil or premium 
grade kerosene to give a viscosity that is between these limits at the test temperature. All test liquids shall be free 
from additives apart from colouring dyes. Provision shall be made to ensure that the test liquid is free from 
undissolved water. The liquid for each test shall be drawn from its storage container at a point above the zone of 
sedimentation. 
Before use, and if needed, all liquids shall be passed through a highly efficient filter medium, the latter being 
adequately supported and suitably clamped at the edges; see the following items from B.3 (2nd, 3rd and 4th items 
under Other equipment ), e.g.: 
 vacuum pump: 85 kPa below atmospheric pressure; 
 filtration apparatus: filter paper disc holder; 
 filter paper disc or membrane: diameter 140 mm, mean pore size between 0,4 µm and 1,1 µm. 
The differential pressure across the filter paper shall not exceed 85 kPa. Providing the test liquid is suitably cleaned, it may be reused up to a maximum of 20 times. 
5.2 Test contaminants for tests to determine instantaneous filtration efficiency and filter life 
5.2.1 Organic contaminant concentrate 
The concentrate (see note) shall consist of a dispersion in a ratio of 1 g of carbon black to a mixture of 90 ml of test 
liquid and 10 ml of dispersant additive. 
For the method of preparation, see annex C. The specification of the carbon black can be found in annex D. 
NOTE This concentrate is difficult to prepare and when prepared requires to be tested for suitability as described in 
annex C. 
                                                      
