ISO 5011:2014

INTERNATIONAL ISO
STANDARD 5011
Third edition
2014-04-01
Inlet air cleaning equipment for
internal combustion engines and
compressors — Performance testing
Séparateurs aérauliques placés à l’entrée des moteurs à combustion
interne et des compresseurs — Détermination des performances
Reference number
©
ISO 2014
© ISO 2014
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Published in Switzerland
ii © ISO 2014 – All rights reserved

Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
3.1 Terms, definitions, symbols and units . 1
3.2 Symbols and units . 3
4 Measurement accuracy and standard conditions . 4
4.1 Measurement accuracy . 4
4.2 Standard conditions . 4
5 Test materials and test conditions . 4
5.1 Test dust . 4
5.2 Test oil for oil bath air cleaners . 4
5.3 Absolute filter materials . 5
5.4 Absolute filter mass . 5
5.5 Temperature and humidity . 5
6 Test procedure for dry-type air cleaners for automotive applications .6
6.1 General . 6
6.2 Test equipment . 6
6.3 Restriction and differential pressure test . 7
6.4 Efficiency test . 8
6.5 Capacity test . 9
6.6 Filter element pressure collapse test.10
6.7 Variable air flow test .10
6.8 Presentation of data .11
7 Test procedure for dry-type air cleaners for industrial applications .11
7.1 General .11
7.2 Test equipment .11
7.3 Restriction and differential pressure test .12
7.4 Initial efficiency test procedure — Absolute filter method .12
7.5 Full-life efficiency and capacity test.13
7.6 Presentation of data .15
7.7 Scavenged air cleaner performance test .15
7.8 Precleaner performance test .17
7.9 Secondary element test procedure .17
8 Test procedure for industrial applications of oil bath air cleaners.19
8.1 General .19
8.2 Test equipment and conditions .19
8.3 Restriction and differential pressure test .20
8.4 Oil carry-over test .20
8.5 Full life efficiency and capacity test .20
8.6 Recovery test .20
8.7 Presentation of data .21
Annex A (normative) Explanation of restriction, differential pressure and pressure loss of an
air cleaner.22
Annex B (normative) Test equipment .24
Annex C (informative) Report sheet on performance testing of air cleaner equipment according to
ISO 5011 — Automotive application .33
Annex D (informative) Report sheet on performance testing of air cleaner equipment according to
ISO 5011 — Industrial application .34
Annex E (informative) Presentation of results — Air cleaner restriction/differential pressure
versus flow .35
Annex F (informative) Presentation of results — Air cleaner capacity .36
Annex G (normative) Airflow and resistance corrections to standard conditions .37
Bibliography .39
iv © ISO 2014 – All rights reserved

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 22, Road vehicles, Subcommittee SC 7, Injection
equipment and filters for use on road vehicles.
This third edition cancels and replaces the second edition (ISO 5011:2000), which has been technically
revised.
INTERNATIONAL STANDARD ISO 5011:2014(E)
Inlet air cleaning equipment for internal combustion
engines and compressors — Performance testing
1 Scope
This International Standard establishes and specifies uniform test procedures, conditions, equipment,
and a performance report to permit the direct laboratory performance comparison of air cleaners.
The basic performance characteristics of greatest interest are air flow restriction or differential
pressure, dust collection efficiency, dust capacity, and oil carry-over on oil bath air cleaners. This test
code therefore deals 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 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition 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 inserted in circular cross-
section conduits running full — Part 1: General principles and requirements
ISO 12103-1, Road vehicles — Test contaminants for filter evaluation — Part 1: Arizona test dust
3 Terms and definitions
3.1 Terms, definitions, symbols and units
For the purposes of this International Standard, the following 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
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 test
either a single air cleaner element or a complete air cleaner assembly
3.1.5
single-stage air cleaner
air cleaner which does not incorporate a separate precleaner
3.1.6
multistage air cleaner
air cleaner consisting of two or more stages, the first usually being a precleaner, followed by one or more
filter elements
Note 1 to entry: If two elements are used, the first is called the primary element and the second one is called the
secondary element.
3.1.7
precleaner
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 specified 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 precleaner
Note 1 to entry: It is expressed as a percentage of the test air flow.
3.1.11
static pressure
pressure in a duct, at the observed air flow rate, measured by connecting 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 pressure 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 expressed as the differential pressure corrected for any difference in the dynamic head at
the measuring points.
Note 2 to entry: For further information, see Annex A.
2 © ISO 2014 – All rights reserved

