ISO/TS 19713-1:2010

Road vehicles — Inlet air cleaning equipment for internal combustion engines and compressors — Part 1: Fractional efficiency testing with fine particles (0,3 µm to 5 µm optical diameter)

ISO/TS 19713-1:2010 describes laboratory test methods to measure engine air cleaner and filter performance by fractional efficiency tests for particles from 0,3 µm to 5 µm optical diameter. Performance includes, but is not limited to, airflow restriction or pressure loss, initial and incremental fractional efficiencies during dust loading. The purpose of this test code is to establish and specify consistent test procedures, conditions, equipment and performance reports in order to enable comparison of filter performances of air cleaners and air filter elements used in engine air induction systems. It specifies the critical characteristics of equipment, test procedure and report format required for the consistent assessment of filter elements in a laboratory test stand. ISO/TS 19713-2 describes fractional efficiency tests with particles from 5 µm to 40 µm optical diameter.

Véhicules routiers — Équipement d'épuration d'air d'entrée pour moteurs à combustion interne et compresseurs — Partie 1: Contrôle d'efficacité fractionnelle avec particules fines (diamètre optique de 0,3 µm à 5 µm)

General Information

• Status: Published
• Publication Date: 15-Jul-2010
• ICS: 43.060.20 - Pressure charging and air/exhaust gas ducting systems
• Technical Committee: ISO/TC 22/SC 34 - Propulsion, powertrain and powertrain fluids
• Drafting Committee: ISO/TC 22/SC 34 - Propulsion, powertrain and powertrain fluids
• Current Stage: 9093 - International Standard confirmed
• Start Date: 09-Oct-2023
• Completion Date: 13-Dec-2025

Standards Content (Sample)

TECHNICAL ISO/TS
SPECIFICATION 19713-1
First edition
2010-07-15
Road vehicles — Inlet air cleaning
equipment for internal combustion
engines and compressors —
Part 1:
Fractional efficiency testing with fine
particles (0,3 µm to 5 µm optical diameter)
Véhicules routiers — Équipement d'épuration d'air d'entrée pour
moteurs à combustion interne et compresseurs —
Partie 1: Contrôle d'efficacité fractionnelle avec particules fines
(diamètre optique de 0,3 µm à 5 µm)

Reference number
©
ISO 2010
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©  ISO 2010
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ii © ISO 2010 – All rights reserved

Contents Page
Foreword .iv
Introduction.v
1 Scope.1
2 Normative references.1
3 Terms and definitions .1
4 Principle.5
5 Test equipment, accuracy and validation.5
5.1 Measurement accuracy.5
5.2 Test stand configuration.5
5.3 Test conditions .13
5.4 Validation.14
5.5 Reference air cleaner assemblies/air filter elements.15
5.6 Routine operating procedure .15
6 Fractional efficiency test .15
6.1 General .15
6.2 Test procedure.16
7 Calculations and data acceptance criteria.17
7.1 General .17
7.2 Symbols and subscripts.17
7.3 Test sequence.18
7.4 Correlation ratio.20
7.5 Penetration/fractional efficiency.20
7.6 Efficiency.21
7.7 Data reduction .21
7.8 Procedure for loading and fractional efficiency.28
7.9 Reporting results of loading tests .28
Annex A (informative) Test report .29
Annex B (normative) Poisson statistics .31
Annex C (normative) Pressure loss data reduction .33
Annex D (informative) Determination of maximum efficiency aerosol concentration.34
Annex E (normative) Accuracy requirements, validation and routine operation.35
Annex F (normative) Aerodynamic diameter .38
Annex G (normative) Method to test efficiency aerosol for proper neutralization .40
Annex H (normative) Leakage .47
Annex I (informative) Aerosol isokinetic sampling.49
Bibliography.52

