KENYA STANDARD                                             DKS 293: 20 20 
 ICS 43.060.30  
                            
 
 
 
 
 
 
 
 
 
 
Oil filters  — Specification  
 
 
 
 
 
 
    
 
 
 
 
 
 
 
 
 
 
 
 
©KEBS 20 20         Third  Edition 20 20 
 
 
 
 
 
 
 
 
 
 DKS 293: 2020                                                                                                           
 
ii                     © KEBS 20 20 — All rights reserved  TECHNICAL COMMITTEE REPRESENTATION  
 
The following organizations were represented on the Technical Committee:  
 
Toyota Ken ya Ltd  
D.T Dobie  
Mitsumoto  
Isuzu E.A  
Kenya Association of Bus Manufacturers (KABM)  
Kenya Motor Repairers Association (KEMRA)  
Nissan  
Numerical Machining Complex (NMC)  
Gede Enterprises  
Mobius Motors  
KUMPIA  
Kenya Industrial Research and development Institute (KIRDI)  
Technical University of Kenya (TUK)  
Motorwise Valuers  
Kenya Auto Bazaar Association  
Honda (Nairobi)  
Egerton University  
Olive Technical Services Ltd  
Kenya Jua Kali Association  
MCI Ltd  
Kenya Bureau of Standards — Secretariat  
 
 
 
 
 
REVISION OF KENYA ST ANDARDS  
 
In order to keep abreast of progress in industry, Kenya Standards shall be regularly reviewed. Suggestions 
for improvements to published standards, addressed to the Managing Director, Kenya Bureau of Standards, 
are welcome.  
 
 
 
 
 
© Kenya Bureau of Standards, 20 20 
  
Copyright. Users are reminded that by virtue of Section 25 of the Copyright Act, Cap. 12 of 2001 of  the Laws of Kenya, copyright 
subsists in all Kenya Standards and except as provided under Section 26 of this Act, no Kenya Standard produc ed by Kenya Bureau of 
Standards may be reproduced, stored in a retrieval system in any form or transmitted by any means without prior permission in  writing 
from the Managing Director . 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 KENYA STANDARD                           DKS 293: 2020 
    ICS 43.060.30  
 
 © KEBS 20 20 — All rights reserved            iii  
 
 
 
 
 
 
 
 
 
 
 
Oil filters  — Specification  
 
 
 
 
 
 
 
 
 
 
KENYA BUREAU OF STANDARDS (KEBS)  
 
Head Office:  P.O. Box 54974, Nairobi -00200, Tel.: (+254  020) 605490, 602350, Fax: (+254 020)  604031  
E-Mail: info@kebs.org,  Web:http://www.kebs.org   
 
Coast Region     Lake Region          Rift Valley Region  
P.O. Box 99376, Momb asa-80100   P.O. Box 2949, Kisumu -40100        P.O. Box 2138, Nakuru -20100  
Tel.: (+254  041) 229563, 230939/40  Tel.: (+254 057) 23549, 22396        Tel.: (+254 051) 210553, 210555  
Fax: (+254  041) 229448    Fax: (+254 057) 21814         
 
 
 
 
 
 DKS 293: 2020                                                                                                           
 
iv                     © KEBS 20 20 — All rights reserved   
 
 
 
Foreword  
 
This Kenya Standard was prepared by the Road Vehicles  Technical Committee under the guidance of the 
Standards Project s Committee , and it is in accordance with the procedures of the  Kenya  Bureau  of 
Standards . 
 
It covers performance requirements for oil filters.    
 
Taking into consideration the views of consumers, it was felt desirable that this standard be prepared to 
improve the quality of filters manufactured in this country.  
 
This Third edition cancels and replaces the 2010  edition which has been technically revised.  
 
During the preparation of this standard,  reference was  made to the following document : 
 
       ISO 4548: Methods of test for full -flow lubricating oil filters for internal combustion engines.  
 
Acknowledgement is hereby made for the assistance der ived from this source . 
 KENYA STANDARD                                DKS 293: 2020 
© KEBS 20 20 — All rights reserved                      1  
 
Oil filters  — Specification  
 
1 Scope  
 
1.1 This Kenya Standard specifies materials, performance requirements and methods of test for oil 
filters.  
 
1.2 This standard applies to oil filters for engine lube oil, hydraulic oil, transmission  oil, gear oil, turbine 
oil, transformer oil and bypass oil.  The standard applies for both the element filters and spin on filters.  
 
