Field testing of general ventilation filtration devices and systems for in situ removal efficiency by particle size and resistance to airflow (ISO 29462:2022)

This document describes a procedure for measuring the performance of general ventilation air cleaning devices in their end use installed configuration. The performance measurements include removal efficiency by particle size and the resistance to airflow. The test procedures include the definition and reporting of the system airflow.
The procedure describes a method of counting ambient air particles of 0,3 μm to 5,0 μm upstream and downstream of the in-place air cleaner(s) in a functioning air handling system. The procedure describes the reduction of particle counter data to calculate removal efficiency by particle size.
Since filter installations vary dramatically in design and shape, a protocol for evaluating the suitability of a site for filter evaluation and for system evaluation is included. When the evaluated site conditions meet the minimum criteria established for system evaluation, the performance evaluation of the system can also be performed according to this procedure.
This document also describes performance specifications for the testing equipment and defines procedures for calculating and reporting the results. This document is not intended for measuring performance of portable or movable room air cleaners or for evaluation of filter installations with an expected filtration efficiency at or above 99 % or at or below 30 % when measured at 0,4 μm.

Betriebserprobung von Filtereinrichtungen und -systemen für die allgemeine Lüftung hinsichtlich ihrer Abscheideeffizienz im eingebauten Zustand bezogen auf die Partikelgröße und den Druckverlust (ISO 29462:2022)

Essais in situ de filtres et systèmes de ventilation générale pour la mesure de l'efficacité en fonction de la taille des particules et de la résistance à l'écoulement de l'air (ISO 29462:2022)

Le présent document décrit un mode opératoire de mesurage des performances des dispositifs de filtration de l'air des ventilations générales dans leur configuration installée d'utilisation finale. Les mesures de performance intègrent l'efficacité d'élimination en fonction de la taille des particules et de la résistance à l'écoulement de l'air. Les modes opératoires d’essais intègrent la définition et la consignation du flux d’air du système.
Le mode opératoire décrit une méthode de comptage des particules dans l'air ambiant de 0,3 μm à 5,0 μm en amont et en aval du ou des épurateurs d’air en place dans un système de traitement de l'air en fonctionnement. Le mode opératoire décrit la détermination des données du compteur de particules pour calculer l'efficacité d'élimination en fonction de la taille des particules.
Puisque les installations de filtration diffèrent considérablement par leur conception et leur forme, un protocole d'évaluation de l'adaptabilité d'un site à l'évaluation des filtres et à l’évaluation des systèmes a été inclus. Lorsque l'évaluation des conditions du site répond aux critères minimaux établis pour l'évaluation du système, l'évaluation des performances du système peut également être réalisée selon ce mode opératoire.
Le présent document décrit également les spécifications de performance des appareils d'essai et définit les modes opératoires de calcul et de consignation des résultats. Le présent document n'a pas vocation à mesurer les performances des épurateurs d’air portables ou mobiles ou à évaluer les installations de filtration à efficacité de filtration attendue égal ou supérieur à 99 % ou égal ou inférieur à 30 % dans le cas d'une mesure à 0,4 µm.

Terensko preskušanje splošnih prezračevalnih filtrirnih naprav in sistemov na kraju samem (kraju vgradnje) glede učinkovitosti odstranjevanja delcev po njihovi velikosti in glede upornosti proti zračnemu toku (ISO 29462:2022)

General Information

Status
Published
Public Enquiry End Date
30-Jun-2020
Publication Date
12-Sep-2022
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
07-Sep-2022
Due Date
12-Nov-2022
Completion Date
13-Sep-2022

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SLOVENSKI STANDARD
SIST EN ISO 29462:2022
01-oktober-2022
Nadomešča:
SIST EN ISO 29462:2013
Terensko preskušanje splošnih prezračevalnih filtrirnih naprav in sistemov na

kraju samem (kraju vgradnje) glede učinkovitosti odstranjevanja delcev po njihovi

velikosti in glede upornosti proti zračnemu toku (ISO 29462:2022)

Field testing of general ventilation filtration devices and systems for in situ removal

efficiency by particle size and resistance to airflow (ISO 29462:2022)