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
In other circumstances, particularly when there is an urgent market requirement for such documents, a
technical committee may decide to publish other types of document:
⎯ an ISO Publicly Available Specification (ISO/PAS) represents an agreement between technical experts in
an ISO working group and is accepted for publication if it is approved by more than 50 % of the members
of the parent committee casting a vote;
⎯ an ISO Technical Specification (ISO/TS) represents an agreement between the members of a technical
committee and is accepted for publication if it is approved by 2/3 of the members of the committee casting
a vote.
An ISO/PAS or ISO/TS is reviewed after three years in order to decide whether it will be confirmed for a
further three years, revised to become an International Standard, or withdrawn. If the ISO/PAS or ISO/TS is
confirmed, it is reviewed again after a further three years, at which time it must either be transformed into an
International Standard or be withdrawn.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO/TS 19713-1 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 7,
Injection equipment and filters for use on road vehicles.
ISO/TS 19713 consists of the following parts, under the general title Road vehicles — Inlet air cleaning
equipment for internal combustion engines and compressors:
⎯ Part 1: Fractional efficiency testing with fine particles (0,3 µm to 5 µm optical diameter)
⎯ Part 2: Fractional efficiency testing with coarse particles (5 µm to 40 µm optical diameter)
iv © ISO 2010 – All rights reserved

Introduction
The engine air cleaner/filter fractional efficiency test methods described in this part of ISO/TS 19713 have
been developed to cover traditional and new particulate air filters in order to remove airborne contaminants
specifically to protect the engine.
Air cleaner fractional efficiency is one of the main air cleaner performance characteristics. This part of
ISO/TS 19713 has been established to address the measurement of this parameter. The objective of the
procedure is to maintain a uniform test method for evaluating fractional efficiency of air cleaners and air filters
on specified laboratory test stands.
The data collected in accordance with this part of ISO/TS 19713 can be used to establish fractional efficiency
characteristics for air cleaners and filters tested in this manner. The actual field operating conditions (including
contaminants, humidity, temperature, mechanical vibration, flow pulsation, etc.) are difficult to duplicate.
However, with the procedure and equipment set forth, comparison of air filter fractional efficiency can be made
with a high degree of confidence.

TECHNICAL SPECIFICATION ISO/TS 19713-1:2010(E)

Road vehicles — Inlet air cleaning equipment for internal
combustion engines and compressors —
Part 1:
Fractional efficiency testing with fine particles (0,3 µm to 5 µm
optical diameter)
1 Scope
This part of ISO/TS 19713 describes laboratory test methods to measure engine air cleaner and filter
performance by fractional efficiency tests for particles from 0,3 µm to 5 µm optical diameter.
Performance includes, but is not limited to, airflow restriction or pressure loss, initial and incremental fractional
efficiencies during dust loading.
The purpose of this test code is to establish and specify consistent test procedures, conditions, equipment and
performance reports in order to enable comparison of filter performances of air cleaners and air filter elements
used in engine air induction systems. It specifies the critical characteristics of equipment, test procedure and
report format required for the consistent assessment of filter elements in a laboratory test stand.
ISO/TS 19713-2 describes fractional efficiency tests with particles from 5 µm to 40 µm optical diameter.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies
ISO 5011:2000, Inlet air cleaning equipment for internal combustion engines and compressors —
Performance testing
ISO 12103-1, Road vehicles — Test dust for filter evaluation — Part 1: Arizona test dust
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
air cleaner assembly
assembly which includes the air cleaner housing and the air filter element
3.1.1
single-stage air cleaner
air cleaner which does not incorporate a separate pre-cleaner
3.1.2
multistage air cleaner
air cleaner consisting of two or more stages, the first usually being a pre-cleaner, followed by one or more
filter elements
NOTE If two elements are used, the first is called the primary element and the second is called the secondary element.
3.1.3
pre-cleaner
device usually using inertial or centrifugal means to remove a portion of the test dust before reaching the filter
element
3.2
air filter element
actual filter supported and sealed within the air cleaner assembly
3.3
test airflow rate
measure of the volume of air passing through the test duct per unit time
NOTE The test airflow rate is expressed in cubic metres per second.
3.4
pressure loss
permanent pressure reduction due to a decrease in the flow energy (velocity head) caused by the filter (Pa at
standard conditions of 20 °C and 101,3 kPa)
3.5
fractional efficiency
E
f,i
ability of the air filter to remove particles of a specified size expressed as a percentage for particle size i
−
CC
1,ii2,
=×100 (1)
E
f,i
C
1,i
where
C is the number of particles per unit volume of specified size, i, upstream;
1,i
C is the number of particles per unit volume of specified size, i, downstream
2,i
NOTE Fractional efficiency is expressed in percent.
3.6
fractional efficiency before dust loading
efficiency before the collected particles have any measurable effect on the efficiency of the filter under test
NOTE The collected particles can affect the measured filter efficiency before enough aerosol is collected to have any
measurable effect on the filter pressure loss.
3.7
incremental fractional efficiency
efficiency, determined at the specified flow rate as a function of particle size at 10 %, 25 %, 50 % and 100 %
of filter life, which is determined by pressure loss across the filter as the filter is loaded with ISO 12103-1 test
dust
2 © ISO 2010 – All rights reserved