2) Suitable products are available commercially. Details (product list) may be obtained from the Secretariat of Technical Committee ISO/TC 22 or from the ISO Central Secretariat. ISO 4020:2001(E) 
© ISO 2001 – All rights reserved   5
 5.2.2 Inorganic contaminant 
The contaminant shall be fused aluminium oxide dust. The particle size distribution shall conform to grades M1 and 
M2 of ISO 12103-2. Normally, grade M2 dust shall be used, however, for filters manufactured from fine paper the finer M1 grade dust shall be used as an alternative contaminant. 
5.3 Test installation, general 
There shall be no sudden changes in tube or hose bore throughout the test rigs. 
6 Tests 
6.1 Test for cleanliness of new filters 
6.1.1 Purpose of the test 
This test shall be carried out first to ascertain whether the clean side of the filter to be tested is free from dirt and of 
other loose particles which may result from production, storage and transport. 
6.1.2 Test installation 
See B.1. The test liquid temperature shall be 23 °C ± 5 °C. 
6.1.3 Other equipment 
See B.1. 
6.1.4 Procedure 
a) Clean and dry the test sieve for 30 min in a drying cabinet at approximately 20 °C above the final boiling point 
of the petroleum ether employed in accordance with 6.1.4 d) and allow to cool for 30 min to ambient temperature. 
b) Weigh the test sieve to the nearest 0,1 mg on a laboratory balance and insert the test sieve in a horizontal 
position in the measuring device ( B.1.7 ). 
c) Pump the test liquid through the circuit for 1 h at twice the rated flow of the filter under test. d) Spray approximately 10 ml of petroleum ether through the cleaning hole on to the inner walls of the measuring 
device in order to wash down particles from the wall and to gather them on the sieve. 
e) Remove the test sieve with tweezers, place it on filter paper and allow to dry. f) Place the test sieve in a clean, dry Petri dish, cover it with a lid, dry and allow to cool as before the first 
weighing. 
g) Weigh the test sieve to the nearest 0,1 mg. The mass of dirt released by the filter is equal to the difference 
between the results of the two weighings of the sieve. 
6.1.5 Test report 
The test report shall indicate at least the following: 
a) the filter make and model; ISO 4020:2001(E) 
6  © ISO 2001 – All rights reserved
 b) a description of the filter tested and internal diameter of connections; 
c) the rated flow, in litres per hour; 
d) the type or blend of test liquid. 
Indicate the mass, in milligrams, of dirt released. 
6.2 Fabrication integrity test 
This test shows whether the filter element is “tight”; i.e. whether it does not contain pores larger than the unused 
filter medium. The test shall be conducted in accordance with ISO 2942. However, test liquid in accordance with annex E shall be used instead of isopropanol, as specified in ISO 2942. If this test is made, it should be carried out prior to the other tests specified, but it may be carried out after the cleanliness test. 
6.3 Test for differential pressure of new filters 
6.3.1 Purpose and application of the test 
The purpose of this test is to measure the differential pressure across the filter at the filter manufacturer’s rated 
flow. This test shall be carried out prior to the tests for instantaneous filtration efficiency and filter life and for water 
separation efficiency, but may be carried out after the cleanliness and fabrication integrity tests. 
NOTE This method is equally applicable for the measurement of the pressure drop in a filter which has been in use for a 
determined period, or at a flow rate different from the nominal rate. 
6.3.2 Test installation 
See B.2. 
The test liquid temperature shall be 23 °C ± 5 °C. 
6.3.3 Other equipment 
See B.2. 
6.3.4 Procedure 
a) Connect the filter to be tested to the test rig, start up the system and prime and vent the filter to ensure 
removal of air from the filter and pressure gauges, inverting the filter if necessary. 
b) Close the control valve ( B.2.10 ) and adjust the pressure by means of the by-pass valve ( B.2.12 ) to that used in 
practice. Adjust the zero of the differential manometer ( B.2.14 ). 
c) Open the control valve to re-establish the pressure reading on the upstream pressure gauge ( B.2.8 ) to that 
used in practice, and partially close the by-pass valve. Thus adjust the flow rate, indicated by the flowmeter 
(B.2.6 ), to the desired value. 
d) Record the value shown on the differential manometer. 
6.3.5 Test report 
The test report shall indicate at least the following: 
a) the filter make and model; b) a description of the filter; whether it is new or used; in the latter case, the approximate period of service; ISO 4020:2001(E) 
© ISO 2001 – All rights reserved   7
 c) the rated flow and the test flow rate, in litres per hour; 
d) the type of blend of test liquid; e) its viscosity at the test temperature, in square millimetres per second; f) the test temperature, in degrees Celsius; 
g) the internal diameter, d, actually used for the pipes itemized in B.2. 
Indicate the differential pressure in Pa. 
6.4 Test for instantaneous filtration efficiency and filter life 
6.4.1 Purpose and application of the test 
The purpose of this test is to measure the percentage retention of specific particles by a filter under defined test 
conditions and at the filter manufacturer’s rated flow. 
It is useful to conduct the test with filters which have already been tested by the cleanliness test, the fabrication 
integrity test or the differential pressure test. 
6.4.2 Test installation 
See B.3. 
The test liquid temperature shall be 23 °C ± 5 °C. 
6.4.3 Other equipment 
See B.3. 
6.4.4 Procedure 6.4.4.1 Description 
The filter test shall be carried out as a continuous process during which the contamination concentration of the test 
liquid being fed to the filter is constant. The effectiveness of the filter under test ( B.3.8 ) is determined by measuring 
the amount of inorganic test dust remaining in the effluent samples initially and during the process of choking. 
Clean test liquid is pumped from the tank ( B.3.1b ) by means of the main delivery pump ( B.3.6 ) through the filter 
under test into the collection tank ( B.3.12 ). This enables the filter to be primed and vented. The organic and 
inorganic contaminants are added as follows:  
a) either as shown in diagram B.3: manually into the tanks ( B.3.1a  and B.1.3b ) with the contaminants held in 
suspension with stirrers ( B.3.2 ); 
b) or as shown in Figure B.4: with the injection pump ( B.3.21 ) the organic contaminant is fed into the tank ( B.3.1a  
or B.3.1b ) and with the injection pump ( B.3.24 ) the inorganic contaminant is fed via the injection nozzle 
(B.3.25 ) before the main delivery pump. The contaminants are held in suspension in the injection tanks by 
recirculating pumps ( B.3.19  and B.3.23 ). 
The main delivery pump transfers this suspension to the filter under test, from which the filtered liquid flows via the 
flow-measuring device [head tube ( B.3.10 )] and the orifice ( B.3.11 ) into the collection tank. Samples of the effluent 
are taken 2 min after the addition of the contaminants and at 4 min intervals thereafter for the determination of the 
inorganic concentration. The continuity of the process is ensured by having a second tank ( B.3.1b ) prepared and ISO 4020:2001(E) 
8  © ISO 2001 – All rights reserved
 ready for use in the event that the whole of the contaminated test liquid contained in the first tank ( B.3.1a ) has 
been used up. 
The test for instantaneous filtration efficiency and filter life ends when the end pressure or any other agreed value is 
attained. 
To determine the instantaneous filtration efficiency of felt filters, terminate the instantaneous filtration efficiency test 
after 20 min and analyse the samples taken during that time period. 
6.4.4.2 Preparation of contaminants 
6.4.4.2.1 Organic contaminant  
See 5.2.1 and annexes C and D. 
Before use ensure that the organic contaminant is thoroughly mixed; an example of the mixing procedure is as 
follows. 
a) The contaminant shall be supplied in a container which is not more than 75 % full. It shall be agitated by hand 
shaking for approximately 5 min. To do this, the container shall be turned upside down and back again a number of times. 
b) Immediately following this, the container shall be placed on its side on a laboratory shaker and agitated at a 
frequency of approximately 250 cycles per minute (approx. 4,2 Hz) at approximately 25 mm amplitude for 2 h. 
c) The container shall then be taken from the shaker and the cap removed. A laboratory stirrer shall be lowered 
into the container to a position as near as possible to the bottom and stirring shall be maintained for 3 h at a 
rotational frequency of approximately 1 000 min
-1. 
d) Immediately after stirring, a sample shall be removed and the solid content determined (see annex F) to 
ensure that it is within (1 ± 0,1) % mass/volume. 
6.4.4.2.2 Inorganic contaminant 
See 5.2.2. 
a) To obtain the test dust samples from the bulk supply, the appropriate standard sampling method, e.g. as 
specified in ISO 8213, shall be used. 
b) Immediately before use, each small quantity of inorganic contaminant shall be dried at a temperature between 
110 °C and 150 °C (see B.3, Other equipment ) for not less than 1 h. 
c) The inorganic contaminant shall be allowed to cool in a desiccator and shall be stored in same. 
6.4.4.3 Test rig and contaminents 
6.4.4.3.1 Preparation of test rig 
a) Prepare the test liquid as described in 5.1. 
b) Flush the test rig by pouring 5 l of clean test liquid into the main tanks and and recirculating for 15 min. This is 
achieved by attaching a separate flexible hose to the flexible transparent hose and suspending the other end 
in either of the tanks. 
c) After this flushing operation, pump out and discard the test liquid; refill the rig with 10 l. ISO 4020:2001(E) 
© ISO 2001 – All rights reserved   9
 d) Clean the test rig with an arrangement in accordance with Figure B.3 or Figure B.4. 
This test shall be carried out prior to the tests for instantaneous filtration efficiency and filter life and for water 
separation efficiency, but may be carried out after the cleanliness and fabrication integrity tests. 
e) After approximately 30 min and before discarding the test liquid, take a sample at the orifice and determine the 
level of contamination using the method specified in 6.4.4.5. 
f) If the level of contamination exceeds 0,004 g/l (i.e. 1 % of the inorganic contaminant concentration), the 
cleaning shall be repeated until this or a lower level is reached. 
g) Prime the system by partially filling the tank ( B.3.1a ) with clean test liquid, and starting the pump to transfer 
test liquid through the filter under test into the collection tank. During this process, vent air from the filter by 
opening bleed orifices normally located on the filter head. 
h) When priming is complete, close the bleed orifices and continue pumping test liquid through the filter until the 
collection tank is almost full but before the level of the test liquid reaches the outlet opening of the main tank 
(B.3.1a ). 
6.4.4.3.2 Preparation of contaminants 
a) For manual feeding, a mixture of organic contaminant concentrate and clean test liquid shall be produced with 
a volume ratio of 1:99 in the tanks. The concentrate shall be thoroughly mixed, as described in 6.4.4.2.1. A 
quantity of inorganic test dust shall be weighed out that will give a concentration of 0,4 g/l in the test liquid 
contained in the tanks. The inorganic contaminant shall be added to a volume of 500 ml from the contents of 
the tank, and then stirred for 15 min at about 1 000 min-1. The suspension of the inorganic contaminant shall 
then be added to the whole amount of test liquid which contains the organic contaminant in the tanks. The prepared test liquid, to which the organic and the inorganic contaminants have now been added, shallt be stirred for at least 30 min with the stirrer before the start of the test. 
b) For separate contaminant injection, the organic contaminant concentrate – prepared as described in 
6.4.4.2.1 – is added to the injection tank ( B.3.22 ). The solids are held in suspension with the recirculating 
pump. The contaminant is injected in the as-delivered state. 
A quantity of 80 g of the inorganic contaminant – prepared as described in 6.4.4.2.2 – is weighed out and manually 
wetted with a rubber scraper in 950 ml of clean test liquid. Then 5 ml of an anti-static agent are added. This is made up to 1 000 ml with clean test liquid and placed in an ultrasonic bath for 3 min to 5 min. The contaminant 
prepared in this way is placed in the injection tank – always in a quantity of 1 000 ml – and kept in suspension with 
the recirculating pump. 
6.4.4.3.3 Preparation of injection device for separate injection of contaminant 
If the injection pumps are not in operation, the intake tubes ( B.3.26 ) shall be removed from the injection tanks and 
the whole injection line shall be flushed with clean test liquid. During this cleaning process the whole test rig is in 
operation as in 6.4.4.3.1, g) though without a test filter in place; i.e., a connector pipe instead of the test filter. When 
the effluent entering the collector vessel is visually clean, preparation of the injection device is completed. The test 
filter is fitted and the test system is evacuated. 
6.4.4.3.4 Setting of injected quantity/calibration 
Calibration or setting of the quantity injected takes place before the final arrangement of the injection lines. 
The volume flow is set with the aid of the orifices [standard graduated tubes ( B.3.20 )]. 
The contents of the individual injection tanks are circulated during this time and the injected quantities are returned 
to the relevant injection tanks. ISO 4020:2001(E) 
10  © ISO 2001 – All rights reserved
 After the target value has been set the injected samples are evaluated gravimetrically; e.g., with a test volume flow 
rate of qt = 75 l/h and the appropriately prepared proportions of contaminant – as described in 6.4.4.3.2 and 
6.4.4.3.3 – the following target values are obtained for the injected quantities: 
 organic contaminant constituent: 12,5 ml/min; 
 inorganic contaminant constituent: 6,25 ml/min; 
 inorganic solids element: 80 mg/ml. 
6.4.4.4 Test procedure 
6.4.4.4.1 Feeding of contaminant/oil mixture 
a) Open the stopcock ( B.3.4 ) at the bottom of the main tank ( B.3.1a ). 
b) Start the main delivery pump ( B.3.6 ) and allow the test liquid to flow through the filter under test ( B.3.8 ) and 
adjust the flow to the required rate (see clause 4) by controlling the speed of the pump. 
c) Record the differential pressure indicated by the differential pressure gauge ( B.3.9 ).  
d) After 1 min, take a 300 ml sample of test liquid from the sampling pipe ( B.3.14 ). 
e) After 2 min, 4 min and at intervals of 4 min thereafter, take 300 ml samples of effluent at the orifice ( B.3.11 ) 
and record the differential pressure. Throughout the test the speed of rotation of the stirrer in the main tanks 
containing test liquid (see B.3) should be carefully controlled to prevent aeration. 
f) When the end pressure or any agreed value is reached, take a final sample from the orifice and a final sample 
from the sampling pipe. 
g) Shut off the pump and close the stopcock at the bottom of the main tank. h) Should the test liquid from main tank become exhausted during the test, open the stopcock at the bottom of 
the reserve tank ( B.3.1b ), close the stopcock at the bottom of the main tank and continue the test. Care shall 
be taken that the test liquid level does not drop so low as to allow air to be entrained. 
i) Care shall be taken that there is no interruption or variation of flow in the course of the test. 
j) Care shall be taken that the filter is not subjected to vibration or shock during the test. 
k) Care shall be taken that pulsation amplitude is less than 1/10 of average inlet pressure. 
6.4.4.4.2 Separate contaminant feeding 
a) Replace intake tubes ( B.3.26 ) in the injection tanks ( B.3.18 ) and ( B.3.22 ). 
b) Open the stopcock at the base of either tank. 
c) The pump is switched on and the test liquid is passed through the filter under test; the flow rate is set by 
regulating the speed of the pump to the required value. 
d) The differential pressure indicated at the differential pressure gauge is noted. 
e) Actuated the injection pumps ( B.3.21 ) and ( B.3.24 ) and operate briefly (max. 15 s) at max. output – to reduce 
start-up time – and then set the desired flow rate on the standard graduated tubes (20) by means of the pump 
controller. The start of the test time is determined by the start of discoloration of the test liquid at the outlet into 
the collection tank ( B.3.12 ). ISO 4020:2001(E) 
© ISO 2001 – All rights reserved   11
 f) After 1 min, take a 300 ml sample of test liquid from the sampling pipe. 
g) After 2 min, after 4 min, and subsequently at intervals of 4 min, 300 ml samples of the effluent are to be taken 
at the orifice and the differential pressure noted.  
h) Either tank shall always be replenished with clean test fluid. 
i) When the end pressure or any agreed value is reached, one final sample shall be taken at the orifice and from 
the sampling pipe. 
j) The injection pumps and main delivery pump are switched off and the relevant stopcock closed. k) The intake pipes shall be removed from the injection tanks and the injection pipes shall be cleaned as in 
6.4.4.3.3. 
l) Care shall be taken to ensure that the test liquid level does not fall so much that air is entrained. 
m) Care shall be taken to ensure that no interruption or variation in flow occurs during the test. 
n) Care shall be taken to ensure that the filter is not subjected to vibration or shock during the test. 
6.4.4.5 Determination of the mass of incombustible (inorganic) particles in the test liquid samples 
6.4.4.5.1 Preparation of the sample 
Each sample shall be passed through the filtration apparatus specified in B.3 (2nd, 3rd and 4th items under Other 
equipment ) or an equivalent apparatus. After filtration, wash the filter medium and the collected solids and the 
walls of the filter holder with a suitable solvent, such as petroleum ether of analytical quality, to remove all traces of the test liquid (150 ml to 200 ml is usually sufficient). 
6.4.4.5.2 Weighing of the residue 
Ignite the filter medium and weigh the residue as specified in 6.4.4.5.3, making a correction for the ash content of 
the filter medium and any change in mass of the inorganic contaminant due to the incineration. 
6.4.4.5.3 Ashing and weighing procedure 
a) Wash a crucible (see B.3) in water to which a little detergent has been added. 
