1 
  
                            DRAFT TANZANIA STANDARD  
MEDC9 (5278 )P3 - INLET AIR CLEANING EQUIPMENT FOR INTERNAL 
COMBUSTION ENGINES AND COMPRESSORS — (Rev TZS 1959:2017  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 TBS 2017                                                                                                          Second Edition   
2 
 INLET AIR CLEANING EQUIPMENT FOR INTERNAL COMBUSTION  ENGINES AND 
COMPRESSORS — (Rev TZS 1959:2017)  
 
 
0.   Foreword  
The increase of importation of motor vehicles, industri al and agricultural machines leads to rise 
of manufacturing and importation of their spare parts and the number of stakeholders involved 
in this sector is rapidly increasing. This draft standard is prepared to control the quality of 
manufactured and import ed inlet air cleaning equipment for internal combustion engines and 
compressors.  
 
1. Scope  
This International Standard establishes and specifies uniform test procedures, conditions, 
equipment, and a performance report to permit the direct laboratory performan ce comparison of 
air cleaners.  
The basic performance characteristics of greatest interest are air f low restriction or differential 
pressure, dust collection efficiency, dust capacity, and oil carry -over on o il bath air cleaners. 
This test code therefore de als with the measurement of these parameters.  
This International Standard is applicable to air cleaners used on internal combustion engines 
and compressors generally used in automotive and industrial applications.  
 
2. References  
The following documents, in wh ole or in part, are normatively refe renced in this document and 
are indispensable for its application. For dated references, only the edi tion cited applies. For 
undated references, the latest edition of the referenced document (including any amendments) 
applies.  
ISO 5167 -1, Measurement of fluid flow by means of pressure differential devices in serted in 
circular cross section  conduits running full — Part 1: General principles and requirements  
ISO 12103 -1, Road vehicles — Test contaminants for filter evaluati on — Part 1: Arizona test 
dust 
3. Terms, D efinitions , Symbol and Units  
3.1 Terms and definitions  
For the purposes of this Tanzania  Standard, the followi ng terms and definitions apply.  
 
3.1.1  Air filter air  cleaner  
Device  which removes particles suspended in the fresh charge  as it is drawn into the engine  or 
compressor  
 
3.1.2  Filter element  
Replaceable  part of the air filter, consisting of the filter material and carrying frame  
 
3.1.3  Secondary  element  
Air cleaner element fitted downstream of the primary element for the purpose of  providing the 
engine with  protection against dust in the event of : 
a) Certain  types of primary element failure, or  
b) Dust being present during the removal of the primary element for servicing  
 
3.1.4  Unit under tes t 
Either  a single air cleaner element or a complete a ir cleaner assembly   
3 
  
3.1.5  Single -stage air cleaner  
Air cleaner which does not incorporate a separate pre  cleaner  
 
3.1.6  Multistage air cleaner  
Air cleaner consisting of two or more stages, the first usually being a pre  cleaner, followed by 
one or more filter element s 
 
Note 1 to entry: If two elements are used, the first is called the primary element a nd the second 
one is called the secondary element.  
 
3.1.7  Pre cleaner  
Device  usually using inertial or centrifugal means to remove a portion of the test dust prior to 
reaching  the filter element  
 
3.1.8  Test air flow  
Measure  of the quantity of air drawn through the air cleaner outlet per unit time  
Note 1 to entry: The flow rate is expressed in cubic metres per minute corrected to standard 
conditions.  
3.1.9  Rated air flow  
Flow  rate specifie d by the user or manufacturer  
Note 1 to entry: It may be used as the test air flow.  
 
3.1.10  Scavenge air flow  
Measure  of the quantity of air used to remove the collected dust from a pre  cleaner  
Note 1 to entry: It is expressed as a percentage of the test air flo w. 
 
3.1.11  Static pressure  
Pressure  in a duct, at the observed air flow rate, measured by connectin g a pressure gauge to a 
hole or holes  drilled in the wall of the duct  
 
Note 1 to entry: In the tests specified in this International Standard, a static pres sure is 
measured by a manometer (usually a liquid manometer) as a negative pressure difference 
against the atmospheric pressure and in the formulae  this is treated as a positive value.  
 
3.1.12  Restriction  
Static  pressure measured immediately downstream of the unit under test 
 
3.1.13  Differential pressure  
Difference  in static pressure measured immediately upstream and downstream of the unit under 
test 
 
3.1.14  Pressure loss  
Measure  of the loss of energy caused by an air cleaner at the observed air flow rate  
Note 1 to entry: It is express ed as the differential pressure corrected for any di fference in the 
dynamic head at the  measuring points.  
Note 2 to entry: For further information, see Annex A.  
3.1.15  Absolute filter  
Filter  downstream of the unit under test to retain the contaminant passed by th e unit under test   
4 
  
3.1.16  Efficiency  
Ability  of the air cleaner or the unit to remove contaminant under specified test conditions  
 
3.1.17  Capacity  
Quantity  of contaminant removed by the unit under test in producing specified terminal 
conditions  
 
3.1.18  Oil carry -over  
Appearan ce of oil at the cleaner outlet  
 
3.1.19  Test terminal condition  
Condition relating to an air cleaner, the occurrence of which signifies the end of the test  
Note 1 to entry: A test terminal condition may be, for example, any one of the fo llowing: the 
restriction or the differential pressure reaches a specified or agreed value; the dust -removing 
efficiency or some other performance parameter falls to a specified or agreed value; oil carry -
over occurs; a dust pot becomes filled.  
 
3.1.20  Automotive application  
Air cleaner g enerally used for internal comb ustion engines in motor vehicles  
 
3.1.21  Industrial application  
Air cleaner generally used for internal combustion engines in heavy -duty trucks, construction 
equipment and agricultural tractors  
 
3.1.22  Mean dust retaining efficiency  
Mean dust retaining efficiency = Weight of the filter after test –weight of the filter before test   x 100%  
                                                          Weight of dust fed to the filter  
 
3.2 Symbols and units  
The following applied units, according to IS O 80000 -1, are used.  As shown on table 1.  
 
Table 1. Symbols and units  
 
Quantity  
  
Symbol  
  
Unit 
 
Volume flow rate  qv m3/min 
Velocity  v m/s 
Density  ρ kg/m3 
Mass flow rate  qm kg/min  
Pressure  p Pa 
Restriction  Δpr Pa 
Differential pressure  Δpd Pa 
Pressu re loss  Δpl Pa 
Mass  m g 
Temperature  T 0C 
Time  t s 
  
5 
 4. Requirements  
4.1 Fabric Requirements  
Fabric shall conform to the requirements specified in table 2  
Table 2.  Requirements of bonded Filter Fabric  
Variety  Fibre  Mass  
g/m2 Thickness  
mm Tensile 
strength 
Machine 
and Cross 
Direction  
Min 
N Bursting 
strength 
Min 
kPa Air 
permeability  
m3/m2/min 
i Polyester 600 2.20 833 3431  14 
ii Polyester  550 2.00 784 3137  16 
iii Polyester  500 1.80 735 2941  18 
iv Polyester  450 1.70 686 2745  20 
v Polyester  400  666 2450  22 
vi Acrylic  600  833 3431  15 
vii Acrylic  550  784 3137  17 
viii Acrylic  500 2.00 735 2941  19 
ix Polyester/ 
Acrylic  550 2.00 784 3431  15 
x Polyester/ 
Acrylic  500 1.90 735 3137  17 
xi Polypropylene  600 2.30 882 3921  18 
xii Polypropylene  550 2.20 833 3529  20 
xiii Polypropylene  500 2.00 784 3431  22 
Methods 
of Test  IS 667  A-4 A-2 A-3 IS 1966  IS 11056  
Tolerance 
Percent  - ±5.0 ±5.0 - - ±10 
 
4.2 Requirements of  mean dust retaining  efficiency   
When tested in accordance to Annex H, the mean dust retaining efficie ncy should be not 
less than 95%  
 
4.3 Requirement of pressure drop  
When tested in accordance to annex G the initial pressure drop across the filter shall not 
exceed 0.003Mpa . 
 
4.4 Requirement for dust holding capacity  
When tested in accordance to annex I, the dust holding capacity shall not be less than 
250g/m2. 
 
