ﺍﻟﻌﺭﺒﻴﺔ ﺍﻟﺨﻠﻴﺞ ﻟﺩﻭل ﺍﻟﺘﻌﺎﻭﻥ ﻤﺠﻠﺱ ﻟﺩﻭل ﺍﻟﺘﻘﻴﻴﺱ  ﻫﻴﺌﺔ 
GCC STANDARDIZATION ORGANIZATION (GSO) 
 
 
 
 
 
 ﻤﺸﺭﻭﻉ : ﻨﻬﺎﺌﻲ  
 
   
GSO2/FDS/ ISO 2942:2011 
ISO 2942:2004 
 
 
 
ﺍﻟﻬﻴﺩﺭﻭﻟﻴﺔ  ﺍﻟﺴﻭﺍﺌل  ﻗﺩﺭﺓ - ﺍﻟﻤﺭﺸﺢ  ﻋﻨﺎﺼﺭ – ﺴﻼﻤﺔ ﻤﻥ ﺍﻟﺘﺤﻘﻕ 
ﺍﻟﻔﻘﺎﻗﻴ ﻟﺘﻜﻭﻥ ﺍﻷﻭﻟﻰ ﺍﻟﻨﻘﻁﺔ ﻭﺘﺤﺩﻴﺩ    ﻊﺍﻟﺘﺼﻨﻴﻊ  
 
Hydraulic fluid power – Filter elements – Verification of 
fabrication integrity and determination of the first bubble point  
 
 
 
 إﻋﺪاد 
 ﺍﻟﻤﺭﻜﺒﺎﺕ  ﻤﻭﺍﺼﻔﺎﺕ  ﻟﻘﻁﺎﻉ ﺍﻟﻔﺭﻋﻴﺔ  ﺍﻟﺨﻠﻴﺠﻴﺔ  ﺍﻟﻔﻨﻴﺔ ﻭﺍﻹﻁﺎﺭﺍﺕﺍﻟﻠﺠﻨﺔ   
   
ﻹﺒﺩﺍﺀ ﺘﻭﺯﻴﻌﻬﺎ  ﺘﻡ ﺨﻠﻴﺠﻴﺔ ﻗﻴﺎﺴﻴﺔ ﻟﻤﻭﺍﺼﻔﺔ  ﻤﺸﺭﻭﻉ  ﺍﻟﻭﺜﻴﻘﺔ ﻫﺫﻩ  ﻟﺫﻟﻙ ﺒﺸﺄﻨﻬﺎ، ﻭﺍﻟﻤﻼﺤﻅﺎﺕ  ﺍﻟﺭﺃﻱ 
 ﻤﻥ ﺍﻋﺘﻤﺎﺩﻫﺎ  ﺒﻌﺩ ﺇﻻ ﺨﻠﻴﺠﻴﺔ ﻗﻴﺎﺴﻴﺔ ﻜﻤﻭﺍﺼﻔﺔ  ﺇﻟﻴﻬﺎ ﺍﻟﺭﺠﻭﻉ  ﻴﺠﻭﺯ ﻭﻻ ﻭﺍﻟﺘﺒﺩﻴل،  ﻟﻠﺘﻐﻴﻴﺭ ﻋﺭﻀﺔ ﻓﺈﻨﻬﺎ
ﺍﻟﺨﻠﻴﺠﻴﺔ  ﺍﻟﻬﻴﺌﺔ ﺇﺩﺍﺭﺓ ﻤﺠﻠﺱ.   ﺁﻭ ﺇﺱ ﺠﻲ/ ﺁﻴﺯﻭ٢٤٩٢ : ١١٠٢  ﺧﻠﻴﺠﻴﺔ  ﻗﻴﺎﺳﻴﺔ  ﻣﻮاﺻﻔﺔ
GSO STANDARD GSO/ISO 2942:2011  
 