 
2 Definitions  
 
For the purposes of this sta ndard,  the definition given in  KS ISO 11841 -1: 2000 and K S ISO 11841 -2: 2000 
as well as F igure 1  and F igure 2 shall apply.  
 
 
 
 
 
Figure 1  a)  Cross section view of a t ypical filter parts  for a spin -on filter  
 
 
 
 
 
 
 DKS 293: 2020 
            
                              © KEBS 20 20 — All rights reserved  2  
 
 
 
 
 
 
 
 
 
 
Figure 1 b) — Typical filter parts for a spin -on filter  
                         DKS 293:20 20 
 
 
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     3 
 
 
 
Figure 2 — Typical cross section drawing of an el ement filter  
 
 DKS 293: 2020 
            
                              © KEBS 20 20 — All rights reserved  4 3 Construction  
 
3.1 General construction  
 
3.1.1  The filter casing shall be capable of withstanding normal mechanical stresses encountered in 
service.   
 
3.1.1.1  The top and bottom caps  for the element filters, shall be strong enough to hold  the filtration m edia 
strongly in position while in service . 
 
3.1.1.2  For the spin on filters  
 
a) The seam shall be strong enough and shall not break in service . 
b) The end plate (base plate) shall be strong enough to hold the engine pressures.  
c) If made of steel sheet, the minimum thickn ess shall be 2.8 mm and shall comply with the 
requirements of sub clause 3.1.6.  
 
3.1.1.3  The inner tube shall remain intact without collapsing during the filter’s life.  
 
3.1.2  The filtering media shall be impregnated oil filter paper with a pore size of 5 to 8 microns ( 50 – 80 
micrometers) , wire gauze, felt material, reinforced impregnated paper (with wire gauze) or any other 
appropriate material that meets the performance requirements specified in this standard as per the particular 
type of application.   
 
a) The burst stre ngth shall be 2.5 – 3 kg/cm3  
b) If the filtration media is made of paper then the minimum grammage for the filtration paper shall be 150 
gsm.  
 
3.1.3  All seals shall be of rubber non -reactive with oil and with a minimum Shore A hardness of 65 
International Rubber Hardness degrees.  
 
3.1.4  All gaskets required for mounting the filter element shall have a minimum Shore A hardness of 45 
International Rubber Hardness degrees.  
 
3.1.5  Glue for b onding paper and other components shall withstand heat.  
 
3.1.6  All metal components of the filte r assembly shall be corrosion resistant or properly treated to prevent 
environmental corrosion. They shall either be made from CRCA, electro -galvaniz ed or appropriately treated. 
When tested in accordance with Annex F , they shall show no sign of corrosion.  
 
3.1.7  Thread size for the spin on filters shall be as specified by the original equipment manufacturer 
(OEM ) for that particular application.  
 
3.1.8  All oil filters shall be fitted with a r elieve valve that shall only open at maximum pressure of the 
casing rated by o riginal equipment manufacturer (OEM).  
 
4 Requirements  
 
4.1 Pressure drop test  
 
When tested as described in  Annex  A, the pressure drop across the filter shall not exceed 0.03 MPa.  
 
4.2 By-pass valve opening pressure -test 
 
When tested as described in Annex  B, the by -pass valve opening pressure shall be within the range 
specified, after observing that the leakage rate through the valve at a pressure equal to 0.7 of the minimum 
permissible opening pressure does not exceed 200 mL/min.  
 
4.3 Contaminant capacity ratio  
 
When tested as described in Annex C, the contaminant capacity ratio in g/mm shall not be less than 0.3.                         DKS 293:20 20 
 
 
© KEBS 20 20 — All rights reserved          
     5 
  
4.4 Resistance to high pressure differential  
 
When tested as described in Annex  C, the filter element shall withstand a minimum pressure differ ential of 
0.5 MPa without evidence of failure.  
 
4.5 Burst pressure test  
 
The f ilter shall withstand a minimum proof pressure of 1.5 MPa without evidence of external leakage .  This is 
achieved by holding 1.5 MPa pressure for five minutes.  
 
4.6 Instruments performa nce  
 
All flow  meters and differential pressure gauges shall be ± 5 % accurate.  Temperature controls shall be 
capable of stabilizing temperature at ± 3 %. 
 
4.7 Marking  
 
4.7.1  The filter and filter packaging shall be legibly and indelibly marked on the outer casing  with the 
following:  
 
a) Manufacturers’ name and/or registered trademark ; 
b) Country of origin ; 
c)  Part number . 
 