4.5 Requirement for Marking  
The filter and filter package shall be legibly marked on the outer casing with the following.  
i. Manufacture name and/or trade mark  
ii. Country of Origin   
6 
 iii. Manufactures part number  
iv. Batch n umber  
v. Manufacturing date  
 
4.6 Measurement accuracy and standard conditions  
4.6.1  Measurement accuracy  
Measure the air flow rate to within ± 2 % of the actual value, except for the variable air flow test 
when accuracy may be ± 2 % of the maximum value of the cyclic flow rate through the cleaner.  
Measure the differential pressure and restriction to within 25 Pa of the actual value.  
Meas ure the temperature to within 0. 5 °C of the actual value.  
Measure the mass to within 1 % of the actual value except where noted.  
Measu re the relative humidity (RH) with an accuracy of ± 2 % RH.  
Measure the barometric pressure to within 3 hPa.  
The measurement equipment shall be calibrated at regular intervals to ensure the required 
accuracy.  
4.6.2  Standard conditions  
All airflow measurements sh all be corrected to a standard condition of 20 °C at 1 013 hPa (1 
013 mbar).  
See Annex G . 
5. Test materials and test conditions  
5.1 Test dust  
5.1.1  Grade  
The test dust to be used shall be ISO 12103 - A2 (ISO Fine) or ISO 1 2103 - A4 (ISO Coarse), 
subject to agreement be tween the filter manufacturer and client. The chemical analysis  and the 
particle size distribution shall conform to ISO 12103 -1. 
In the absence of an agreement on the dust : 
— For single -stage filters, use ISO Fine test dust, and  
— For multistage filters, u se ISO Coarse test dust.  
 
5.1.2  Preparation  
Before using the test dust, a quantity sufficient to cover the test requirem ents shall be mixed in a 
sealed container for a minimum of 15 min. The test dust shall then be allo wed to become 
acclimatized  to a constant ma ss under the prevailing test conditions.  
 
NOTE : To ensure a constant rate of dust feed with some dust feeders, it may  be found 
necessary to heat the dust prior to being fed to the injector.  
 
5.2 Test oil for oil bath air cleaners  
The oil used for testing oil b ath air cleaners shall be that specified by the filter m anufacturer and 
agreed by the user for use at the appropriate ambient temperature. If an oil is not s pecified, the 
test oil shall be a heavy -duty oil and the viscosity at the temperature of the test s hall be adjusted 
as follows:   
7 
 — 85 mm2/s for oil carry -over and restriction/differential pressure tests;  
— 330 mm2/s for efficiency and capacity tests, including an oil carry -over test after the capacity 
test. 
5.3 Absolute filter materials  
5.3.1  Filter media  
The abso lute filter may consist of fibre  glass media with a minimum thi ckness of 12,7 mm and a 
minimum density of 9,5 kg/m3 The fibre mass  shall be 0,76 g to 1,27 g and t he moisture 
absorption shall be less than 1 % by mass after exposure to 50 °C and 95 % relativ e humidity 
for 96 h. The absolute filte r media shall be installed with nap side facing upstream, in an airtight 
holder that adequately supports the media. The face velocity shall not exceed approx. 0 .8 m/s to 
maintain media integrity.  
As an alternative, a non-woven filter media with the efficiency described in 5.3.2 may be used.  
To reduce any subsequent errors in the measurements caused by los ses of fibres or materials, 
the absolute filter shall be subject to a flow of at least 110 % of the rated  flow of am bient air for 
15 min before the first test weighing.  
 
NOTE the  use of an absolute filter with a ba cking will minimize fibre loss.  
5.3.2  Validation of absolute filter media efficiency, Ea 
Arrange two absolute filters in tandem. Perform a filter efficiency test and determine the mass 
increase of each absolute filter according to the test procedure given in 6.4.3 or 7.5.2:  
 
Ea =    
         X 100%  ...................................................................................................(1)  
 
 Where:  
  Ea is the absolute folter efficiency;  
  Δm Ais the mass increase of upstream absolute filter  
  Δm Bis is the mass increase of downstream absolute filter.  
 
The absolute filter efficiency should be a minimum of 99 % for t he contaminant presented to it.  
5.4 Abso lute filter mass  
The absolute filter shal l be weighed, to the nearest 0. 01 g, after the mas s has stabilized. 
Stabilization may be achieved by storage in a ventilated oven at a constant temperature  of 105 
°C ± 5 °C. The absolute filter shall be weighed insi de the oven. Alternatively, air conditioned 
according to 5.5 may be drawn through the absolute filter for 15 min then the filter is weighed. 
Repea t this procedure until the mass has stabilized.  
 
5.5 Temperature and humidity  
All tests shall be conducted with ai r entering the air cleaner at a temperatu re of 23 °C ± 5 °C. 
Tests shall be conducted at a relative humidity of (55 ± 15) %, the permissible v ariation at each 
weighing stage throughout each single test being ± 2 %.  
The test results of an air cleaner will b e affected by the relative humidity of  the air passing 
through it and the results of otherwise identical tests carried out near the two ext remes of the 
permitted range of relative humidity may not be directly comparable. The tests should be  
conducted withi n the narrowest range of temperature and humidity possible.  
 
6. Test procedure for dry -type air cleaners for automotive applications  
 
6.1 General   
8 
 Performance tests shall be performed on a complete air cleaner asse mbly or on a single air 
cleaner element; tests on a complete air cleaner assembly are preferred. The tes ts shall consist 
of an air flow restriction/differential pressure test, an efficiency test and a capacit y test. In 
addition, a pressure collapse test shall be performed on the air filter element.  
 
6.2 Test equipment  
6.2.1  Typical arrangements to determine resistance to air flow, dust capacit y, dust removal 
characteristics and rupture collapse cha racteristics are shown in Annex B, Figures B.1 
and B.6 to B.11.  
Use a dust feeder which when used with the dust injector  in Figures B.2 and B.3 is 
capable of metering dust over the range of delivery rates required. This dust feed system 
shall not change  the primary particle size distribution of the contaminant. The air feed 
pressure sh all be 100 kPa minimum. The ISO heavy -duty injector pressure shall be 280 
kPa minimum.  
 
The dust feed system shall be validated as follows.  
a) Charge the dust feeder with a pre -weighed amount of test dust.  
b) Simultaneously start the dust feed system and timer.  
c) At 5-min intervals, determine the mass of dust dispensed. Conti nue mass determinations 
of dust increments for 30 min.  
d) Adjust the dust feeder until the average delivery rate is within 5 % of the desired rate and 
the deviation in delivery rate from the average is not more than 5 %.  
 
6.2.2  Use a dust -transfer tube between the dust feeder and the injector  of a size suitable to 
maintain dust  suspension.  
6.2.3  Use the dust injector described in Table 1 and shown in Figures B.2 and B.3.  
 
Table 3  — Recommended ISO dust injectors (see Figures B.2 and B.3)  
 
Dust feed  rate 
(g/min)  
  
0 to 26   
26 to 45   
> 45 
 
Injector type  
  
ISO injector   
ISO injector or ISO 
heavy – duty injector   
ISO heavy – duty 
injector  
 
The specified ISO injector has been shown to feed dust satisfactorily at rates up to 45 g/min. 
Where dust feed ra tes greater than this are required, more than one injector will have to be 
used. It should be noted that the design of the system feeding test dust to the injector may affect 
this maximum rate of dust feed.  
The maximum attainable dust feed rate should ther efore be determined prior to the dust 
feed/injector system being used for tests.  
Injector nozzles are subject to natural erosion. Erosion may affect the distribution and delivery of 
test contaminant. Therefore, it is recommended to use a design with replac eable parts.  
 
6.2.4  Use an inlet tube conforming to Figure B.4.  
The dust injector and inlet tube shall be positioned in such a way that there is no loss of 
dust.  
  
9 
 6.2.5  Use a manometer or other differential pre ssure measuring device with the specified 
accuracy.  
 
6.2.6  For air cleaner assembly testing, use a housing and set -up agreed upon by the 
manufacturer and user conforming to Figure B.11. For air filter element testing, use a 
test set -up and shroud conforming to Figures B.1 and B.5 or an arrangement as shown 
in Figures B.6 or B.7. Where the test equipment is as shown in Figure B.6, the dust is 
fed into the chamber and, to ensure that it does not adhere to the walls and is evenly 
distributed, dry compressed air jets on flexible tubing should be provided in the test 
chambe r, arranged so to agitate any dust that settles out.  
 
