Air intake filter systems for rotary machinery - Test methods - Part 1: Static filter elements (ISO 29461-1:2021)

This document specifies methods and procedures for determining the static performance of particulate air filters used in air intake filter systems for rotary machinery such as stationary gas turbines, compressors and other stationary internal combustion engines. It applies to air filters with an efficiency of 85 % or more for the MPPS (EPA and HEPA filters) which are tested according to ISO 29463 (all parts) and filters with a lower efficiency which are tested according to ISO 16890 (all parts). The procedures described in both ISO 16890 (all parts) and ISO 29463 (all parts) are applied and extended by this document to air filters which operate at flow rates within the range 0,24 m3/s (850 m3/h) up to 2,36 m3/s (8 500 m3/h).
Static filter systems normally use multiple stages of coarse, fine and optional EPA or HEPA filter elements to protect the machinery. The scope of this document includes methods for performance testing of individual filter elements. It does not include methods for the direct measurement of the performance of entire systems as installed in service except in cases where they can meet the qualification criteria for the test assembly. Nevertheless, cumulative filter efficiencies of multistage systems of fine filters can be calculated by using the methods described in ISO 16890-1.
This document refers to static (barrier) filter systems but can also be applied to other filter types and systems in appropriate circumstances, for example to evaluate the initial efficiency of cleanable and surface loading filters.
The performance results obtained in accordance with this document cannot be quantitatively applied (by themselves) to predict performance in service with regard to efficiency and lifetime.

Ansaugfiltersysteme von Rotationsmaschinen - Prüfverfahren - Teil 1: Statische Filterelemente (ISO 29461-1:2021)

Dieses Dokument legt Prüfverfahren für die Ermittlung der Leistung von Partikelluftfiltern für den Einsatz in Ansaugfiltersystemen für Rotationsmaschinen, z. B. stationäre Gasturbinen, Kompressoren und andere stationäre Verbrennungskraftmaschinen, fest. Es ist anzuwenden für Luftfilter mit einem Wirkungsgrad von 85 % oder mehr für die MPPS (EPA- und HEPA Filter), die nach ISO 29463 (alle Teile) geprüft werden, und Filter mit einem geringeren Wirkungsgrad, deren Prüfung nach ISO 16890 (alle Teile) erfolgt. Die sowohl in ISO 16890 (alle Teile) als auch in ISO 29463 (alle Teile) festgelegten Verfahren werden durch dieses Dokument angewendet und auf Luftfilter erweitert, die mit Durchflussraten im Bereich von 0,24 m3/s (850 m3/h) bis zu 2,36 m3/s (8 500 m3/h) betrieben werden.
Statische Filtersysteme verwenden üblicherweise mehrere Stufen grober, feiner und optional EPA- oder HEPA Filterelemente zum Schutz der Maschinen. Der Anwendungsbereich dieses Dokuments beinhaltet Verfahren zur Leistungsprüfung individueller Filterelemente. Nicht enthalten sind Verfahren für die direkte Messung der Leistung von gesamten Systemen, wie sie im Betrieb installiert sind, ausgenommen die Fälle, in denen die Qualifikationskriterien für den Prüfaufbau erfüllt werden können. Nichtsdestotrotz können kumulative Filterwirkungsgrade mehrstufiger Systeme von Feinfiltern mit den in ISO 16890 1 festgelegten Verfahren berechnet werden.
Dieses Dokument bezieht sich auf statische (Barriere-)Filtersysteme, kann aber auch unter geeigneten Umständen auf andere Filtertypen und Systeme angewendet werden, z. B. um den Ausgangswirkungsgrad von reinigbaren und Oberflächenfiltern zu bewerten.
Die nach diesem Dokument für die Leistung ermittelten Ergebnisse können nicht unmittelbar zur quantitativen Vorhersage der Leistung bezogen auf Wirkungsgrad und Lebensdauer für den jeweiligen Anwendungsfall des Filters verwendet werden.