Betriebserprobung von Filtereinrichtungen und -systemen für die allgemeine Lüftung

hinsichtlich ihrer Abscheideeffizienz im eingebauten Zustand bezogen auf die
Partikelgröße und den Druckverlust (ISO 29462:2022)

Essais in situ de filtres et systèmes de ventilation générale pour la mesure de l'efficacité

en fonction de la taille des particules et de la résistance à l'écoulement de l'air (ISO

29462:2022)
Ta slovenski standard je istoveten z: EN ISO 29462:2022
ICS:
13.040.20 Kakovost okoljskega zraka Ambient atmospheres
23.120 Zračniki. Vetrniki. Klimatske Ventilators. Fans. Air-
naprave conditioners
91.140.30 Prezračevalni in klimatski Ventilation and air-
sistemi conditioning systems
SIST EN ISO 29462:2022 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN ISO 29462:2022
---------------------- Page: 2 ----------------------
SIST EN ISO 29462:2022
EN ISO 29462
EUROPEAN STANDARD
NORME EUROPÉENNE
August 2022
EUROPÄISCHE NORM
ICS 91.140.30 Supersedes EN ISO 29462:2013
English Version
Field testing of general ventilation filtration devices and
systems for in situ removal efficiency by particle size and
resistance to airflow (ISO 29462:2022)

Essais in situ de filtres et systèmes de ventilation Betriebserprobung von Filtereinrichtungen und -

générale pour la mesure de l'efficacité en fonction de la systemen für die allgemeine Lüftung hinsichtlich ihrer

taille des particules et de la résistance à l'écoulement Abscheideeffizienz im eingebauten Zustand bezogen

de l'air (ISO 29462:2022) auf die Partikelgröße und den Druckverlust (ISO
29462:2022)
This European Standard was approved by CEN on 22 July 2022.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this

European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references

concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN

member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by

translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management

Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and

United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 29462:2022 E

worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST EN ISO 29462:2022
EN ISO 29462:2022 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

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SIST EN ISO 29462:2022
EN ISO 29462:2022 (E)
European foreword

This document (EN ISO 29462:2022) has been prepared by Technical Committee ISO/TC 142 "Cleaning

equipment for air and other gases" in collaboration with Technical Committee CEN/TC 195 “Cleaning

equipment for air and other gases” the secretariat of which is held by UNI.

This European Standard shall be given the status of a national standard, either by publication of an

identical text or by endorsement, at the latest by February 2023, and conflicting national standards

shall be withdrawn at the latest by February 2023.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

This document supersedes EN ISO 29462:2013.

Any feedback and questions on this document should be directed to the users’ national standards

body/national committee. A complete listing of these bodies can be found on the CEN website.

According to the CEN-CENELEC Internal Regulations, the national standards organizations of the

following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,

Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,

Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of

North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the

United Kingdom.
Endorsement notice

The text of ISO 29462:2022 has been approved by CEN as EN ISO 29462:2022 without any modification.

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SIST EN ISO 29462:2022
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SIST EN ISO 29462:2022
INTERNATIONAL ISO
STANDARD 29462
Second edition
2022-07
Field testing of general ventilation
filtration devices and systems for in
situ removal efficiency by particle size
and resistance to airflow
Essais in situ de filtres et systèmes de ventilation générale pour la
mesure de l'efficacité en fonction de la taille des particules et de la
résistance à l'écoulement de l'air
Reference number
ISO 29462:2022(E)
© ISO 2022
---------------------- Page: 7 ----------------------
SIST EN ISO 29462:2022
ISO 29462:2022(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on

the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below

or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
© ISO 2022 – All rights reserved
---------------------- Page: 8 ----------------------
SIST EN ISO 29462:2022
ISO 29462:2022(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction .............................................................................................................................................................................................................................. vi

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

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

3 Terms, definitions, and abbreviated terms ............................................................................................................................. 1

3.1 Terms and definitions ...................................................................................................................................................................... 1

3.2 Abbreviated terms .............................................................................................................................................................................. 3

4 Test equipment and setup .......................................................................................................................................................................... 4

4.1 Particle counter ..................................................................................................................................................................................... 4

4.2 Diluter ............................................................................................................................................................................................................. 4

