High-efficiency filters and filter media for removing particles in air — Part 1: Classification, performance testing and marking

ISO 29463-1:2011 establishes a classification of filters based on their performance, as determined in accordance with ISO 29463-3, ISO 29463-4 and ISO 29463-5. It also provides an overview of the test procedures, and specifies general requirements for assessing and marking the filters, as well as for documenting the test results. It is intended for use in conjunction with ISO 29463‑2, ISO 29463‑3, ISO 29463-4 and ISO 29463-5.

Filtres à haut rendement et filtres pour l'élimination des particules dans l'air — Partie 1: Classification, essais de performance et marquage

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Status
Withdrawn
Publication Date
06-Oct-2011
Withdrawal Date
06-Oct-2011
Current Stage
9599 - Withdrawal of International Standard
Start Date
04-Oct-2017
Completion Date
04-Oct-2017
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INTERNATIONAL ISO
STANDARD 29463-1
First edition
2011-10-15
High-efficiency filters and filter media for
removing particles in air —
Part 1:
Classification, performance testing and
marking
Filtres à haut rendement et filtres pour l'élimination des particules dans
l'air —
Partie 1: Classification, essais de performance et marquage
Reference number
ISO 29463-1:2011(E)
ISO 2011
---------------------- Page: 1 ----------------------
ISO 29463-1:2011(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2011

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,

electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or

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Published in Switzerland
ii © ISO 2011 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 29463-1:2011(E)
Contents Page

Foreword ............................................................................................................................................................ iv

Introduction ......................................................................................................................................................... v

1  Scope ...................................................................................................................................................... 1

2  Normative references ............................................................................................................................ 1

3  Terms and definitions ........................................................................................................................... 2

4  Symbols and abbreviations .................................................................................................................. 3

5  Classification ......................................................................................................................................... 3

6  Requirements ......................................................................................................................................... 4

6.1  General ................................................................................................................................................... 4

6.2  Material ................................................................................................................................................... 4

6.3  Nominal air volume flow rate ............................................................................................................... 5

6.4  Pressure difference ............................................................................................................................... 5

6.5  Filtration performance .......................................................................................................................... 5

7  Test methods — General requirements and test procedures overview .......................................... 5

7.1  General ................................................................................................................................................... 5

7.2  Test rigs .................................................................................................................................................. 5

7.3  Test conditions ...................................................................................................................................... 5

7.4  Test aerosols ......................................................................................................................................... 6

7.5  Test methods — Principles .................................................................................................................. 6

8  Assessment of the filter, documentation, test reports .................................................................... 12

9  Marking ................................................................................................................................................. 12

Annex A (informative) Filtration of nanoparticles ......................................................................................... 13

Annex B (informative) Summary of classification and test methods .......................................................... 14

Bibliography ...................................................................................................................................................... 16

© ISO 2011 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO 29463-1:2011(E)
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.

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 29463-1 was prepared by Technical Committee ISO/TC 142, Cleaning equipment for air and other gases.

ISO 29463 consists of the following parts, under the general title High-efficiency filters and filter media for

removing particles in air:
 Part 1: Classification, performance, testing and marking
 Part 2: Aerosol production, measuring equipment, particle-counting statistics
 Part 3: Testing flat sheet filter media
 Part 4: Test method for determining leakage of filter element — Scan method
 Part 5: Test method for filter elements
iv © ISO 2011 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 29463-1:2011(E)
Introduction

ISO 29463 (all parts) is derived from EN 1822 (all parts) with extensive changes to meet the requests from

non-EU p-members. It contains requirements, fundamental principles of testing and the marking for high-

efficiency particulate air filters with efficiencies from 95 % to 99,999 995 % that can be used for classifying

filters in general or for specific use by agreement between users and suppliers.

ISO 29463 (all parts) establishes a procedure for the determination of the efficiency of all filters on the basis of

a particle counting method using a liquid (or alternatively a solid) test aerosol, and allows a standardized

classification of these filters in terms of their efficiency, both local and overall efficiency, which actually covers

most requirements of different applications. The difference between ISO 29463 (all parts) and other national

standards lies in the technique used for the determination of the overall efficiency. Instead of mass

relationships or total concentrations, this technique is based on particle counting at the most penetrating

particle size (MPPS), which, for micro-glass filter mediums, is usually in the range of 0,12 µm to 0,25 µm. This

method also allows testing ultra-low penetration air filters, which was not possible with the previous test

methods because of their inadequate sensitivity. For membrane filter media, separate rules apply; they are

described in ISO 29463-5:2011, Annex B. Although no equivalent test procedures for testing filters with

charged media is prescribed, a method for dealing with these types of filters is described in ISO 29463-5:2011,