b) Dry the crucible and, using tongs, place it in a muffle furnace controlled at 800 °C ± 50 °C for 1 h. The crucible 
shall be handled with tongs from this stage onwards. 
c) Remove the crucible and place it in a desiccator until cool (i.e. for at least 1 h); weigh to the nearest 0,1 mg. 
d) Remove the filter medium from the filter holder with care, keeping it horizontal so that no insolubles are lost. 
e) If a membrane is used, roll it into a cylindrical form, holding the lower end of the filter medium above the 
crucible, and carefully squeeze with thumb and forefinger of both hands to form a “flat tube”. 
NOTE The membrane may be moistened to avoid cracking. Moistening may be achieved by carefully holding the 
membrane in contact with the flat surface of a clean sponge dampened with distilled water. 
f) Fold the filter medium in half until small enough to go into the crucible. 
g) Place the crucible and its contents on a hot-plate to incinerate the larger portion of combustible material; care 
shall be taken to avoid open conflagration of the contents. ISO 4020:2001(E) 
12  © ISO 2001 – All rights reserved
 h) When all the filter material has been incinerated on the hotplate, place the crucible in the muffle furnace 
controlled at 800 °C ± 50 °C. 
i) After 2 h, remove the crucible and place it in a desiccator to cool for at least 1 h before re-weighing to the 
nearest 0,1 mg. 
j) Subtract the initial mass of the crucible from the final mass to obtain the mass of the residue; i.e. of the 
incombustible (inorganic) material. 
k) The results shall be corrected by the subtraction of the mass of ash obtained from an unused filter medium. 
6.4.4.5.4 Calculation of instantaneous filtration efficiency 
The mass of inorganic material in each effluent sample shall be related to the average mass of inorganic material in 
the initial and final applied influx samples. 
The percentage instantaneous filtration efficiency is given by the formula: 
12
1100mm
m-¥  
where 
m1 is the average mass, in grams, of inorganic material in the applied influent; 
m2 is the mass, in grams, of inorganic material in the effluent. 
This formula applies to each test; i.e. with and without water saturation of the element. 
6.4.5 Test to determine the effect of water (optional) 
Immerse an unused filter element in the test liquid for 10 min, remove and drain for 10 min. Then immerse it in 
water for 30 min, after which remove it and allow it to drain for 10 min before installation in the test rig. Then carry 
out the test for instantaneous filtration efficiency and filter life in accordance with the procedure specified in 6.4.4. 
6.4.6 Test report 
The test report shall indicate at least the following: 
a) procedure used (6.4.4.4.1 or 6.4.4.4.2); 
b) the filter make and model; 
c) a description of the filter; whether it is new or used; in the latter case, the approximate period of service; 
d) the rated flow and the test flow rate, in litres per hour; 
e) the type or blend of test liquid; 
f) its viscosity at the test temperature, in square millimetres per second; 
g) the test temperature, in degrees Celsius; 
h) the organic contaminant (see 5.2.1): 
 supplier; 
 batch No.; ISO 4020:2001(E) 
© ISO 2001 – All rights reserved   13
  volume, V9, in millilitres, of test liquid to choke reference paper 633/9, should be near to the standard 
volume V0 of 25 ml. 
NOTE A choking volume range of 25 ml is permitted for reference paper 633/9 as a check on quality. 
i) inorganic contaminant (see 5.2.2): 
 supplier; 
 grade; 
 batch No.; 
 50 % mean particle size, in micrometres. 
6.4.7 Test results 
6.4.7.1 Presentation of test results 6.4.7.1.1 Instantaneous filtration efficiency 
Stage Efficiency  
% Dp 
kPa 
Initial (2 min)   
4 min   
8 min   
12 min and at 4 min intervals until the end 
pressure is reached   
Figure 1 — Presentation of filtration efficiencies 
6.4.7.1.2 Filter life 
In terms of time: 
measured time ( t1) to choke test filter to 70 kPa or any other agreed value: ..... min; 
The measured time ( t1) shall be corrected to make allowances for variations in the choking ratios of different 
batches of organic contaminants, using the equation: 
0
21
9VttV=  
where 
t2 is the corrected time; 
V0 is the standard volume (25 ml) to choke the reference paper 633/9; 
V9 is the average volume to choke the reference paper 633/9 with the batch of contaminant used in the test. ISO 4020:2001(E) 
14  © ISO 2001 – All rights reserved
 NOTE This correction to the measured time enables more accurate comparisons to be made between filter tests, using 
different batches of contaminant, over a period of time. See also C.3 when changes have been made to the reference papers 
used to determine V0. 
6.4.7.1.3 Diagram 
The diagram showing instantaneous filtration efficiency and differential pressure versus choking time is shown in 
annex G. 
6.5 Test for water separation efficiency 
6.5.1 Purpose and application of the test 
With this test, it is possible to determine the quantity of water separated by the filter from a water-oil dispersion. This 
test only applies to filters which are claimed to separate water. The test may be conducted with new or used filters. 
NOTE The main pump ( B.4.8 ), as specified in B.4, limits the use of the test to filters with rated flows up to 50 l/h. Filters 
with higher rated flows require the use of two or more pumps operating in parallel. If two or more pumps are used, the rated fl ow 
value is to be multiplied by the number of pumps. 
6.5.2 Test installation 
See B.4 and annex E. 
The test liquid temperature shall be 23 °C ± 5 °C. 
NOTE 1 The test installation is designed for filters downstream of the fuel supply pump (pressure side), but it is suitable for  
filters upstream of the fuel supply pump (suction side) as well. 
For this test, ordinary diesel fuel oil, free from anti-smoke additives and undissolved water shall be used. 
The test liquid shall be treated with Fuller’s Earth (see B.5), followed by the addition of cetane number improver. 
NOTE 2 This treatment of test liquid will tend to eliminate differences in testing fuel/water separators at different laborator ies 
in different geographic locations. 
6.5.3 Other equipment 
See B.4. 
6.5.4 Procedure 
6.5.4.1 Preparation and calibration 
a) All equipment shall be clean and free from water. Fit a new element in the absorbent filter ( B.4.24 ), if 
necessary. 
b) Fill the main tank ( B.4.1 ) with test liquid free from undissolved water. Open by-pass valve ( B.4.11 ) and check 
that the stopcock ( B.4.13 ) is shut. Start the main pump(s) ( B.4.8 ) and adjust by-pass valve, so that the flow 
through the pump is 50 l/h. If two or more pumps are used, this value shall be multiplied by their number. 
c) If a recirculation system is used, allow the collection tank ( B.4.20 ) to fill partly and refill the main tank. Start the 
transfer pump ( B.4.21 ), flush the coalescer ( B.4.23 ) and absorbent filter ( B.4.24 ) then adjust valve ( B.4.25 ) to 
balance the main flow. 
d) Fill the water tank ( B.4.3 ) with distilled or deionized water. Open valve ( B.4.6 ) and adjust it to give a flow of 
1 l/h. If two or more pumps are used, this value shall be multiplied by their number. The percentage water 
content in the test liquid will then be approximately 2 % and the water will be dispersed by the action of the ISO 4020:2001(E) 
© ISO 2001 – All rights reserved   15
 main pump(s). It is essential to keep the level in the water tank reasonably constant, otherwise frequent 
adjustment of valve ( B.4.6 ) will be necessary. For this purpose, it is recommended that a constant-level device 
(B.4.4 ) be fitted. 
e) Stop the water feed by shutting valve ( B.4.6 ). 
NOTE The overflow valve should be made non-operative during these operations. 
6.5.4.2 Test to determine the separation of undissolved water 
a) Fit the filter to be tested ( B.4.15 ) into the circuit. Open valve ( B.4.17 ) [plus, if necessary, valve ( B.4.19 )] and 
the stopcock. Flush the filter under test to remove air locks. Set the flow to the rated value of the filter under 
test or to any other required value by adjusting valves ( B.4.17 ) and ( B.4.19 ) and at the same time adjusting the 
by-pass valve so that the flow through the main pump is 50 l/h ± 2,5 l/h (see note). If two or more pumps are 
used, this value shall be multiplied by their number. Note and maintain constant the level in the head tube 
(B.4.18 ). 
NOTE The reason for maintaining this flow through the main pump, regardless of the rated flow of the filter under test, is to 
maintain a standard condition with regard to water droplet size. 
b) Open valve ( B.4.6 ) and adjust to give a flow of 1 l/h ± 0,05 l/h. If two or more pumps are used, this value shall 
be multiplied by their number. The filter under test will now receive test liquid having a water concentration of 
approximately 2 %. Note the differential pressure in the manometer ( B.4.16 ). 
c) Continue the flow for a period of 60 min, taking 100 ml samples at the outlet ( B.4.19 ) after 5 min, and then at 
5 min intervals. As the test proceeds, water will collect in the bowl of the filter under test. This water shall be 
drained off whenever the bowl is 50 % full. Water shall not be drained off when a sample is being taken. If the 
bowl is not transparent, measure its volume and calculate the draining time interval, assuming 100 % water separation. After the final sample has been taken, again note the differential pressure on the manometer. 
d) Analyse the samples of effluent taken as described in 6.5.4.2 c) for undissolved water content in accordance 
with the method specified in E.2, or by the Karl Fischer method (ISO 760). 
6.5.5 Test report and test results 
6.5.5.1 The test report shall indicate at least the following: 
a) the filter make and model; 
b) a description of the filter, whether it is new or used; in the latter case, the approximate period of service; c) the rated flow and the test flow rate, in litres per hour; d) the type or blend of test liquid; e) its viscosity at the test temperature, in square millimetres per second; 
f) the test temperature, in degrees Celsius. 6.5.5.2 The test results shall be presented as follows: 
a) in graphical form, as shown in annex E; 
b) initial differential pressure across filter under test, in kilopascals or pascals; c) final differential pressure across filter under test, in kilopascals or pascals. ISO 4020:2001(E) 
16  © ISO 2001 – All rights reserved
 6.6 Collapse/burst test of the filter element 
6.6.1 Purpose of the test 
The purpose of this test is to determine the resistance of the filter element to rupture under applied differential 
pressure. 
It is useful to conduct the test with filters which have already been tested by the fabrication integrity test. 
6.6.2 Test installation 
See B.6. For this test, an engine lubricating oil in the ISO VG 46 to ISO VG 150 (SAE 20 to SAE 40) range shall be used. 
The test liquid temperature shall be 
15
1023 °C+-. Other temperatures may be used as agreed between the filter 
manufacturer and the engine manufacturer. 
6.6.3 Other equipment 
See B.6. 
6.6.4 Procedure 
Use any surface contaminant or pulverized vinsol resin (P.V. resin); the particle size distribution shall be: 
 100 % to pass 850 µm 
 85 % to pass 180 µm 
 50 % to pass 75 µm (see ISO 565) 
Prepare a concentrate containing 100 g of contaminant per litre of test liquid. Pour into the tank 5 l of test liquid. 
Start the pump and adjust the flow to the rated flow of the filter under test, then start the stirrer. Every 5 min, add 25 ml of the concentrate to the tank. 
Plot a graph of differential pressure against time. Failure of the filter element is indicated by a permanent fall in 
differential pressure, or by a marked drop in the rate of pressure rise. Continue the test until failure or until a differential pressure of 300 kPa or any value agreed upon between filter manufacturer and customer, is  
reached — whichever occurs first. 
6.6.5 Test to determine the effect of water (optional) 
Immerse an unused filter element in the test liquid for 10 min, remove and drain for 10 min. Then immerse it in 
water for 30 min, after which remove it and allow it to drain for 10 min before installation in the test rig. Carry out the collapse/burst test in accordance with the procedure specified in 6.6.4. 
6.6.6 Test report 
The test report shall indicate at least the following: 
a) the filter make and model; 
b) a description of the filter; whether it is new or used; in the latter case, the approximate period of service; 
c) the rated flow, in litres per hour; 
d) the collapse/burst pressure, in kilopascals. ISO 4020:2001(E) 
© ISO 2001 – All rights reserved   17
 6.7 Burst test of complete filters 
6.7.1 Purpose of the test 
The purpose of this test is to determine the mechanical resistance of the complete filter to internal pressure. 
6.7.2 Test installation 
 Laboratory hydraulic hand pump, with suitable connections or adaptors to attach to the filter under test. 
 Pressure gauge. 
 Test liquid, the properties of which are shown in annex A, suitably coloured for visual observation of leakage. 
The test liquid temperature shall be 15
1023 °C+-. Other temperatures may be used as agreed upon between the filter 
manufacturer and the engine manufacturer. 
6.7.3 Test procedure 
a) Install the detachable filter housing on an appropriate head, applying the recommended average tightening 
torque. Connect to the pump by means of a suitable adaptor. Install spin-on filters on an appropriate adaptor, 
applying the recommended tightening torque for the filter under test. 
b) Connect the pump outlet pipe to the inlet of the filter or adaptor and ensure that the outlet from the filter is 
open. 
c) Position the filter so that the outlet is at the highest point relative to the remainder of the filter. d) Introduce test liquid into the filter by operating the hydraulic pump until test liquid is seen to emerge from the 
outlet connector of the filter. This indicates that all the air has been excluded from the system. 
e) Close the filter outlet using a suitable plug and clean off all surplus test liquid. f) Raise the internal pressure to 100 kPa, and maintain for 30 s, checking the filter for leaks and other adverse 
effects during the raising and maintenance periods of pressure. 
g) Reduce the pressure to zero by opening the venting cock on the pump, wait 30 s and check for permanent 
distortion or other visual defects. Attempt to rotate the housing by hand to ensure that pressure has not caused 
loosening. Relative movement of one half to the other of the housing assembly should be checked. 
h) Close the venting cock and repeat the above procedure, increasing the pressure in steps of 100 kPa. i) Continue until ultimate failure (i.e. bursting or leaking) occurs or until a pressure of 1 000 kPa or any value 
agreed upon between filter manufacturer and customer, is reached. 
6.7.4 Test report 
The test report shall indicate at least the following: 
a) the filter make and model; 
b) a description of the filter, whether it is new or used; in the latter case, the approximate period of service; c) the rated flow, in litres per hour; d) the failure pressure, in kilopascals or no failure at 1 000 kPa; ISO 4020:2001(E) 
18  © ISO 2001 – All rights reserved
 e) the mode of failure and its location; 
f) the torque applied in accordance with 6.7.3 a). 
6.8 Pulsating pressure fatigue test 
6.8.1 Purpose of the test 
The purpose of this test is to determine the mechanical resistance of the complete filter to pulsating pressure such 
as would occur under service conditions. 
6.8.2 Test installation 
See B.7. 
6.8.2.1 Pulse rig,  as shown in Figure B.9, capable of producing – in accordance with the values given in 
Table 1 – the pressure waveform indicated in 6.8.5, Figure 2, with suitable adaptors to attach the filter under test to 
the rig. An alternative rig is permissible provided that the pressure waveform is as indicated in 6.8.5, Figure 2. 
6.8.2.2 Suitable torque wrench and adaptors.  
6.8.2.3 Test liquid,  the properties of which are given in annex A. It shall be suitably coloured for visual 
observation of leakage. The test liquid temperature shall be 60 °C ± 20 °C. Other temperatures may be used as 
agreed upon between the filter manufacturer and the engine manufacturer. 
6.8.3 Test procedure 
a) Install the filter on an appropriate adaptor, applying the recommended tightening torque for the filter to be 
tested. 
b) Connect the test adaptor into the pipework system of the pulse test rig. 
c) Start the pump, ensuring that the valve ( B.7.4 ) is fully open before commencing the test, by operating the 
solenoid valve control switch and the main switch. 
d) Allow the rig to run under the above conditions until all air has been excluded from the system, shut the 
solenoid valves, adjust the valve until the test pressure, as agreed with the engine manufacturer, is attained. 
Switch on the solenoid valves to obtain a pressure waveform as indicated in 6.8.5, Figure 2. Any further adjustments during the test should be made as necessary during the periods when the solenoid valves are closed in order to avoid the filter being overloaded. 
e) Set the counter to zero. f) When using the test rig illustrated, open the inlet and return valves of the water cooling system and adjust the 
water flow to regulate the reservoir oil temperature (preferred maximum: 80 °C). Ensure that the thermostat 
situated in the rig oil reservoir is set at 80 °C as this is fitted as a safety device to switch off the rig, should the temperature rise to this level. 
g) Allow the test to continue, making visual checks for signs of failure at frequent intervals, until failure occurs or 
until the required number of pulses, as agreed with the engine manufacturer, has been applied. 
h) To stop the test, fully open the valve and switch off the pump and solenoid valve control switch. 
i) Check and record the tightening torque (i.e. turn in the tightening direction). 
j) Remove the filter, allow to drain, and visually examine the filter to determine the failure point and type of 
failure. ISO 4020:2001(E) 
© ISO 2001 – All rights reserved   19
 6.8.4 Test report 
The test report shall indicate at least the following: 
a) the filter make and model; b) a description of the filter, whether it is new or used; in the latter case, the approximate period of service; 
c) the rated flow, in litres per hour; 
d) the test pressure, in kilopascals; e) the mode of failure and its location; f) the torque applied initially and at the end of the test [see 6.8.3 a) and 6.8.3 i)]; g) the number of cycles to failure or the number of cycles completed, as agreed [see 6.8.3 g)]. 
6.8.5 Hydraulic pulse 
The diagrammatic waveform is shown in Figure 2. 
 