4.3 Pump ........................................................................................................................................... ..................................................................... 4

4.4 Sampling system ................................................................................................................................................................................... 4

4.4.1 General ........................................................................................................................................................................................ 4

4.4.2 Sampling probes ................................................................................................................................................................. 5

4.4.3 Sampling lines ....................................................................................................................................................................... 5

4.4.4 Sampling locations ............................................................................................................................................................ 5

4.4.5 Valve (manual or automatic) .................................................................................................................................... 6

4.4.6 Isoaxial sampling nozzle ............................................................................................................................................. 6

4.4.7 Flow meter ............................................................................................................................................................................... 7

4.5 Air velocity measurement instrument .............................................................................................................................. 7

4.6 Relative humidity (RH) measurement instrument ................................................................................................ 7

4.7 Temperature measurement instrument .......................................................................................................................... 7

4.8 Resistance to airflow measurement instrument ..................................................................................................... 7

4.9 Test equipment maintenance and calibration ............................................................................................................ 7

5 Site evaluation ........................................................................................................................................................................................................ 8

5.1 General ........................................................................................................................................................................................................... 8

5.2 Filter installation pre-testing inspection ....................................................................................................................... 8

5.3 Approval for testing ........................................................................................................................................................................... 8

6 Test procedure .......................................................................................................................................................................................................8

6.1 Air velocity ................................................................................................................................................................................................. 8

6.2 Relative humidity (RH) ................................................................................................................................................................... 9

6.3 Temperature ............................................................................................................................................................................................. 9

6.4 Resistance to airflow ........................................................................................................................................................................ 9

6.5 Removal efficiency ........................................................................................................................................................................... 10

6.5.1 Removal efficiency tests ........................................................................................................................................... 10

6.5.2 Sampling method ............................................................................................................................................................ 10

6.6 Sampling probes ................................................................................................................................................................................. 14

6.6.1 Location of sampling probes ................................................................................................................................. 14

6.6.2 Location of upstream sampling probes ...................................................................................................... 14

6.6.3 Location of downstream sampling probes — Filter efficiency test................................... 14

6.6.4 Location of downstream sampling probes — System efficiency test .............................. 14

7 Expression of results ....................................................................................................................................................................................14

7.1 General information........................................................................................................................................................................ 14

7.2 Data collection ..................................................................................................................................................................................... 16

8 Errors and data analyses .........................................................................................................................................................................17

8.1 General ........................................................................................................................................................................................................ 17

8.2 Relative humidity (RH) ................................................................................................................................................................ 17

8.3 Air temperature .................................................................................................................................................................................. 17

8.4 Aerosol composition ....................................................................................................................................................................... 17

8.5 Uniformity of aerosol concentration ................................................................................................................................ 17

8.6 Coincidence errors — Particle counter ......................................................................................................................... 18

iii
© ISO 2022 – All rights reserved
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SIST EN ISO 29462:2022
ISO 29462:2022(E)

8.7 Particle losses ....................................................................................................................................................................................... 18

9 Calculation of results ...................................................................................................................................................................................18

9.1 Calculation of removal efficiency ........................................................................................................................................ 18

9.1.1 General ..................................................................................................................................................................................... 18

9.1.2 Dataset sample average ........................................................................................................................................... .. 18

9.1.3 Minimum upstream concentration ................................................................................................................. 19

9.1.4 Particle size range efficiency................................................................................................................................ 20

9.1.5 Average efficiency by particle size .................................................................................................................. 20

9.2 Calculation of uncertainty .........................................................................................................................................................20

9.2.1 General .....................................................................................................................................................................................20

9.2.2 95 % confidence limit.................................................................................................................................................. 20

9.3 Coefficient of variation (C ) ...................................................................................................................................................... 21

10 Optional enhanced test system .........................................................................................................................................................22

10.1 Application of enhanced test system ............................................................................................................................... 22

10.2 Principle of the enhanced test system ............................................................................................................................ 22

10.3 Determination of the corrected particle size ........................................................................................................... 23

10.4 Presentation of results ................................................................................................................................................................. 24

Annex A (informative) Filter installation pre-testing inspection form ......................................................................25

Annex B (informative) Approval for testing form ..............................................................................................................................27

Annex C (informative) Example of how to complete testing ...................................................................................................28

Bibliography .............................................................................................................................................................................................................................42

© ISO 2022 – All rights reserved
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SIST EN ISO 29462:2022
ISO 29462:2022(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.