Annex C. Specific requirements for test method, frequency, and reporting requirements can be modified by

agreement between supplier and customer. For lower-efficiency filters (group H, as described below),

alternate leak test methods noted in ISO 29463-4:2011, Annex A, can be used by specific agreement between

users and suppliers, but only if the use of these other methods is clearly designated in the filter markings as

noted in ISO 29463-4:2011, Annex A. Although the methods prescribed in this part of ISO 29463 can be

generally used to determine filter performance for nano-size particles, testing or classification of filters for

nano-size particles is beyond the scope of this part of ISO 29463 (see Annex A for additional information).

There are differences between ISO 29463 (all parts) and other normative practices common in several

countries. For example, many of these rely on total aerosol concentrations rather than individual particles. For

information, a brief summary of these methods and their reference standards are provided in

ISO 29463-5:2011, Annex A.
© ISO 2011 – All rights reserved v
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INTERNATIONAL STANDARD ISO 29463-1:2011(E)
High-efficiency filters and filter media for removing particles in
air —
Part 1:
Classification, performance testing and marking
1 Scope

This part of ISO 29463 establishes a classification of filters based on their performance, as determined in

accordance with ISO 29463-3, ISO 29463-4 and ISO 29463-5. It also provides an overview of the test

procedures, and specifies general requirements for assessing and marking the filters, as well as for

documenting the test results. It is intended for use in conjunction with ISO 29463-2, ISO 29463-3,

ISO 29463-4 and ISO 29463-5.
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 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 29463-2:2011, High-efficiency filters and filter media for removing particles in air — Part 2: Aerosol

production, measuring equipment, particle-counting statistics

ISO 29463-3:2011, High-efficiency filters and filter media for removing particles in air — Part 3: Testing flat

sheet filter media

ISO 29463-4:2011, High-efficiency filters and filter media for removing particles in air — Part 4: Test method

for determining the leakage of filter element — Scan method

ISO 29463-5:2011, High-efficiency filters and filter media for removing particles in air — Part 5: Test method

for filter elements
ISO 29464 , Cleaning equipment for air and other gases — Terminology
1) To be published.
© ISO 2011 – All rights reserved 1
---------------------- Page: 6 ----------------------
ISO 29463-1:2011(E)
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 29464 and the following apply.

3.1
filter medium
material used for filtering
3.2
folded pack
pack of the filter medium formed by uniform individual folds
3.3
filter element
filter
folded pack enclosed by a frame
3.4
efficiency

ratio of the number of particles retained by the filter to the number of the particles entering it

3.5
particle size efficiency
efficiency for a specific particle diameter

NOTE The efficiency plotted as a function of the particle diameter gives the fractional efficiency curve.

3.6
overall efficiency

efficiency, averaged over the whole superficial face area of a filter element under given operating conditions of

the filter
3.7
local efficiency

efficiency at a specific point of the filter element under given operating conditions of the filter

3.8
nominal air volume flow rate

air volume flow rate at which the filter element shall be tested, as specified by the manufacturer

3.9
filter face area
cross-sectional area of the filter element including the frame
3.10
superficial face area
cross-sectional area of the filter element through which the air flow passes
3.11
effective filter medium area

area of the filter medium contained in the filter element (without areas covered by sealant, spacers, struts,

etc.) through which the air flow passes
3.12
nominal filter medium face velocity
nominal air volume flow rate divided by the effective filter medium area
3.13
quasi-mono-disperse aerosol

aerosols whose distribution has a geometric standard deviation between   1,15 and   1,5

g g
2 © ISO 2011 – All rights reserved
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ISO 29463-1:2011(E)
4 Symbols and abbreviations

For the purposes of this document, the following symbols and abbreviations apply.

d particle diameter
E efficiency
P penetration
p pressure
 geometric standard deviation
CPC condensation particle counter

DEHS Sebacic acid: bis (2-ethyl hexyl-) ester (trivial name: di-ethyl-hexyl-sebacate)

DMA differential electric mobility analyser
DMPS differential mobility particle sizer

MPPS most penetrating particle size, that is the particle size for which the filtration efficiency is a minimum

OPC optical particle counter

PAO poly-alpha-olefin, mineral oil with Chemical Abstract Service Registry number of 68649-12-7

PSL poly-styrene latex (solid spheres)
5 Classification

Filters and filter elements are classified in groups and classes based on their efficiency or penetration for the

MPPS particles by testing in accordance with Clause 6 and with ISO 29463-5. According to this part of

ISO 29463, filter elements fall into one of the following groups.

a) group E: EPA filters (efficient particulate air filter, also commonly referred to as sub-HEPA)

The efficiency of the filters is determined by statistical sample testing only in accordance with

ISO 29463-5. Group E filters cannot and shall not be leak tested.
b) group H: HEPA filters (high-efficiency particle air filter)

Filters are individually tested and their efficiency is determined at MPPS in accordance with ISO 29463-5.