NOTE 1 The values of filter pressure loss, ∆P , at which the incremental fractional efficiencies are measured can be
i
calculated from
∆=P ∆PL+∆()∆P−∆P (2)
iiod o
where
∆P is the initial pressure loss;
o
∆L is the fraction of filter life;
i
∆P is the specified terminal pressure loss.
d
NOTE 2 If necessary, the requester and the tester can agree upon different criteria for incremental fractional efficiency.
3.8
fractional penetration
P
f,i
ratio of the concentration of particles of specified size exiting the filter to the concentration of particles of
specified size entering the filter expressed in a percentage for particle size i
PE=−100 (3)
f,iif,
NOTE Fractional penetration is expressed in percent.
3.9
test dust loading
mass of test dust collected by the air cleaner assembly or air filter element at a specified flow rate expressed
in grams
3.10
particle measurement device
aerosol spectrometer
instrument for sizing, or counting, or sizing and counting, aerosol particles
NOTE Recommended particle counters are optical particle counters (OPC) or other counters demonstrating good
correlation in measuring particle sizes, e.g. aerodynamic particle counters (APC).
3.11
test aerosol
particles suspended in air, used for filter efficiency evaluation or dust loading
3.11.1
fractional efficiency test aerosol
aerosol used to measure the efficiency of the test filter, the concentration of which is low enough to prevent
coincidence-related errors in the particle counters, and does not change the filter efficiency due to loading
NOTE The aerosol charge is reduced so that it approximates a Boltzman equilibrium charge distribution. The
requirements for the efficiency challenge aerosol are given in 5.2.10 and 5.2.11.
3.11.2
loading test aerosol
aerosol used to load the filter, the concentration of which is high enough to allow loading of the filter in a
reasonable amount of time
NOTE The requirements for the loading test aerosol are given in 5.2.13.2.
3.12
correlation ratio
R
ratio of the number of particles observed at the downstream sampling location to the number of particles at the
upstream sampling location when no filter is installed in the test system
NOTE 1 This number can be greater or less than 1.
NOTE 2 The method of calculating the correlation ratio is given in Annex B.
3.13
log mean diameter
D
l,i
weighted mean diameter calculated by
1/ 2
DD=×D (4)
()
l,ii i +1
where
D is the lower threshold of particle size range;
i
D is the upper threshold of particle size range
i+1
3.14
geometric (volume equivalent) diameter
D
g,i
diameter of a sphere with the same volume as the particle being measured
NOTE For a spherical particle, it is the diameter of the sphere.
3.15
optical (equivalent) diameter
D
o,i
diameter of a particle of the type used to calibrate an optical sizing instrument that scatters the same amount
of light as the particle being measured
NOTE Optical diameter depends on the instrument, the type of particle used to calibrate the instrument (usually
polystyrene latex spheres), the optical properties of the particle being measured, and the size of the particle.
3.16
aerodynamic (equivalent) diameter
D
ae
diameter of a sphere of density 1 g/cm with the same terminal velocity as the particle being measured, due to
gravitational force in calm air
NOTE 1 The aerodynamic diameter will be used to report results to avoid different diameter measures due to different
sizing and counting techniques.
NOTE 2 Annex F provides additional information about aerodynamic diameter.
3.17
high efficiency particulate air
HEPA
filter having 99,95 % efficiency at most penetrating particle size (class H13 in accordance with EN 1822), or
99,97 % (or higher) fractional efficiency at 0,3 µm using DOP aerosol as defined by IEST RP-CC001
recommended practice
4 © ISO 2010 – All rights reserved