1   
ﺘﻘﺩﻴﻡ  
 ﺍﻷﺠﻬﺯﺓ  ﻋﻀﻭﻴﺘﻬﺎ  ﻓﻲ ﺘﻀﻡ ﺇﻗﻠﻴﻤﻴﺔ ﻫﻴﺌﺔ ﺍﻟﻌﺭﺒﻴﺔ ﺍﻟﺨﻠﻴﺞ ﻟﺩﻭل ﺍﻟﺘﻌﺎﻭﻥ ﻤﺠﻠﺱ ﻟﺩﻭل ﺍﻟﺘﻘﻴﻴﺱ ﻫﻴﺌﺔ
ﻟ ﺍﻟﻭﻁﻨﻴﺔ  ﺍﻟﻘﻴﺎﺴﻴﺔ ﺍﻟﻤﻭﺍﺼﻔﺎﺕ  ﺇﻋﺩﺍﺩ ﺍﻟﻬﻴﺌﺔ ﻤﻬﺎﻡ ﻭﻤﻥ ، ﺍﻟﻌﺭﺒﻴﺔ ﺍﻟﺨﻠﻴﺞ ﺩﻭل ﻓﻲ ﻭﺍﻟﻤﻘﺎﻴﻴﺱ  ﻠﻤﻭﺍﺼﻔﺎﺕ
 ﻤﺘﺨﺼﺼﺔ  ﻓﻨﻴﺔ ﻟﺠﺎﻥ ﺒﻭﺍﺴﻁﺔ ﺍﻟﺨﻠﻴﺠﻴﺔ  . 
 ﺍﻟﻔﻨﻴﺔ ﺍﻟﻠﺠﻨﺔ ﻋﻤل ﺒﺭﻨﺎﻤﺞ ﻀﻤﻥ ﺍﻟﻌﺭﺒﻴﺔ ﺍﻟﺨﻠﻴﺞ ﻟﺩﻭل ﺍﻟﺘﻌﺎﻭﻥ ﻤﺠﻠﺱ ﻟﺩﻭل ﺍﻟﺘﻘﻴﻴﺱ ﻫﻴﺌﺔ ﻗﺎﻤﺕ ﻭﻗﺩ  
 ٢ﺭﻗﻡ-١ " ﻟﻘﻁﺎﻉ ﺍﻟﻔﺭﻋﻴﺔ ﺍﻟﺨﻠﻴﺠﻴﺔ  ﺍﻟﻔﻨﻴﺔ ﺍﻟﻠﺠﻨﺔ  ﺍﻟﻤﺭﻜﺒﺎﺕ  ﻤﻭﺍﺼﻔﺎﺕ  ﻭﺍﻹﻁﺎﺭﺍﺕ  "  ﺒﺘﺒﻨﻲ
 ﺁﻴﺯﻭ  ﺭﻗﻡ ﺍﻟﺩﻭﻟﻴﺔ ﺍﻟﻘﻴﺎﺴﻴﺔ ٢٤٩٢ﺍﻟﻤﻭﺍﺼﻔﺔ /٤٠٠٢ " ﻗﺩﺭﺓ ﺍﻟﺴﻭﺍﺌل ﺍﻟﻬﻴﺩﺭﻭﻟﻴﺔ -ﻋﻨﺎﺼﺭ ﺍﻟﻤﺭﺸﺢ – 
ﺍﻟﺘﺤﻘﻕ ﻤﻥ ﺴﻼﻤﺔ ﺍﻟﺘﺼﻨﻴﻊ ﻭﺘﺤﺩﻴﺩ ﺍﻟﻨﻘﻁﺔ ﺍﻷﻭﻟﻰ ﻟﺘﻜﻭﻥ ﺍﻟﻔﻘﺎﻗﻴﻊ“   – ﺃﺼﺩﺭﺘﻬﺎ  ﻭﺍﻟﺘﻲ " ﺍﻟﻤﻨﻅﻤﺔ
ﻟﻠﺘﻘﻴﻴﺱ ﺍﻟﺩﻭﻟﻴﺔ"  ﺍﻟﻌﺭﺒﻴﺔ ﺒﺎﻟﻠﻐﺔ ﺘﺭﺠﻤﺘﻬﺎ  ،ﻭﺘﻤﺕ  ﺍﻟﻤﻤﻠﻜ ﻭﻗﺎﻤﺕ ﺔ  ﻤﺸﺭﻭﻉ  ﺒﺈﻋﺩﺍﺩ ﺍﻟﺴﻌﻭﺩﻴﺔ  ﺍﻟﻌﺭﺒﻴﺔ 
ﺍﻟﻤﻭﺍﺼﻔﺔ  ﻫﺫﻩ  . 
 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 2942:2004  “Hydrau lic fluid power – Filter 
elements – Verification of fabrication in tegrity and determin ation of the first 
bubble point " issued by International Organization for Standardization which 
has been translated into  Arabic. The Draft Standa rd 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 2942:2004(E)
© ISO 2004
  