The filter is leak tested in accordance with ISO 29463-4 where, in addition to the reference leak scan

method, four alternate methods for leak testing are allowed. Alternate norms used for leak testing should

be clearly identified on the filter and certifications.
c) group U: ULPA filters (ultra low penetration air filter)

Filters are individually tested and their efficiency is determined at MPPS in accordance with ISO 29463-5.

Filters are leak tested according to scan method in accordance with ISO 29463-4. No alternate leak

testing is allowed.
A detailed specification for each filter group and class is given in Table 1.

Detailed information about the permissible test methods in accordance with ISO 29463 (all parts) for each

filter group and class of filters is given in Table B.1.
© ISO 2011 – All rights reserved 3
---------------------- Page: 8 ----------------------
ISO 29463-1:2011(E)
Table 1 — Filter classification
a,b
Overall value Local value
Filter class and
Efficiency Penetration Efficiency Penetration
group
% % % %
c c
ISO 15 E 95 5 — —
c c
ISO 20 E 99 1 — —
c c
ISO 25 E 99,5 0,5 — —
c c
ISO 30 E 99,90 0,1 — —
ISO 35 H 99,95 0,05 99,75 0,25
ISO 40 H 99,99 0,01 99,95 0,05
ISO 45 H 99,995 0,005 99,975 0,025
ISO 50 U 99,999 0,001 99,995 0,005
ISO 55 U 99,999 5 0,000 5 99,997 5 0,002 5
ISO 60 U 99,999 9 0,000 1 99,999 5 0,000 5
ISO 65 U 99,999 95 0,000 05 99,999 75 0,000 25
ISO 70 U 99,999 99 0,000 01 99,999 9 0,000 1
ISO 75 U 99,999 995 0,000 005 99,999 9 0,000 1
See 7.5.2 and ISO 29463-4.

Local penetration values lower than those given in this table may be agreed upon between the supplier and customer.

Filters of group E cannot and shall not be leak tested for classification purposes.

For group H filters, local penetration is given for reference MPPS particle scanning method. Alternate limits may be specified when

photometer or oil thread leak testing is used.
6 Requirements
6.1 General

The filter element shall be designed or marked so as to prevent incorrect mounting.

The filter element shall be designed so that when correctly mounted in the ventilation duct, no leak occurs

along the sealing edge.

If, for any reason, dimensions do not allow testing of a filter under standard test conditions, assembly of two or

more filters of the same type or model is permitted, provided no leaks occur in the resulting filter.

6.2 Material

The filter element shall be made of material suitable to withstand the normal usage and exposures to those

temperatures, humidity and corrosive environments that they are likely to encounter.

The filter element shall be designed so that it is able to withstand the mechanical constraints that they are

likely to encounter during normal use.

Dust or fibres released from the filter media by the air flow through the filter element shall not constitute a

hazard or nuisance for the people (or devices) exposed to filtered air.
4 © ISO 2011 – All rights reserved
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ISO 29463-1:2011(E)
6.3 Nominal air volume flow rate

The filter element shall be tested at the nominal air volume flow rate for which the filter has been designed by

the manufacturer.
6.4 Pressure difference

The pressure difference across the filter element is recorded at the nominal air volume flow rate.

6.5 Filtration performance

The filtration performance is expressed by the efficiency or the penetration as measured by the prescribed

procedures in ISO 29463-5. After testing in accordance with Clause 7, filter elements are classified in

accordance with Table 1.

Filters with filter media having an electrostatic charge are classified in accordance with Table 1, on the basis

of their discharged efficiency or penetration in accordance with ISO 29463-5:2011, Annex C.

7 Test methods — General requirements and test procedures overview
7.1 General

The complete test method is comprised of the following three steps, which can be performed independently:

 test for flat sheet filter media, in accordance with ISO 29463-3;

 test for determining the leakage of filter elements (scan method), in accordance with ISO 29463-4;

 test for determining the efficiency of filters, in accordance with ISO 29463-5.

Clause 7 provides the general requirements for the features common to all tests, as well as an overview of the

test procedures.

