ISO/TR 6409:2023

Road vehicles - Analysis of technical changes of ISO 5011:2020

This document analyses the impact of changes to ISO 5011:2020 as regards to the following: - precleaner efficiency; - elimination of two secondary element tests (collapse and blocking); - revisions to the recommended ISO dust injector (Table 1); - validation of the absolute filter weighing method; and - inclusion of Annex H, "Penetration sensitivity". These changes refine the precleaner efficiency calculation, eliminate seldom used tests, which were lengthy or costly, further clarify dust injector use, the validation of the absolute material, and the precision of the efficiency measurement.

Véhicules routiers — Analyse des changements techniques de l'ISO 5011:2020

General Information

• Status: Published
• Publication Date: 16-Apr-2023
• ICS: 43.060.20 - Pressure charging and air/exhaust gas ducting systems
• Technical Committee: ISO/TC 22/SC 34 - Propulsion, powertrain and powertrain fluids
• Drafting Committee: ISO/TC 22/SC 34 - Propulsion, powertrain and powertrain fluids
• Current Stage: 6060 - International Standard published
• Start Date: 17-Apr-2023
• Due Date: 11-Dec-2022
• Completion Date: 17-Apr-2023

Overview

ISO/TR 6409:2023 is a technical report from ISO that analyses the technical changes introduced in ISO 5011:2020 (Inlet air cleaning equipment for internal combustion engines and compressors). The report explains how the 2020 revision affects test methods and results for air cleaner systems used on road vehicles, with emphasis on precleaner efficiency, dust injector specifications, filter weighing validation, and the newly included Annex H (“Penetration sensitivity”).

Key topics and technical requirements

• Precleaner efficiency calculation
  ISO 5011:2020 revises how precleaner efficiency is calculated by explicitly including the mass gain of the air cleaner housing (in addition to primary, secondary and absolute filter gains). This change closes the gap between “dust removed” and “dust retained in the system” methods and can simplify evaluation where direct measurement of ejected dust is difficult.

• Elimination of collapse and secondary blocking tests
  Two seldom-used, time‑consuming tests from ISO 5011:2014 (secondary element rupture under increased differential pressure and the repeated-use secondary blocking test) were removed. Labs can still perform the older tests by agreement or apply substitute collapse/challenge procedures provided in ISO 5011:2020.

• Revised recommended ISO dust injector (Table 1)
  The injector guidance now differentiates light‑duty and heavy‑duty injectors with feed-rate ranges per injector (0–5 g/min, 5–26 g/min, >26 g/min). The standard encourages arrays of injectors to avoid clogging and to improve dust distribution. A new dust injector design (Figure B.18) is documented and compared with prior designs using performance maps and shadowgraphy.

• Validation of the absolute filter weighing method
  The report describes the requirement to validate the absolute (gravimetric) weighing technique used to quantify dust captured on absolute filters to ensure reliable efficiency measurements.

• Annex H - Penetration sensitivity
  Inclusion of Annex H gives examples and guidance on assessing penetration sensitivity, improving precision in reported efficiency.

Practical applications and users

This report is practical for:

• Test laboratories performing ISO 5011 dust capacity and efficiency tests
• Automotive and heavy‑equipment manufacturers and suppliers (air cleaners, precleaners, filter elements)
• R&D and quality teams involved in inlet air system validation
• Certification bodies and procurement engineers specifying performance requirements

Benefits include improved repeatability of precleaner efficiency, reduced test burden by eliminating rarely used procedures, clearer guidance on dust injection setups, and better confidence in gravimetric measurements.

Related standards

• ISO 5011:2020 - Inlet air cleaning equipment for internal combustion engines and compressors (primary normative reference)
• ISO/IEC Directives (development and editorial context)

Keywords: ISO/TR 6409:2023, ISO 5011:2020, precleaner efficiency, dust injector, air cleaner testing, filter weighing validation, penetration sensitivity, collapse test, blocking test.

Standards Content (Sample)