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 of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to

the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see

www.iso.org/iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 142, Cleaning equipment for air and other

gases, in collaboration with the European Committee for Standardization (CEN) Technical Committee

CEN/TC 195, Cleaning equipment for air and other gases, in accordance with the Agreement on technical

cooperation between ISO and CEN (Vienna Agreement).

This second edition cancels and replaces the first edition (ISO 29462:2013), which has been technically

revised.
The main changes are as follows:
— subclause 4.2 has been modified;
— some editorial corrections have been made.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www.iso.org/members.html.
© ISO 2022 – All rights reserved
---------------------- Page: 11 ----------------------
SIST EN ISO 29462:2022
ISO 29462:2022(E)
Introduction

The purpose of this document is to provide a test procedure for evaluating the in situ performances

of general ventilation filtration devices and systems. Although any filter with a filtration efficiency at

or above 99 % or at or below 30 % when measured at 0,4 μm can theoretically be tested using this

document, it can be difficult to achieve statically acceptable results for these type of filtration devices.

Supply air to the heating, ventilation and air-conditioning (HVAC) system contains viable and non-viable

particles of a broad size range. Over time these particles cause problems for fans, heat exchangers and

other system parts, decreasing their function and increasing energy consumption and maintenance.

For health issues, the fine particles (< 2,5 µm) are the most detrimental.

Particles in the 0,3 μm to 5,0 μm size range are typically measured by particle counters that can

determine the concentration of particles in specific size ranges. These instruments are commercially

available and determine particle size along with the concentration level by several techniques (e.g. light

scattering, electrical mobility separation, or aerodynamic drag). Devices based on light scattering are

currently the most convenient and commonly used instruments for this type of measurement and are

therefore the type of device used within this document.

Particles in the size range 1,0 μm to 5,0 μm are present in low numbers (less than 1 %, by count) in

outdoor and supply air and have higher sampling-system losses. Results in the range > 1,0 μm therefore

have lower accuracy and should be interpreted accordingly.

During in situ measurement conditions, the optical properties of the particles can differ from the optical

properties of the particles used for calibrating the particle counter and testing it in the laboratory. Thus

the particle counter can size the particles differently but count the overall number of particles correctly.

By adding an extra reference filter, the effect of varying measuring conditions can be reduced.

Additionally, using this enhanced test method, the results can be used to correct the measured

efficiencies in relation to the efficiency of the reference filter measured in laboratory using a

standardized test aerosol.

The results from using the standard method or the enhanced method give both users and manufacturers

a better knowledge of actual filter and installation properties.

It is important to note that field measurements generally result in larger uncertainties in the results

compared to laboratory measurements. Field measurements can produce uncertainty from temporal

and spatial variability in particle concentrations, from limitations on sampling locations due to air

handling unit configurations, and from the use of field instrumentation. These factors can result

in lower accuracy and precision in the calculated fractional efficiencies compared to laboratory

measurements. This document is intended to provide a practical method in which the accuracy and

precision of the result are maximized (and the precision of the result quantified) by recommending

appropriate sampling locations, sample quantities, and instrumentation. This document is not intended

to serve as a filter performance rating method. The results obtained from the test method described in

this document do not replace those obtained through tests conducted in the laboratory.

© ISO 2022 – All rights reserved
---------------------- Page: 12 ----------------------
SIST EN ISO 29462:2022
INTERNATIONAL STANDARD ISO 29462:2022(E)
Field testing of general ventilation filtration devices and
systems for in situ removal efficiency by particle size and
resistance to airflow
1 Scope

This document describes a procedure for measuring the performance of general ventilation air cleaning

devices in their end use installed configuration. The performance measurements include removal

efficiency by particle size and the resistance to airflow. The test procedures include the definition and

reporting of the system airflow.