a  Maximum pressure.  
b  < 10 % maximum pressure.  
Figure 2 — Diagrammatic waveform of the hydraulic pulse (t1 to t3 see Table 1)  
6.8.6 Test procedure (if no agreement)  
In the absence of an agreement between the engine manufacturer and the filter manufacturer the test values, given 
in Table 1, shall be used for the pulsating pressure fatigue test. ISO 4020:2001(E) 
20  © ISO 2001 – All rights reserved
 Table 1 — Values to be used for tests (if no agreement) 
Hydraulic pulse 
Pressure pulse waveform (see Figure 2)  Type of fuel  
injection pump  Number of 
cycles max. pressure 
kPa frequency 
Hz t1 + t2 
s t2 
s t3 
s 
in-line 10 5 500 ± 20 < 5 a > 0,2 a W 0,02 a W 0,05 
rotary distributor 4 ¥ 104 200 ± 20     
a Ensure that less than 10 % of the maximum pressure is reached between the pulses. 
6.9 Vibration resistance fatigue test 
The purpose of such a test is to determine the mechanical resistance to vibration under normal service conditions. 
Depending on the application and location of the filter on the road vehicle, the vibration fatigue test parameters 
shall be as agreed between engine manufacturer and filter manufacturer. 
If the filter is directly mounted to the engine and if there is no such agreement the test method specified in 
ISO 4548-7 may be applied. 
 ISO 4020:2001(E) 
© ISO 2001 – All rights reserved   21
 Annex A  
(normative)  
 