 INTERNATIONAL 
STANDARD  ISO
2942
Fourth edition
2004-08-15
Hydraulic fluid power — Filter 
elements — Verification of fabrication integrity and determination of the first bubble point 
Transmissions hydrauliques — Éléments filtrants — Vérification de la 
conformité de fabrication et détermination du point de première bulle 
 ISO 2942:2004(E) 
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ii © ISO 2004 – All rights reserved
  ISO 2942:2004(E) 
© ISO 2004 – All rights reserved  iii
 Contents Page 
Foreword....................................................................................................................... ..................................... iv  
Introduction ................................................................................................................... ..................................... v  
1 Scope........................................................................................................................ .............................. 1  
2 Normative references ......................................................................................................... .................. 1  
3 Terms and definitions........................................................................................................ ................... 1  
4 Apparatus and materials ...................................................................................................... ................ 2  
5 Test methods................................................................................................................. ........................ 3  
5.1 General procedure .......................................................................................................... ...................... 3  
5.2 Verification of fabrication integrity (absence of air bubbles)........................................................... 4  
5.3 Determination of the first bubble point.................................................................................... ........... 4  
6 Data presentation............................................................................................................ ...................... 5  
7 Identification statement..................................................................................................... ................... 5  
Annex A  (normative)   Test report for verification of filter element fabrication integrity and 
determination of first bubble point ............................................................................................ ......... 6  
Bibliography ................................................................................................................... .................................... 7  
 ISO 2942:2004(E) 
iv © ISO 2004 – 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 2. The main task of technical committees is to prepare International Standards. 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 document may be the subject of patent 
rights. ISO shall not be held responsible for identifying any or all such patent rights. 
ISO 2942 was prepared by Technical Committee ISO/TC 131, Fluid power systems , Subcommittee SC 6, 
Contamination control . 
This fourth edition cancels and replaces the third edition (ISO 2942:1994) which has been technically revised. ISO 2942:2004(E) 
© ISO 2004 – All rights reserved  v
 Introduction 
In hydraulic fluid power systems, power is transmitted and controlled through a liquid under pressure within an 
enclosed circuit. Filters maintain fluid cleanliness by removing insoluble contaminants. 
The ability of a filter to achieve and maintain the required level of performance depends, among other 
parameters, upon its filtration rating and structural integrity. Any imperfections in the structure, either through poor manufacturing techniques or lack of strength, will allow bypassing of unfiltered fluid. 
The integrity of the element after manufacture can be evaluated using a non-destructive filter integrity test. 
This test determines whether flaws are present which would allow the fluid to bypass the filtering process and provides for quality control. The test is also used to evaluate whether damage has been sustained by the 
element during both service and laboratory tests. 
The first bubble point test is used for investigative product development and/or production process evaluation.  
The acceptability of filtration performance cannot be determined by the first bubble point test. 
 INTERNATIONAL STANDARD ISO 2942:2004(E)
 