3.18
neutralization
aerosol whose charge distribution is reduced until it provides a Boltzman equilibrium charge distribution
4 Principle
The primary objective of this test procedure is to enable an assessment of air cleaners for pressure loss and
fractional efficiency against standardized laboratory particulate challenges. Because the test methods exclude
the full range of possible particulate challenges and environmental effects, the relative ranking of filters may
change in service. Note that absolute comparability is only possible with air cleaners of the same shape and
size, as well as of the same position in the test duct. In order to get comparable results to the dust loading
capacity, gravimetric efficiency and airflow restriction/pressure loss tests, the fractional efficiency test can be
done simultaneously. (See ISO 5011.)
5 Test equipment, accuracy and validation
5.1 Measurement accuracy
Accuracy requirements are given in Table E.1.
5.2 Test stand configuration
5.2.1 General
Complete vehicle manufacturer air cleaner assemblies or individual air filter elements may be tested. The test
stand shall consist of the following major components and shall be arranged as shown in Figure 2.
NOTE 1 Results can vary depending on configuration.
NOTE 2 Air cleaner assembly orientation will affect performance. It is advisable that air cleaner assemblies be oriented
and tested as installed in the vehicle.
Figure 2 shows a set-up to measure the performance of an air cleaner assembly.
Figure 3 shows a recommended air cleaner housing to measure the performance of a panel-type air filter
element.
Figure 4 shows a recommended air cleaner housing to measure the performance of a cylindrical-type air filter
element.
5.2.2 Unit under test
5.2.2.1 General
The unit under test may be an air cleaner housing with filter element or elements or it may be a housing
designed to hold a filter element with appropriate inlet and outlets. The unit under test may be or may include
a pre-cleaner. The scope of this test procedure does not include the testing of air cleaner systems without
tubular inlet and outlet connections. However, designs such as perforated or louvered inlet systems could be
tested with the unit under test inside a plenum that would include a tubular inlet. Non-tubular air cleaner
systems outside the scope of this test procedure may still be evaluated as agreed upon between the tester
and customer.
5.2.2.2 Air cleaner assembly
Air cleaner assemblies shall be evaluated using the set-up shown in Figure 2.
5.2.2.3 Evaluating panel air filter elements
In general, panel-type air filter elements may be tested using the recommended housing shown in Figure 3.
5.2.2.4 Evaluating cylindrical/round air filter elements
Figure 4 shows a recommended housing to test cylindrical-type air filter elements. This housing design is
similar to the one recommended in ISO 5011.
5.2.3 Ducting
Upstream and downstream cylindrical ducting shall be made of conductive material and all components shall
be commonly grounded from the aerosol inlet section to the downstream sampling section.
5.2.4 Airflow conditioning
Inlet air shall be conditioned in accordance with the requirements of ISO 5011, i.e. (23 ± 5) °C and (55 ± 15) %
relative humidity (RH). The inlet air shall be filtered with a HEPA filter if the background particle concentration
exceeds the requirements in 7.7.2.3 and 7.7.4.3.
5.2.5 Test configurations
The upstream and downstream ducting can be constructed vertically (recommended), horizontally, or a
combination based on space constraints. The example in this procedure shows a vertical configuration to test
both air cleaners and panel-type air filters. The particle samplers are located vertically in each test section,
which reduces the probability of particle loss and enables sampling of large particle sizes of interest. The
underlying test system design will reduce particle losses and meet the requirements of Tables E.1 and E.2.
5.2.6 Airflow ducting
The test system should be capable of handling user-specified flow rates. Further, the test system will maintain
the required flow rates with air cleaner assembly pressure loss up to 10 kPa. Primary duct sizing shall conform
to the “nominal” duct diameter and flow ranges in Table 1. Higher and lower flow rates may use duct sizes
scaled appropriately.
Table 1 — Duct diameter versus flow range
Nominal duct Flow range Flow range
Area Velocity Reynolds number
diameter low high
2 3 3
mm m/s at low flow at high flow
m m/h m /h
50 0,002 02 11,6 85 425 40 407 202 034
100 0,008 1 5,8 170 850 40 407 202 034
150 0,018 2 5,2 340 1 700 53 876 269 378
200 0,032 4 5,8 680 3 400 80 813 404 067