Systèmes de filtration d'air d'admission pour machines tournantes - Méthodes d'essai - Partie 1: Éléments filtrants pour filtres statiques (ISO 29461-1:2021)

Le présent document spécifie des méthodes et modes opératoires pour la détermination de la performance statique des filtres à air pour l’élimination des particules utilisés dans les systèmes de filtration d’air d’admission pour les machines tournantes telles que les turbines à gaz fixes, les compresseurs et autres moteurs à combustion interne fixes. Il s’applique aux filtres à air avec une efficacité de 85 % ou plus pour la MPPS (filtres EPA et HEPA) qui sont soumis à essai selon l’ISO 29463 (toutes les parties) et aux filtres avec une efficacité inférieure qui sont soumis à essai selon l’ISO 16890 (toutes les parties). Les modes opératoires décrits dans l’ISO 16890 (toutes les parties) et dans l’ISO 29463 (toutes les parties) sont appliqués et étendus par le présent document aux filtres à air fonctionnant à des débits compris dans la plage de 0,24 m3/s (850 m3/h) à 2,36 m3/s (8 500 m3/h).
Les systèmes de filtres statiques utilisent généralement plusieurs étages d'éléments filtrants grossiers, fins et, en option, EPA ou HEPA pour protéger les machines. Le domaine d'application du présent document inclut des méthodes pour les essais de performance des éléments filtrants individuels. Il n’inclut pas les méthodes pour une mesure directe des performances des systèmes dans leur totalité tels qu'installés en service sauf dans les cas où ils peuvent répondre aux critères de qualification du montage d'essai. Néanmoins, les efficacités cumulées des filtres des systèmes multi-étages de filtres fins peuvent être calculées en utilisant les méthodes décrites dans l’ISO 16890-1.
Le présent document concerne les systèmes de filtration (barrière) statiques mais peut aussi s’appliquer à d’autres types de filtres et systèmes de filtration dans des circonstances appropriées, par exemple pour évaluer l’efficacité initiale de filtres nettoyables et à chargement superficiel.
Les résultats de performance obtenus conformément au présent document ne peuvent pas être utilisés quantitativement (par eux-mêmes) pour prédire les performances en service en termes d’efficacité et de durée de vie.

Zračni filtrski sistemi rotacijskih strojev - Preskusne metode - 1. del: Statični filtrski elementi (ISO 29461-1:2021)

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Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
06-Oct-2021
Completion Date
06-Oct-2021

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SLOVENSKI STANDARD
SIST EN ISO 29461-1:2021
01-december-2021
Nadomešča:
SIST EN ISO 29461-1:2013

Zračni filtrski sistemi rotacijskih strojev - Preskusne metode - 1. del: Statični

filtrski elementi (ISO 29461-1:2021)

Air intake filter systems for rotary machinery - Test methods - Part 1: Static filter elements

(ISO 29461-1:2021)
Ansaugfiltersysteme von Rotationsmaschinen - Prüfverfahren - Teil 1: Statische
Filterelemente (ISO 29461-1:2021)

Systèmes de filtration d'air d'admission pour machines tournantes - Méthodes d'essai -

Partie 1: Éléments filtrants pour filtres statiques (ISO 29461-1:2021)
Ta slovenski standard je istoveten z: EN ISO 29461-1:2021
ICS:
29.160.99 Drugi standardi v zvezi z Other standards related to
rotacijskimi stroji rotating machinery
SIST EN ISO 29461-1:2021 en,fr,de

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

---------------------- Page: 1 ----------------------
SIST EN ISO 29461-1:2021
---------------------- Page: 2 ----------------------
SIST EN ISO 29461-1:2021
EN ISO 29461-1
EUROPEAN STANDARD
NORME EUROPÉENNE
October 2021
EUROPÄISCHE NORM
ICS 29.160.99 Supersedes EN ISO 29461-1:2013
English Version
Air intake filter systems for rotary machinery - Test
methods - Part 1: Static filter elements (ISO 29461-
1:2021)

Systèmes de filtration d'air d'admission pour machines Ansaugfiltersysteme von Rotationsmaschinen -

tournantes - Méthodes d'essai - Partie 1: Éléments Prüfverfahren - Teil 1: Statische Filterelemente (ISO

filtrants pour filtres statiques (ISO 29461-1:2021) 29461-1:2021)
This European Standard was approved by CEN on 13 July 2021.