When using compressed air for agitating dust, care shall be taken not to eject any dust 
out of the chamber. To ensure that no dust is ejected from the chamber, a negative 
pressure should be maintained b etween the chamber and the atmosphere.  
 
6.2.7  Use an outlet tube conforming to Figure B.4.  
The cross -section shall  be the same as the air cleaner outlet. In the case of non -uniform 
flow conditions caused by special ou tlet tubes, special precautions may be requi red. 
 
6.2.8  Use an air flow rate measuring system having the accuracy described in 4.1.  
Validate the air flow rate measuring system. The air flow meter shall b e of an acceptable 
design, such as a calibrated orifice and manometer conforming to ISO 51 67-1. The 
orifice unit shall be permanently marked  such that it can be identified after calibration. 
Corrections shall be made for variations in absolute pressure and temperature at the 
meter inlet and the air flow r ate shall be expressed in cubic metres per minute cor rected 
to standard conditions (see 4.2).  
 
6.2.9  Use an air flow rate control system capable of maintaining the in dicated flow rate to 
within 1 % of the selected value during steady -state and variable air flow operation.  
 
6.2.10  Use a blower/exhauster for inducing air f low through the syste m, which has adequate 
flow rate and pressure characteristics for the filters to be tested. Pulsation of flow rate 
shall be so low that it is not measurable by the flow rate measuring system.  
 
6.2.11  Grounding is required for all test apparatu s to reduce the effects o f static charges and to 
improve the consistency of the test results. Grounding of metallic and non -metallic 
surfaces, housings, dust transport tubes, injectors and associated hardware is 
recommended.  
 
6.3 Restriction and differential p ressure test  
6.3.1  The purpose of this test is to determine the restriction/diff erential pressure/pressure loss 
across the unit under test which will result when air is passed through under 
predetermined conditions.  
Airflow restriction or differential pressure i s measured with a clean filte r element, or 
elements, at five equally spaced airflows of between 50 % and 150 % of the rated air 
flow, or as agreed upon between the user and manufacturer.  
 
6.3.2  Condition the unit at the airflow rate at which the unit is t ested f or at least 15 min under 
temperature and humidity conditions as specified in 5.5 until the mass has stabilized.   
10 
  
6.3.3  Set up the test stand as shown in Figures B.8 or B.9 and Figures B.14 or B.15 . Seal all 
joints to prevent air leaks. Connect pressure taps.  
 
6.3.4  Measure and record the restriction and the differential p ressure versus the flow rate at 
approximately 50 %, 75 %, 100 %, 125 % and 150 % of the rated air flow , or as agreed 
upon between the user  and manufacturer.  
 
6.3.5  Record the ambient temperature, pressure an d relative humidity.  
 
6.3.6  Correct the recorded restriction and differential pressure to st andard conditions in 
accordance with Annex G.  
 
6.3.7  For pressure loss determination, use the formula given in Annex A.  
 
6.3.8  Plot the results as shown in Annex E or equivalent.  
 
6.4 Efficiency test  
 
6.4.1  Purpose  
The purpose of this test is to determine the retention capabilities of the unit under test. This t est 
can be conducted with either constant or variable air flow and with coarse dust  or fine test dust. 
If desired, efficiency tests can  be performed concurrently with capacity tests (see 6.5 ). 
Determination of the efficiency at constant test air flow can be performed at the rated air flow or 
any percentage thereof, as agreed upon by the user and manufacturer. Determination of 
efficie ncy a t variable air flow can be performed using variable air flow cycle according to 6.7.  
 
6.4.2  Types  
Three types of efficiency tests can be performed, as follows:  
a) full-life efficiency determined when the terminal condition, i.e. the ter minating differential 
pressur e, is reached;  
b) Incremental  efficiency determined when, for example, 10 %, 2 5 % and 50 % of the 
terminating differential pressure minus the initial differential pressure are reached;  
c) Initial  efficiency determined after the addition of 20 g of con taminant or  the number of 
grams numerically equivalent to 6 times the air flow in cubic metres per minute, 
whichever is the greater.  
 
6.4.3  Test procedure — Absolute filter method  
6.4.3.1.  Based on the test flow, calculate the test dust feed rate using a dust concentration  of 
1,0 g/m3 of air; in special cases (e.g. small filters) 0,25 g/m3 or 0,5 g/m3 may be allowed.  
6.4.3.2.  Condition the unit under test according to 6.3.2, then measure and record the mass.  
 
6.4.3.3.  Weigh the absolute filter pad as specified in 5.4 and re cord mass before assembly 
within absolute filter housing.  
 
6.4.3.4.  Set up test stand as shown in Figure B.11 for air cleaner assemblies, or as shown in 
Figure B.1,  B.6 or B.7 for air filter elements. Seal all joints to prevent air leakage.  
 
6.4.3.5.  Recor d the temperature and relative humidity.   
11 
  
6.4.3.6.  Prepare the specified test dust according to 5.1 and weigh out the quantity required for 
test in a suitable test container. For full -life efficiency tests, the quantity shoul d be approximately 
125 % of the  estimated capacity of the unit under test. Record the mass of the container and 
dust to the nearest 0,1 g.  
 
6.4.3.7.  Start the air flow through the test stand and stabilize at the test flo w rate. Record the 
differential pressure.  
 
6.4.3.8.  Load the dust f eeder from the dust container and adjust the feed rate to inject dust at 
the concentration calculated in 6.4.3.1. Reload the dust feeder from the dus t container 
throughout the test as necessary.  
 
6.4.3.9.  At specified time intervals (a minimum of five poin ts is recomm ended), record the 
differential pressure at the test flow and the elapsed test time.  
 
6.4.3.10.  Continue the test until the specified terminal condition is reached.  
 
6.4.3.11.  Record the tem perature and relative humidity.  
 
6.4.3.12.  The dust on  the exterior surfaces of a cleaner assembly o r any which may have settled 
in the test chamber/ducting on the inlet side of a test element shall be coll ected carefully and 
transferred to the pre  weighed dust container together with any dus t remaining in th e dust 
feeder.  
 
6.4.3.13.  Reweigh the dust container and subtract the result from the mass recorded in 6.4.3.6.  
The difference is the mass of dust fed to the unit under test.  
 
6.4.3.14.  Carefully remove the unit under test without losing any dust. Note any  evidence of seal 
leakage or unusual conditions. Weigh the unit, in grams, to within 1 % of  the actual value. The 
increase in mass of the unit under test is this mass minus the mass determined in 6.4.3.2 . In the 
full-life efficiency test [see 6.4.2 a)] thi s increase in mass is the capacity of the unit under test.  
 
6.4.3.15.  Brush any observed dust on the downstream side of the test unit onto the absolute 
filter.  Carefully remove the absolute filter. Repeat step 6.4.3.3 and determine the difference in 
mass. This is the increase in mass of the absolute filter.  
 
6.4.3.16.  Calculate the material balance, B, of the test dust. For the test t o be valid, this value 
shall be within the range 0,98 to 1,02:  
 
B          
   ........................ .............. ........... .......................................................(2)  
   
Where:  
 ∆mF is the increase in mass of the absolute filter  
 ∆mU is the increase in mass of the unit under test  
 mD is the total mass of dust fed.  
 
6.4.3.17  Calculate the efficiency, E, by the following method:  
  
12 
 E =    
         x 100 % ..................... ..........................................................................(3)  
where the symbols are as in Formula (2).  
6.4.4  Test procedure — Direct weighing method  
The direct weigh ing method may be used for cumulative efficiency d etermination where the 
humidity can be controlled to within ± 1,0 % and the accuracy of the increase in mass of the 
filter dete rmined to within 0,1 %.  Where a suitable large, accurate balance is available, it is 
permissible to use a direct weighing method of assessing the performance of the unit under test. 
In such cases the air cle aner under test shall be tested according to the procedure in 6.4.3 
omitting the operations described in 6.4.3.3, 6.4.3.15, 6.4. 3.16 and  6.4.3.17. Calculate the 
efficiency, E, as follows:  
 
E =    
   x 100%  .................................................... .................................................(4)  
 
where the symbols are as in Formula (2).  
The test report should i ndicate the method of efficiency determination used.  
6.5 Capacity test  
6.5.1  The purpose of this test is to determine the total mass gain of the uni t under test at the 
terminating condition. This test can be conducted with either constant or variable air flow and 
with coarse or fi ne test dust contaminant. If desired, the capacity determination can be 
performed concurrently with the efficiency test (see 6.4).  
 