−3
NOTE A 10 µm particle with a specific gravity of 2 settles at about 6 × 10 m/s in still air. At the minimum velocity of
approximately 5,1 m/s, this would result in a 10 mm drop in that 10 µm particle over a 3 m run.
5.2.7 Inlet filtration
Test inlet airflow shall be filtered with a HEPA filter to remove the majority of ambient aerosol, if required, in
accordance with Annex E.
6 © ISO 2010 – All rights reserved

5.2.8 Flow uniformity
The test system shall be designed to provide uniform and steady airflow to the air cleaner assembly or to the
air filter element under test, as stated in the test set-up.
NOTE Uniform airflow is required in sections where isokinetic samplers are located when evaluating air cleaner
assemblies. Proper flow distribution will facilitate a representative aerosol sample being drawn by the isokinetic samplers.
See 5.2.10.4 for flow uniformity measurements.
5.2.9 Leakage
It is important to minimize leakage into the test system to obtain good data. Depending on where the leakage
occurs, it can cause major errors in particle counting.
As a minimum, all connections and joints should be checked for visual leakage using soap bubbles. Any
known soap solution can be used for the test. Preferably, the soap solution (foam) will be applied using a
brush at all connections and joints. Leaks are especially important on the clean side of the air cleaner. See
Annex H for more information.
5.2.10 Fractional efficiency test aerosol generator
5.2.10.1 General
The aerosol generator for fractional efficiency tests shall provide a stable and homogenous aerosol
concentration and size distribution. The size distribution of the aerosol shall have sufficient particles for
statistical evaluation in each size class, as explained in Clause 7. If high-resolution particle spectrometers are
used, size classes may be combined to achieve the required counts using the size ranges in 5.2.13. The total
concentration of the aerosol in the test duct shall not exceed the limit of the particle counter, as discussed in
5.2.13.3. The efficiency test aerosol concentration shall be low enough so there is no change in efficiency
during the test, as measured by the penetration data acceptance criteria in 7.7.4 (i.e. no loading effects). The
size distribution and concentration stability requirements are established by the data quality requirements in
Clause 7.
5.2.10.2 Aerosol generation
The potassium chloride aerosol generator for fractional efficiency tests shall nebulize a saline solution to
produce a homogeneous mist aerosol with stable concentration and size distribution. The droplets shall be
dried to form salt particles by using, for example, dry dilution air, heat, or desiccant. The efficiency test aerosol
generator shall be capable of dispersing KCl (potassium chloride aerosol) at a concentration low enough to
meet coincidence error requirements for the particle counter used. Compressed air used to operate and
transport the challenge aerosol should be HEPA filtered and dried before entering the feeding system.
5.2.10.3 Aerosol dispersion
The efficiency test aerosol should be injected against the airflow coming from the inlet HEPA filter(s). Care
should be taken to keep the injection velocity low enough to keep the larger particles in the challenge aerosol
from impacting on the walls of the inlet aerosol ductwork. The objective is to allow the inlet air to turn the
challenge aerosol and result in a more uniform distribution of concentration and particle size distribution
across the duct, even before it enters the upstream static mixer.
5.2.10.4 Aerosol uniformity
During validation of uniformity and concentration of the efficiency test aerosol, no air cleaner shall be installed
in the location of the test filter (see Figure 2). Instead, a smooth, straight pipe or an elbow may be used. The
uniformity of the particle size distribution and the concentration of the test aerosol used for fractional efficiency
tests may be verified by use of a particle-sizing instrument that will also be used in the test system. This
particle-sizing instrument shall draw samples upstream and downstream of the air cleaner mounting position
using the isokinetic samplers. For each test duct the minimum and maximum flow rate will be used for this
evaluation (see Table 1). Samples shall be drawn by the isokinetic samplers along a diameter at three
locations. For tube diameter D, locations will be 0,15D, 0,5D and 0,85D (see Figure 1). The measurements
will be performed in a plane along two perpendicular diameters. A minimum of three samples shall be drawn
at each sampling location, and the resulting number distribution shall be averaged. As far as possible, the
samples will be taken at random. The average values for each reported particle-size range shall not vary by
more than ±10 % for channels less than 5 µm particles among the five locations. This indicates that the
efficiency test aerosol is uniformly distributed across the test duct, and that the centreline sample is
representative of the overall challenge.

