Air intake filter systems for rotary machinery - Test methods - Part 2: Filter element endurance test in fog and mist environments (ISO 29461-2:2022)

This standard specifies general requirements, test rig and equipment, qualification, test materials, test procedure and report for determining water endurance performance of air filter elements used in air intake filtration systems for rotary machinery such as stationary gas turbines, compressors and other stationary internal combustion engines

Ansaugfiltersysteme von Rotationsmaschinen - Prüfverfahren - Teil 2: Dauertest für Filterelemente in Nebel- und Nebelumgebungen (ISO 29461-2:2022)

Dieser Teil von ISO 29461 legt die allgemeinen Prüfanforderungen, den Prüfstand und die Prüfausrüstung, die Prüfmaterialien, das Prüfverfahren und den Prüfbericht für die Bestimmung des Wasserbeständigkeitsverhaltens von Luftfilterelementen fest, die in Lufteinlassfiltersystemen für Rotationsmaschinen wie stationäre Gasturbinen, Kompressoren und andere stationäre Verbrennungsmotoren verwendet werden.
Die Prüfung bewertet das Wasserbeständigkeitsverhalten von Luftfilterelementen unter Laborbedingungen. Die nach diesem Teil von ISO 29461 für die Leistung ermittelten Ergebnisse können nicht unmittelbar zur quantitativen Vorhersage der Leistung bezogen auf Wasserbeständigkeit und Lebensdauer für den jeweiligen Anwendungsfall des Filters verwendet werden.

Systèmes de filtration d'air d'admission pour machines tournantes - Méthodes d'essai - Partie 2: Essai d'endurance d'élément filtrant en brouillard et environnement brumeux (ISO 29461-2:2022)

Le présent document spécifie les exigences générales d'essai, le banc et les équipements d'essai, les produits pour l'essai, le mode opératoire d'essai et le rapport pour la détermination des performances de résistance à l'eau des éléments filtrants utilisés dans les systèmes de filtration d'air d'admission des machines tournantes comme les turbines à gaz stationnaires, les compresseurs et autres moteurs stationnaires à combustion interne.
L'essai évalue la performance de résistance à l'eau des éléments filtrants dans des conditions de laboratoire. Les données de performances obtenues conformément au présent document ne peuvent pas être utilisées quantitativement (par elles-mêmes) pour prédire les performances en service en termes de résistance à l'eau et de durée de vie.

Zračni filtrski sistemi rotacijskih strojev - Preskusne metode - 2. del: Preskus vzdržljivosti filtrskih elementov v okolju z meglo in sparino (ISO 29461-2:2022)

General Information

Status
Published
Public Enquiry End Date
30-Sep-2021
Publication Date
19-Sep-2022
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
16-Sep-2022
Due Date
21-Nov-2022
Completion Date
20-Sep-2022

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SLOVENSKI STANDARD
SIST EN ISO 29461-2:2022
01-november-2022
Zračni filtrski sistemi rotacijskih strojev - Preskusne metode - 2. del: Preskus
vzdržljivosti filtrskih elementov v okolju z meglo in sparino (ISO 29461-2:2022)

Air intake filter systems for rotary machinery - Test methods - Part 2: Filter element

endurance test in fog and mist environments (ISO 29461-2:2022)

Ansaugfiltersysteme von Rotationsmaschinen - Prüfverfahren - Teil 2: Dauertest für

Filterelemente in Nebel- und Nebelumgebungen (ISO 29461-2:2022)

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

Partie 2: Essai d'endurance d'élément filtrant en brouillard et environnement brumeux

(ISO 29461-2:2022)
Ta slovenski standard je istoveten z: EN ISO 29461-2:2022
ICS:
29.160.99 Drugi standardi v zvezi z Other standards related to
rotacijskimi stroji rotating machinery
SIST EN ISO 29461-2:2022 en,fr,de

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

---------------------- Page: 1 ----------------------
SIST EN ISO 29461-2:2022
---------------------- Page: 2 ----------------------
SIST EN ISO 29461-2:2022
EN ISO 29461-2
EUROPEAN STANDARD
NORME EUROPÉENNE
September 2022
EUROPÄISCHE NORM
ICS 29.160.99
English Version
Air intake filter systems for rotary machinery - Test
methods - Part 2: Filter element endurance test in fog and
mist environments (ISO 29461-2:2022)