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, Turkey 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

© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 29461-1:2021 E

worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST EN ISO 29461-1:2021
EN ISO 29461-1:2021 (E)
Contents Page

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

---------------------- Page: 4 ----------------------
SIST EN ISO 29461-1:2021
EN ISO 29461-1:2021 (E)
European foreword

This document (EN ISO 29461-1:2021) 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 April 2022, and conflicting national standards shall be

withdrawn at the latest by April 2022.

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 29461-1:2013.

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, Turkey and the

United Kingdom.
Endorsement notice

The text of ISO 29461-1:2021 has been approved by CEN as EN ISO 29461-1:2021 without any

modification.
---------------------- Page: 5 ----------------------
SIST EN ISO 29461-1:2021
---------------------- Page: 6 ----------------------
SIST EN ISO 29461-1:2021
INTERNATIONAL ISO
STANDARD 29461-1
Second edition
2021-09
Air intake filter systems for rotary
machinery — Test methods —
Part 1:
Static filter elements
Systèmes de filtration d'air d'admission pour machines tournantes —
Méthodes d'essai —
Partie 1: Éléments filtrants pour filtres statiques
Reference number
ISO 29461-1:2021(E)
ISO 2021
---------------------- Page: 7 ----------------------
SIST EN ISO 29461-1:2021
ISO 29461-1:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

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
ii © ISO 2021 – All rights reserved
---------------------- Page: 8 ----------------------
SIST EN ISO 29461-1:2021
ISO 29461-1:2021(E)
Contents Page

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

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

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

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

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Symbols and abbreviated terms ........................................................................................................................................................... 2

5 Testing and classification of filter efficiencies ...................................................................................................................... 2

6 Determination of the air flow resistance versus the mass of test dust captured ..............................4

7 Conditioning method to determine the minimum fractional test efficiency .........................................5

8 Reporting ...................................................................................................................................................................................................................... 5

Annex A (normative) Net area calculation ..................................................................................................................................................... 7

Bibliography .............................................................................................................................................................................................................................15

© ISO 2021 – All rights reserved iii
---------------------- Page: 9 ----------------------
SIST EN ISO 29461-1:2021
ISO 29461-1:2021(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 29461-1:2013), which has been technically

revised.
The main changes compared to the previous edition are as follows:

— a new test method, referring to ISO 16890 (all parts) and ISO 29463 (all parts), has been added;

— a classification table has been added;

— previous Annexes A, B, C and D have been deleted; previous Annex E has become Annex A.

A list of all parts in the ISO 29461 series can be found on the ISO website.

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.
iv © ISO 2021 – All rights reserved
---------------------- Page: 10 ----------------------
SIST EN ISO 29461-1:2021
ISO 29461-1:2021(E)
Introduction

In rotating machinery applications, the filtering systems, typically a set of filter elements arranged in

a suitable manner, are an important part of the whole turbine/compressor system. The development

of turbine machinery used for energy production or others has led to more sophisticated equipment;

and therefore the importance of good protection of these systems has become more important in the

recent years. It is known that particulate contamination can deteriorate a turbine power system quite

substantially if not taken care of.

This event is often described as “erosion”, “fouling” and “hot corrosion” where salt and other corrosive

particles are known as potential problems. Other particulate matters can also cause significant

reduction of efficiency of the systems. It is important to understand that air filter devices in such systems

are located in various environmental conditions. The range of climate and particulate contamination is

very wide, ranging from deserts to humid rain forests to arctic environments. The requirements on

these filter systems are obviously different depending on where they will be operating.

ISO 29461 (all parts) has based the performance of the air intake filter systems not only upon heavy

dust collection but also particulate efficiency in a size range that is considered to be the problematic

area for these applications. Both ultra-fine and fine particles, as well as larger particles, should be

considered when evaluating turbine fouling. In typical outdoor air, ultra-fine and fine particles in the

size range from 0,01 μm to 1 μm contribute to > 99 % of the number concentration and to > 90 % of the

surface contamination. The majority of the mass normally comes from larger particles (>1,0 μm).