6.5.2 Condition the unit according to 6.3.2. Perform the test as described in 6.4.3 or 6.4.4.  
 
6.5.3 Assuming a constant ratio of elapsed time versus dust feed of the  test unit, record the data 
and plot the curve of restriction versus mass gain. Refer to 6.4.3.9 for restriction and time 
interval data.  
 
Determine the mass gain values as follows:  
 
∆mt = t1/tT x ∆m UT  ..................................... ....................... ....................................(5)  
 
Where:  
 ∆mt is the increase in mass at end of each time interval  
 t1 is the total time at the end if interval  
 tT is the total time at end of test  
 ∆mUT is the total  
  
6.6 Filter element pressure collapse test  
6.6.1 The purpose of this test is to determine the ability of an air filter e lement to withstand a 
specified differential pressure and/or to determine the differential pressure at which collapse 
occurs   
13 
 
 
6.6.2 Set up the test stand to perform the basic dust capacity test in accordance with Figure B.1, 
B.6, B.7 or B.11. Either the element from the prior capacity or efficiency test o r a new element 
can be used for this test.  
 
6.6.3 Increase the air fl ow through the stand and, if necessary, feed dust at any convenient r ate 
until the specified differential pressure is reached or until element collaps e is indicated by a 
decrease in differential pressure or increase in air flow.  
 
6.6.4 Record the maximum d ifferential pressure attained, the reason for terminating the test, 
and the condition of the element after test.  
 
6.7 Variable air flow test  
6.7.1 As an option to the constant air flow test, a variable air flow tes t can be carried out by 
using a variable air f low cycle similar that shown in Figure 1.  
 
6.7.2 In the case of oil bath air cleaners and large air cleaners (e.g. flow  rate > 5 m3/min), the 
duration of every partial flow section may be 5 min instead of 1 min.  
 
6.7.3 Based on the average test flow for th e cycle being used, calculate the dust feed rate as in 
6.4.3.1.  The dust feed rate should remain constant.  
 
6.7.4 All differential pressure drop determinations shall be made at maximum air flow.  
 
6.7.5 Perform tests using variable air flow in place of the constant air fl ow, however, with the 
following changes:  
 after the end of each cycle the differential pressure shall be determined at the maximum 
flow; and  
 the efficiency shall be determined at least after three cycles if the duration of partial flow 
sectio n is 1 min and after every cycle if the duration of partial flow section is 5 min, and 
after the end of test . 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
14 
 Figure 1 — Typical variable flow cycle (average flow 60 %)  
6.8 Presentation of data  
For presentation of data, use Annexes C, E and F or equivalent . 
7. Test procedure for dry -type air cleaners for industrial applications  
 
7.1 General  
Performance tests shall be performed on a complete air cleaner includi ng pre  cleaner, primary 
element, and secondary element, if normally provided. The tests shall  consist of an airflow 
restri ction/differential pressure test, an initial efficiency test, and a combined efficiency and dust 
capacity test.  
It is difficult, if not impossible, to select a test dust size distribution and concentration which will 
be represe ntative of all service conditions. Therefore, based on primaril y practical 
considerations, the different types of air cleaners have been classified as to their most proba ble 
service conditions, and the test dust grade and concentration selected accordingly  from Table 2.  
 
Table 4, Test duct and concentration  
  
 
Air cleaner type  
  
Test dust a  
Concentration  
 
Single stage  
  
Coarse or fine   
1g/m3 
 
Multistage  
  
Coarse or fine   
2g/m3 
 
a In accordance with ISO 12103 - 1. see 51.1  
 
 
7.2 Test equipment  
 
7.2.1  Typical test  arrangements are shown in Figures B.12, B.14 and B.15.  
 
7.2.2  The dust feeding system shall be the same as described in 6.2.1.  
 
7.2.3  The dust transfer tube shall be the same as described in 6.2.2. Con cerning the dust feed 
rate, see also Table 1.  
7.2.4  Tubular air cleaner inlet: the cross -sectional area of the upstre am piezometer tube shall 
be the same as the air cleaner inlet (see Figure B.4).  
 
7.2.5  Rectangular or open face inlet: the same as 7.2.4 except the over all length and 
placement of the piezometer shall be 24 and 16 tim es the hydraulic radius respectively 
(hydraulic radius = area divided through perimeter).  
 
7.2.6  The peripheral air inlet or stack type pre  cleaners shall be tested i n a chamber which 
ensures the even distribution and delivery of test dust to the inlet of the un it. Care shoul d 
be taken in the design of the chamber to ensure that all the test dust is fed to the filter. If 
dust settling o ccurs, then compressed air jets may be used to re -entrain the test dust.  
15 
 Typical examples of chambers are shown in Figure B.13.  When using compressed air 
for agitating dust, care should be taken not to eject dust out of the chamber.  To ensure 
that no dust is ejected, a negative pressure should be  maintained between the chamber 
interior and the atmosphere.  
 
7.2.7  The outlet downstream piez ometer tube shall be as shown in Figure B.4. The inside 
diameter of  the outlet downstream piezometer tube shall be the same as the air cleaner 
outlet tube . In the case of non-uniform flow conditions caused by special outlet tubes, 
special precautions may b e required.  
 
7.2.8  The absolute filter shall comprise the material specified in 5.3.  
 
7.2.9  Use an air flow measuring system as described in 6.2.8, an air f low control system as 
described in 6.2.9 and a blower/exhauster as described in 6.2.10.  
 
7.2.10  Grounding is required o f all test apparatus to reduce the effects o f static charges and to 
improve consistency of the test results. Grounding of metallic and non -metallic sur faces, 
housings, dust transport tubes, injectors and associated hardware is recommended.  
 
7.3 Restriction and  differential pressure test  
 Test shall be performed according to 6.3.  
 
7.4 Initial efficiency test procedure — Absolute filter method  
 
7.4.1  Condition the unit to the air flow at which the unit is teste d for at least 15 min under the 
temperature and humidity condit ions specified in 5.5.  If desired, conditioning of the 
absolute filter pad and air cleaner can be performed concurrently.  
 
7.4.2  Weigh the absolute filter pad as specified in 5.4 and record the mass before assembly in 
the absolute filter housing.  
 
7.4.3  Prepare the te st dust according to 5.1.1 and weigh out a quantity equal to 11 g/m2 of the 
primary element media area. Place the pre  weighed dust in the dust feeder.  
 
7.4.4  If it is practicable, weigh the complete unit under test.  
7.4.5  Weigh the dust feed system with the dust and r ecord the mass.  
 
7.4.6  Set up the air cleaner as shown in Figure B.12 or B.13, sealing all connections to 
prevent air leakage, and maintain the air flow at the test flow rate.  
 
7.4.7  Start the dust feeder and adjust the feed rate to maintain conti nuous injection of th e 
complete quantity of test dust over a period of 30 min.  
 
7.4.8  Record the temperature and relative humidity.  
 
7.4.9  Brush any observed dust on the downstream side of the test unit onto  the absolute filter. 
Carefully remove and reweigh the absolute filter pad as in 5 .4. Calculate the incr ease in 
mass by comparison with the mass recorded in 7.4.2.  
  
16 
 7.4.10  Collect all dust which has settled on the exterior surface, inlet ducting or test chamber, or 
the inlet side of the test unit and transfer this dust to the dust feed system.  
 
7.4.11  Reweigh the dust feed system to within 1 % of the actual value, and calcu late the mass 
of dust injected into the test cleaner by comparison with the initial mass of the dust feed 
system from 7.4.5.  
 