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

tournantes - Méthodes d'essai - Partie 2: Essai Prüfverfahren - Teil 2: Dauertest für Filterelemente in

d'endurance d'élément filtrant en brouillard et Nebel- und Nebelumgebungen (ISO 29461-2:2022)

environnement brumeux (ISO 29461-2:2022)
This European Standard was approved by CEN on 24 June 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 29461-2:2022 E

worldwide for CEN national Members.
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SIST EN ISO 29461-2:2022
EN ISO 29461-2:2022 (E)
Contents Page

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

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SIST EN ISO 29461-2:2022
EN ISO 29461-2:2022 (E)
European foreword

This document (EN ISO 29461-2:2022) 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 March 2023, and conflicting national standards shall

be withdrawn at the latest by March 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.

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 29461-2:2022 has been approved by CEN as EN ISO 29461-2:2022 without any

modification.
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SIST EN ISO 29461-2:2022
---------------------- Page: 6 ----------------------
SIST EN ISO 29461-2:2022
INTERNATIONAL ISO
STANDARD 29461-2
First edition
2022-08
Air intake filter systems for rotary
machinery — Test methods —
Part 2:
Filter element endurance test in fog
and mist environments
Systèmes de filtration d'air d'admission pour machines tournantes —
Méthodes d'essai —
Partie 2: Essai d'endurance d'élément filtrant en brouillard et
environnement brumeux
Reference number
ISO 29461-2:2022(E)
© ISO 2022
---------------------- Page: 7 ----------------------
SIST EN ISO 29461-2:2022
ISO 29461-2:2022(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 29461-2:2022
ISO 29461-2:2022(E)
Contents Page

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

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

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

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

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

4 Symbols and abbreviated terms..........................................................................................................................................................3

5 General requirements .................................................................................................................................................................................... 4

6 Test conditions .......................................................................................................................................................................................................4

6.1 Test air ........................................................................................................................................................................................................... 4

6.2 Test water .................................................................................................................................................................................................... 4

7 Test rig and equipment .................................................................................................................................................................................5

7.1 Test rig ........................................................................................................................................................................................................... 5

7.2 Water spray device ............................................................................................................................................................................. 6

7.3 Humidifying device ............................................................................................................................................................................ 6

7.4 Water collecting groove ................................................................................................................................................................. 6

8 Qualification of test rig and apparatus ........................................................................................................................................ 6

8.1 Pressure system test ......................................................................................................................................................................... 6

8.2 Air leakage test....................................................................................................................................................................................... 6

8.3 Air velocity uniformity in the test duct ............................................................................................................................ 6

8.4 Pressure drop of test duct with no test filter installed ...................................................................................... 6

8.5 Stability of wet environment ..................................................................................................................................................... 6

8.6 Water fog concentration and sedimentation check ............................................................................................... 7

8.7 Water tightness test with no test filter installed ..................................................................................................... 7

8.8 Water droplet size distributions............................................................................................................................................. 7

8.9 Summary of qualification requirements ......................................................................................................................... 7

8.10 Apparatus maintenance ................................................................................................................................................................. 8

9 Test procedure .......................................................................................................................................................................................................8

9.1 Preparation of filter to be tested ............................................................................................................................................ 8

9.2 Initial pressure drop ......................................................................................................................................................................... 9

9.3 Test procedure for water endurance performance of filter elements ................................................... 9

9.3.1 General ........................................................................................................................................................................................ 9

9.3.2 Wet equilibrium pre-treatment ............................................................................................................................ 9

9.3.3 Water fog test ..................................................................................................................................................................... 10

9.4 Water penetration ratio ............................................................................................................................................................... 10

10 Test report ...............................................................................................................................................................................................................10

10.1 General ........................................................................................................................................................................................................ 10

10.2 Interpretation of test reports ................................................................................................................................................. 11

10.3 Summaries of test results .......................................................................................................................................................... 11

10.4 Water fog mass and pressure drop....................................................................................................................................12

10.5 Marking ......................................................................................................................................................................................................12

Annex A (informative) Resistance to air flow and water generation mass calculation .............................13

Annex B (informative) Water endurance test for vertical installed air filters ....................................................14

Annex C (informative) Water endurance of air filter elements without wet equilibrium pre-

treatment ..................................................................................................................................................................................................................17