4.7.2  Additional markings indicated on the filter or package shall necessitate additional verifications that 
the filters comply with the claims indicated.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 DKS 293: 2020 
            
                              © KEBS 20 20 — All rights reserved  6  
Annex A  
(normative)  
 
Determination of pressure drop/flow characteristics  
 
 
A.1 Apparatus  
 
The recommended test rig is shown diagrammatically in Figure  A.1.  It shall consist of an insulated sump 
capable of holding the requir ed volume of oil and accommodating a thermostatically controlled heater 
capable of maintaining the required temperature to ± 2.00C.  Local overheating of the oil shall be avoided.  
 
A pipe shall connect the base of the sump with the inlet port of a motor dr iven pump.  The outlet port of the 
pump shall connect by further pipework with the filter inlet.  
 
The pump delivery is directed to a four -way connector, one limb of which accommodates an indicating 
thermostat, another the bypass return line to the sump.  T he fourth limb is connected to a flowmeter, which 
shall be suitable for use with oils of 24 cSt and 100 cSt kinematics  viscosity and shall register the flow to an 
accuracy of ± 2 per cent, in the pipeline leading to the filter.  As an alternative , the flow meter may be installed 
in the filter outlet pipe. The bypass return to the sump and the filter  outlet pipe shall  terminate below the 
surface of the oil when the oil is in circulation.  
 
Two regulating valves shall be provided for the purpose of flow control , one being situated in the filter bypass 
pipe (6) and the other in the filter outlet pipe (4) ( see Figure A.1).  An On -OFF valve (1) shall also be installed 
in the filter feed pipe.  The pipes connecting the filter shall have a bore equivalent to that of the filter inlet and 
outlet ports or those incorporated in the engine block.  A straight run of at least 12 pipe diameters shall be 
provided before the filter and 8 pipe diameters after the filter.  
 
Tappings for pressure measurement shall be made at 1 pipe  diameter and 4 pipe diameters from the filter 
inlet and outlet ports respectively.  Pressure tappings shall also be made into the test filter in communication 
with the upstream and downstream sides of the filter element.  Whenever practicable, the pressur e gauge 
tappings shall be positioned to measure pressure in quiescent locations within the filter.  
 
Differential pressure gauges, preferably of the mercury manometer type, are recommended, in addition to an 
inlet pressure gauges, calibrated in kN/m2.  
 
The slurry addition vessel, quadrant and filtrate receptacle shown in Figure A1 are not necessary for the test 
in this section, but are required and referred to in subsequent sections.  
 
A.2 Test liquids   
 
A.2.1 Straight mineral oils shall be used.  The temper ature of the oil shall be controlled to achieve 
kinematic viscosities of 24 cSt and 490 cSt, but it shall not exceed 100°C. 
 
A.3 Test procedure  
 
A.3.1 The filter shall be unused and the test liquid and apparatus clean.  The term clean implies that when 
the test liquid is circulated through the test rig and the filter at the rated flow for 5 min no increase in pressure 
across the filter occurs.  
 
A.3.2 The filter shall be installed for test as shown in Figure A.1 using connectors or adaptors in case of 
flange d and headless filters.  
 
A.3.3 The required quantity of clean test liquid shall be added to the sump and circulated through the test 
system via the bypass pipe only.  No test liquid shall pass through the filter at this stage.   
 
 
 
                         DKS 293:20 20 
 
 
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Figure A.1 – diagrammatic arrangement of test rig for determination of   pressure 
differential/flow characteristics, element by pass component performance, initial particle 
retention, variation in particle retention life and cumulative efficiency  
  
A.3.4 The heater shal l be switched on and the thermostat shall be adjusted to the required temperature to 
give correct viscosity.  
 
A.3.5 Upon stabilization of temperature , the test liquid shall be  allowed to flow through the filter at 
approximately 50 per cent rated flow, and the temperature allowed to restabilize.  
 
A.3.6 Readings of flow rate against pressure differences across the filter and filter element shall then be 
obtained by adjustment to the bypass and outlet valves shown in Figure A.1.  
 
The adjustment of these shall  be such that the inlet pressure exceeds the indicated pressure difference, in 
order to ensure a positive pressure at filter outlet.  
             