7.4.12  If it is practicable, reweigh the complete unit under t est. 
 
7.4.13  Calculate the initial efficiency, Ei, as follows:  
 Ei =         
   x 100%  ......................... ...................... .......... .......... ...................(6 ) 
7.4.14  If it was practicable to weigh and reweigh the complete unit un der test, the efficiency 
may be calculated from Formula (3) in 6.4.3.17. Validation of the test shall be carried out 
according to 6.4.3.16.  
 
7.5 Full-life efficiency and capacity test  
 
7.5.1  Air cleaner dust capacity  
Air cleaner dust capacity is a function of air cleaner size, ai rflow test, termi nal condition and 
grade of test dust employed. To permit a comparison between different air cleaners, the dust 
capacity is , therefore, determined at test air flow to the specified terminal condition with f our 
intermediate points. In the absence of such a specification, a restriction of 6 kPa (60 mbar) 
should be used as the terminal condition.  In the case of the terminating condition being the 
restriction, it does no t include the restriction added by the dust mixing duct and test shroud. The  
test can be conducted with either constant or variable air flow according to 6.7.  
 
7.5.2  Test procedure — Absolute filter method  
 
7.5.2.1 Condition the unit to the air flow at which the unit is tested for at  least 15 min under 
temperature and humidity condition s as specified in 5.5. If desired, conditioning of the absolute 
filter pad and air cleaner can be performed concurrently.  
 
7.5.2.2 Weigh the absolute filter pad as specified in 5.4 and record the  mass before mounting it 
within the absolute filter housing.  
 
7.5.2.3 Prepare a sufficient quantity of test dust according to 5.1 of th e selected grade and store 
in a suitable container in the test area to stabilize to constant mass. The amoun t of dust, 
calculated according to the relevant concentration specified sh ould be more than sufficient to  
cover the expected duration of the test. Record the mass.  
 
7.5.2.4 If it is practicable, weigh the complete unit under test and record the mass.  
 
7.5.2.5 Set up air cleaner as shown in Figure B.12, sealing all connecti ons to  prevent air 
leakage, and maintain the air flow at the test flow rate.  
 
7.5.2.6 Load the dust feeder from the dust container and adjust the feed rate to coincide within 
the concentration specified in Table 2. Reload the dust feeder from the dust container as 
necessary throughout the test.  
  
17 
 7.5.2.7 Record the temperature and relative humidity.  
 
7.5.2.8 Record at least four intermediate values of the mass of dust fed to t he test unit (feed rate 
x time) and the corresponding restriction/differential pressure a t approximately uniform time 
intervals.  
 
7.5.2.9 Correct the restriction/differential pressure/pressure los s values to standard conditions 
according to Annex G and plot them against dust fed to the air cleaner, as shown in Annex E . 
Label the ordinate ―rest riction‖ or ―differential pressure‖ or ―pressure loss‖ as appropriate.  
 
7.5.2.10 Continue the test until the specified terminal condition is att ained. In the case of air 
cleaners having no limiting dust capacity, e.g. cyclone air cleaners, the test shall n ot be stopped 
before the cleaner has been fed with a sufficient quantity of dust for its efficiency  to be 
determined as accurately as required. The minimum quantity shall be 50 g of dust.  
 
7.5.2.11 Brush any observed dust on the downstream side of the test  unit onto the absolute 
filter.  Carefully remove and reweigh the absolute filter pad and determine the  increase in mass 
by comparison with the mass recorded in 7.5.2.2.  
 
7.5.2.12 Collect all the dust which has settled on exterior surfa ces/ducting/test cham ber or the 
inlet side of the test unit and transfer this dust to the original dust contain er. Transfer all unused 
dust in the dust feed device to the original dust container and reweigh the contai ner and dust. 
By subtraction of this mass from the mass reco rded in 7.5.2.3, determine the total mass of dust 
injected into the test unit.  
 
7.5.2.13 If it is practicable, reweigh the complete unit under test.  
7.5.2.14 Calculate the capacity, C, of the unit under test as follows:  
 
C = m D -  mF .................... ............................. .......................... ..............................(7 ) 
 
Where:  
 mD is the mass of duct fed  
  mF is the increase in mass of the absolute filter.  
 
7.5.2.15 Calculate the full -life efficiency, Ef, as follows:  
 
Ef =         
          .........................................................................................(8)  
 
where the symbols are as in Formula (7).  
 
7.5.2.16 If it was practicable to weigh and reweigh the complete unit under test, the efficiency 
may be calculated using Formula (3) in 6.4.3.17. Validation of the test shall be carried out 
according to  6.4.3.16.  
 
7.5.3 Test procedure — Direct weighing method  
The direct weighing method may be used for cumulative efficiency determination where the 
humidity  can be controlled to within ± 1,0 % and the accuracy of the mass increase of the filter 
determined within 0,1 %.  Where a suitably large, accurate balance is available, it is permissible 
to use a direct weighing method of assessing capacity and accumulativ e efficiency. In such  
18 
 cases the air cleaner under test shall be tested according  to the procedure detailed in 7.5.2 with 
the following changes.  
a) Weigh the air cleaner under test before and after the test and record t he increase in mass 
of the test unit. Thi s mass is the capacity of the unit under test.  
b) Disregard operations 7.5.2.2; 7.5.2.11; 7.5.2.14 and 7.5.2.15.  
c) Calculate the full -life efficiency, Ef, as follows:  
Ef =    
   x 100%  ..................................................................................................(9)  
where:  
      is the increase in mass of the unit under test  
    is the total mass of dust fed.  
The test report should indicate the method of efficiency determination used.  
 
7.6 Presentation of data  
Data should be presented as given in Annexes D, E and F or equivalents.  
 
7.7 Scavenged air cleaner performance test  
 
7.7.1  General  
This sub clause  describes those variations in the test procedures specif ied in this International 
Standard that are necessary for the testing of air cleaners that are scavenged in o peration by a 
proportion of the air input that is bled off for this purpose.  
The flow equation is as follows:  
  
qVA = q VB + q VC ................... ............................................................................(10)  
  
 where:  
  qVA is the inlet air flow rate:  
  qVB is the cleaned air flow rate;  
  qVC is the scavenged air flow rate.  
 
7.7.2  Additional equipment  
A typical test arrangement is shown  in Figure B.16 and shall comprise the following.  
a) Exhauster: an exhauster shall be provided to handle the scaveng ed flow and shall be capable 
of maintaining it at a steady -state during the whole test.  
b) Air flow meter: an air flow meter shall be provid ed to measure the  scavenged air flow rate 
having an accuracy in accordance with 4.1.  
c) Pressure tapings : the pressure tapings  used shall conform to Figure B.4.  
d) Scavenged air filter: a filter shall be provided in the scavenged air fl ow of sufficient eff iciency 
and capacity to protect the apparatus downstream of it against the effec ts of the dust in the 
scavenged air flow.  
 
7.7.3  Restriction and differential pressure test  
The test shall be conducted in accordance with 6.3 with the following changes.  
a) The scaveng ed air flow shall be started before the cleaned air flow.  
b) The scavenged air flow shall preferably be stopped at the same time as the cleaned air 
flow; it shall  not be stopped before the cleaned air flow.   
19 
 c) Measurements shall be made with the scavenged air fl ow adjusted to be a specified 
proportion  of the cleaned air flow (interaction between the scavenged air flow and the 
cleaned air flow may require some re -adjustment to be made to maintain this 
proportion).  
 
7.7.4  Full-life efficiency and capacity test  
7.7.4.1 Most of the air cleaners that are scavenged in operation by a prop ortion of the air input 
that is bled off for this purpose are comparatively large in size. The absolute filter test method is 
therefore  recommended.  
 
7.7.4.2 Unless otherwise specified, the sc avenged air flow shall be main tained at a fixed 
proportion of the cleaned air flow, as agreed between the manufacturer and user.  
 
7.7.4.3 The test dust concentration shall be that in the inlet air flow.  
 
7.7.4.4 The scavenged air flow shall be started befo re the cleaned air flow.  
 
7.7.4.5 The scavenged air flow should preferably be stopped at the same time as the cleaned 
air flow. It shall not be stopped before the cleaned air flow.  
 