Annex D (normative) Water penetration ratio test ...........................................................................................................................19

Annex E (informative) Leak detection and first water droplet detection procedure ..................................20

Annex F (informative) Examples of completed test reports ....................................................................................................23

iii
© ISO 2022 – All rights reserved
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SIST EN ISO 29461-2:2022
ISO 29461-2:2022(E)

Bibliography .............................................................................................................................................................................................................................31

© ISO 2022 – All rights reserved
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SIST EN ISO 29461-2:2022
ISO 29461-2:2022(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).
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.
© ISO 2022 – All rights reserved
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SIST EN ISO 29461-2:2022
ISO 29461-2:2022(E)
Introduction

The ISO 29461 series provides a way to compare these products in a similar method and define what

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

aim is to compare the performance of different filters and filter types with respect to the operating

conditions in which they will be finally used.

Air intake filter system of rotary machinery is an important part of the whole gas turbine and air

compressor systems. It usually consists of filter elements with a suitable way to be installed. The

operating environment of rotary machinery including gas turbine and compressor and their air intake

filtration units are complicated and challenging. Air filters intercept water mist and droplets when air

passes through the air filter unit in case the equipment is working in rainy, foggy, hazy or other high-

humidity environments or a local production environment which contains a large amount of water

vapour, e.g. the cooling tower. If excessive water holds up, the performance of filters can be affected;

pressure drop rises rapidly, causing a shut down in severe cases.

Reliability and non-break down operation of rotary machinery are regarded as a top priority for the

end users, with the rapidly rising pressure drop under high-humidity conditions usually being their

main concern. There are rotary machinery operating accidents caused by high-humidity conditions all

over the world, whether it be inland or along the river or coastal.

To meet the requirements of production and operation, the water endurance performance of air filter

elements needs to be considered besides assessing the performance of initial pressure drop, filtration

efficiency and dust-holding capacity, especially when the air filter elements are used in high-humidity

environments or intake air contains a large quantity of liquid droplets.

This document provides a water endurance test method for filter elements and can be used for

evaluating performance variation trends of filter elements when encountering water and fog. This

document can be used for:
— product development for filter manufacturers;
— supplier selection for end users;
— development of water endurance media by media manufacturers.

This document provides a repeatable, easy-to-conduct and economical test method, which is applicable

to pulse-jet cleaning filter elements and filter elements for general ventilation.

© ISO 2022 – All rights reserved
---------------------- Page: 12 ----------------------
SIST EN ISO 29461-2:2022
INTERNATIONAL STANDARD ISO 29461-2:2022(E)
Air intake filter systems for rotary machinery — Test
methods —
Part 2:
Filter element endurance test in fog and mist
environments
1 Scope

This document specifies general test requirements, the test rig and equipment, the test materials and

the test procedure and report for determining water endurance performance of air filter elements used

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

stationary internal combustion engines.

The test evaluates water endurance performance of air filter elements under laboratory conditions. The

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

themselves) to predict performance in service with regard to water endurance 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 16890-2:2022, Air filters for general ventilation — Part 2: Measurement of fractional efficiency and air

flow resistance
3 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 Air flow and pressure drop
3.1.1
air flow rate
volume of air flowing through the filter per unit time
[SOURCE: ISO 29464:2017, 3.1.24]
3.1.2
test air flow rate
volumetric airflow rate used for testing
[SOURCE: ISO 29464:2017, 3.3.2]
© ISO 2022 – All rights reserved
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SIST EN ISO 29461-2:2022
ISO 29461-2:2022(E)
3.1.3
pressure drop
difference in absolute (static) pressure between two points in a system
Note 1 to entry: Resistance to air flow is measured in Pa.
[SOURCE: ISO 29464:2017, 3.1.36]
3.1.4
initial pressure drop
pressure drop (3.1.3) of the clean filter operating at the test airflow rate
[SOURCE: ISO 29464:2017, 3.3.17]
3.1.5
final test pressure drop

maximum pressure drop (3.1.3) of the filter up to which the filtration performance is measured

[SOURCE: ISO 29464:2017, 3.3.15]
3.2 Filters
3.2.1
test device
filter element (3.2.2) being subjected to performance testing
[SOURCE: ISO 29464:2017, 3.1.38]
3.2.2
filter element

structure made of the filtering material, its supports and its interfaces with the filter housing