Test liquid for fuel filter test 
Kinematic viscosity  6 mm2/s to 4 mm2/s at an ambient temperature of between 10 °C and 40 °C 
(see ISO 3104) 
Density at 15 °C  0,816 g/ml to 0,850 g/ml (see ISO 3675) 
Flash point 99 °C to 127 °C (see ISO 2719) 
Pour point -10 °C max. (see ISO 3016) 
Additives  none 
Sulfur content  0,1 % ( m/m) max. (see ASTM D 2784) 
Surface tension  (29 ± 1)⋅10-3 N/m (see ASTM D 971) 
Distillation: 
Initial boiling point  252 °C (see ISO 3405) 
50 % reclaimed boiling point 275 °C (see ISO 3405) 
Final boiling point 320 °C (see ISO 3405) 
The test liquid shall not contain components in such a concentration that irritation of a normal skin could be caused. 
 
a  Viscosity limits for test liquid.  
Figure A.1 — Typical viscosity/temperature curve for test liquid ISO 4020:2001(E) 
22  © ISO 2001 – All rights reserved
 Annex B  
(normative)  
 
Test installations 
B.1 Test for cleanliness of new filters (see 6.1)  ISO 4020:2001(E) 
© ISO 2001 – All rights reserved   23
 Dimensions in millimetres 
Key 
1 Cleaning plug 
2 Inlet 
3 Outlet  
 
Figure B.1 — Test rig for cleanliness of new filters ISO 4020:2001(E) 
24  © ISO 2001 – All rights reserved
 Dimensions in millimetres 
 
NOTE 1 Test sieve of polyamide, fabric basket or twill weave; size of aperture width, 28 µm; wire diameter 25 µm ± 1 µm; 
open area of sieve 28 %. 
NOTE 2 This drawing is only an example. However, dimensions specified and specificatons given for the test sieve are to 
complied with. 
Figure B.1a — Enlargement of measuring device B.1.7 
Test rig components: 
B.1.1 Tank with test liquid , minimum capacity 10 l, overlapping cover. 
B.1.2 Suction pipe . 
B.1.3 Feed pump , only pumps of plunger or diaphragm shall be used. The flow rate of the pump shall be 
approximately twice the rated flow of the filter under test at a differential pressure of 20 kPa. 
B.1.4 Electric motor . 
B.1.5 Pressure pipe . 
B.1.5a Flexible hose . 
B.1.6 Filter under test . 
B.1.7 Measuring device  (see Figure B.1a). 
B.1.8 Pressure gauge , measuring range 0 kPa to 150 kPa (above atmospheric pressure). 
B.1.9 Return pipe . 
B.1.10 Flowmeter , adapted to normal test flow. 
B.1.11 Air vent . 
Other equipment: 
Drying cabinet . 
Laboratory balance , with an accuracy of ± 0,1 mg. 
Two Peri dishes , with lids. 
Tweezers . 
Soft hair brush . 
Wash bottle , 100 ml, filled with petroleum ether. 
Filter paper . ISO 4020:2001(E) 
© ISO 2001 – All rights reserved   25
 B.2 Test for differential pressure of new filters (see 6.3) 
 
a > 12d 
b = 8d ± d/2 
c = 12 d ± d/2 
d > 8d 
where d is the internal diameter of the pipes. 
Figure B.2 — Test rig for differential pressure of new filters 
Test rig components: 
B.2.1 Tank with test liquid , mimimum capacity 10 l. 
B.2.2 Cover of the tank , with air vent. 
B.2.3 Suction pipe . 
B.2.4 Variable-speed motor-pump set , capable of non-pulsating delivery of the nominal flow at the pressure 
used in normal practice. 
B.2.5 Pressure pipe . 
B.2.6 Suitable flowmeter . 
B.2.7 Filter under test . 
B.2.8 Pressure gauge , with a measuring range of 0 kPa to 150 kPa (above atmospheric pressure). 
B.2.9 Filter connecting pipes , internal diameter, d, identical to filter inlet and outlet bores. 
B.2.10 Control valve . 
B.2.11 Return pipe . 
B.2.12 By-pass valve . 
B.2.13 By-pass pipes . 
B.2.14 Differential manometer , adapted to the measuring range. 
B.2.15 Thermometer . 
Other equipment: 
Stop-watch. ISO 4020:2001(E) 
26  © ISO 2001 – All rights reserved
 B.3 Test for instantaneous filtration efficiency and filter life (see 6.4)  
B.3.1 Feeding of contaminant/test liquid mixture (manually) 
 
a, b, c, d   See Figure B.2.  
Figure B.3 — Test rig for manual feeding ISO 4020:2001(E) 
© ISO 2001 – All rights reserved   27
 B.3.2 Separate contaminant feeding (with injection pumps) 
 