7.7.4.6 The full -life efficiency, Ef, of the air cleaner shall be calculat ed as follows  
 
Ef =      
    x 100%  .....................................................................................(11)  
 
 where;  
  d1 is the average dust concentration at the inlet of the air cleaner = m1/v1  
  d2 is the average dust concentration at the outlet o f the air cleaner = m2/v2  
   
 in which;  
  m1 is the mass of dust fed to the air cleaner;  
  m2 is the mass of dust leaving the clean side of the air cleaner;  
  v1 is the volume of air fed to the air cleaner;  
  v2 is the volume of air leaving the clean side of the air cleaner.  
 
7.7.4.7 The capacity, C, of the unit shall be calculated in accordance with Formula (12) as 
follows:  
C = ( mD X    
     ) -     ...............................................................................(1 2) 
  
where:  
 qVA is the inlet air flow rate;  
 qVB is the cleaned air flow rate;  
 mD is the total mass of dust fed;  
      is the increase in mass of the absolute filter  
. 
7.7.5  Presentation of data  
Data should be presented as given in Annexes D, E and F or equivalents.  
 
7.8 Pre cleaner performance test  
 
7.8.1  Pre cleaner dust removal   
20 
 When testing with pre  cleaners that employ either an automatic dust unlo ading valve o r a dust 
cup, the following provisions with respect to dust removal shall be made. For pre cleaners that 
are scavenged, see 7.7.  
a) Automatic unloaded  valve: for test purposes, a sealed jar or container may be substituted for 
the unloaded  valve.  
b) Dust cu p: the dust shall not be emptied during the dust capacity test until at least two -thirds 
full. 
Also, the number of servicing intervals shall be noted in the performance report.  
The user should be aware that the above provisions ensure optimum air cleaner p erformance 
and it is advisable to consult the air cleaner manufacturer for specific instructions or test 
procedures for any given air cleaner installation.  
 
7.8.2  Pre cleaner efficiency  
The pre  cleaner efficiency shall be determined during the dust capacity test , based on the total 
mass of dust fed to the air cleaner and either the sum of the gain in mass of the primary and 
secondary elements and the absolute filter, or the mass of dust removed by the pre  cleaner.  
7.8.3  Presentation of data  
Data should be presented as given in Annexes D, E and F or equivalents.  
 
7.9 Secondary element test procedure  
7.9.1  General  
The requirement for a secondary element is that it should block rapidly in the event of a leak 
occurring in the primary element, passing a minimum of dust in the process.  To evaluate this, a 
specific efficiency test shall be performed. During normal and correct operation of the air 
cleani ng system, it is desirable that the secondary element should not block during the lives of 
one or more primary e lements. To evaluate this, a secondary element blocking test shall be 
performed. This may be carri ed out as part of the full -life efficiency and capacity test as 
specified in 7.5.  
 
7.9.2  Specific efficiency test  
7.9.2.1 Preparation  
Using the housing normally employed to retain the secon dary elements, prepare a ―dummy‖ 
primary element, i.e. a complete element skeleton lacking only the media but including any swirl 
vane present.  
Place the secondary element and the dummy primary element into the housing.  
 
7.9.2.2 Test procedure  
 
7.9.2.2.1 The test shall be conducted in accordance with the full -life efficiency and capacity test 
given in 7.5, but with the following specifications.  
 
7.9.2.2.2 The terminating conditions for dust feeding shall be a differential pressure across the 
housing of 10 k Pa (100 mbar) or as agreed upon between the user and manufacturer.  
 
7.9.2.2.3 The dust used shall be ISO Fine when a pre -cleaner is not provided. ISO Coarse shall 
be used where a pre -cleaner is used.  
 
7.9.2.2.4 The airflow shall be the full rated airflow a s agreed between the customer and 
supplier.  
 
7.9.2.2.5 The test dust concentration shall be 0,1 g/m3.   
21 
 7.9.2.2.6 Where applicable, the requirements of 7.8.1 and 7.8.1 a) (pre -cleaner dust removal) 
shall be adhered to. The pre cleaning efficiency will be dif ferent from normal during this test. 
However, should a large reduction be noted, the reasons for this should be checked and any 
observations recorded.  
 
7.9.2.2.7 At the end of the test, after measuring the efficiency, the flow rate shall be increased to 
produce a differential pressure across the housing of 12,5 kPa (125 mbar). The secondary 
element shall not rupture under these conditions.  
 
7.9.3  Expression of results  
Calculate the efficiency as in 7.5.2.15 or 7.5.3 c).  
 
7.9.4  Secondary element blocking test  
7.9.4.1 Ge neral  
The test determines the increase in restriction/differential pressure and mass of a secondary 
element caused by the dust that has passed through the primary element.  
 
7.9.4.2 Preparation  
Use a clean primary element and secondary element in the housin g normally employed. 
Determine the mass of the secondary element after conditioning in accordance with 7.5.2.1  
 
 
7.9.4.3 Test procedure  
7.9.4.3.1 Set up the air cleaner as in 6.3 (restriction and differential pressure test). Measure and 
record the restrict ion/differential pressure of the unit at the rated flow only. Replace the later 
reference primary element by a new primary element.  
 
7.9.4.3.2 Conduct a full life efficiency and capacity test as specified in 7.5.  
 
7.9.4.3.3 Replace the primary element with  the reference one used at the start of the test. 
Repeat the restriction and differential pressure test of 7.9.4.3.1. Note the result.  
 
7.9.4.3.4 Remove the secondary element and reweigh.  
 
7.9.4.3.5 Repeat tests with more primary elements, using the same s econdary element until a 
specified weight increase or differential pressure increase of the secondary element has 
occurred. These values should be agreed between user and manufacturer.  
Replace the last primary element by the reference element and note the differential pressure 
and reweigh the secondary element. The performance of the secondary element depends on 
the efficiency of the primary element.  
 
7.9.4.4 Expression of results  
Calculate the increase in restriction/differential pressure of the unit from 7.9.4.3.3 and 7.9.4.3.1 
and the increase in mass of the secondary element.  
 
8. Test procedure for industrial applications of oil bath air cleaners  
8.1 General  
Performance tests shall be performed on a complete oil bath air cleaner. The tests shall c onsist 
of a restriction/differential pressure test, an oil carry -over test, a combined capacity and 
efficiency test, and  a recovery test.  
  
22 
 8.2 Test equipment and conditions  
8.2.1 Test the oil in accordance with 5.2.  
 
8.2.2 Test dusts prepared according to 5.1.2 shall be use d at a concentration of 1 g/m3 air flow. 
Either fine or coarse test dust may be specified.  
 
8.2.3 All tests shall be carried out with the air cleaner at a level posi tion unless otherwise 
specified by the user or by the particular clause of the test procedu re. Before the  test, the air 
cleaner shall be prepared in the following manner:  
a) thoroughly wash and dry the air cleaner;  
b) fill the oil cup/reservoir to the indicated level with the specified oil;  
c) allow air to flow through the cleaner at the rated air flow f or 15 min;  
d) stop the air flow or allow a draining period of 15 min;  
e) refill the cup/reservoir with oil to the specified level for the particular test.  
 
8.2.4 A typical arrangement for testing oil bath air cleaners of the tubular inlet type is shown in  
Figure  B.12.  
 
8.2.5 Air cleaners of the peripheral inlet type shall be tested in a  chamber which ensures the 
even distribution and delivery of test dust to the inlet of the unit. Care shoul d be taken in the 
design of the chamber to ensure that all the test dust is fed to the filter. If dust setting oc curs, 
then a compressed air jet may be used to re -entrain the test dust. Typical examples of 
chambers are shown in Figure B.13.  
When using compressed air for agitating dust, care should be taken not to eject dust out  of the 
chamber.  
To ensure that no dust is ejected, a negative pressure should be  maintained between the 
chamber interior and the atmosphere.  
 
8.2.6 All tests shall be carried out under the conditions detailed in 5.5.  
Grounding is required for all test app aratus to reduce the effects of st atic charges and to 
improve the consistency of the test results. Grounding of metallic and non -metallic surfaces, 
housings, dust transport  tubes, injectors and associated hardware is recommended.  
 
8.3 Restriction and differen tial pressure test  
Tests shall be performed according to 6.3 with the following changes:  
a) Perform  the restriction/differential pressure test versus flow rate at more than 100 % only as 
long as no oil carry -over occurs;  
b) The air flow shall be maintained  until the differential pressure across the air cleaner has 
stabilized.  
 