© ISO 2004 – All rights reserved  1
 Hydraulic fluid power — Filter elements — Verification of 
fabrication integrity and determination of the first bubble point 
1 Scope 
This International Standard specifies a bubble-point test method applicable to filter elements used in hydraulic 
fluid power systems. It can be used either to verify the fabrication integrity of a filter element (by checking the 
absence of bubbles) or to permit the localization of the largest pore of the filter element by determining the first 
bubble point. 
Verification of fabrication integrity defines the acceptability of the filter elements for further use or testing. The first bubble point is established through continuation of the fabrication integrity test. It is under no 
circumstances a functional characteristic of a filter element; in particular, it cannot be used for extrapolation to the concepts of filtration rating, efficiency or retention capacity and should be used for information only. 
2 Normative references 
The following referenced documents are indispensable for the application 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 5598, Fluid power systems and components — Vocabulary  
ISO 6295, Petroleum products — Mineral oils — Determination of interfacial tension of oil against water — 
Ring method.  
3 Terms and definitions 
For the purposes of this International Standard, the definitions given in ISO 5598 and the following apply.  
3.1 
filter element 
porous device that performs the actual process of filtration 
NOTE This definition differs from that given in ISO 5598, which reads: “The component which ensures the retention 
of contaminant.” 
3.2 
fabrication integrity physical acceptability of a filter element to meet the specification designated by the filter manufacturer 
3.3 
first bubble point 
pressure at which the first bubble stream appears when a filter element is tested using the method specified in 
this International Standard 
NOTE In the absence of manufacturing defects, this value is indicative of the largest pore of the filtering medium. ISO 2942:2004(E) 
2 © ISO 2004 – All rights reserved
 4 Apparatus and materials 
4.1 Bubble-point testing apparatus , as shown in Figure 1, is comprised of the elements 4.1.1 to 4.1.5: 
4.1.1 Compressed-air supply , with filter(s) and pressure regulator(s), adjustable up to 10 kPa (100 mbar). 
4.1.2 Pressure-measuring device , with an accuracy of ± 5 % of the reading. 
4.1.3 Temperature-measuring device , with an accuracy of ± 0,5 °C. 
4.1.4 Test container , for submerging the filter element under test. 
4.1.5 Device , for restraining the filter element during immersion to the required depth and allowing rotation 
about the element’s major axis either manually or with an automatic mechanism. 
4.2 Test liquid 
The test liquid shall be clean propan-2-ol (isopropyl alcohol or IPA) or an alternative liquid designated by the 
filter element manufacturer. Its cleanliness shall be consistent with subsequent test requirements. Its surface tension shall be regularly checked in accordance with the requirements of ISO 6295. It is advisable to renew 
the liquid when its surface tension varies by ± 15 % from the original value.  
If the test element has been exposed to other hydraulic fluids prior to being subjected to the fabrication 
integrity test, then it is permissible to use the same type of hydraulic fluid as the fabrication integrity test liquid, 
provided that the requirements of 4.2 are met. If this is not possible, all residual previous liquid shall be removed by appropriate means before testing. This is to ensure correct and consistent wetting of the element’s media. Test data can be compared only between tests that have used the same type of test liquid at equal testing conditions. ISO 2942:2004(E) 
© ISO 2004 – All rights reserved  3
 Dimensions in millimetres 
 