A.3.7 At least eight readings shall be obtained at approximately equal increments of flow rate between 10 
per cent and 110 per cent of the test flow rate.  The flow rate shall be held constant for a minimum period of 
10 s before taking each pressure differential reading across the complete filter and filter element only.  
DKS 293: 2020 
            
                              © KEBS 20 20 — All rights reserved  8  
 
 
 
Annex B  
(normative)   
 
Determination of element bypass component characteristics  
 
B.1 Test rig as in A.1 and test liquids as in A.2 apply.  The filter shall be unused and the test liquid and 
apparatus clean.  The term clean implies that when the test liquid is circulated through the test rig and  the 
filter at the rated flow for 5 min no increase in pressure across the filter occurs.  
 
B.2 The filter element shall be removed from the filter and in its place a non -permeable dummy element 
of identical dimensions installed.  In respect of sealed unit oil filters from which the element cannot be readily 
removed and replaced by a non -permeable dummy element, it is necessary to open the unit and remove the 
bypass component for testing in a separate housing.  
 
B.3 The filter shall be installed for test as s hown in Figure A.1 using suitable connectors or adaptors in 
the case of flanged or headless filters.  
 
B.4 The required quantity of clean test liquid shall be added to the sump and circulated through the test 
system via the bypass pipe only.  The heater sha ll also be switched on and the thermostat adjusted to 
required temperature.  
 
B.5 Upon stabilization of temperature , the test liquid shall be allowed to flow through the filter bypass 
component at approximately 50 per cent rated flow and the temperature all owed to restabilize.  
 
B.6 The flow rate through the filter bypass component shall be reduced to zero and the pressure 
difference shall be increased slowly, by adjusting the bypass valve.  The pressure difference at which a 
continuous stream of oil starts t o issue from the outlet shall be noted.  
 
B.7 Readings of pressure difference against flow rate at eight approximately equal increments of flow 
rate up to 110 % of the filter’s rated capacity shall be obtained.  This is carried out by adjustment to the 
bypa ss and outlet valves.  The adjustment of these shall be such that the inlet pressure exceeds the 
indicated pressure difference.  The flow rate shall be maintained constant for a minimum period of 10 
seconds before taking each reading.  
 
B.8 The flow rate sh all then be decreased by the same increments as used in B.7 and the pressure 
difference noted in each case.  
 
B.9 The pressure difference shall be decreased to 75 % of the mean of the designed opening pressure 
range, and the rate of leakage, if any, shall b e measured by means of a stopwatch and graduated measure.  
Valve (5), shown in Figure A.1, is a convenient place where this leakage can be collected.  The pressure at 
the inlet shall be further reduced until a continuous stream of oil from the  filter is ju st discontinued, and the 
pressure difference noted.  If the flow from the filter ceases above 75 % of the designed opening pressure, 
the pressure difference at which this occurs shall be recorded.  
 
 
 
 
 
 
 
 
 
 
 
 
 
                         DKS 293:20 20 
 
 
© KEBS 20 20 — All rights reserved          
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Annex C  
(normative)  
Contaminant capacity ra tio test  
 
C.1 Contaminants shall be inorganic such as fused aluminium oxide dust and organic such as carbon 
black.  
 
C.2 The recommended test rig and slurry addition vessel are shown diagrammatically in Figures A.1, C.1 
and C.2 
 
 
 
 
 
 
 
 
 
Figure C.1 – Filter installation for particle retention test  
 
 
 
DKS 293: 2020 
            
                              © KEBS 20 20 — All rights reserved  10 Figure  C.2 – Details of slurry addition vessel  
 
 
 
C.3  A volume of clean test liquid shall be added to the sump and recirculated through the test system 
via the bypass pipe only.  No liquid shall pass through t he filter at this stage.  
 
C.4 Upon stabilization of temperature , the test liquid shall be allowed to flow through the filter with the 
valves set in such a position as to by pass the slurry addition vessel and re -enter the sump.  
 
C.5 The flow rate shall be adjusted through the filter with an inlet pressure of 0.35 Mpa and temperature 
allowed to stabilize.  
 
C.6 The dust not offered to the element shall also be collected as follows:  
 
The beaker used for mixing the slurry shall be placed beneath the small drain  cock situated in the base of the 
slurry addition vessel, the drain cock opened and the bleed screw removed.  
 
C.7 When the test liquid has drained from the slurry addition vessel, the domed top shall be removed 
and all inte rnal surfaces rinsed with 100 mL  of petroleum ether.  The rinsing liquid shall be collected through 
the vessel drain cock into the beaker.  
 
C.8 The percentage of contaminants retained shall be calculated as below:  
 
 Contaminant capacity ratio (g/mm)   =  
HWc        
 Where 
  Wc is  total weight of solids in test filter added during the entire test period to the filter, g;  
 
  H    is   length of filter housing, mm.  
 