8.4 Oil carry -over test  
8.4.1  Dust shall not be fed to the cleaner during this test.  
8.4.2 The cleaner, prepared in accordance with 8.2.3, shall be ass embled, weighed and 
attached to the test r ig. The room temperature and humidity shall be recorded. The 
recommended oil shall be  used for the test and the test shall be conducted at a temperature to 
be agreed between the user and manufacturer.  
 
8.4.3 Each oil bath air cleaner tested in accordance w ith this clause shal l be tested in one of two 
ways, as agreed between the manufacturer and the purchaser. The two ways are as follows:  
a) a test at a single flow rate, above the rated flow, as agreed between the manufacturer and 
purchaser, to determine whe ther or not oil carry -over occurs at that flow rate;   
23 
 b) a test at increasing flow rates, starting at 80 % of the rated flow and increasing in increments 
of10 % of the rated flow, to determine the air flow rate at which oil carry -over occurs.  
 
8.4.4 The tes t in 8.4.3  
a) shall be conducted for a minimum of 60 min for each filter tested. The test in 8.4.3  
b) shall be conducted for at least 10 min at each flow rate.  
 
8.4.5 At the end of the test at each flow rate, the air cleaner outlet sha ll be examined for signs of  
oil carry -over using an observation chamber with a target plate covered wi th a suitable paper 
which turns transparent at the impact of oil droplets (see Annex B, Figure B.17).  
 
8.4.6 At the end of the test described in 8.4.3, the air cleaner shall b e remo ved and weighed 
again and the loss of oil by mass shall be recorded.  
 
8.4.7 If an oil bath air cleaner is to be or may be operated in an inclined position, t he tests 
described in 8.4.3 shall be repeated in full with the cleaner inclined at the angles  and d irections 
in which it may be required to operate, with such additional margins as may be agre ed between 
the manufacturer and purchaser.  
 
8.5 Full li fe efficiency and capacity test  
The dust capacity/efficiency characteristics of oil bath air cleaners s hall be a ssessed by the 
methods described in 7.5 for industrial air cleaners with the exceptions detail ed below. It is 
essential, when testing oil bath cleaners, to ensure that no oil carry -over occurs at the rated  test 
air flow. Significant oil losses of this kind  will affect the masses recorded for the absolute filte r 
and/or unit under test, which will influence the final test results. The tests may be conducted 
with eithe r constant or variable air flow according to 6.7. The exceptions in te st procedures are 
the following;  
a) Condition the unit under test according to 8.2.3. Measure and record the mass.  
b) Use the test dust at the concentration detailed in 8.2.2.  
c) At the end, perform an oil carry -over test accordin g to 8.4.3 b).  
 
8.6 Recovery test  
After the capacity test, dra in and clean the unit under test to the precise instructions 
recommended by the cleaner manufacturer and resume the test without dust feed for 20 min, 
noting the restriction/differential pressure at 5 min intervals during this period. The recovery 
capabili ties of the test unit will be assessed  by comparison of these results with those obtained 
for a new, unused test cleaner.  
 
8.7 Presentation of data  
Data should be presented as given in Annexes D, E and F or equivalents.  
 
 
   
24 
 Annex A  
(Normative ) 
Explanation of r estriction, differential pres sure and pressure loss of an air cleaner  
When differential pressure across an separator has been measured ( p2 – p1 in Table A.1 ), any 
difference in the cross -sectional area of the ducts at the upstream and downstrea m pressure 
tapping points shall be taken into account in determining the differential pressure across the 
separator. The differential pressure across the separator is given by the formula:  
 
∆p1 = ∆p d - ∆pc .................................................................................................( A1) 
 
where:  
 ∆pd is the measured differential pressure.  
 
∆pc =      
  -       
 ...... ................................ .......................................................( A2) 
 
where:  
   is the density of the air.  
 V1 is the velocity of the air in the duct at the upstream pressure tapping point;  
 V2  is the velocity of the air in the duct at the downstream pressure tap ping point . 
 
When the upstream pressure is equal to atmospheric and therefore only the static pressure in 
the downstream duct has been measured, the pressure loss across the air  cleaner can be 
calculated from the dynamic head, pdyn, required to accelerate the air from rest to its velocity in 
the downstream duct.  
The pressure loss  p1 across the cleaner is then given by the formula A3; 
 
 p1 =  pr -  pdyn ..................................................................................... .........(A3)  
 
where;  
  p1 = p2 is the restriction/static pressure at the downstream pressure ta pping point.  
 
NOTE 1 In the tests specified in this International Standard, a static pres sure is measured by a 
manometer (usually as a liquid manometer) as a negative pressure difference against t he 
atmospheric pressure; in the formulae, this is treated as  a positive value.  
 
 
 
 
   
25 
 Table A.1 — Illustration of restriction, differential pressure and pressure loss of an air 
cleaner  
Term Air cleaner drawing  
 
 
Term  
  
Air cleaner drawing air 
from the atmosphere   
Air cleaner drawing 
air through an inlet 
duct 
  
Expla nation  
 
Static pressure 
upstream of air 
cleaner  
  
-  
p1  
Used to measure 
restriction of inlet tube  
 
Static pressure 
downstream air 
cleaner = 
restriction  
  
 pr = p 2  
 pr = p 2  
Used when no inlet 
tube. see figure B.8, 
B.9, and B.15  
 
Differential 
pressure  
  
-  
 pd =  pr - p1 = p 2 - p1  
Used with normally 
equal diameter 
piezometers, see 
figure B.14  
 
 
Pressure loss  
  
 p1 = pr - pdyn = p2 -      
   
 p1= pd- pc=(p2-p1) - 
     
  -       
  
  
Used when inlet and 
outlet piezomet ers 
have different 
diameters.  
 
 
 
NOTE 2 ISO 5011 is written for tests conducted by pulling air through the unit u nder test. The 
pressures in the inlet and outlet tubes are below ambient. Restriction is reported as a positive 
value. Therefore for the formu lae in Table A.1 to be correct, the gauge pressures p1 and p2 are 
assumed to measure  as a positive values when the pressure in the inlet and outlet tubes 
(upstream and downstream piezometers) are below ambient pressure.  
 
 
 
 
 
 
   
26 
 Annex B  
(Normative ) 
Test equipment  
 
 
 
 
See Figures B.1 to B.17.  
 
 
 
 
 
 
 
Key 
1 Dust injector (see Figures B.2 and B.3)  
2 Inlet tube (see Figure B.4)  
3 Test shroud (see Figure B.5)  
4 Outlet tube (see Figure B.4)  
5 Pressure measuring device  
6 Absolu te filter  
7 Air flow meter  
8 Air flow control  
9 Exhauster  
 
  Figure B.1 — Filter element efficiency/capacity test set -up 
 
 
 
 
 
 
27 
  
 
 
 
 
 
Key 
1 Air entry  
2 Dust entry  
3 Dust/air exit  
 
 
 
 
Figure B.2 — ISO dust injector  
 
 
 
28 
  
 
 
 
Key 
1 Air entry  
2 Dust entry  
3 Du st/air exit  
4 Vinyl tubing erosion shield  
5 Stainless -steel tubing of wall thickness 1. 65 mm  
6 Stainless -steel tubing of wall thickness 0 .81 mm  
7 Vinyl tubing of diameter 9. 53 mm  
NOTE See Table 1  
a Make from a 3/4 - 16 hexagonal HD bolt  
   
  Figure B.3 — ISO heavy -duty dust injector  
 
 
 
 
 
 
29 
  
 
Dimensions in millimetres  
Key 
a) Outlet tube: 4 D min; inlet tube: 6 D min 
 
Figure B.4 — Inlet/outlet piezometer tube  
 
 
 
Key 
1 Diffusor cone  
2 Sealing plate  
3 Unit under test  
 
 
Figure B.5 — Filter element test shroud  
 
 
30 
  
 
Key 
1 Dust injector (see Figures B.2 and B.3) 6 Absolute filter  
2 Dust chamber 7 Air flow meter  
3 Unit under test with diffusor cone (see Figure B.5) 8 Air flow control  
4 Outlet tube (see Figure B.4) 9 Exhauster  
5 Pressure measuring device 10 Compressed ai r feed  
11 Compressed air feed flexible tubes  
NOTE In this figure, a single air cleaner element is installed  
 