Turbo-machinery filters comprise a wide range of products from filters for very coarse particles to

filters for very fine, sub-micron particles. The range of products varies from depth to surface loading

systems, which can be regenerated e.g. by pulse cleaning. The filters and the systems have to withstand

a wide temperature and humidity range, very low to very high dust concentration and mechanical

stress. The shape of products existing today can be of many different types and have different functions

such as droplet separators, coalescing products, filter pads, metal filters, inertial filters, filter cells,

bag filters, panel-type, cleanable and depth loading filter cartridges and pleated media surface filter

elements.

ISO 29461 (all parts) provides a way to compare these products in a similar way and define what

criteria are important for air filter intake systems for rotary machinery performance protection.

The aim is to compare different filters and filter types with respect to the operating conditions they

finally will be used in. For instance, if a filter or a filter system is meant to operate in an extreme, very

dusty environment, the real particulate efficiency of such a filter cannot be predicted because the dust

loading of the filter plays an important role. A further part of ISO 29461 will address the performance

of cleanable and surface loading filters. Filters in turbo-machinery applications can also face very harsh

operating conditions such as high air flow rates or water and salt ingress. Further parts of ISO 29461

will address the performance of filters under such harsh conditions.
© ISO 2021 – All rights reserved v
---------------------- Page: 11 ----------------------
SIST EN ISO 29461-1:2021
---------------------- Page: 12 ----------------------
SIST EN ISO 29461-1:2021
INTERNATIONAL STANDARD ISO 29461-1:2021(E)
Air intake filter systems for rotary machinery — Test
methods —
Part 1:
Static filter elements
1 Scope

This document specifies methods and procedures for determining the static performance of particulate

air filters used in air intake filter systems for rotary machinery such as stationary gas turbines,

compressors and other stationary internal combustion engines. It applies to air filters with an efficiency

of 85 % or more for the MPPS (EPA and HEPA filters) which are tested according to ISO 29463 (all parts)

and filters with a lower efficiency which are tested according to ISO 16890 (all parts). The procedures

described in both ISO 16890 (all parts) and ISO 29463 (all parts) are applied and extended by this

3 3

document to air filters which operate at flow rates within the range 0,24 m /s (850 m /h) up to

3 3
2,36 m /s (8 500 m /h).

Static filter systems normally use multiple stages of coarse, fine and optional EPA or HEPA filter elements

to protect the machinery. The scope of this document includes methods for performance testing of

individual filter elements. It does not include methods for the direct measurement of the performance

of entire systems as installed in service except in cases where they can meet the qualification criteria

for the test assembly. Nevertheless, cumulative filter efficiencies of multistage systems of fine filters

can be calculated by using the methods described in ISO 16890-1.

This document refers to static (barrier) filter systems but can also be applied to other filter types and

systems in appropriate circumstances, for example to evaluate the initial efficiency of cleanable and

surface loading filters.

The performance results obtained in accordance with this document cannot be quantitatively applied

(by themselves) to predict performance in service with regard to efficiency and lifetime.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements 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 15957, Test dusts for evaluating air cleaning equipment
ISO 16890 (all parts), — Air filters for general ventilation

ISO 29463 (all parts), — High efficiency filters and filter media for removing particles from air

ISO 29464, Cleaning of air and other gases — Terminology
3 Terms and definitions

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

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
© ISO 2021 – All rights reserved 1
---------------------- Page: 13 ----------------------
SIST EN ISO 29461-1:2021
ISO 29461-1:2021(E)
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
EPA filter
efficient particulate air filter

filters with performance complying with requirements of filter class ISO T10 to ISO T12 as per this

document
Note 1 to entry: EPA filters cannot be and shall not be leak tested.
3.2
initial gravimetric arrestance
100

ratio of the mass of a standard test dust retained by the filter to the mass of dust fed after the first 100 g

of dust load
Note 1 to entry: This measure is expressed as a weight percentage.
4 Symbols and abbreviated terms