Detailed information about the permissible test methods for filter elements in accordance with ISO 29463 (all

parts) for each filter group and class of filters is given in Table B.1.
7.2 Test rigs

Test rigs shall be in accordance with ISO 29463-3, ISO 29463-4 and ISO 29463-5 for the respective tests.

The measuring equipment shall be in accordance with ISO 29463-2.
7.3 Test conditions

The air in the test channel used for testing shall comply with the following requirements:

 temperature: 23 °C  5 °C;
 relative humidity 75 %.

The temperature shall remain constant during the entire test procedure within 2 °C, and the relative humidity

within 5 %.

The cleanliness of the test air shall be ensured by appropriate pre-filtering, so that in operation without

addition of aerosol the particle number concentration measured with the particle counting method is less than

352 000 particles/m . The test specimen shall have the same temperature as the test air and, hence, shall be

conditioned at test requirements (temperature and relative humidity) long enough to be in equilibrium.

© ISO 2011 – All rights reserved 5
---------------------- Page: 10 ----------------------
ISO 29463-1:2011(E)
7.4 Test aerosols

For the testing of filters in accordance with this part of ISO 29463, a liquid test aerosol shall be used as the

reference test method. Alternatively, a solid aerosol may be used for leak testing (see ISO 29463-4:2011,

Annex E). Possible aerosol substances include, but are not limited to, DEHS, PAO and PSL. For further

details, see ISO 29463-2:2011, 4.1.

The use of alternative materials for challenge aerosols may be agreed between supplier and customer when

the materials specified in this part of ISO 29463 are unacceptable.

The concentration and the size distribution of the aerosol shall be constant, within experimental limits, over

time. Details of aerosol generation for testing is addressed in the other parts of ISO 29463. For the leak test

and the efficiency test of the filter element, the count mean particle diameter of the test aerosol shall

correspond to the most penetrating particle size (MPPS) for the filter medium.
7.5 Test methods — Principles
7.5.1 Test method for flat sheet filter media

The fractional efficiency curve of flat sheet filter medium samples is determined in new condition (material as

supplied by the medium manufacturer) and in discharged condition (see ISO 29463-5:2011, Annex C). If these

measurements reveal that the filter medium has a significant charge, the filter elements shall be classified on

the basis of the discharged flat sheet efficiency or penetration measurements in accordance with

ISO 29463-5:2011, Annex C.

From the fractional efficiency curve, generated this way, the most penetrating particle size (MPPS) shall be

determined.
7.5.1.1 Test samples

The testing procedure requires at least five flat sheet samples of the filter material that makes up the filter

elements.

The test samples shall be free from folds, creases, holes and other irregularities. The test samples shall have

a minimum size of 200 mm  200 mm.
7.5.1.2 Test apparatus

The arrangement of the test apparatus is shown in Figure 1. The test rig is described in detail in ISO 29463-3.

The individual measuring instruments and other devices are described in ISO 29463-2. An aerosol is

produced in the aerosol generator, then passed through a conditioner (for example to evaporate a solvent)

and neutralized, before being brought together with the particle-free mixing air to the test filter medium

mounting assembly.

Sampling points are positioned upstream and downstream from the test filter medium mounting assembly

from which a part of the flow is directed to the particle counter. The upstream sampling point is connected with

a known ratio dilution circuit to reduce the high particle concentration down to the actual measuring range of

the particle counter.

When using the total count counting method (CPC), a differential electric mobility analyser (DMA) is included

before the aerosol neutralizer to separate out a (quasi-) mono-disperse fraction of the required particle size

from the initial poly-disperse aerosol.

If a counting method with particle size analysis (OPC) is used, the size distribution of a poly-disperse aerosol

can be measured before and after the test specimen.
6 © ISO 2011 – All rights reserved
---------------------- Page: 11 ----------------------
ISO 29463-1:2011(E)

Instead of using a single particle counter that measures the unfiltered and filtered air consecutively, it is also

permissible to use two particle counters of equal optical design (wave length of light source, light scattering

angle, etc.) simultaneously for both measurements. When using two particle counters, the two counters shall

be correlated by measuring the same aerosol to correct for any response differences. It is known that OPCs of

the same model can give different responses.

After the downstream sampling point, the test aerosol is directed through an exhaust filter and extracted by a

pump. The apparatus is completed by devices to measure (and regulate) the air volume flow rate and the

differential pressure across the filter under test.
The measurement data are recorded and evaluated by a computer.