3.1.15
absolute filter
filter downstream of the unit under test to retain the contaminant passed by the unit under test
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
appearance 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 following: 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 generally used for internal combustion engines in passenger cars
3.1.21
industrial application
air cleaner generally used for internal combustion engines in heavy-duty trucks, construction equipment
and agricultural tractors
3.2 Symbols and units
The following applied units, according to ISO 80000-1, are used.
Quantity Symbol Unit
Volume flow rate q m /min
v
Velocity v m/s
Density ρ kg/m
Mass flow rate q kg/min
m
Pressure p Pa
Restriction Δp Pa
r
Differential pressure Δp Pa
d
Pressure loss Δp Pa
l
Mass m g
Temperature T °C
Time t s
4 Measurement accuracy and standard conditions
4.1 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.
Measure the temperature to within 0,5 °C of the actual value.
Measure the mass to within 1 % of the actual value except where noted.
Measure 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.
4.2 Standard conditions
All airflow measurements shall 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 12103 - A4 (ISO Coarse), subject
to agreement between 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, use ISO Coarse test dust.
5.1.2 Preparation
Before using the test dust, a quantity sufficient to cover the test requirements shall be mixed in a sealed
container for a minimum of 15 min. The test dust shall then be allowed to become acclimatised to a
constant mass 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 bath air cleaners shall be that specified by the filter manufacturer and agreed
by the user for use at the appropriate ambient temperature. If an oil is not specified, the test oil shall be
a heavy-duty oil and the viscosity at the temperature of the test shall be adjusted as follows:
— 85 mm /s for oil carry-over and restriction/differential pressure tests;
— 330 mm /s for efficiency and capacity tests, including an oil carry-over test after the capacity test.
4 © ISO 2014 – All rights reserved

5.3 Absolute filter materials
5.3.1 Filter media
The absolute filter may consist of fibreglass media with a minimum thickness of 12,7 mm and a minimum
1)
density of 9,5 kg/m . The fibre diameter shall be 0,76 g to 1,27 g and the moisture absorption shall be
less than 1 % by mass after exposure to 50 °C and 95 % relative humidity for 96 h. The absolute filter
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 losses of fibres or materials, the
absolute filter shall be subject to a flow of at least 110 % of the rated flow of ambient air for 15 min
before the first test weighing.
NOTE The use of an absolute filter with a backing will minimize fibre loss.
5.3.2 Validation of absolute filter media efficiency, E
a
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:
Δm
A
E = ×100% (1)
a
Δ+mmΔ
AB
where
E is the absolute filter efficiency;
a
Δm
A is the mass increase of upstream absolute filter;
Δm
B is the mass increase of downstream absolute filter.
The absolute filter efficiency should be a minimum of 99 % for the contaminant presented to it.
5.4 Absolute filter mass
The absolute filter shall be weighed, to the nearest 0,01 g, after the mass 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 inside the oven. Alternatively, air conditioned according to 5.5 may be drawn
through the absolute filter for 15 min then the filter is weighed. Repeat this procedure until the mass
has stabilized.
5.5 Temperature and humidity
All tests shall be conducted with air entering the air cleaner at a temperature of 23 °C ± 5 °C. Tests shall
be conducted at a relative humidity of (55 ± 15) %, the permissible variation at each weighing stage
throughout each single test being ± 2 %.
The test results of an air cleaner will be affected by the relative humidity of the air passing through it
and the results of otherwise identical tests carried out near the two extremes of the permitted range of
relative humidity may not be directly comparable. The tests should be conducted within the narrowest
range of temperature and humidity possible.
1) A suitable material is commercially available. Details may be obtained from the secretariat of ISO/TC 22 or from
the ISO Central Secretariat.
6 Test procedure for dry-type air cleaners for automotive applications
6.1 General
Performance tests shall be performed on a complete air cleaner assembly or on a single air cleaner
element; tests on a complete air cleaner assembly are preferred. The tests shall consist of an air flow
restriction/differential pressure test, an efficiency test and a capacity 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 capacity, dust removal characteristics
and rupture collapse characteristics 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 shall 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. Continue 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 1 — Recommended ISO dust injectors (see Figures B.2 and B.3)
Dust feed rate (g/min) 0 to 26 26 to 45 > 45
ISO injector or
Injector type ISO injector 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 rates 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 therefore 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 replaceable 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.
6.2.5 Use a manometer or other differential pressure 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
6 © ISO 2014 – All rights reserved