For the application of this document, the following symbols and abbreviated terms apply:

ePM Minimum efficiency value with x = 1 µm, 2,5 µm or 10 µm of the conditioned filter element,

x, min
% (see ISO 16890-1)
ePM Efficiency with x = 1 µm, 2,5 µm or 10 µm, % (see ISO 16890-1)
MPPS Most penetrating particle size
5 Testing and classification of filter efficiencies

Filters with an efficiency of 85 % or more for the MPPS (EPA and HEPA filters) shall be tested

according to ISO 29463 (all parts), while filters with a lower efficiency shall be tested according to

ISO 16890 (all parts). Filters are classified in groups and classes based on their efficiency as defined in

Table 1.
NOTE For the classification of ISO ePM and
...

SLOVENSKI STANDARD
oSIST prEN ISO 29461-1:2021
01-januar-2021

Zračni filtrski sistemi rotacijskih strojev - Preskusne metode - 1. del: Statični

filtrski elementi (ISO/DIS 29461-1:2020)

Air intake filter systems for rotary machinery - Test methods - Part 1: Static filter

elements (ISO/DIS 29461-1:2020)
Ansaugfiltersysteme von Rotationsmaschinen - Prüfverfahren - Teil 1: Statische
Filterelemente (ISO/DIS 29461-1:2020)

Systèmes de filtration d'air d'admission pour machines tournantes - Méthodes d'essai -

Partie 1: Éléments filtrants pour filtres statiques (ISO/DIS 29461-1:2020)
Ta slovenski standard je istoveten z: prEN ISO 29461-1
ICS:
29.160.99 Drugi standardi v zvezi z Other standards related to
rotacijskimi stroji rotating machinery
oSIST prEN ISO 29461-1:2021 en,fr,de

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

---------------------- Page: 1 ----------------------
oSIST prEN ISO 29461-1:2021
---------------------- Page: 2 ----------------------
oSIST prEN ISO 29461-1:2021
DRAFT INTERNATIONAL STANDARD
ISO/DIS 29461-1
ISO/TC 142 Secretariat: UNI
Voting begins on: Voting terminates on:
2020-10-26 2021-01-18
Air intake filter systems for rotary machinery — Test
methods —
Part 1:
Static filter elements

Systèmes de filtration d'air d'admission pour machines tournantes — Méthodes d'essai —

Partie 1: Éléments filtrants pour filtres statiques
ICS: 29.160.99
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 29461-1:2020(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 29461-1:2021
ISO/DIS 29461-1:2020(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
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
---------------------- Page: 4 ----------------------
oSIST prEN ISO 29461-1:2021
ISO/DIS 29461-1:2020(E)
Contents Page

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

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

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

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

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

4 Symbols and abbreviated terms ........................................................................................................................................................... 2

5 General requirements ..................................................................................................................................................................................... 3

6 Testing and classification of filter efficiencies ...................................................................................................................... 3

7 Determination of the air flow resistance versus the mass of test dust captured ..............................5

8 Conditioning method to determine the minimum fractional test efficiency .........................................5

9 Reporting ...................................................................................................................................................................................................................... 6

Annex A (normative) Net area calculation ..................................................................................................................................................... 8

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

© ISO 2020 – All rights reserved iii
---------------------- Page: 5 ----------------------
oSIST prEN ISO 29461-1:2021
ISO/DIS 29461-1:2020(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.

This second edition cancels and replaces the first edition (ISO 29461-1:2013), which has been technically

revised.
The main changes compared to the previous edition are as follows:
— New test method, referring to ISO 16890 and ISO 29463
— A classification table
— Deletion of Annex A, B, C and D
A list of all parts in the ISO 29461 series can be found on the ISO website.

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.
iv © ISO 2020 – All rights reserved
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oSIST prEN ISO 29461-1:2021
ISO/DIS 29461-1:2020(E)
Introduction

In rotating machinery applications, the filtering systems, typically a set of filter elements arranged in

a suitable manner, are an important part of the whole turbine/compressor system. The development

of turbine machinery used for energy production or others has led to more sophisticated equipment

and therefore the importance of good protection of these systems has become more important in the

recent years. It is known that particulate contamination can deteriorate a turbine power system quite

substantially if not taken care of.