[SOURCE: ISO 29464:2017, 3.2.77]
3.2.3
upstream
area or region from which fluid flows as it enters the test device (3.2.1)
[SOURCE: ISO 29464:2017, 3.1.39]
3.2.4
downstream
area or region into which fluid flows on leaving the test device (3.2.1)
[SOURCE: ISO 29464:2017, 3.1.11]
3.2.5
static filter

air filter that will be removed (exchanged) after it has reached its final test pressure drop (3.1.5) and

that is not cleaned with jet pulses or other means in order to fully, or partially, retrieve its initial

performance (pressure drop and efficiency)
[SOURCE: ISO 29464:2017, 3.3.12]
3.2.6
pulse jet filter

cleanable air filter, that typically is cleaned with air jet pulses to provide a longer service life

[SOURCE: ISO 29464:2017, 3.3.11]
© ISO 2022 – All rights reserved
---------------------- Page: 14 ----------------------
SIST EN ISO 29461-2:2022
ISO 29461-2:2022(E)
3.3
test duration

period of reaching a certain pressure drop (3.1.3) or other termination conditions to end the test

3.4 Test materials
3.4.1
water fog
water droplets and mist generated by water spray device
3.4.2
saturated air

air that contains the maximum amount of water vapour it can hold at its temperature and pressure

3.4.3
water fog mass concentration
mass of liquid water droplets per unit volume of air
3.5
two-fluid nozzle
nozzles capable of spraying fine mists by mixing fluid and air at the same time
3.6
coefficient of variation
standard deviation of a group of measurements divided by the mean
[SOURCE: ISO 29464:2017, 3.2.31]
4 Symbols and abbreviated terms
water fog mass concentration, g/m
saturated wet air moisture content, g/kg
ambient air moisture content, g/kg
water mass penetrated through tested filter at the end of the test, kg
total water fog generation amount, kg
tot
sedimentary water mass upstream of filter, kg
total water fog generation amount per hour, kg/h
water fog generation amount per hour at saturated humidifying air, kg/h
wm, 1
water fog generation amount per hour, kg/h
wm, 2
atmospheric pressure, Pa
absolute air pressure upstream of filter, Pa
partial vapour pressure of water in air, Pa
saturated vapour pressure of humidifying air, Pa
volumetric flow of non-humidifying air, m /h
temperature downstream of filter, °C
© ISO 2022 – All rights reserved
---------------------- Page: 15 ----------------------
SIST EN ISO 29461-2:2022
ISO 29461-2:2022(E)
dry bulb temperature of ambient air, °C
temperature upstream of filter, °C
wet bulb temperature of ambient air, °C
testing time, min
total testing time, min
tot
filter initial pressure drop at the test air flow rate, Pa
filter final test pressure drop at the test air flow rate, Pa
filter pressure drop at the test air flow rate at the T time after spraying, Pa
water penetration ratio
ρ 3
ambient air density, kg/ m
air density upstream of filter, kg/m
saturated wet air density, kg/m
relative humidity, %
relative humidity upstream of filter, %
relative humidity downstream of filter, %
CV coefficient of variation
5 General requirements

Air filter systems normally use multiple stages of coarse and fine filter elements to protect the

machinery. The scope of this document includes methods for a water endurance test 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.

The test client can refer to the test results to rank the water endurance performance of multiple

candidate filters.
6 Test conditions
6.1 Test air

Room air or outdoor air is used as the test air source. The air temperature shall be in the range of

10 °C to 38 °C (before wet equilibrium pre-treatment). The exhaust flow shall be discharged outdoors,

indoors or re-circulated. Filtration of the exhaust flow is recommended when the test aerosol or loading

dust is present.
6.2 Test water

The test water pH value shall be in the range of 6 to 8; alkalinity shall be no more than 50 mg/l; full

hardness shall be no more than 70 mg/l. The temperature of the test water shall not be higher than the

temperature of the test air.
© ISO 2022 – All rights reserved
---------------------- Page: 16 ----------------------
SIST EN ISO 29461-2:2022
ISO 29461-2:2022(E)
7 Test rig and equipment
7.1 Test rig

The test rig consists of several square duct sections with typical 610 mm × 610 mm nominal inner

dimensions except for the section where the filter is installed. This section has nominal inner dimensions

between 616 mm and 622 mm. The length of this duct section shall be at least 1,1 times the length of the

filter, with a minimum length of 1,5 m. A schematic diagram of the test rig is shown in Figure 1.