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
chamber, 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 between
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 outlet tubes, special precautions
may be required.
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 be of an acceptable design, such
as a calibrated orifice and manometer conforming to ISO 5167-1. 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 rate shall be expressed in cubic
metres per minute corrected to standard conditions (see 4.2).
6.2.9 Use an air flow rate control system capable of maintaining the indicated 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 flow through the system, 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 apparatus to reduce the effects of 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 pressure test
6.3.1 The purpose of this test is to determine the restriction/differential pressure/pressure loss
across the unit under test which will result when air is passed through under predetermined conditions.
Airflow restriction or differential pressure is measured with a clean filter 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 tested for at least 15 min under
temperature and humidity conditions as specified in 5.5 until the mass has stabilized.
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 pressure 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 and relative humidity.
6.3.6 Correct the recorded restriction and differential pressure to standard 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 test 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 efficiency at 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 terminating differential pressure,
is reached;
b) incremental efficiency determined when, for example, 10 %, 25 % 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 contaminant 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/m of
3 3
air; in special cases (e.g. small filters) 0,25 g/m or 0,5 g/m 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 record 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 Record the temperature and relative humidity.
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 should 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 flow rate. Record the differential
pressure.
6.4.3.8 Load the dust feeder 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 dust container throughout the test
as necessary.
6.4.3.9 At specified time intervals (a minimum of five points is recommended), 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 temperature and relative humidity.
6.4.3.12 The dust on the exterior surfaces of a cleaner assembly or any which may have settled in
the test chamber/ducting on the inlet side of a test element shall be collected carefully and transferred
to the preweighed dust container together with any dust remaining in the dust feeder.
8 © ISO 2014 – All rights reserved

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)] this 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 to be valid, this value shall be
within the range 0,98 to 1,02:
Δ+mmΔ
Fu
B = (2)
m
D
where
Δm is the increase in mass of the absolute filter;
F
Δm
u is the increase in mass of the unit under test;
m is the total mass of dust fed.
D
6.4.3.17 Calculate the efficiency, E, by the following method:
Δm
u
E= ×100% (3)
Δ+mmΔ
uF
where the symbols are as in Formula (2).
6.4.4 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 increase in mass of the filter determined 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 cleaner 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:
Δm
u
E = ×100% (4)
m
D
where the symbols are as in Formula (2).
The test report should indicate 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 unit under test at the terminating
condition. This test can be conducted with either constant or variable air flow and with coarse or fine
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:
t
l
Δ=m ×Δm (5)
t UT
t
T
where
is the increase in mass at end of each time interval;
Δm
t
t is the total time at end of interval;
t is the total time at end of test;
T
Δm is the total increase in mass of unit under test at end of test.
UT
6.5.4 In the case of the terminal condition being the restriction, it does not include the restriction
added by the dust mixing device and test shroud.
6.6 Filter element pressure collapse test
6.6.1 The purpose of this test is to determine the ability of an air filter element to withstand a specified
differential pressure and/or to determine the differential pressure at which collapse occurs
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 or a new element can be used for
this test.
6.6.3 Increase the air flow through the stand and, if necessary, feed dust at any convenient rate until
the specified differential pressure is reached or until element collapse is indicated by a decrease in
differential pressure or increase in air flow.
6.6.4 Record the maximum differential 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 test can be carried out by using a
variable air flow 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 m /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 the 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 flow, 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 section is
1 min and after every cycle if the duration of partial flow section is 5 min, and after the end of test.
10 © ISO 2014 – All rights reserved

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 including precleaner, primary element,
and secondary element, if normally provided. The tests shall consist of an airflow restriction/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
representative of all service conditions. Therefore, based on primarily practical considerations, the
different types of air cleaners have been classified as to their most probable service conditions, and the
test dust grade and concentration selected accordingly from Table 2.
Table 2 — Test dust and concentration
a
Air cleaner type Test dust Concentration
Single stage Coarse or fine 1 g/m
Multistage Coarse or fine 2 g/m
a
In accordance with ISO 12103-1. See 5 1.1.
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. Concerning the dust feed rate, see
also Table 1.
7.2.4 Tubular air cleaner inlet: the cross-sectional area of the upstream 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 overall length and placement of the
piezometer shall be 24 and 16 times the hydraulic radius respectively (hydraulic radius = area divided
through perimeter).
7.2.6 The peripheral air inlet or stack type precleaners shall be tested in a chamber which ensures the
even distribution and delivery of test dust to the inlet of the unit. Care should be taken in the design of the
chamber to ensure that all the test dust is fed to the filter. If dust settling occurs, then compressed air jets
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.
7.2.7 The outlet downstream piezometer 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 be 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 flow control system as described
in 6.2.9 and a blower/exhauster as described in 6.2.10.
7.2.10 Grounding is required of all test apparatus to reduce the effects of static charges and to improve
consistency of the test results. Grounding of metallic and non-metallic surfaces, 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 tested for at least 15 min under the
temperature and humidity conditions 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 test dust according to 5.1.1 and weigh out a quantity equal to 11 g/m of the primary
element media area. Place the preweighed 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 record 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 continuous injection of the 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 increase in mass by comparison with
the mass recorded in 7.4.2.
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 calculate the mass of dust
injected into the test cleaner by comparison with the initial mass of the dust feed system from 7.4.5.
12 © ISO 2014 – All rights reserved

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