NOTE For tube diameter D, the sampling positions are the following:
⎯ horizontal: 0,15D; 0,5D; 0,85D;
⎯ vertical: 0,15D; 0,85D.
Figure 1 — Location of isokinetic sampling points for validation
5.2.11 Aerosol neutralizer
The efficiency test aerosol shall be neutralized by passing it through a radioactive (minimum 5 mCi) or other
ion generating device. The feed aerosol shall be neutralized to approach a Boltzman equilibrium charge
distribution.
Generated and dispersed particles often obtain a high level of electrical charge. To obtain comparable results
for different aerosols and different generation methods, the aerosol's charge distribution shall be reduced until
it provides a Boltzman equilibrium charge distribution. A Boltzman equilibrium charge distribution is the
minimum stable charge level and is reached by an aerosol when it is aged. This state of an aerosol cannot be
generated artificially in a comparably short time. For many applications, e.g. filter testing, it is sufficient to
reduce the charges, utilizing ionized air, to a minimum level. To reach this charge level quickly in a test system
the efficiency aerosol is mixed with a high concentration of air ions. To create a high level of air ions, an
electrostatic corona (ion blower) or radioactive air ionizer shall be used. The ionizer shall produce a sufficient
concentration of bipolar air ions to mix with the aerosol so that the resulting aerosol has a charge distribution
that approximates a Boltzman distribution. An aerosol that has Boltzman equilibrium charge distribution is said
to be neutralized. The aerosol is not neutral in the sense that all of the particles are neutral, i.e.
⎯ the level of neutralization shall be optimized by methods described in Annex G;
⎯ aerosol may become charged in transport through tubing and test duct, so the neutralization should take
place as close as practical to the filter under test;
⎯ a neutralizer is required for fractional-efficiency tests and is optional for dust-holding capacity tests.
5.2.12 Upstream and downstream sample probes
Sampling probes shall be isokinetic (local velocity of duct and probe to be equal) to within ±20 %. The same
probe design should be used before and after the filter. Sampling probes shall be located on the centreline of
the test duct. Sample probes shall be located at least seven diameters downstream of any bends, reducers,
expanders, etc. The sampling probe shall be at least four diameters upstream of any bends, reducers,
expanders, etc. The samplers will also be located in the centre of the duct. The probes shall be made of
8 © ISO 2010 – All rights reserved