The test rig can be operated either in a negative or positive pressure air flow arrangement; and negative

pressure operation is recommended. The test duct shall be sealed well to avoid water fog leakage if

operated in positive pressure. A condensed water borehole should be provided at the lowest point in

the fan housing in the event of formation of condensation.

The duct material shall be electrically conductive and electrically grounded and shall have a smooth

interior finish and be sufficiently rigid to maintain its shape at the operating pressure. Smaller parts

of the test duct can be made in glass or plastic to expose the filter and equipment to view. Provision of

windows to allow monitoring of test progress is desirable.
Dimensions in millimetres
Key

A duct section of the test rig (inlet plenum) 7 example of water droplet size instrument location

B upstream duct section of the test rig 8 upstream pressure measuring point
C duct section of filter to be tested 9 upstream water collecting groove
D diameter of recirculated duct 10 filter to be tested
E dow
...

SLOVENSKI STANDARD
oSIST prEN ISO 29461-7:2021
01-september-2021
Zračni filtrski sistemi rotacijskih strojev - Preskusne metode - 7. del: Preskus

vzdržljivosti filtrskih elementov v okolju z meglo in sparino (ISO/DIS 29461-7:2021)

Air filter intake systems for rotary machinery - Test methods - Part 7: Filter element

endurance test in fog and mist environments (ISO/DIS 29461-7:2021)

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

Partie 7: Essai d'endurance d'élément filtrant en brouillard et environnement brumeux

(ISO/DIS 29461-7:2021)
Ta slovenski standard je istoveten z: prEN ISO 29461-7
ICS:
29.160.99 Drugi standardi v zvezi z Other standards related to
rotacijskimi stroji rotating machinery
oSIST prEN ISO 29461-7:2021 en,fr,de

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

---------------------- Page: 1 ----------------------
oSIST prEN ISO 29461-7:2021
---------------------- Page: 2 ----------------------
oSIST prEN ISO 29461-7:2021
DRAFT INTERNATIONAL STANDARD
ISO/DIS 29461-7
ISO/TC 142 Secretariat: UNI
Voting begins on: Voting terminates on:
2021-07-20 2021-10-12
Air intake filter systems for rotary machinery — Test
methods —
Part 7:
Filter element endurance test in fog and mist
environments

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

Partie 7: Essai d'endurance d'élément filtrant en brouillard et environnement brumeux

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 29461-7:2021(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 2021
---------------------- Page: 3 ----------------------
oSIST prEN ISO 29461-7:2021
ISO/DIS 29461-7:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

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oSIST prEN ISO 29461-7:2021
ISO/DIS 29461-7:2021(E)
Contents Page

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

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

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

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

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

4 Symbols and abbreviated terms ........................................................................................................................................................... 3

5 General requirements ..................................................................................................................................................................................... 4

6 Test condition .......................................................................................................................................................................................................... 4

6.1 Test air ............................................................................................................................................................................................................ 4

6.2 Test water .................................................................................................................................................................................................... 5

7 Test rig and equipment .................................................................................................................................................................................. 5

7.1 Test rig ............................................................................................................................................................................................................ 5

7.2 Water spray device .............................................................................................................................................................................. 6

7.3 Humidifying device ............................................................................................................................................................................. 6

7.4 Water collecting groove ................................................................................................................................................................... 6

8 Qualification of test rig and apparatus .......................................................................................................................................... 6

8.1 Pressure system test .......................................................................................................................................................................... 6

8.2 Air leakage test........................................................................................................................................................................................ 6

8.3 Air velocity uniformity in the test duct .............................................................................................................................. 6

8.4 Pressure drop of test duct with no test filter installed ......................................................................................... 6

8.5 Stability of wet environment ...................................................................................................................................................... 6

8.6 Water fog concentration and sedimentation check ......... ........................................................................................ 7

8.7 Water tightness test with no test filter installed ....................................................................................................... 7

8.8 Water droplets size distributions ........................................................................................................................................... 7

8.9 Summary of qualification requirements ........................................................................................................................... 8

8.10 Apparatus maintenance .................................................................................................................................................................. 8

9 Test procedure ........................................................................................................................................................................................................ 8