The test apparatus may also be operated in an overpressure mode. In this case, the extraction pump is not

required and the mixing air is supplied from a compressed air line. If so desired, the measurement and

regulation of the air volume flow rate may then be carried out on the upstream side.

pressu-
flow rate
aerosol-
rized aerosol- test filter
exhaust
aerosol-
measure- pump
neutra- sampling sampling
condi- mounting
air DMA
filter
generator
ment
lizer
tioning assembly
condi-
tioner
p.T.RH-
delta-p-
air
dilution
measure- measure-
filter
ment ment
CPC
OPC
computer
exhaust
filter
Figure 1 — Arrangement of apparatus for testing the filter medium
7.5.1.3 Measurement procedure

The performance of the filter medium is determined by testing a circular sample with an exposed area of

100 cm at the nominal filter medium face velocity. Details of the measurements are described in ISO 29463-3.

In order to establish the penetration versus particle size curve, the penetration values for at least six particle

size points approximately logarithmically equidistant are determined.

For this measurement, quasi-mono-disperse test aerosol from a DMA with appropriate median values of the

particle diameter is used, and their concentrations determined upstream and downstream of the test sample.

Alternatively, the size distribution of a poly-disperse aerosol may be determined by OPCs upstream and

downstream of the test sample in at least six particle size classes. In each case, it shall be ensured that the

measuring range of the particle counter and the range of produced particle sizes includes the minimum of the

efficiency curve (MPPS).
© ISO 2011 – All rights reserved 7
---------------------- Page: 12 ----------------------
ISO 29463-1:2011(E)
7.5.1.4 Evaluation of test results

From the measurements on the five test samples, an efficiency versus particle size curve shall be drawn (see

Figure 2 for an example), from which the position and value of the minimum efficiency shall be determined.

Arithmetic mean values shall be determined for
 the minimum efficiency,
 the particle size at the minimum efficiency (MPPS),
 the pressure difference.

The particle size at the MPPS shall subsequently be used as the mean size of the test aerosol in the filter

element leakage test (see 7.5.2) and in the efficiency test (see 7.5.3).
99,999 999 0,000 001
1,5 cm/s
0,000 01
99,999 99
3 cm/s
0,000 1
99,999 9
0,001
99,999
0,01 0,02 0,05 0,1 0,2 0,5 1

Figure 2 — Particle size efficiency, E, and penetration, P, of an ULPA-filter medium as function of the

particle diameter, d , for two different filter medium velocities — Example
8 © ISO 2011 – All rights reserved
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ISO 29463-1:2011(E)
7.5.2 Test method for determining the leakage of filter elements — Scan method

The leak test serves to test the filter elements of groups H and U for local penetration and the absence of

leaks, respectively (see Table 1). The reference method and basis for this test is the particle counting scan

method as described in ISO 29463-4.

Filter elements of group H shall be leak tested using one of the five leak test methods described in

ISO 29463-4:2011: the reference scanning method, the oil thread leak test, the aerosol photometer filter scan

leak test, the PSL leak test, or the 0,3 μm to 0,5 μm particle efficiency leak test (ISO 29463-4:2011,

Annexes A, B, E, F). Group U filters shall be leak tested using the MPPS scanning method only, in

accordance with ISO 29463-4. All leak tests shall be performed at the nominal/rated air flow of the tested filter

element.

For group H filters with filter shapes that create a highly turbulent air flow (e.g. V-bank or cylindrical filters) for

which the reference scan method cannot be applied, leak testing by either of the two alternative methods may

be applied: the oil thread leak test (ISO 29463-4:2011, Annex A) or the 0,3 μm to 0,5 μm particle efficiency

leak test (ISO 29463-4:2011, Annex F). For group U filters with similar construction (e.g. V-bank or cylindrical

filters), the alternative methods might not be sensitive enough to measure the local penetration limits specified

in Table 1. Therefore, group U filters, leak tested with the alternative methods, shall be marked: “Alternative

leak tested, method A or F” on their label and test report, to clearly indicate that a less stringent leak test

criteria has been applied.
7.5.2.1 Test specimen

For leak testing, a filter element is required that can be sealed into the test rig and subjected to an air flow

direction in accordance with the final requirements.
7.5.2.2 Test apparatus

The arrangement of the individual components of the test apparatus for the scan test is shown in Figure 3.

The pre-filtered test air is drawn in by a fan and passed through a secondary filter (see 7.2). The air volume

flow rate is measured by a standardized air volume flow measuring device in accordance with ISO 5167-1, or

any other volume flow rate measuring device that can be calibrated, and shall be kept constant by a flow rate

controller. A neutralized aerosol with a mean size corresponding to the MPPS of the filter medium and at the

nominal face velo
...

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