KENYA STANDARD        DKS 294:20 20 
ICS 43.060.20  
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Road vehicles — Air filters —Specification  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
©KEBS 20 20         Third  Edition 20 20 DKS 294:20 20 
 
ii                     © KEBS  2020 — All rights reserved  TECHNICAL COMMITTEE REPRESENTATION  
 
The following organizations were represented on the Technical Committee:  
 
Toyota Kenya 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 STAN DARDS  
 
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 St andards, 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 produced  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 294:20 20 
ICS 43.060.20  
 © KEBS 20 20— All rights reserved            iii  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Road vehicles — Air filters  — Specification  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
KENYA BUREAU OF STANDARDS (KEBS)  
 
Head Office:  P.O. Box 54974, Nairobi -00200, Tel.: (+254  020) 605490, 602350, Fax: (+254 020)  604031  
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Fax: (+254  041) 229448    Fax: (+254 057) 21814  
 
 DKS 294:20 20 
 
iv                     © KEBS  2020 — All rights reserved  Foreword  
 
This Kenya Standard was prepared by the Road Vehicles Technical Committee  under the supervision of the 
Standards Project s Committee  and is in accordance with the procedures of the Kenya Bureau  of Standards .  
 
This standard covers performanc e requirements fo r air filters.  
 
Taking into consideration the views of consumers, it was felt necessary to revise  this standard to improve the 
quality of  air filters used in Kenya.  
 
In the preparation of this standard reference was made to  the following document:  
 
BS 1701 , Inlet air cleaning equipment for internal combustion engines and compressors  — 
Performance testing.  
 
Acknowledgement is hereby made for the assistance received from this sour ce. 
 
 
 
 
  
KENYA STANDARD                DKS 294:20 20 
 
 
© KEBS 2020 — All rights reserved                      1  
 
Road vehicles —Air filters  — Specification  
 
 
1 Scope  
 
This Kenya St andard specifies materials, performance requirements, and methods of te st for road vehicles 
air filters.  
 
2 Materials  
 
2.1 The use of dissimilar metals in the filter assembly, especially brass, copper or steel in contact with 
aluminium alloy shall be avoid ed. 
 
2.2 The filter shall be capable of withstanding flame due  to engine backfires in spark -ignition engines 
without damage.  
 
2.3 The filtering media shall be paper w ith a maximum pore size of 2.5 microns, or any other suitable 
material giving the same fil tering capacity.  
 
2.4 Adhesive  coatings and bonding materials on the filtering media shall have a flash point  of not less 
than 170oC. 
 
2.5 The cell sides shall be made of material sheet ( metal or plastic ) and shall provide positive support 
for the filterin g media. They shall have adequate rigidity for normal handling and installation.  
 
3 Tests  
 
3.1 Pressure drop test  
 
When tested in accordance with Annex A , the initial pressure drop across the filter shall not excee d 
0.003  Mpa.  
 
3.2 Mean dust retaining eff iciency  
 
When tested in accordance with Annex B, the mean dust retaining efficiency shall be not  less than 95 %. 
 
3.3 Dust holding capacity test  
 
When tested in accordance with Annex C, the dust holding capacity shall be not less than 250 g/m2. 
 
4 Marking  
 
4.1 The filter and filter packaging shall be legibly and indelibly marked on the outer casing with the 
following:  
 
i) Manufacturers’ name and/or registered trade  mark ; 
 
ii) Country of origin ; 
 
iii) Manufacturers’ part number . 
 
4.2 Additional markings indi cated on the filter or package shall necessitate additional verifications that 
the filters comply with the claims indicated.  
 KS 294: 2020  
 
                             © KEBS 2020 — All rights reserved  2 Annex A  
(normative)  
 
Determination of pressure drop  
 
A.1  The test shall be carried out with the filter in a level position in th e rig shown in Figure A.1. 
 