9.1 Preparation of filter to be tested.............................................................................................................................................. 8

9.2 Initial pressure drop .......................................................................................................................................................................... 9

9.3 Test procedure for water endurance performance of filter elements ..................................................... 9

9.3.1 General...................................................................................................................................................................................... 9

9.3.2 Wet equilibrium pretreatment ............................................................................................................................ 9

9.3.3 Water fog test ...................................................................................................................................................................... 9

9.4 Water penetration ratio ................................................................................................................................................................10

10 Test report ................................................................................................................................................................................................................10

10.1 General ........................................................................................................................................................................................................10

10.2 Interpretation of test reports ..................................................................................................................................................10

10.3 Summaries of test results ...........................................................................................................................................................11

10.4 Water fog mass and pressure drop .....................................................................................................................................12

10.5 Marking ......................................................................................................................................................................................................12

Annex A (informative) Resistance to air flow and water generation mass calculation ................................13

Annex B (informative) Water endurance test for vertical installed air filters .......................................................14

Annex C (informative) Water endurance of air filter elements without wet equilibrium

pretreatment .........................................................................................................................................................................................................16

Annex D (normative) Water penetration ratio test ............................................................................................................................18

Annex E (informative) Leak detection and first water droplet detection procedure .....................................19

Annex F (informative) Examples of completed test reports ......................................................................................................22

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oSIST prEN ISO 29461-7:2021
ISO/DIS 29461-7:2021(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.
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.
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oSIST prEN ISO 29461-7:2021
ISO/DIS 29461-7:2021(E)
Introduction

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

define what criteria are important for air intake filter 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.

Air intake filter system of rotary machinery is an important part of the whole gas turbine and air

compressor systems. It usually consists of filter elements with a suitable way to be installed. The

operating environment of rotary machinery including gas turbine and compressor and their air intake

filtration units are complicated and challenging. Air filters intercept water mist and droplets when

air pass through the air filter unit in case the equipment is working in rainy, fog, haze or other high

humidity environment or local production environment which contains large amount of water vapour,

for example the cooling tower. If excessive water holds up, the performance of filters may be affected,

pressure drop raises up rapidly, even causes shut down in severe cases.

Reliability and non-break down operation of rotary machinery is regarded as top priority for end user,

the pressure drop raises up rapidly in high humidity conditions is usually their main concern. There are

rotary machinery operating accidents caused by high humidity conditions all over the world, no matter

it’s inland or along the river or coastal.

To meet the requirements of production and operation, water endurance performance of air filter

elements shall be considered besides assessing the performance of initial pressure drop, filtration

efficiency and dust-holding capacity, especially the air filter elements are used in high-humidity

environments or intake air contains a large quantity of liquid droplets.

This document provides a water endurance test method for filter elements and can be used for

evaluating performance variation trend of filter elements when encounter water and fog. This standard

can be used for:
— product development for filter manufacturers;
— supplier selection for end users;
— development of water endurance media by media manufacturers.

This document provides a repeatable, easy to conduct and economic test method, which shall be applied

for pulse-jet cleaning filter elements, and also for filter elements for general ventilation.

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oSIST prEN ISO 29461-7:2021
DRAFT INTERNATIONAL STANDARD ISO/DIS 29461-7:2021(E)
Air intake filter systems for rotary machinery — Test
methods —
Part 7:
Filter element endurance test in fog and mist
environments
1 Scope

This part of ISO 29461 specifies general test requirements, test rig and equipment, test materials, test

procedure and report for determining water endurance performance of air filter elements used in air

intake filter systems for rotary machinery such as stationary gas turbines, compressors and other

stationary internal combustion engines.

The test evaluates water endurance performance of air filter elements under laboratory conditions.