The procedure describes a method of counting ambient air particles of 0,3 μm to 5,0 μm upstream and

downstream of the in-place air cleaner(s) in a functioning air handling system. The procedure describes

the reduction of particle counter data to calculate removal efficiency by particle size.

Since filter installations vary dramatically in design and shape, a protocol for evaluating the suitability

of a site for filter evaluation and for system evaluation is included. When the evaluated site conditions

meet the minimum criteria established for system evaluation, the performance evaluation of the system

can also be performed according to this procedure.

This document also describes performance specifications for the testing equipment and defines

procedures for calculating and reporting the results. This document is not intended for measuring

performance of portable or movable room air cleaners or for evaluation of filter installations with an

expected filtration efficiency at or above 99 % or at or below 30 % when measured at 0,4 μm.

2 Normative references
There are no normative references in this document.
3 Terms, definitions, and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1.1
air filter bypass

proportion of the challenge air stream that passes around an air cleaner without interacting with the

air cleaner (test device)

[SOURCE: ISO 29464:2017; 3.1.3, modified — The preferred terms "bypass" and "sneakage" have been

deleted and "(test device)" has been added.]
3.1.2
air velocity
rate of air movement at the test device
Note 1 to entry: It is expressed in m/s (ft/min) to three significant figures.
© ISO 2022 – All rights reserved
---------------------- Page: 13 ----------------------
SIST EN ISO 29462:2022
ISO 29462:2022(E)
[SOURCE: ISO 29464:2017, 3.1.2, modified — “at the test de
...

SLOVENSKI STANDARD
oSIST prEN ISO 29462:2020
01-junij-2020
Terensko preskušanje splošnih prezračevalnih filtrirnih naprav in sistemov na

kraju samem (kraju vgradnje) glede učinkovitosti odstranjevanja delcev po njihovi

velikosti in glede upornosti proti zračnemu toku (ISO/DIS 29462:2020)

Field testing of general ventilation filtration devices and systems for in situ removal

efficiency by particle size and resistance to airflow (ISO/DIS 29462:2020)

Betriebserprobung von Filtereinrichtungen und -systemen für die allgemeine Lüftung

hinsichtlich ihrer Abscheideeffizienz im eingebauten Zustand bezogen auf die
Partikelgröße und den Druckverlust (ISO/DIS 29462:2020)

Essais in situ de filtres et systèmes de ventilation générale pour la mesure de l'efficacité

en fonction de la taille des particules et de la perte de charge (ISO/DIS 29462:2020)

Ta slovenski standard je istoveten z: prEN ISO 29462
ICS:
13.040.20 Kakovost okoljskega zraka Ambient atmospheres
23.120 Zračniki. Vetrniki. Klimatske Ventilators. Fans. Air-
naprave conditioners
91.140.30 Prezračevalni in klimatski Ventilation and air-
sistemi conditioning systems
oSIST prEN ISO 29462:2020 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
oSIST prEN ISO 29462:2020
---------------------- Page: 2 ----------------------
oSIST prEN ISO 29462:2020
DRAFT INTERNATIONAL STANDARD
ISO/DIS 29462
ISO/TC 142 Secretariat: UNI
Voting begins on: Voting terminates on:
2020-04-14 2020-07-07
Field testing of general ventilation filtration devices and
systems for in situ removal efficiency by particle size and
resistance to airflow

Essais in situ de filtres et systèmes de ventilation générale pour la mesure de l'efficacité en fonction de la

taille des particules et de la perte de charge
ICS: 91.140.30
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 29462:2020(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION. ISO 2020
---------------------- Page: 3 ----------------------
oSIST prEN ISO 29462:2020
ISO/DIS 29462:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
---------------------- Page: 4 ----------------------
oSIST prEN ISO 29462:2020
ISO/DIS 29462:2020(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

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

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

3 Terms, definitions, and abbreviations ........................................................................................................................................... 1

3.1 Terms and definitions ....................................................................................................................................................................... 1

3.2 Abbreviations ........................................................................................................................................................................................... 3

4 Test equipment and setup .......................................................................................................................................................................... 4

4.1 Particle counter ...................................................................................................................................................................................... 4

4.2 Diluter ............................................................................................................................................................................................................. 4