This event is often described as “erosion”, “fouling” and “hot corrosion” where salt and other corrosive

particles are known as potential problems. Other particulate matters may also cause significant

reduction of efficiency of the systems. It is important to understand that air filter devices in such systems

are located in various environmental conditions. The range of climate and particulate contamination is

very wide, ranging from deserts to humid rain forests to arctic environments. The requirements on

these filter systems are obviously different depending on where they will be operating.

ISO 29461 has based the performance of the air intake filter systems not only upon heavy dust

collection but also particulate efficiency in a size range that is considered to be the problematic area for

these applications. Both ultra-fine and fine particles, as well as larger particles, should be considered

when evaluating turbine fouling. In typical outdoor air, ultra-fine and fine particles in the size range

from 0,01 μm to 1 μm contribute to > 99 % of the number concentration and to > 90 % of the surface

contamination. The majority of the mass normally comes from larger particles (>1,0 μm).

Turbo-machinery filters comprise a wide range of products from filters for very coarse particles to

filters for very fine, sub-micron particles. The range of products varies from depth to surface loading

systems, which can be regenerated e.g. by pulse cleaning. The filters and the systems have to withstand

a wide temperature and humidity range, very low to very high dust concentration and mechanical

stress. The shape of products existing today can be of many different types and have different functions

such as droplet separators, coalescing products, filter pads, metal filters, inertial filters, filter cells,

bag filters, panel-type, cleanable and depth loading filter cartridges and pleated media surface filter

elements.

ISO 29461 series of standards will provide a way to compare these products in a similar way and

define what criteria are important for air filter intake systems for rotary machinery performance

protection. The performance of products in this broad range must be compared in a good manner.

Comparing different filters and filter types must be done with respect to the operating conditions they

finally will be used in. For instance, if a filter or a filter system is meant to operate in an extreme, very

dusty environment, the real particulate efficiency of such a filter cannot be predicted because the dust

loading of the filter plays an important role. A further part of ISO 29461 will address the performance

of cleanable and surface loading filters. Filters in turbo-machinery applications can also face very harsh

operating conditions such as high air flow rates or water and salt ingress. Further parts of ISO 29461

will address the performance of filters under such harsh conditions.
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oSIST prEN ISO 29461-1:2021
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oSIST prEN ISO 29461-1:2021
DRAFT INTERNATIONAL STANDARD ISO/DIS 29461-1:2020(E)
Air intake filter systems for rotary machinery — Test
methods —
Part 1:
Static filter elements
1 Scope

ISO 29461 specifies methods and procedures for determining the performance of particulate air filters

used in air intake filter systems for rotary machinery such as stationary gas turbines, compressors and

other stationary internal combustion engines. It applies to air filters with an efficiency of 85 % or more

for the MPPS (EPA and HEPA filters) which are tested according to ISO 29463 part 1 to 5 and filters with

a lower efficiency which are tested according to ISO 16890 part 1 to 4. The procedures described in

both, the ISO 16890 series and the ISO 29463 series, are applied and extended by this part of ISO 29461

3 3 3

to air filters which operate at flow rates within the range 0,24 m /s (850 m /h, 500 ft /min) up to

3 3 3
2,36 m /s (8500 m /h, 5000 ft /min).

This part of ISO 29461 refers to static (barrier) filter systems but can also be applied to other filter

types and systems in appropriate circumstances, for example to evaluate the initial efficiency of

cleanable and surface loading filters.