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 water endurance 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 29464:2017, Cleaning of air and other gases — Terminology

ISO 16890-2:2016, Air filters for general ventilation — Part 2: Measurement of fractional efficiency and air

flow resistance

ISO 29461-1, Air intake filter systems for rotary machinery — Test methods — Part 1: Static filter elements

3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 24964 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 https:// www .electropedia .org/
3.1 Air flow and pressure drop
3.1.1
air flow rate
volume of air passing through the filter per unit time
[SOURCE: ISO 29464:2017, 3.1.24]
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ISO/DIS 29461-7:2021(E)
3.1.2
rated flow

flow rate through a test device, either as stated by the manufacturer for defined conditions of use or as

agreed between the interested parties for a particular installation
[SOURCE: ISO 29464:2017, 3.1.27]
3.1.3
test air flow rate
volumetric airflow rate used for testing
[SOURCE: ISO 29464:2017, 3.3.2]
3.1.4
pressure drop
pressure differential across the filter element at the test airflow rate
[SOURCE: ISO 29464:2017, 3.1.36]
3.1.5
initial pressure drop
pressure drop of the clean filter operating at the test airflow rate
[SOURCE: ISO 29464:2017, 3.3.17]
3.1.6
final test pressure drop

maximum pressure drop of the filter up to which the filtration performance is measured

[SOURCE: ISO 29464:2017, 3.3.15]
3.1.7
final test pressure drop recommended

maximum operating pressure drop of the filter to terminate the test as recommended at rated airflow

3.2 Filters
3.2.1
test device
filter element being subjected to performance testing
[SOURCE: ISO 29464:2017, 3.1.38]
3.2.2
filter element

structure made of the filtering material, its supports and its interfaces with the filter housing

[SOURCE: ISO 29464:2017, 3.2.77]
3.2.3
upstream
U/S
area or region from which fluid flows as it enters the test device
[SOURCE: ISO 29464:2017, 3.1.39]
3.2.4
downstream
D/S
area or region into which fluid flows on leaving the test device
[SOURCE: ISO 29464:2017, 3.1.11]
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3.2.5
static filter

air filter that will be removed (exchanged) after it has reached its final test pressure drop and that is

not cleaned with jet pulse or other means in order to fully, or partially, retrieve its initial performance

(pressure drop and efficiency)
[SOURCE: ISO 29464:2017, 3.3.12]
3.2.6
pulse-jet filter

cleanable air filter, that typically is cleaned with air jet pulse to provide a longer service life

[SOURCE: ISO 29464:2017, 3.3.11]
3.3
test duration

period of reaching a certain pressure drop or other termination conditions to end the test

3.4 Test materials
3.4.1
water fog
water droplets and mist generated by water spray device
3.4.2
saturated air

air that contains the maximum amount of water vapour it can hold at its temperature and pressure

3.4.3
water fog mass concentration
mass of liquid water droplets per unit volume of air
4 Symbols and abbreviated terms

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

water fog mass concentration, g/m
saturated wet air moisture content, g/kg
ambient air moisture content, g/kg
water mass penetrated through tested filter at the end of test, kg
total water fog generation amount, kg
tot
sedimentary water mass upstream of filter, kg
total water fog generation amount per hour, kg/h
water fog generation amount per hour at saturated humidifying air, kg/h
wm, 1
water fog generation amount per hour, kg/h
wm, 2
p atmospheric pressure, Pa
absolute air pressure upstream of filter, Pa
partial vapour pressure of water in air, Pa
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saturated vapour pressure of humidifying air, Pa
volumetric flow of non-humidifying air, m /h
temperature downstream of filter, °C
dry bulb temperature of ambient air, °C
temperature upstream of filter, °C
wet bulb temperature of ambient air, °C
testing time, min
total testing time, min
tot
filter initial pressure drop at the test airflow rate, Pa
filter final test pressure drop at the test airflow rate, Pa
filter pressure drop at the test airflow rate at the T time after spraying, Pa
water penetration ratio
ρ 3
ambient air density, kg/ m
air density upstream of filter, kg/m
saturated wet air density, kg/m
relative humidity, %
relative humidity upstream of filter, %
relative humidity downstream of filter, %
DEHS liquid (DiEthylHexylSebacate) used for generating the DEHS test aerosol
ISO International Organization for Standardization
5 General requirements

Air filter systems normally use multiple stages of coarse and fine filter elements to protect the

machinery. The scope of this part of ISO 29461 includes methods for water endurance test 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.