a, b, c, d  See Figure B.2.  
Figure B.4 — Test rig for injection pump feeding 
Test rig components:  
B.3.1a Main tank with test liquid , this is round tank with smooth sides, minimum capacity 50 l, diameter 
approximately 380 mm, conical bottom with 90° included angle, central outlet, overlapping cover. 
B.3.1b  Reserve main tank with test liquid  (description as for B.3.1a). 
B.3.2 Stirrer , with a rotational speed of approximately 200−1, positioned as close to the bottom as possible. See 
Figure B.5a. 
B.3.3 Pipe , with a minimum internal diameter of 12mm. 
B.3.4 Stopcock , on/off, straight-through bore type. 
B.3.5 Hose , with a minimum internal diameter of 12 mm. 
B.3.6 Pump (main delivery pump) , peristaltic, with two rollers and a nominal hose bore diameter of 8 mm; 
continuously-variable speed control. The material of the tube shall be neoprene. ISO 4020:2001(E) 
28  © ISO 2001 – All rights reserved
 B.3.7 Pipe , with a minimum internal diameter of 12 mm. 
B.3.8 Filter under test . 
B.3.9 Differential pressure gauge , with a measuring range of 0 kPa to 70 kPa. 
B.3.10 Head tube , made of glass and with an arbitrary scale to check flow rate in conjuction with B.3.11. 
B.3.11 Orifice , to provide pressure for B.3.10. 
B.3.12 Collection tank , minimum capacity 50 l, same as B.3.1a but without the cover. 
B.3.13 Filter connecting pipes , inlet diameter, d, identical to the filter inlet and outlet bores. 
B.3.14 Samplig pipe,  metal of nominal internal diameter 6 mm. 
B.3.15 Pulse damper , suitable for reducing amplitude of pulses to not more than 1/10 of the actual average inlet 
pressure. 
B.3.16 Membrane clean-up filter  (see Figure B.5b). 
B.3.17 Separate hose , of minimum internal diameter 12 mm. 
Supplementary test rig components for separate contaminant feeding (optional) (Figure B.4 only): 
The test rig equipment of Figure B.3 shall comply with Figure B.4 apart from the stirrers ( B.3.2 ) which are not 
required. 
B.3.18 Injection tank , this is a round tank with smooth sides, diameter 170 mm, a cylindrical height of 220 mm, 
conical bottom with less than 90° included angle, central outlet, overlapping cover, capacity (cylindrical part of the 
vessel) approximately 5 l; 
B.3.19 Recirculating pump , for the organic contaminant. This shall be a hose pump producing at least 5 l/min or 
15 kPa; the tubes shall have 4 mm maximum internal diameter; the pump outlet shall be designed so that the flow can be clearly seen on the liquid surface. 
B.3.20 Standard graduated tubes , for monitoring injected quantities. All injection lines and injection hoses shall 
have 1,6 m maximum internal diameter, as otherwise there is a danger of contaminant deposits forming.  
Size and capacity of the standard graduated tubes with float: 
 diameter, internal: 3,9 m; external: 10,5 mm; 
 length of graduated scale: 210 mm; 
 for the float material mu-metal should be used; i.e. metal with magnetic characteristics; 
 for the inorganic contaminant component: 
flow capacity for water: q
v = 1,3 ml/min to 27 ml/min (max. 1,6 l/h); 
 for the organic contaminant component: 
flow capacity for water: qv = 2,1 ml/min to 42 ml/min (max. 2,5 l/h). 
These throughputs are sufficient for test flow rates up to qt = 75 l/h; for larger flow rates it is necessary to have 
larger standard graduated tubes, or – even better – two tubes arranged in parallel. 
The quantity of organic contaminant is monitored with a ring initiator, which determines the float position in a non-
contacting manner, as a limit switch function. The limit switching point should be checked manually at regular intervals by means of the controller of the injection pump (B.3.21). ISO 4020:2001(E) 
© ISO 2001 – All rights reserved   29
 B.3.21 Injection pump , these shall be hose pumps with a maximum input of 150 W. The following data are 
proposed: 
 hose diameter: 0,5 mm to 8,0 mm; 
 delivery, depending on hose diameter: 2 ml/min to 200 ml/min; 
 tachometer generator, accuracy ± 1 %, temperature stabilized; 
 operation: forward and reverse; 
 number of rollers: 4. 
To reduce pulsation, pump heads with double hoses and with offset, spring-loaded roller guides are recommended. 
Injection hose material: Viton. 
B.3.22 Injection tank  (see B.3.18). 
B.3.23 Recirculating pump for inorganic contaminant  (see B.3.19). 
B.3.24 Injection pump  (see B.3.21). 
B.3.25 Injection nozzle for inorganic contaminant , The nozzle tube (internal diameter 1,6 mm, external 
diameter 3,2 mm) shall be inserted in the middle of the delivery line [pipe (B.3.7)] (internal diameter 12 mm); the 
end of the nozzle tube has an outlet diameter of 1,0 mm. The injection direction is in the direction of the flow. 
B.3.26 Flexible intake tube , these shall be arranged so that they can deliver clean test liquid from a separate 
tank to clean the whole injection line. 
Other equipment: 
Laboratory balance , with an accuracy of ± 0,1 mg. 
Vacuum pump , operating at a maximum of 85 kPa below atmospheric pressure. 
Filtration apparatus , filter paper disc holder (see Figure B.6). 
Filter paper disc or membrane , with a mean pore size between 0,4 µm and 1,1 µm and a diameter of 140 mm 
(see Figure B.6). 
Drying oven , capable of being controlled at 130 °C ± 20 °C, for drying inorganic contaminant (for dryinf filter paper 
disc/membrane see annex C). 
Desiccator. 
Muffle furnace , capable of being controlled at 800 °C ± 50 °C. 
Hotplate , for preliminary combustion of filter disc, capable of being controlled at approximately 500 °C. 
Crucibles , of porcelain or quartz, diameter approximately 40 mm and depth 36 mm. 
Stop-watch. Petri dishes with lid , of glass and with a diameter of 65 mm, for storage of used filter papers. 
Beakers , of glass and with a capacity of 400 ml. 
Measuring cylinder , of glass and with a capacity of 2 l. 
Tongs , for holding the crucibles. ISO 4020:2001(E) 
30  © ISO 2001 – All rights reserved
 Dimensions in millimetres 
 
a There are 15 blades at 50° to the horizontal. 
a) Detail of stirrer (B.3.2) ISO 4020:2001(E) 
© ISO 2001 – All rights reserved   31
  
b) Detail of membrane clean-up filter (B.3.16)  
Figure B.5 — Details of stirrer and membrane clean-up filter as used in the feeding test rigs ISO 4020:2001(E) 
32  © ISO 2001 – All rights reserved
 Dimensions in millimetres 
 
Key 
1 Rubber bung (size to suit flask) 4 Earth terminal 
2 Clamp bolts (6) 5 Drainage channels 
3 Filter paper disc of diameter 140 mm 
a  Concentric rings at 7 mm pitch.  
Figure B.6 — Filtration apparatus ISO 4020:2001(E) 
© ISO 2001 – All rights reserved   33
 B.4 Test for water separation efficiency (see 6.5) 
 
a, b, c, d See Figure B.2.  
Figure B.7 — Test rig for water separation efficiency 
Test rig components: 
B.4.1 Main tank with test liquid , minimum capacity 50 l. 
B.4.2 Flow meter , with a measuring range of 0 l/h to 200 l/h. 
B.4.3 Water tank with distilled water , minimum capacity, 1 l. 
B.4.4 Constant-level device , minimum capacity 4 l (optional). 
B.4.5 Flow meter , with a measuring range of 0 l/h to 4 l/h. 
B.4.6 Valve , adjustable. 
B.4.7 Main pipe , minimum internal diameter 12 mm. 
B.4.8 Main pump , diaphragm type, capable of generating consistent water droplet size distribution (see 
also E.1). 
B.4.9 Electric motor . 
B.4.10 Stopcock for  sampling , mounted at a distance of approximately 8 d from the outlet of B.4.8, on/off, 
straight-through bore type with a 56 mm length of 1,2 mm bore pipe at the outlet. ISO 4020:2001(E) 
34  © ISO 2001 – All rights reserved
 B.4.11 By-pass valve , adjustable. 
B.4.12 By-pass pipes , minimum internal diameter 12 mm. 
B.4.13 Stopcock , on/off, straight-through bore type. 
B.4.14 Filter connecting pipes , internal diameter, d, identical to filter inlet and outlet bores and straight for the 
lengths specified in the diagram. 
B.4.15 Filter under test . 
B.4.16 Differential pressure measuring device  (manometer), with a measuring range of 0 kPa to 40 kPa. 
B.4.17 Valve , adjustable. 
B.4.18 Head tube with scale , with a measuring range of 0 mm to 300 mm. 
B.4.19 Orifice or adjustable valve . 
B.4.20 Collection tank , 3) minimum capacity 10 l. 
B.4.21 Transfer pump , 3) minimum flow rate 200 l/h. 
B.4.22 Transfer pipes , 3) minimum internal diameter 12 mm. 
B.4.23 Coalescer , 3) capable of reducing free water content to less than 300 mg/l. 
B.4.24 Absorbent filter , 3) minimum flow rate 200 l/h, capable of removing any undissolved water after B.4.23 
and the additives from the fuel (see Fuller's Earth under Other equipment ). 
B.4.25 Valve , 3) adjustable. 
Other equipment: 
Sample bottle,  capacity 100 ml. 
Ultrasonic bath,  frequency 30 kHz to 50 kHz. 
Laboratory centrifuge,  capable of producing a centrifugal force of approximately 1 500 g 
Centrifuge tubes,  capable of reading down to 0,04 % of tube volume. 
Methylene blue powder. 
Surfactant,  water-miscible, surface tension-reducing agent. 
Acetone. 
Fuller's Earth  (see B.4.24). 
Microlitre syringe. 
B.5 Fuel treatment to obtain test liquid as specified in 6.5.1  (treatment with Fuller’s Earth)  
B.5.1 Take the required volume of ordinary diesel fuel in the fuel sump and continuously recirculate the fuel by 
filtering it through commercially available Fuller’s Earth or clay cartridge filters in place of the clean-up filter. 
B.5.2 Periodically (about every 4 h) take a sample of the fuel in a beaker. Filter the sample through a 0,45 mm 
membrane and measure the interfacial tension with distilled water at 20 °C ± 1,5 °C. The platinum ring detachment 
method (ASTM-D 971) is recommended, although other correlatable methods may be used. Stop the fuel treatment 
when the interfacial tension is between 25 and 30 ¥ 10-3 N/m. 
                                                      