4.3 Pump ................................................................................................................................................................................................................ 4

4.4 Sampling system .................................................................................................................................................................................... 4

4.4.1 General...................................................................................................................................................................................... 4

4.4.2 Sampling probes ............................................................................................................................................................... 5

4.4.3 Sampling lines .................................................................................................................................................................... 5

4.4.4 Sampling locations ......................................................................................................................................................... 5

4.4.5 Valve (manual or automatic) ................................................................................................................................. 6

4.4.6 Isoaxial sampling nozzle ........................................................................................................................................... 6

4.4.7 Flow meter ............................................................................................................................................................................ 7

4.5 Air velocity measurement instrument ............................................................................................................................... 7

4.6 Relative humidity measurement instrument ......... ....................................................................................................... 7

4.7 Temperature measurement instrument ........................................................................................................................... 7

4.8 Resistance to airflow measurement instrument ....................................................................................................... 7

4.9 Test equipment maintenance and calibration ............................................................................................................. 7

5 Site evaluation ......................................................................................................................................................................................................... 8

5.1 General ........................................................................................................................................................................................................... 8

5.2 Filter installation pre-testing inspection .......................................................................................................................... 8

5.3 Approval for testing ............................................................................................................................................................................ 8

6 Test procedure ........................................................................................................................................................................................................ 8

6.1 Air velocity .................................................................................................................................................................................................. 8

6.2 Relative humidity .................................................................................................................................................................................. 9

6.3 Temperature .............................................................................................................................................................................................. 9

6.4 Resistance to airflow .......................................................................................................................................................................... 9

6.5 Removal efficiency ............................................................................................................................................................................10

6.5.1 Removal efficiency tests .........................................................................................................................................10

6.5.2 Sampling method .................. .................................................... ....................................................................................10

6.6 Sampling probes .................................................................................................................................................................................14

7 Expression of results .....................................................................................................................................................................................14

7.1 General information ........................................................................................................................................................................14

7.2 Data collection ......................................................................................................................................................................................16

8 Errors and data analyses ...........................................................................................................................................................................17

8.1 General ........................................................................................................................................................................................................17

8.2 Relative humidity ...............................................................................................................................................................................17

8.3 Air temperature ...................................................................................................................................................................................17

8.4 Aerosol composition .......................................................................................................................................................................17

8.5 Uniformity of aerosol concentration .................................................................................................................................17

8.6 Coincidence errors — Particle counter ..........................................................................................................................17

8.7 Particle losses........................................................................................................................................................................................18

9 Calculation of results ....................................................................................................................................................................................18

9.1 Calculation of removal efficiency .........................................................................................................................................18

9.1.1 Dataset sample average ..........................................................................................................................................18

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9.1.2 Minimum upstream concentration ...............................................................................................................19

9.1.3 Particle size range efficiency ..............................................................................................................................19

9.1.4 Average efficiency by particle size .................................................................................................................20

9.2 Calculation of uncertainty ..........................................................................................................................................................20

9.2.1 General...................................................................................................................................................................................20

9.2.2 95 % confidence limit ...............................................................................................................................................20

9.3 Coefficient of variation (CV) .....................................................................................................................................................21

10 Optional enhanced test system ...........................................................................................................................................................21

10.1 Application of enhanced test ...................................................................................................................................................21

10.2 Principle of the enhanced test system .............................................................................................................................22

10.3 Determination of the corrected particle size .............................................................................................................23

10.4 Presentation of results ..................................................................................................................................................................23

Annex A (informative) Filter installation pre-testing inspection form .........................................................................25

Annex B (informative) Approval for testing form ................................................................................................................................27

Annex C (informative) Example of how to complete testing .....................................................................................................29

Bibliography .............................................................................................................................................................................................................................43

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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 of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 142, Cleaning equipment for air and

other gases.

This second edition cancels and replaces the first edition (ISO 29462:2013), which has been technically

revised.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
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Introduction

The purpose of this International Standard is to provide a test procedure for evaluating the in-situ

performances of general ventilation filtration devices and systems. Although any filter with a filtration

efficiency at or above 99% or at or below 30% when measured at 0,4 μm could theoretically be tested

using this International Standard, it may be difficult to achieve statically acceptable results for these

type of filtration devices.