electrically conductive metallic tubing with a smooth inside surface. The design of the probes and sampling
lines will reduce particle losses. The inlet of the sampling probes shall be sharp edged and shall be located
near the centre of the duct. Both the upstream/downstream sampling lines should be identical, straight (or no
more than one bend) and as short as possible. See Annex I for details on isokinetic sampling. A short
(u 50 mm) flexible connection to the particle counter may be used to allow some flexibility and reduce stress
on the counter inlet. PTFE may not be used as flexible tubing. Use conductive tubing (e.g. plasticized PVC)
instead. For more information on tubing, see the Bibliography.
Sampling probe ducting to the particle counter must be set up in a way that no sedimentation of large particles
takes place, i.e.
⎯ vertical orientation of the tubing;
⎯ sufficient flow velocity;
⎯ short connection length between particle counter and sampling probe;
⎯ avoidance of bends in the tubing;
⎯ no sharp angles if bends are necessary.
5.2.13 Loading test aerosol generator (see ISO 5011)
5.2.13.1 General
Loading aerosol generation shall be in accordance with ISO 5011:2000, 6.2.1 to 6.2.4.
5.2.13.2 Loading test aerosol (air cleaner assembly only)
A dust injector (see ISO 5011:2000, Figure B.2 or B.3) shall be used to disperse the loading test aerosol
(ISO 12103-1 A2 test dust). The dust feeder location is shown in Figure 2. Test dust shall be injected
downstream from the upstream sample probe in order to reduce upstream optics contamination problems.
The injector nozzle shall extend into the duct so that dust is injected at a point beyond the adjacent sample
probe. The nozzle will extend into the duct to the entrance of the piezometer tube. The inside diameter of the
extension tube will be the same as the outside diameter of the injector nozzle. A slight offset (but close to the
centre as possible) of either the probe or the injector extension, or both, may be required so they can extend
past each other inside the duct elbow. The extension nozzle shall be centred in the duct.
5.2.13.3 Loading test aerosol dust feeder
A dust feeder capable of feeding a stable (within ±5 %) concentration of 1g/m of air at the test flow rate shall
be used. Reference the dust feeder specifications and validation procedure in ISO 5011.
5.2.14 Upstream and downstream particle counters
5.2.14.1 General
Upstream and downstream particle counters shall be of the same model and shall be matched as closely as
possible. A single particle counter can also be used for efficiency measurements using sequential
measurements alternately sampling upstream and downstream. The use of a single particle counter sampling
downstream only is not allowed. The airborne particle counters shall be capable of counting particles in the
0,3 µm to 5 µm optical size range and 0,5 µm to 10,0 µm aerodynamic size range. It is also desirable for the
particle counters to have a design incorporating clean sheath air to protect and keep the optics clean. The
particle counters may also need to be adapted with an exhaust port that can be routed back to the test system
vacuum. Without this exhaust set up, the particle counters may not be able to perform at the rated flow.
Counters must be calibrated using NIST traceable PSL (polystyrene latex) spheres (see calibration procedure
in ASTM F328). Correlation shall be done in accordance with Clauses 6 and 7 with an elbow, or a tube, or an
elbow and tube the same size as the test ducting in place of the air cleaner assembly. The inlet/outlet duct
orientation shall be maintained during correlation measurements and testing. Data should also be reported in
equivalent aerodynamic size ranges. Most laboratories currently use optical particle counters, however, the
technical advantages of using aerodynamic particle counters is also well recognized. The particle counter
shall be able, at a minimum, to discriminate eight logarithmically spaced particle size classes.
There is a finite measurable delay for particle transport from the upstream sample probe to the downstream
sample probe. It is possible to improve data quality by starting the downstream sample count after a delay
equal to the transport time between the sample probes. The transport time can be measured or calculated.
5.2.14.2 Particle counter calibration
The particle counters shall be calibrated with polystyrene latex particles of appropriate size prior to system
start-up and a minimum of once a year to verify that the size calibration has not changed. It is recommended
that the particle counter calibration be verified periodically during the year between calibrations. If the counter
shows an unacceptable change in the calibration, the counter should be serviced.
5.2.14.3 Particle counter zero
The particle counters will be checked using a cartridge filter on the inlet (> 99,99 % efficient at 0,12 µm). The
particle counter shall count ten particles or less per minute per channel.
5.2.14.4 Maximum particle concentration
The maximum total particle concentration shall be established to prevent coincidence counting (i.e. counting
more than one particle at a time). A recommended method for establishing this limit is to conduct filter
efficiency tests at a series of different concentrations and compare the results. The maximum concentration is
determined at the point where increasing the concentration by a factor of two causes the fractional efficiency
in the smallest size range at the higher concentration to be more than 5 % less than the fractional efficiency at
the lower concentration. Another method is to increase the concentration in steps (e.g. by using a diluted and
an undiluted aerosol) and determine the concentration where the particle counter starts showing significant
deviation from the expected concentration in the smallest size range. An example is given in Annex D.
5.2.14.5 Particle counter flow
The particle counter flow rate shall remain constant within ±5 % for the duration of a test including the
correlation done before the test.
5.2.14.6 Upstream/downstream particle counter correlation ratios
Correlation shall be performed using an elbow, or a tube, or an elbow and tube, the same size as the test
ducting in place of the air cleaner assembly and in the same orientation as the air cleaner assembly
inlet/outlet tubes under test. See 7.6 to calculate correlation ratios.
5.2.15 Inlet and outlet piezometer tubes
Inlet and outlet piezometer tubes shall be installed upstream and downstream of the air cleaner unit under test.
Inlet and outlet transition tubes shall adapt the unit under test to the piezometers if they are a different size
from the piezometer. The inlet and outlet piezometer tubes shall be designed as specified in ISO 5011.
5.2.16 Airflow measurement
Measure airflow with accuracy in accordance with Annex E. Convert all volume flow rates to actual conditions
at the inlet of the device under test.
10 © ISO 2010 – All rights reserved

5.2.17 High efficiency test and purge time measurement
As part of system set-up and validation, conduct an initial efficiency test using a HEPA or ultra low particulate
air (ULPA) filter as the filter under test. The standard fractional efficiency test as described in Clause 6 should
be followed. The fractional efficiency in all size ranges should be greater than 99,9 %.
These measurements can be used to establish the minimum purge times when switching from upstream to
downstream sampling with sequential sampling systems. If the purge time is too short, the downstream count
will include residual particles from the upstream sample causing the measured efficiency to be low.