3) Optional item. If these items are omitted, B.4.1 and B.4.3 shall have minimum capacity of 200 l. ISO 4020:2001(E) 
© ISO 2001 – All rights reserved   35
 B.5.3 Remove the Fuller’s Earth filters from the test loop or adjust valve positions such that the Fuller’s Earth 
filter is isolated from the test loop. 
B.5.4 Add to the Fuller’s Earth-treated fuel 0,1 % (1 000 ppm) of a cetane number improver. 
NOTE Since cetane number improvers are commercially available additives and since they may have a finite shelf life, it is 
advisable to check the interfacial tension of this treated fuel (with a cetane number improver against distilled water  
(ASTM-D 971). If the fuel treatment is successful and the cetane number improver additive is acceptable, the interfacial tensio n 
within 1 h of cetane number improver addition should be between 23 ¥ 10-3 N/m and 28 ¥ 10-3 N/m. 
B.5.5 Circulate the fuel with additive through the pump for at least two complete turnovers of the fuel volume in 
the sump. The fuel treatment is now complete. 
B.6 Collapse/burst test of the filter element (see 6.6)  
 
Figure B.8 — Test rig for the collapse/burst test 
Test rig components: 
B.6.1 Tank with test liquid , minimum capacity 5 l. 
B.6.2 Pump , gear type driven by an electric motor with continuously-variable speed control and capable of 
supplying a flow of 200 l/h or a pressure of up to 2 000 kPa above atmospheric pressure. 
B.6.3 Differential pressure gauge . 
B.6.4 Filter under test . 
B.6.5 Flowmeter , with a measuring range of 0 l/h to 200 l/h. 
B.6.6 Stirrer . 
B.6.7 Pipes , minimum internal diameter 12 mm. 
Other equipment: Glass jar , capacity 1 l. 
Laboratory stirrer . ISO 4020:2001(E) 
36  © ISO 2001 – All rights reserved
 B.7 Pulsating pressure fatigue test (see 6.8) 
 
Figure B.9 — Test rig for pulsating pressure fatigue test 
Test rig components: 
B.7.1 Oil reservoir . 
B.7.2 Pump assembly . 
B.7.3 Filter under test . 
B.7.4 Inlet pressure control valve . 
B.7.5 Solenoid valve . 
B.7.6 Pressure gauge . 
B.7.7 Solenoid valve . 
B.7.8 Solenoid sequence timer and counter , to operate B7.5 and B.7.7. 
B.7.9 Cooling coils (heat exchanger) . 
B.7.10 Thermostat . 
B.7.11 Metal pipes , internal diameter 12 mm. ISO 4020:2001(E) 
© ISO 2001 – All rights reserved   37
 Annex C  
(normative)  
 
Organic contaminant 
C.1 Apparatus 
All apparatus employed in the preparation of the contaminant shall be thoroughly cleaned by washing in detergent 
solution, rinsing in clean water and dried. 
C.2 Preparation 
a) Place a 250 ml beaker containing a quantity of carbon black powder (see also annex D) in an air oven, 
controlled at 120 °C ± 2 °C for 16 h. Remove the  beaker and allow to cool in a desiccator. Filter about 2 l of 
the test liquid through a cellulose acetate membrane into a 3 l beaker, measure 1 980 ml of the filtrate and add 
220 ml of ashless dispersant additive, measured in a measuring cylinder. Stir the mixture with a laboratory-
type stirrer, running at a speed of approximately 250 min-1, for a period of 1 h. 
b) Weigh 22 g ± 0,1 g of dried carbon black into a beaker, and then carefully transfer to a mortar, washing out the 
beaker with some of the oil/additive mixture with a squeeze-type wash bottle. By means of the pestle and mortar, wet the carbon black and gradually “cream” in with further additions of the oil/additive mixture. As the preparation proceeds, pour some of the carbon black/oil mixture into a 3 l beaker, and with further additions of the filtrate to the mortar, continue the “creaming” process until the carbon black/oil mixture is a smooth, thin 
paste. Transfer the contents of the mortar to the beaker and carry out the final washing of the pestle and 
mortar with the remaining quantity of the oil/additive mixture. (The time spent on this stage of “creaming” is about 1 h 30 min.) 
c) Stir the contents of the 3 l beaker thoroughly for approximately 1 h using the laboratory-type stirrer, running at 
approximately 250 min
-1. Transfer the mixture to a ball mill porcelain pot containing a charge of carbon steel 
balls and, after sealing, rotate the pot horizontally on rollers at a rotational frequency of approximately 50 min-1 
for 24 h.  
The internal dimensions of the porcelain pot shall be approximately 175 mm diameter, 200 mm deep. The number and diameters of the carbon steel balls shall be:  162 of 13 mm Ø 
 60 of 19 mm Ø 
 26 of 25 mm Ø 
d) At the end of the ball milling period, remove the pot from the rollers, transfer its contents to a clean 3 l beaker 
and allow the pot to drain. 
e) Stir the concentrate with a glass rod. Remove a suitable sample volume in order to determine the 
concentration of insolubles in the dispersion. Carry out the analysis according to the procedure given in annex F, to ensure that the solids concentration is within 1 % ± 0,1 % ( m/V). Immediately transfer 200 ml of the 
concentrate to a clean 3 l beaker and dilute with filtered test liquid to a total volume of 2 l, washing out the 
measuring cylinder with filtered test liquid. Stir the mixture for approximately 1 h with the laboratory-type stirrer, 
running at approximately 250 min
-1. Then carry out choking tests with reference filter papers of two grades, 
eight of each grade being tested. The contaminant shall be fed by means of an appropriate pump at a flow rate ISO 4020:2001(E) 
38  © ISO 2001 – All rights reserved
 of 5 ml/min. The filter test area for each test paper shall be 25 cm2. Measure the volumes to choke the filter 
papers when the end pressure is reached.  
For details of the filter holder assembly for choking tests, see Figure C.1. 
Dimensions in millimetres 
Key 
1 Four studs 
2 Cork gasket, 1,5 mm thick 3 Filter paper 
4 Filter bed 
a 24 equally-spaced, 1,5 mm 
diameter holes around the groove. 
b 16 equally-spaced, 1,5 mm 
diameter holes around the groove. 
c 8 equally-spaced, 1,5 mm 
diameter holes around the groove. 
d 4 equally-spaced, 1,5 mm 
diameter holes around the groove.  
Figure C.1 — Filter holder assembly for choking tests ISO 4020:2001(E) 
© ISO 2001 – All rights reserved   39
 C.3 Correlation test 
When changing from one set of reference papers to a new one, it is necessary to carry out a correlation test in 
accordance with C.2 e). Since the choking volume of the reference papers is used for correction of filter life test 
results, this correlation test enables filter life results to be compared, whenever they were obtained. 
The new standard volume 0V¢ (see 6.4.7.1.2) is then given by the formula 
y
00
xV
VVV=¢  
where 
V0 is the old standard volume; 
Vx is the choking volume of the old reference paper; 
Vy is the choking volume of the new reference paper. 
It is essential that the choking volumes of the two reference papers be determined in parallel, i.e. at the same time 
and with the contaminant from the same tank. Since the choking times are different, this can be done with a 
separate pump for each paper. However, it is more convenient to use a single pump with two hoses, both set for a higher rate of flow than the 5 ml/min required, using by-pass arrangements so that the flow through the papers can be controlled independently. 
Measures shall be taken to keep pressure fluctuations low; i.e. it is better to use a smaller bore hose and run the 
pump fast than vice versa. The choking pressure is taken to be the maximum of the fluctuations. However, towards 
the end of the test, the differential pressure increases rapidly, as is usual when filters approach their choked 
conditions, so that the effect of pressure fluctuations on the time to reach the choking pressure is insignificant. 
 ISO 4020:2001(E) 
40  © ISO 2001 – All rights reserved
 Annex D  
(normative)  
 