Supply air to the Heating, Ventilation and Air-Conditioning (HVAC) system contains viable and non-

viable particles of a broad size range. Over time these particles will cause problems for fans, heat

exchangers and other system parts, decreasing their function and increasing energy consumption and

maintenance. For health issues, the fine particles (<2,5 µm) are the most detrimental.

Particles in the 0,3 μm to 5,0 μm size range are typically measured by particle counters that can

determine the concentration of particles in specific size ranges. These instruments are commercially

available and will determine particle size along with the concentration level by several techniques (e.g.,

light scattering, electrical mobility separation, or aerodynamic drag). Devices based on light scattering

are currently the most convenient and commonly used instruments for this type of measurement and

are therefore the type of device used within this International Standard.

Particles in the size range 1,0 μm to 5,0 μm are present in low numbers (less than 1%, by count) in

outdoor and supply air and have higher sampling-system losses. Results in the range >1,0 μm will

therefore have lower accuracy and so the results should be interpreted with respect to this.

During in-situ measurement conditions, the optical properties of the particles may differ from

the optical properties of the particles used for calibrating the particle counter and testing it in the

laboratory. Thus the particle counter could size the particles differently but count the overall number of

particles correctly.

By adding an extra reference filter, the effect of varying measuring conditions can be reduced.

Additionally, using this enhanced test method, the results can be used to correct the measured

efficiencies in relation to the efficiency of the reference filter measured in laboratory using a

standardized test aerosol.

The results from using the standard method or the enhanced method will give both users and

manufacturers a better knowledge of actual filter and installation properties.

It is important to note that field measurements generally result in larger uncertainties in the results

compared to laboratory measurements. Field measurements may produce uncertainty from temporal

and spatial variability in particle concentrations, from limitations on sampling locations due to air

handling unit configurations, and from the use of field instrumentation. These factors may result in lower

accuracy and precision in the calculated fractional efficiencies compared to laboratory measurements.

This International Standard is intended to provide a practical method in which the accuracy and

precision of the result are maximized (and the precision of the result quantified) by recommending

appropriate sampling locations, sample quantities, and instrumentation. This International Standard is

not intended to serve as a filter performance rating method. The results obtained from the test method

described in this International Standard do not replace those obtained through tests conducted in

the laboratory.
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DRAFT INTERNATIONAL STANDARD ISO/DIS 29462:2020(E)
Field testing of general ventilation filtration devices and
systems for in situ removal efficiency by particle size and
resistance to airflow
1 Scope

This International Standard describes a procedure for measuring the performance of general ventilation

air cleaning devices in their end use installed configuration. The performance measurements include

removal efficiency by particle size and the resistance to airflow. The procedures for test include the

definition and reporting of the system airflow.

The procedure describes a method of counting ambient air particles of 0,3 μm to 5,0 μm upstream and

downstream of the in-place air cleaner(s) in a functioning air handling system. The procedure describes

the reduction of particle counter data to calculate removal efficiency by particle size.

Since filter installations vary dramatically in design and shape, a protocol for evaluating the suitability

of a site for filter evaluation and for system evaluation is included. When the evaluated site conditions

meet the minimum criteria established for system evaluation, the performance evaluation of the system

can also be performed according to this procedure.

This International Standard also describes performance specifications for the testing equipment

and defines procedures for calculating and reporting the results. This International Standard is not

intended for measuring performance of portable or movable room air cleaners or for evaluation of

filter installations with and expected filtration efficiency at or above 99 % or at or below 30 % when

measured at 0,4 μm.
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 7726, Ergonomics of the thermal environment — Instruments for measuring physical quantities

ISO 14644-3, Cleanrooms and associated controlled environments — Part 3: Test methods

ISO 21501-4, Determination of particle size distribution — Single particle light interaction methods —