The test client can refer to the test results to rank the water endurance performance of multiple

candidate filters.
6 Test condition
6.1 Test air

Room air or outdoor air is used as the test air source. The air temperature shall be in the range of 10 °C

to 38 °C (before wet equilibrium pretreatment). The exhaust flow shall be discharged outdoors, indoors

or re-circulated. Filtration of the exhaust flow is recommended when test aerosol or loading dust may

be present.
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6.2 Test water

The test water PH value shall be in the range of 6 to 8, alkalinity shall be no more than 50 mg/l, full

hardness shall be no more than 70 mg/l. The temperature of test water shall not be higher than the

temperature of test air.
7 Test rig and equipment
7.1 Test rig

The test rig consists of several square duct sections with typical 610 mm × 610 mm nominal inner

dimensions except for the section where the filter is installed. This section has nominal inner dimensions

between 616 mm and 622 mm. The length of this duct section shall be at least 1,1 times the length of the

filter, with a minimum length of 1,5 m. Schematic diagram of the test rig is shown in Figure 1.

The test rig can be operated either in a negative or positive pressure airflow arrangement, and negative

pressure operation is recommended. The test duct must be sealed well to avoid water fog leakage if

positive pressure operated. Recommend a condensed water borehole at the lowest point in the fan

housing in the event of formation of condensation.

The duct material shall be electrically conductive and electrically grounded and shall have a smooth

interior finish and be sufficiently rigid to maintain its shape at the operating pressure. Smaller parts of

the test duct could be made in glass or plastic to see the filter and equipment. Provision of windows to

allow monitoring of test progress is desirable.
Key

A duct section of the test rig (inlet plenum) 7 example of water droplet size instrument location

B upstream duct section of the test rig 8 upstream pressure measuring point
C duct section of filter to be tested 9 upstream water collecting groove
D diameter of recirculated duct 10 filter to be tested
E downstream duct section of the test rig 11 midstream water collecting groove
downstream measuring point of temperature and
F recirculated duct section of the test rig 12
humidity
1 HEPA filter 13 downstream pressure measuring point
2 humidifying device 14 downstream water collecting groove
3 water flow mass metering device 15 final filter- eliminate water
4 water flow mass metering device 16 frequency converted fan
5 water spray device 17 air flow measuring point
upstream measuring point of temperature and
humidity
Figure 1 — Schematic diagram of the test rig
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7.2 Water spray device

Water spray device is used to generate uniform water fog continuously to feed the filter to be tested

during the test.

Two-fluid nozzle is recommended and the spraying direction with respect to the inlet airflow shall be

the same. The distance between the nozzle orifices and the duct section of filter to be tested shall be no

less than 1 m.

Water fog particle size can be adjusted by compressed air and water flow velocity. The cumulative

volume of water fog particles in the size range of 5 μm to 30 μm shall be more than 90 % of the total

water fog volume.

The water fog mass flow shall be controlled precisely, the deviation shall not exceed 3 % of the measured

value, which shall meet the requirements of 8.6.

Other types of water spray devices, such as ultrasonic humidifier, nozzle humidifier, can be used if these

devices can achieve the same performance.
7.3 Humidifying device

The humidifying device shall maintain the required humidity in the test duct, which can be used for wet

equilibrium pretreatment. The optional humidifying devices, such as ultrasonic humidifier, atomizer,

shall meet the requirements of 8.5.
7.4 Water collecting groove

The water collecting grooves shall be installed at the bottom of upstream and downstream of tested

filter to collect water during the test.
8 Qualification of test rig and apparatus
8.1 Pressure system test
Carry out pressure system test in accordance with ISO 16890-2, 8.2.1.
8.2 Air leakage test
Carry out air leakage test in accordance with ISO 16890-2, 8.2.8.
8.3 Air velocity uniformity in the test duct

Carry out the test of air velocity uniformity in the test duct in accordance with ISO 16890-2, 8.2.9.

8.4 Pressure drop of test duct with no test filter installed

Carry out the test of pressure drop of test duct with no test filter installed in accordance with

ISO 16890-2, 8.2.12.
8.5 Stability of wet environment

The temperature measuring instrument used shall be capable of measuring temperature with an

accuracy of ±1 °C. The relative humidity measuring instrument used shall be capable of measuring

relative humidity with an accuracy of ±2 %. The temperature and relative humidity measuring

instruments shall be calibrated annually.
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When test air flow rate is 3 400 m /h, turn on humidifying device until the measuring relative humidity

of upstream and downstream test duct exceed 95 %. Record the temperature and relative humidity at

the first time.

Record the temperature and relative humidity of upstream and downstream test duct every 2 min. The

total test time is 30 min.
The relative humidity of upstream and downstream shall always exceed 95 % du
...

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