  Figure B.6 — Efficiency/capacity test set -up using a dust chamber  
 
 
 
Key 
1 Dust injector (see Figures B.2 and B.3) 6 Absolute filter  
2 Inlet tube (see Figure B.4) 7 Air flow meter  
3 Panel filter chamber 8 Air flow control  
4 Outlet tube (see Figure B.4) 9 Exhauster  
5 Pressure measuring device  
 
Figure B.7 — Set-up for p anel filter element efficiency/capacity test  
 
31 
  
 
 
 
Key 
1 Unit under test  
2 Outlet tube (see Figure B.4)  
3 Restriction measuring device  
 
 
Figure B.8 — Set-up for restriction test  
 
 
 
Key 
1 Unit under test  
2 Orifice (see Figure B.10)  
3 Outlet tube (see Figure  B.4) 
4 Restriction measuring device  
 
Figure B.9 — Set-up for restriction test  
 
 
32 
  
 
Key 
ØD = ØD in Figure B.4  
 
 
Figure B.10 — Ideal flow orifice  
 
 
 
 
 
 
 
 
Key 
1 Dust injector (see Figures B.2 and B.3)  
2 Inlet tube (see Figure B.4)  
3 Unit under test  
4 Outlet tube (see Figure B.4)  
5 Pressure measuring device  
 
 
Figure B.11 — Set-up for efficiency/capacity test  
 
 
33 
  
 
 
Key 
1 Dust injector (see Figures B.2 and B.3) 6 Absolute filter  
2 Inlet tube (see Figure B.4) 7 Air flow meter  
3 Unit under test 8 Air flow control  
4 Outlet tube (see Figure B.4) 9 Exhauster  
5 Pressure measuring device  
 
Figure B.12 — Set-up for tubular air c leaner efficiency/capacity test  
 
 
 
 
 
 
 
 
Key 
1 Dust/air entry  
 
Figure B.13 — Arrangement for non -tubular inlet air cleaner test chamber  
 
 
 
34 
  
 
 
 
 
Key 
1 Unit under test  
2 Outlet tube (see Figure B.4)  
3 Differential pressure measuring device  
4 Inlet tube (see Figure B.4)  
 
Figure B.14 — Set-up for differential pressure test  
 
 
 
 
 
 
 
 
 
Key 
1 Unit under test  
2 Outlet tube (see Figure B.4)  
3 Restriction m easuring device  
 
Figure B.15 — Set-up for restriction test  
 
 
35 
  
 
Key 
1+2 Unit under test 6 Air flow control  
1 Pre  cleaner,  
2 Main cleaner  
3 Outlet tube (see Figure B.4 ) 
4 Absolute filter 5 Air flow meter   
6 scavenged  
7 Scavenge air duct  
8 Scavenge air du ct filter  
9 Scavenge air duct flow meter  
10 Exhauster  
11 Restriction measuring device  
 
 
Figure B.16 — Set-up for scavenged air cleaner efficiency/capacity test  
 
 
 
 
 
36 
  
 
Key 
1 Unit under test  
2 Observation chamber  
3 Target plate covered with paper  
4 Observati on window  
5 Outlet to air exhauster  
 
Figure B.17 — Oil carry -over test — Observation chamber  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
 
37 
 Annex C  
(informative)  
 
 
 
 
 
 
 
  
 
38 
 Annex D  
(informative)  
 
 
 
  
 
39 
 Annex E  
(informative)  
 
 
 
 
 
40 
 Annex F  
(informative)  
 
 
 
 
 
 
 
 
41 
 Annex G  
(normative)  
Airflow and resistance corrections to standard conditions  
 
Airflow restriction/differential pressure/pressure loss and dust capacity data shall be reported for 
standard conditions of 20ºC and 1013hPa (1013mPa). The resistance, ∆p, of the air c leaner can 
be represented by the following expression.  
 
∆p = K 1µqv + K 2 q2v  
 
where:  
 K1 is an empty constant;  
 K2 is an empirical constant;  
 µ is the dynamic viscosity, in millipascal seconds;  
   is the air density, in kilograms per cubic metre;  
 qv is the volume flow rate, in cubic metre per minute;  
 qm is mass flow rate, in kilograms  per minute.  
 
Substituting   
  for q v 
 
∆p = K 1µ(  
 ) + K 2 (  
 )2  
 
Rearranging terms gives;  
 
 ∆p = K 1µqm + K 2 qm2  
 
Thus by maintaining the mass flow con stant and limiting the variation in ambient temperature to 
keep the change in viscosity small,  ∆p will remain constant. Therefore;  
 
 0∆p0 =  ∆p 
 
∆p0 =  ∆p/ 0   
 
where subscript 0 indicates standard conditions.  
 
Observed restriction/differential press ure/pressure loss values shall the refore be corrected to 
standard conditions by using the following equation:  
 
∆p0 =  
     X    
      X ∆pr, or ∆pd, or ∆p1  
 
p is the observed ambient pressure;  
T is the observed ambient temperature;  
Δpr is the measured air cleaner restriction;  
Δpd is the differential pressure;  
Δpl is the pressure loss.  
 
 
 
   
42 
 Annex G  
(normative)  
Determination of pressure drop  
 
G.1 The test shall be carried out with the filter in a level position in the rig shown in figure G .1 
 
G.2 The filter shall be thoroughly cleaned and the air shall be draw through it at its rated 
capacity until two consecutive readings, at intervals of not less than 15 min, show no loss in 
weight.  
G.3 The aspirated air shall be clean and free from fumes . Its temperature shall be maintained at 
25oC ± 3oC and relative humidity at 55◦C ± 5%.  
G.4 The test shall be carried out without dust being fed into filter, and initial pressure drop shall 
be determin ed at 100%, 80%, 60%, 40%, 20% a nd 10% of the maximum r ate of air flow.  
G.5 in each c ase the air flow shall be maintained for 5 min before the pressure drop is 
ascertained.  
 
  
 
 
 
Figure G.1 -Test rig for filters  
 
  
 
43 
 Annex H  
(normative)  
 
Determination of mean dust retaining efficiency  
 
H.1 The test shall be con ducted with the filter in a level position in the rid shown in Figure H.1.  
H.2 The filter shall be cleaned thoroughly and then air shall be drawn through it at its rated 
capacity until; two consecutive readings, at intervals of not less 15 min, show no in weight.  
 
H.3The aspirated shall be clean  and the free from fumes. Its temperature shall be maintained at 
25◦C ± 3% and relative humidity at 55%±5%  
 
H.4 The filter shall be weighed and together with the dust feed gear, installed in a level position 
on the t est rig.  
 
H.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.  
 
H.6 The exhauster shall be started and the air flow through the filter adjusted to the maximum 
air flo w of the filter under the test. This air flow shall be maintained for 10 min from the 
beginning of the test.  
 
H.7 The time and the aspirated air temperature (wet and dry bulbs) shall be recorded at the end 
of each cycle.  
 
H.8 The design dust / air ratio, s hall 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 
specified .The dust feed apparatus shall be calibrated prior to each test, to ensure that the 
abov e limits are maintained.  
 
H.9 The test shall consists of two –hour cycles, each as given in table in H.1  
 
 
Air flow  
(percentage of filter rated capacity)   
Time (minutes)  
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 collec ted, by carefully brushing into a suitable container. The dust collected shall then be 
nearest 0.1g, and shall not exceed 1% by weight of the total dust feed.  
  
44 
 H.10 The filter efficiency shall be calculated as follows  
 
 
i.e weight of dust in dust –feed ge ar 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 the  dust chamber or inlet and that 
collected from the exterior of the filter housing.  
 
 
 
 
 
  
 
45 
 Annex I  
(normative)  
 
Dust holding capacity test 
 
I.1 The test shall be conducted as in Annex B.  
 
I.2 The dust holding capacity in g/m2 is the weight in grams  of dust which can be accommodated 
during the test at the design dust/ air ration, while maintaining the specified efficiency given in 
3.2 and  without exceeding the pressure drop of 0.015KPa divided by the area of the filter of the 
filter element.