Part 4: Light scattering airborne particle counter for clean spaces
3 Terms, definitions, and abbreviations
3.1 Terms and definitions
For the purpose of this document, the following terms and definitions apply.
3.1.1
air filter bypass

unfiltered air that has passed through the AHU filter installation but remained unfiltered because it

bypassed the installed air filters
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3.1.2
air velocity
rate of air movement at the filter
Note 1 to entry: It is expressed in m/s (fpm) to three significant figures.
[SOURCE: ISO 29464:2017; 3.1.2]
3.1.3
allowable measurable concentration of the particle counter

fifty percent of the maximum measurable concentration as stated by the manufacturer of the particle

counter (3.1.12)
[SOURCE: ISO 29464:2017; 3.2.115]
3.1.4
coefficient of variation
standard deviation of a group of measurements divided by the mean
[SOURCE: ISO 29464:2017; 3.2.31]
3.1.5
coincidence error

error which occurs because at a given time more than one particle is contained in the measurement

volume of a particle counter

Note 1 to entry: The coincidence error leads to a measured number concentration (3.1.7) which is too low and a

value for the particle diameter (3.2.124) which is too high.
[SOURCE: ISO 29464:2017; 3.2.32]
3.1.6
diluter
dilution system

system for reducing the sampled concentration to avoid coincidence error in the particle counter

[SOURCE: ISO 29464:2017; 3.2.46]
3.1.7
filter efficiency

removal efficiency of a filter as determined by this International Standard, where upstream and

downstream particle count measurements are taken close to the filter being tested

3.1.8
filter installation

filtration devices and systems such as a single filter or a group of filters mounted together with the

same inlet and outlet of air
[SOURCE: ISO 29464:2017; 3.2.85]
3.1.9
general ventilation

process of moving air from outside the space, recirculated air, or a combination of these into or about a

space or removing it from the space
[SOURCE: ISO 29464:2017; 3.2.100]
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3.1.10
isoaxial sampling

sampling in which the flow in the sampler inlet is moving in the same direction as the flow being sampled

[SOURCE: ISO 29464:2017; 3.2.104]
3.1.11
isokinetic sampling

technique for air sampling such that the probe inlet air velocity is the same as the velocity of the air

surrounding the sampling point
[SOURCE: ISO 29464:2017; 3.2.105]
3.1.12
particle counter

device for detecting and counting numbers of discrete airborne particles present in a sample of air

[SOURCE: ISO 29464:2017; 3.2.114]
3.1.13
particle size range
defined particle counter channel
[SOURCE: ISO 29464:2017; 3.2.137]
3.1.14
reference filter

small dry media-type filter that has been laboratory tested for removal efficiency by particle size

3.1.15
removal efficiency by particle size
removal efficiency

ratio of the number of particles retained by the filter to the number of particles measured upstream of

the filter for a given particle-size range
[SOURCE: ISO 29464:2017; 3.2.149]
3.1.16
resistance to airflow

loss of static pressure caused by the filter and filter loading which is measured with the filter operating

at the measured air velocity
Note 1 to entry: It is expressed in Pa (in WG) to two significant figures.
3.1.17
system efficiency

removal efficiency of a filter system where upstream and downstream particle count measurements

may be across several filter banks or other system components
[SOURCE: ISO 29464:2017; 3.2.163]
3.2 Abbreviations
AHU Air Handling Unit
CV Coefficient of Variation
D/S Downstream of test device
HEPA High Efficiency Particle Air (as per ISO 29463-1)
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HVAC Heating, Ventilating and Air-Conditioning
MERV Minimum Efficiency Reporting Value
OPC Optical Particle Counter
RH Relative Humidity
U/S Upstream of test device
ULPA Ultra Low Penetration Air
VAV Variable Air Volume
VFD Variable Frequency Drive
4 Test equipment and setup
4.1 Particle counter

The particle counter should be capable of measuring particles in the size range 0,3 µm ― 5,0 µm, in a

minimum of four ranges with a minimum of two ranges below 1,0 μm (for example: 0,3 µm ― 0,5 μm,

0,5 µm ― 1,0 μm, 1,0 µm ― 2,0 μm and 2,0 µm ― 5,0 μm). For maintenance and calibration of the particle

counter, see 4.9
4.2 Diluter

A dilution system capable of diluting the aerosol concentration so the particle concentration level is

within the acceptable concentration limit may be used. Choose a suitable dilution ratio so that the

measured concentration of parti
...

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