Key 
1 compressed air supply 
2 compressed air filter 
3 pressure regulator 4 test container 5 test liquid 6 thermometer 7 filter element under test 
8 pressure-measuring device 
Figure 1 — Typical bubble-point testing apparatus 
5 Test methods  
WARNING — Exercise care when using solvents with low flash points, as there could be a risk of fire 
or explosion. Appropriate precautions should be taken to avoid inhalation of fumes from these solvents. Always use suitable protective equipment. Attention is drawn to local health and safety 
procedures. 
5.1 General procedure 
5.1.1 Check that the manufacturer’s identification number or part number of the filter element to be tested 
complies with the manufacturer’s specification. 
5.1.2 Install the clean filter element in the bubble-point testing apparatus (see 4.1), with the major axis of 
the filter element parallel to the surface of the test liquid (see 4.2). ISO 2942:2004(E) 
4 © ISO 2004 – All rights reserved
 5.1.3 Submerge the filter element in the test liquid, which shall be at a temperature of (22 ± 5) °C. 
5.1.4 Allow the filter element to remain submerged in the test liquid for 5 min before proceeding, to ensure 
that the filter element media fibres are wetted. The filter element may be soaked in the test container (4.1.4) 
prior to its being secured in the restraining device (4.1.5). If soaking is carried out while the filter element is secured in the restraining device, ensure that no pressure is applied to the filter during the soaking period. 
5.1.5 Ensure that the lines connecting the pressure-measuring device (4.1.2) to the rest of the apparatus 
are void of liquid. 
5.2 Verification of fabrication integrity (absence of air bubbles) 
5.2.1 Apply just enough air pressure to the inside of the filter element to clear any lines of test liquid and to 
pressurize the element. If necessary, readjust the depth of the test liquid covering the element to (12 ± 3) mm 
above the top of the filter media. 
5.2.2 After the pressure stabilizes, rotate the element around its major axis and gradually increase the 
pressure in a minimum of four suitable increments [for example, 100 Pa (1 mbar)]. Allow the element at least 
one rotation of 360° at each increment while checking for evidence of bubbles. Continue increasing the pressure until the value designated by the filter manufacturer is reached. 
NOTE Air bubbles might be trapped on or within the outer structure of the filter element, resulting in a few spurious 
bubbles. These bubbles can be ignored. A steady stream of bubbles from the filter element at or below the manufacturer’s 
designated pressure is the only consideration. 
Adequate lighting is required for reliable observation. 
Increase air pressure slowly to allow equilibrium to be established and to prevent overshooting of pressure. 
Avoid mechanical vibration or jarring of the test element to prevent upsetting bubble equilibrium, which will give an erroneous and an unrepresentative first bubble-point value. The speed at which the filter element is rotated should be controlled so as not to disturb or release air from the element. 
Adjust the depth of the test liquid covering the filter element to (12 ±3) mm above the top of the filter media 
throughout the test. 
5.2.3 Record the temperature of the test liquid. 
5.2.4 The acceptance criterion is that there shall be no evidence of a single continuous stream of bubbles at 
or below the pressure specified by the manufacturer. Record the acceptance or failure of the filter element in 
accordance with the requirements of Annex A. 
5.3 Determination of the first bubble point 
5.3.1 Gradually apply air pressure progressively to the inside of the filter element in accordance with 5.2.1, 
while rotating it about its axis in accordance with 5.2.2. Increase the pressure in suitable increments, 
beginning at zero pressure or, if this test is a continuation of the fabrication integrity test, at the pressure 
reached in 5.2.2. 
Stop the pressure rise as soon as a single continuous stream of bubbles appears. Record the corresponding 
pressure (this is the first bubble point), the test liquid temperature and the location of the bubbles. 
NOTE Air bubbles might be trapped on or within the outer structure of the filter element, resulting in a few spurious 
bubbles. These bubbles can be ignored. 
Avoid mechanical vibration or jarring of the test element to prevent upsetting the bubble equilibrium, which 
causes erroneously low pressure readings. ISO 2942:2004(E) 
© ISO 2004 – All rights reserved  5
 5.3.2 Completely release the air pressure in the filter element to allow the filter-element medium to be 
thoroughly wetted with liquid, repeat the procedures given in 5.3.1 an additional two times (to give a total of 
three times), and record the corresponding pressures and locations. 
NOTE  When applying the pressure the second and third times, it is permitted to increase the pressure from 0 % to 
50 % of the pressure measured in 5.3.1 rapidly and without respecting the suitable increments. 
6 Data presentation 
Record the result of the verification of fabrication integrity and the data for the determination of the first bubble 
point in accordance with the typical test report shown in Annex A. 
7 Identification statement (Reference to this International Standard) 
It is highly recommended that manufacturers who elect to comply with this International Standard use the 
following conformance statement in test reports, catalogues and sales literature: 
“Filter element fabrication integrity verified and/or first bubble point determined in accordance with 
ISO 2942:2004, Hydraulic fluid power — Filter elements — Verification of fabrication integrity and 
determination of the first bubble point  ”. ISO 2942:2004(E) 
6 © ISO 2004 – All rights reserved
 Annex A  
(normative)  
 
Test report for verification of filter element fabrication integrity 
and determination of first bubble point 
Date of test:  Operator:  
Test liquid 
Type:  Surface tension: m·N/m
Temperature: °C  
Filter element 
Manufacturer:  
Manufacturer’s identification 
number or part number:  
Batch number/date code:  
Used/Unused:  
Comment:  
Fabrication integrity 
Appearance of a continuous stream of bubbles:  YES    NO 
If yes, location of continuous stream of bubbles:  filter material    side seam    end cap 
at the pressure of __________ kPa (_______ mbar), as specified by the manufacturer. 
First bubble point 
Pressure measured when the first single continuous stream of bubbles appears: 
Reading Pressure Location of 
bubbles  Comment 
First reading: kPa mbar filter material 
 end cap 
 side seam  
Second 
reading: kPa mbar filter material 
 end cap 
 side seam  
Third reading: kPa mbar filter material 
 end cap 
 side seam  
 ISO 2942:2004(E) 
© ISO 2004 – All rights reserved  7
 Bibliography 
[1] ISO 1219-11), Fluid power systems and components — Graphic symbols and circuit diagrams — 
Part 1: Graphic symbols for conventional use and data-processing applications  
                                                      
1) To be published. (Revision of ISO 1219-1:1991) ISO 2942:2004(E) 
ICS  23.100.60 
Price based on 7 pages 
© ISO 2004 – All rights reserved