Key
1 HEPA inlet air filter 12 unit under test
2 challenge aerosol feeder 13 outlet transition tube (if required)
3 aerosol neutralizer 14 outlet piezometer tube
4 static mixer 15 downstream isokinetic sample probe
5 upstream isokinetic sample probe 16 downstream particle counter
6 dust injector 17 absolute filter
7 loading dust feeder 18 airflow straightener
8 upstream particle counter 19 airflow meter
9 dilution (if required) 20 airflow pump (exhauster)
10 inlet piezometer tube 21 particle counter exhaust port
11 inlet transition tube (if required)
Figure 2 — Test set-up to evaluate air cleaner assembly
Key
D , D tube diameters
1 2
F cross-sectional area of the panel filter element paper pack
H cross-sectional area of the housing
L , L length of air cleaner housing
1 2
α angle u 30° around the perimeter of the diffuser
a
D = D and depends on the test flow rate (see Table 1).
1 2
b
Smooth transition from a round duct to a rectangular cross-section.
c
Filter should be sealed to the plate, for example see ISO 5011.
d
Ratio of H to F shall not be less than 0,5.
e
L = L and depends on area H and included angle α.
1 2
Figure 3 — Test set-up for panel-type and axial flow cylindrical-type air filter elements
12 © ISO 2010 – All rights reserved

Key
D , D tube diameters
1 2
A area
1 diffuser plate/cone
2 sealing plate
3 cylindrical round conical tapered air filter
a
D = D and depends on the test flow rate (see Table 1).
1 2
b
Area A is adjusted so that the annular face velocity of entry is in the range of (900 ± 50) m/min.
Figure 4 — Test set-up for cylindrical radial flow-type air filter elements
5.3 Test conditions
5.3.1 General
All tests shall be conducted with air entering the air cleaner assembly or air filter element in accordance with
5.2.4, with the permissible humidity variation throughout one single test being ±2 %.
5.3.2 Test aerosol
5.3.2.1 Fractional test aerosol
For this part of ISO/TS 19713, the KCl (potassium chloride) test aerosol shall be used.
5.3.2.2 Loading test aerosol
For this part of ISO/TS 19713, the following test dust shall be used:
⎯ for single-stage air cleaner assemblies and air filter elements: ISO 12103-1 A2 test dust;
⎯ for pre-cleaners and multistage air cleaner assemblies: ISO 12103-1 A4 test dust.
5.3.3 HEPA filter
A HEPA filter is used to provide clean air to the test stand. Limits on the maximum acceptable background
counts are given in 7.7.2.3 and 7.7.4.3. A high efficiency filter may be used downstream to protect the flow
meter and air moving devices.
5.4 Validation
Prior to initial use, the test stand shall be validated in accordance with Table E.2
IMPORTANT — If the test set-up undergoes any hardware/component changes, it needs to be re-
verified and re-evaluated for that portion of the test stand and for those changes.
The validation certifying the performance of a system in accordance with this part of ISO/TS 19713 shall be
documented, including the following:
a) system diagram and detailed description, including particle generator used:
⎯ particle materials used in the tests, including tractability;
⎯ manufacturer and model of the particle counters;
⎯ calibration data for the particle counter(s);
⎯ calibration data for flow measuring device;
⎯ manufacturer, model number and date of manufacture for the neutralizer system used;
b) calibration data for pressure loss;
c) system performance on flow uniformity;
d) system performance on particle concentration uniformity;
e) data demonstrating that the coincidence counting error meets the criteria of Table E.2;
f) data demonstrating the performance of the neutralizer as described in Annex G;
g) data showing the agreement between upstream and down
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