Specification for carbon black powder used for the organic contaminant 
concentrate 
D.1  Description 
An amorphous black solid in the form of a very fine powder. 
D.2  Composition 
Elemental carbon with very minor quantities of moisture, hydrogen, oxygen and inorganic substances. 
D.3  Source 
Manufactured by the incomplete combustion of oil. 
D.4  Density 
The density shall be in the range from 1 700 kg/m3 to 1 900 kg/m3. 
D.5  Particle size distribution 
The particle size distribution shall conform to the following related statistical data and to Figure F.1: 
 Mean particle diameter = 66,2 nm 
 Standard deviation = ± 30,5 nm 
 Surface area = 35,1 m2/g ISO 4020:2001(E) 
© ISO 2001 – All rights reserved   41
  
Figure D.1 — Histogram showing the frequency of varying particle diameters ISO 4020:2001(E) 
42  © ISO 2001 – All rights reserved
 Annex E  
(normative)  
 
Supplementary details for water separation test 
E.1 Diaphragm pump 
Static pressure (no flow): 34,5 kPa to 55,1 kPa above atmospheric pressure. 
Displacement per stroke: 8,5 cm3 maximum. 
Movement up: 2,72 mm maximum. 
Movement down: 2,84 mm maximum. 
Fuel flow through 3 mm orifice at 1 500 min-1 cam speed: 90 l/h minimum. 
Valve orifice diameter (two): 10 mm Diaphragm effective diameter: 60 mm 
Cam rotational frequency during test: 1 425 min
-1 ± 26 min-1. 
E.2 Method of determining undissolved water content 
E.2.1 Each sample of test liquid shall be ultrasonically dispersed at 30 kHz to 50 kHz for 5 min and then shaken 
by hand a few times. 
E.2.2 Fill a clean centrifuge tube from the sampling point ( B.4.19 ) (see B.4). 
E.2.3 Add a trace of methylene blue powder sufficient to adequately colour the water. 
E.2.4 Using a microlitre syringe, dispense approximately 1 µl of water-miscible surfactant into the tube and 
ultrasonically disperse for 5 min. (This will remove water adhering to the sides of the centrifuge tube.) 
E.2.5 Centrifuge the tube for 10 min at approximately 1 500 g centrifugal force ( g = gravity). 
E.2.6 Remove the tube from the centrifuge and read off the volume of water indicated by the blue portion on the 
capillary scale. Subtract 1 µl to compensate for the surfactant. (To clean the tube, tip out the majority of the contents and refill with acetone; agitate the capillary contents with a fine wire; centrifuge in the inverted position for 5 min.) ISO 4020:2001(E) 
© ISO 2001 – All rights reserved   43
  
a Draining of separated water. 
Figure E.1 — Curve showing undissolved water in effluent ISO 4020:2001(E) 
44  © ISO 2001 – All rights reserved
 Annex F  
(normative)  
 
Determination of the insoluble content 
F.1  Scope 
This annex specifies the method that shall be used for determining the insoluble content of the organic contaminant 
concentrate. 
F.2  Principle 
The concentrate sample is passed through a cellulose acetate membrane of 47 mm or 60 mm diameter, the pore size being 0,22 µm. 
F.3  Test equipment 
See Figure F.1 and F.3.1 to F.3.8. 
Key 
1 Glass filter funnel 
2 Sample filtering membrane and 
control mebrane 
3 Spring-loaded clamp 
4 Static earth terminal for connecting 
wire discharging static charges to earth 
5 PVC tubes for connection to 
vacuum pump 
6 Büchner flask of suitable capacity 7 Stopper 8 Sintered glass support 
 
Figure F.1 — Test assembly used for the determination of insoluble content ISO 4020:2001(E) 
© ISO 2001 – All rights reserved   45
 F.3.1 Laboratory oven,  capable of being maintained at a temperature of 105 °C ± 5  °C. 
F.3.2 Vacuum pump assembly , with a pump driven by an electric motor, capable of reaching at least 70 kPa 
below atmospheric pressure. 
F.3.3 Desiccator . 
F.3.4 Petri dishes,  to hold membranes of 60 mm diameter. 
F.3.5 Force-feed wash-bottle,  with a capacity of at least 500 ml. 
F.3.6 Laboratory balance , accurate to 0,1 g. 
F.3.7 Volumetric flask (calibrated) , with a capacity of 50 ml. 
F.3.8 Petroleum ether , pre-filtered analytical grade, boiling range 40 °C to 60 °C. 
F.4  Procedure 
a) Wash a filter holder and two Petri dishes ( F.3.4 ), suitably marked for each sample to be analysed (see note), in 
warm water to which a detergent has been added. 
NOTE Each sample to be analysed requires the use of two membranes; one is used for filtering the sample, and the other 
used underneath the filtering membrane as a control membrane. This enables corrections to mass to be made as a result of 
changes in humidity, temperature etc. 
b) Hold the filter holder and Petri dishes with clean tongs and rinse thoroughly with acetone delivered from a 
force-feed wash-bottle ( F.3.5 ). 
c) Place the filter holder and Petri dishes in an oven ( F.3.1 ) set at a temperature of 105 °C ± 5 °C for at least 1 h. 
d) Remove the filter holder from the oven, and place in a desiccator ( F.3.3 ) to cool, until required for use. 
e) Remove the Petri dishes from the oven, and place in a desiccator to cool for a minimum period of 1 h. 
f) Remove the Petri dishes from the desiccator, place a cellulose acetate membrane in each Petri dish, and 
replace in the oven for at least 1 h. 
g) Remove the Petri dishes, with the membranes, from the oven, and place in desiccator to cool for at least 1 h. 
Remove from the desiccator and stand in the atmosphere for at least 1 h, then remove each membrane in turn and weigh to the nearest 0,1 mg using the laboratory balance ( F.3.6 ). Record the mass, and replace the 
membrane in the Petri dish until required. This procedure shall be closely followed in order to ensure high 
repeatability. 
h) Measure 50 ml of the contaminant to be analysed into a calibrated volumetric flask ( F.3.7 ). Pour 500 ml of 
petroleum ether into a force-feed wash-bottle. 
i) Remove the filter holder from the desiccator, place the appropriate pre-weighed control membrane and sample 
filtering membrane into the filter holder, with the control membrane beneath the filtering membrane, and assemble the filter holder (see Figure F.3). Install on a suitable Büchner flask, ensure that the filter holder is 
suitably earthed and apply a pressure of 70 kPa below atmospheric pressure using the vacuum pump ( F.3.2 ). 
j) Pour the organic contaminant concentrate on to the filtering membrane and simultaneously wash through with 
250 ml of petroleum ether ( F.3.8 ) delivered from a force-feed wash-bottle. Some of this 250 ml shall be used to 
wash out the volumetric flask. ISO 4020:2001(E) 
46  © ISO 2001 – All rights reserved
 k) Wash down the inside wall of the filter holder and continue washing through the membrane with petroleum 
ether until a total of 500 ml has been used. At this stage there should be no traces of the concentrate carrier liquid on the membrane. 
l) Dismantle the filter holder and return the sample filtering membrane and control membrane to the appropriate 
Petri dishes, and replace in the oven set at 105 °C ± 5 °C for at least 1 h. 
m) Remove the Petri dishes containing the membranes from the oven and place in a desiccator to cool for a 
minimum period of 1 h. 
n) Remove the Petri dishes containing the membranes from the desiccator and stand in the atmosphere for at 
least 1 h, then remove each membrane in turn and weigh to the nearest 0,1 mg and record the masses. 
o) The mass of insolubles present shall then be determined as follows: correct the mass of the clean sample 
filtering membrane by applying the difference in mass occurring on the control membrane after filtering (i.e., add the difference if an increase occurs, or subtract the difference if a decrease occurs). 
p) Express the results as percentage, mass to volume.  ISO 4020:2001(E) 
© ISO 2001 – All rights reserved   47
 Annex G  
(normative)  
 
Diagram for showing instantaneous filtration efficiency and differential 
pressure versus choking time 
 
Figure G.1 ISO 4020:2001(E) 
48  © ISO 2001 – All rights reserved
 Bibliography 
[1] ISO 1219-1:1991, Fluid power systems and components — Graphic symbols and circuit diagrams — Part 1: 
Graphic symbols  ISO 4020:2001(E) 
ICS  43.060.40 
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© ISO 2001 – All rights reserved