The performance results obtained in accordance with this part of ISO 29461 cannot be quantitatively

applied (by themselves) to predict performance in service with regard to efficiency and lifetime. Other

factors influencing performance to be taken into account are described in the annexes.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements 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 15957, Test dusts for evaluating air cleaning equipment

ISO 16890-1, Air filters for general ventilation — Part 1: Technical specifications, requirements and

classification system based upon particulate matter efficiency (ePM)

ISO 16890-2, Air filters for general ventilation — Part 2: Measurement of fractional efficiency and

resistance to air flow

ISO 16890-3, Air filters for general ventilation — Part 3: Determination of the gravimetric efficiency and

the air flow resistance versus the mass of test dust captured

ISO 16890-4, Air filters for general ventilation — Part 4: Conditioning method to determine the minimum

fractional test efficiency

ISO 29463-1, High efficiency filters and filter media for removing particles from air — Part 1: Classification,

performance, testing and marking

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

sheet filter media

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

determining leakage of filter elements-Scan method
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oSIST prEN ISO 29461-1:2021
ISO/DIS 29461-1:2020(E)

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

filter elements
ISO 29464:2017, Cleaning of air and other gases — Terminology
3 Terms and definitions

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

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

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
coarse filter

filtration device with particle removal efficiency ePM < 50 % in the PM10 particle range

Note 1 to entry: as per ISO 16890-1.
[SOURCE: ISO 29464:2017, 3.2.74, modified — Note 1 to entry has been added.]
3.2
efficient particulate air filter
EPA filter

filters with performance complying with requirements of filter class ISO T10 – ISO T12 as per this

document
Note 1 to entry: EPA filters cannot be and shall not be leak tested.
3.3
initial gravimetric arrestance
100

ratio of the mass of a standard test dust retained by the filter to the mass of dust fed after the first 100

g of dust load
Note 1 to entry: This measure is expressed as a weight percentage.
3.4
high efficient particulate air filter
HEPA filter

filters with performance complying with requirements of filter class ISO 35 H – ISO 45 H as per

ISO 29463-1
[SOURCE: ISO 29464:2017, 3.2.84]
3.5
particulate matter efficiency
ePMx

efficiency of an air cleaning device to reduce the mass concentration of particles with an optical

diameter between 0,3 µm and x µm
[SOURCE: ISO 29464:2017, 3.2.140]
4 Symbols and abbreviated terms

For the application of this document, the following symbols and abbreviated terms apply:

2 © ISO 2020 – All rights reserved
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oSIST prEN ISO 29461-1:2021
ISO/DIS 29461-1:2020(E)
A Initial gravimetric arrestance, %
100

ePM Minimum efficiency value with x = 1 µm, 2,5 µm or 10 µm of the conditioned filter element,

x, min
% (see ISO 16890-1)
ePM Efficiency with x = 1 µm, 2,5 µm or 10 µm, % (see ISO 16890-1)
ISO International Organization for Standardization
MPPS Most penetrating particle size
5 General requirements

Static filter systems normally use multiple stages of coarse, fine and optional also EPA or HEPA filter

elements to protect the machinery. The scope of this part of ISO 29461 includes methods for performance

testing of individual filter elements. It does not include methods for the direct measurement of

the performance of entire systems as installed in service except in cases where they can meet the

qualification criteria for the test assembly.
6 Testing and classification of filter efficiencies

Filters with an efficiency of 85 % or more for the MPPS (EPA and HEPA filters) are tested according to

ISO 29463 part 1 to 5, while filters with a lower efficiency are tested according to ISO 16890 part 1 to 4.

Filters are classified in Groups and Classes based on their efficiency as defined in Table 1.

Note: For the classification of ISO ePM and ISO ePM filters only the ePM values are used.

1 2,5 x, min

HEPA filters (class T13) have to be individually tested and their efficiency determined at MPPS according

to 29463-5. Filters shall be individually leak tested according to ISO 29463-4 where, in addition to the

reference leak scan method, four alternate methods for leak testing are allowed. For HEPA filters with

geometries which do not allow a scan testing, like e.g. cartridges or V-bank filters, the oil thread test

method or one of the other suitable (non-scanning) methods described in ISO 29463-4 can be applied.

Alternate norms used for leak testing should be clearly identified on the filter and certifications.

In order to extent the volume flow rate and the range of filter geometries (e.g. cylindrical filters)

deviations and extensions to the test rig defined by ISO 16890-2 and ISO 29463-5, respectively, are

described below.
The test rig consists of several square duct
...

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