ISO 5011:2025

International
Standard
ISO 5011
Fifth edition
Inlet air cleaning equipment for
2025-09
internal combustion engines and
compressors — Performance testing
Séparateurs aérauliques placés à l'entrée des moteurs à
combustion interne et des compresseurs — Détermination des
performances
Reference number
© ISO 2025
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
Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and symbols . 1
3.1 Terms and definitions .1
3.2 Symbols .3
4 Measurement accuracy and standard conditions . 4
4.1 Measurement accuracy and precision .4
4.2 Standard conditions .4
5 Test materials and test conditions . 4
5.1 Test dust .4
5.1.1 Grade .4
5.1.2 Preparation .5
5.2 Test oil for oil bath air cleaners .5
5.3 Absolute filter materials .5
5.3.1 Filter media .5
5.3.2 Validation of absolute filter media efficiency, E .5
a
5.4 Absolute filter mass .6
5.4.1 Validation of the absolute filter weighing method .6
5.5 Temperature and humidity .6
6 Test procedure for dry-type single-stage air cleaners . 6
6.1 General .6
6.2 Test equipment .6
6.3 Restriction and differential pressure test .8
6.4 Efficiency test .8
6.4.1 Purpose .8
6.4.2 Types .8
6.4.3 Test procedure — Absolute filter method .9
6.4.4 Test procedure — Direct weighing method .10
6.5 Capacity test .10
6.6 Filter element pressure collapse test . . .11
6.7 Variable airflow test .11
6.8 Presentation of data . . 12
7 Test procedure for dry-type multistage air cleaners .12
7.1 General . 12
7.2 Test equipment . 12
7.3 Restriction and differential pressure test . 13
7.4 Initial efficiency test procedure — Absolute filter method . 13
7.5 Full-life efficiency and capacity test . .14
7.5.1 Air cleaner dust capacity.14
7.5.2 Test procedure — Absolute filter method .14
7.5.3 Test procedure — Direct weighing method . 15
7.6 Presentation of data .16
7.7 Variations for scavenged airflow performance testing .16
7.7.1 General .16
7.7.2 Additional equipment .16
7.7.3 Restriction and differential pressure test .17
7.7.4 Full-life efficiency and capacity test .17
7.7.5 Presentation of data .17
7.8 Precleaner performance test .17
7.8.1 Precleaner dust removal .17
7.8.2 Precleaner efficiency .18
7.8.3 Presentation of data .18

iii
7.9 Secondary element test procedure .18
7.9.1 General .18
7.9.2 Specific efficiency test .18
7.9.3 Expression of results .19
8 Test procedure for oil bath air cleaners . 19
8.1 General .19
8.2 Test equipment and conditions .19
8.3 Restriction and differential pressure test . 20
8.4 Oil carry-over test. 20
8.5 Full life efficiency and capacity test . 20
8.6 Recovery test .21
8.7 Presentation of data .21
Annex A (normative) Explanation of restriction, differential pressure and pressure loss of an
air cleaner .22
Annex B (normative) Test equipment .24
Annex C (informative) Report sheet on performance testing of air cleaner equipment according
to ISO 5011 — Dry-type single-stage air cleaners.36
Annex D (informative) Report sheet on performance testing of air cleaner equipment according
to ISO 5011 — Dry-type multistage air cleaners .
...