A.2  The filter shall be thoro ughly cleaned and then air shall be drawn through it at its rated capacity 
until two consecutive readings, at inter vals of not less than 15 min , show no loss in weight.  
 
A.3  The aspirated air shall  be clean and free from fumes. Its tem perature shall be maintained at  25oC ± 
3 oC and relative humidity at 55oC ± 5 %. 
 
A.4 The test shall be carried out without dust being fed into the filter, and initial pressure drop shall be 
determined at 100 %, 80 %, 60 %, 40 %, 20 % and 10 % of the maximum rate of air flow.  
 
A.5  In each ease the air flow s hall be maintained for 5 min  before the pressure drop is ascertained.  
 
 
 
 
 
 
 
 
Figure A.1 – Test rig for filters  
 
 KS 294: 2020  
 
© KEBS 2020 — All rights reserved           3 Annex B  
(normative)  
 
Determination of the mean d ust retaining efficiency  
 
B.1 The test shall be conducted with the filter in a level position in the rig shown in Figure A.1. 
 
B.2 The filter shall be cleaned thoroughly and then air shall be drawn through it at its rated capacity 
until; two consecutive re adings, at inter vals of not less than 15 min , show no loss in weight.  
 
B.3 The a spirated air shall be clean and free from fumes. Its temperature shall be maintained at 25 oC 
± 3 oC and relative humidity at 55  % ± 5 % 
 
B.4  The filter  shall be weighed and t ogether with the dust feed gear, installed in a level position on the 
test rig.  
 
B.5 The dust feed gear  shall be charged with the required amount of test dust, averaging 10 microns in 
size, and weighed to the nearest 0.1 g.  
 
B.6 The exhauster  shall be star ted and the air flow through the filter adjusted to the maximum air flow 
of the filt er under the test. This air flow  shall be maintained for 10 min  from the beginning of the test.  
 
B.7 The time and the aspirated air temperature (wet and dry bulbs) shall be  recorded at the start and at 
the end of each cycle.  
 
B.8  The design dust/air ration, shall  be maintained throughout the test within limits of ± 5 % and the 
total amount of dust charged to the dust feed gear shall be fed to the filter in the time specifie d. The dust 
feed apparatus shall be calibrated prior to each test, t o ensure that the above limits are maintained.  
 
B.9 The test shall consist of two-hour cycles, each as given in Table B.1.  
 
Table B.1 — Two-hour cycle  
 
Air flow  
(percentage of filter rate d capacity)  Time (m inutes)  
100 15 
20 15 
80 30 
10 15 
50 15 
80 30 
 
At the end of each two -hour cycle, the pressure drop at maximum air shall be recorded  The dust retaining 
efficiency shall be determined as quickly as possible in the following manner:  
 
All the dust on the exterior of the filter and any which may have settled in the test chamber shall be collected, 
by carefully brushing into a suitable container. The dust collected shall then be weighed to the nearest 0.1 g , 
and shall not exceed 1 % by weight of the total dust feed.  
 
B.10  The filter efficiency shall be calculated as follows:  
 
Efficiency % =
100  
CAB     
 
where,  
 
A = weight of filter before test,  
B = weight of the filter after test,  and 
C = weight of the dust fed to the filt er. 
 
i.e. weight of dust in dust -feed gear at the start of the test less the amount of dust in the dust -feed gear at the 
end of the test and less the amount of dust left in the dust chamber or inlet and that collected from the 
exterior of the filter housin g. 
 KS 294: 2020  
 
                             © KEBS 2020 — All rights reserved  4  
Annex C  
(normative)  
 
Dust holding capacity test  
 
C.1 The test shall be conducted as in A nnex B.  
 
C.2  The dust holding capacity in g/m2 is the weight in grammes of dust which can be accommodated 
during the test at the design dust/air ration, while mai ntaining the specified efficiency given in 3.2 and without 
exceeding the pressure drop of 0.015 KPa divided by the area of the filter element.