 
 
                        DKS 293:20 20 
 
 
© KEBS 20 20 — All rights reserved          
     11 
  
Annex D 
(normative)  
 
Resistance to high pressure difference  
 
D.1 The filter element shall be unused.  
 
D.2 The required volume of liquid shall be added to the sump and circulated through the test system via 
the bypass pipe only.  No test liquid shall pass through the filter at this stage.  
 
D.3 The heater shall be switched on and oil temperature adjusted to obt ain a viscosity of approximately 
100 cSt.  
 
D.4 Having stabilized the oil viscosity conditions, the flow of oil shall be directed to the filter element, and 
the flow rate raised to a level sufficient to produce a pressure differential of 0.5 MPa.  This pres sure shall be 
maintained for a period of 5 min.  
 
D.5 The element shall be inspected for the following defects:  
 
a) Permanent distortion of the con figuration of the filter medium;  
b) Deterioration of end seals;  
c) Permanent distortion or partial collapse of any othe r component of the filter element; and  
d) Element fracture.  
 
Element fracture may not be visible and the immersion of the element in water and application of air pressure 
internally shall be used in detecting weakened areas by noting any voluminous emission o f air bubbles.  The 
applied pressure shall give a measurement on a water manometer of 76 mm and the element shall be placed 
horizontally not more than 6 mm below the surface of the water  and rotated during the test.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 DKS 293: 2020 
            
                              © KEBS 20 20 — All rights reserved  12  
 
Annex     E 
(normative)  
 
Burst pressure test  
 
The burst pressure test shall be performed as follows:  
 
a) Gradually apply pressure to the filter of up to 1.5 Mpa.  
b) Hold the pressure constant for 5 min.  
c) Check the filter for external leakage or other defects as in D.5. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
                         DKS 293:20 20 
 
 
© KEBS 20 20 — All rights reserved          
     13 
  
 
 
Annex    F 
(normative)  
 
Salt fog resistance  test 
 
F.1  Apparatus  
 
F.1.1  Fog cabinet  
 
A fog cabinet having the following features : 
 
a) Exposure chamber:  The chamber shall be made from, or coated with a corrosi on resistant material, 
and shall be so constructed that the spray circulates freely and equally about all test panels.  
b) Racks  for supporting the test panels:  The racks shall be made from, or coated with a corrosion 
resistant material and shall be so constru cted that the test panels are held at an angle of 15° from 
the vertical, without touching each other or any other metal and without any salt solution dripping 
from one panel to another.  
c) Salt solution reservoir:  The reservoir shall be of adequate size and s hall be made from, or coated 
with a corrosion resistant material. It shall be so constructed that no condensation products of the 
spray can drip into the reservoir.  
d) Atomizing nozzles:  The nozzles shall be made from a suitable plastic and shall be so design ed that 
they will produce a finely divided salt solution spray. The apparatus shall be fitted with baffles to 
prevent the salt fog striking the test panels directly.  
e) Air supply:  The compressed air entering the atomizers shall be filtered to remove all impu rities. 
Means shall be provided to humidify and heat the compressed air as required. The air pressure shall 
be constant to within ± 700 Pa and sufficient to provide a finely divided salt solution fog.  
f) Heating of chamber and temperature control:  The exposur e chamber shall be suitably heated and its 
temperature controlled by means of a thermostat. The use of an immersion heater is not permitted.  
 
F.2  Test specimen  
 
A test specimen, cut from a filter  and having suitable holes for suspending them from the rack s. 
  
F.3   Test conditions in the exposure chamber  
 
F.3.1   The temperature in the exposure chamber shall be maintained at 33 – 36 °C.  
 
F.3.2   The degree of atomiz ation shall be such that suitable fog collectors placed at any point in the 
exposure zone wil l collect, over an average running period of at least 16  h, from 0. 5 – 3 mL  of solution per 
hour for each 80 cm2 of horizontal collecting area. The solution so collected shall have a pH value of 6 .5 – 
7.2 when measured electrometrically.  
 
F.4  Procedure  
 
F.4.1  Bring the exposure chamber to the test conditions. Mount the test specimens, by means of glass or 
plastic hooks, on the supporting racks according to F.1.1 b) and insert the racks in the exposure chamber.  
 
F.4.2  Close the exposure chamber and operat e the cabinet continuously for a period of 48 h, using the test 
specimen in F.2, ensuring that the impact point is within the borders of the test specimen. Then examine the 
each specimen for defects (see clause 3.1.6 ).