TECHNICAL ISO/TR
REPORT 6409
First edition
2023-04
Road vehicles — Analysis of technical
changes of ISO 5011:2020
Véhicules routiers — Analyse des changements techniques de l'ISO
5011:2020
Reference number
© ISO 2023
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
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or ISO’s member body in the country of the requester.
ISO copyright office
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Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Precleaner efficiency calculation . 1
5 Collapse and blocking tests .3
6 Revised recommended ISO dust injector table . 4
7 Dust injector (ISO 5011:2020, Figure B.18) . 5
8 Validation of the absolute filter weighing method (ISO 5011:2020, 5.4.1) .10
9 ISO 5011:2020, Annex H – Examples on how to implement it.10
10 Orifice flow test round robin results .13
11 Conclusion: impact of the changes .17
Bibliography .18
iii
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
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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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use
of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed
patent rights in respect thereof. As of the date of publication of this document, ISO had not received
notice of (a) patent(s) which may be required to implement this document. However, implementers are
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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 22, Road vehicles, Subcommittee SC 34,
Propulsion, powertrain and powertrain fluids.
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
Introduction
This document describes the major changes made to ISO 5011:2014 with the ISO 5011:2020 revision.
v
TECHNICAL REPORT ISO/TR 6409:2023(E)
Road vehicles — Analysis of technical changes of ISO
5011:2020
1 Scope
This document analyses the impact of changes to ISO 5011:2020 as regards to the following:
— precleaner efficiency;
— elimination of two secondary element tests (collapse and blocking);
— revisions to the recommended ISO dust injector (Table 1);
— validation of the absolute filter weighing method; and
— inclusion of Annex H, "Penetration sensitivity".
These changes refine the precleaner efficiency calculation, eliminate seldom used tests, which were
lengthy or costly, further clarify dust injector use, the validation of the absolute material, and the
precision of the efficiency measurement.
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 5011:2020, Inlet air cleaning equipment for internal combustion engines and compressors —
Performance testing
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 5011:2020 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/
4 Precleaner efficiency calculation
Background:
In ISO 5011:2014 it was possible, using just the gain on the primary, secondary, and absolute filters
alone, to calculate the precleaner efficiency. This approach was logical, in so far as the measure of the
precleaner efficiency was defined by that which actually loaded on the primary, regardless of whether
it was removed entirely from the system.
This can occur:
— due to the casual removal of the elements (causing dust to fall off in the air cleaner and lowering the
primary gain);
— due to dust trapped within the precleaner housing itself, which commonly occurs during the initial
feed to a system.
It was felt that even if the dust did not reach the primary, and thus cause an increase in restriction, that
it might potentially re-entrain at some point if dislodged and could thus reach the primary.
The new change to ISO 5011:2020, 7.8.2 makes this impossible, as it now includes specifically the gain
in the air cleaner in the calculation (Figure 1).
ISO 5011:2020, 7.8.2 Precleaner efficiency
The precleaner efficiency is defined by the dust removed from the air stream prior to the primary
filter housing. Precleaner efficiency (E ) shall be determined during the dust capacity test, based
p1
on the total mass of dust fed to the air cleaner and the sum of the gain in mass of the primary,
secondary elements, housing and the absolute filter. Calculate the precleaner full life efficiency, E
p1
(expressed as a percentage), as follows:
mm−Δ()++ΔΔmm
DP SF
E = 100 (1)
p1
m
D
where
m is the total mass of dust fed;
D
Δm is the increase in mass of the, primary element and primary housing, if present;
P
Δm is the increase in mass of the secondary element, if present;
S
Δm is the increase in mass of the absolute filter.
F
Figure 1 — Examples of using the older ISO 5011:2014 calculation versus ISO 5011:2020, and
how this compares with the ‘dust ejected’ method
Impact:
1) If prior to this, only the gain on the primary, secondary, and absolute were used – then this changes
the results of the precleaner efficiency.
2) With a 100 % material balance (all masses were measured and collected), the new method
eliminates the difference between calculating using amount removed versus that which passes into
the primary air cleaner housing.
3) It is anticipated to be easier, under some circumstances where the method of removal makes it
difficult to measure the mass removed (dust ejected into the air for example), to calculate the
efficiency.
NOTE A future standard for precleaner efficiency testing is under development.
5 Collapse and blocking tests
The elimination of: ISO 5011:2014, 7.9.2.2.7
ISO 5011:2014, 7.9.2.2.7 “At the end of the test, after measuring the efficiency, the flow rate shall be
increased to produce a differential pressure across the housing of 12,5 kPa (125 mbar). The secondary
element shall not rupture under these conditions.”
Background: ISO 5011:2014, 7.9.2.2.7 was a test designed to challenge the secondary element at the end
of a loading test, i.e. once the secondary had been subjected to the inefficiency of the primary loading.
This was done through increasing the airflow up to a preset differential pressure. The test required
that the airflow be increased after the efficiency masses were taken (i.e. resulting in the removal and
reinstallation of the primary). This is difficult to do without causing a change due to the loss of dust
cake, and it could be messy. This test was eliminated from ISO 5011:2020.
Impact:
1) If the customer requests, then the test can be tested per ISO 5011:2014.
2) The lab can use ISO 5011:2020, 6.6 "Filter element pressure collapse test" as a substitute collapse
challenge.
The elimination of: ISO 5011:2014, 7.9.4 "Secondary element blocking test"
Background: ISO 5011:2014, 7.9.4 was a method of measuring the effects of the gain on a secondary
element which resulted from its repeated use with replacement/new primaries in a series of loadings.
Since it was the inefficiency of the primary which determined the loading of the secondary, this
reflected the ‘real world’ loading of a secondary element. However, due to the cost and time involved in
the procedure, and lack of customer interest, it was eliminated from ISO 5011:2020.

Elements eliminated from ISO 5011:2014:
ISO 5011:2014, 7.9.4 "Secondary element blocking test"
7.9.4.1 General
The test determines the increase in restriction/differential pressure and mass of a secondary
element, caused by the dust that has passed through the primary element.
7.9.4.2 Preparation
Use a clean primary element and secondary element in the housing normally employed. Determine
the mass of the secondary element after conditioning in accordance with 7.5.2.1.
7.9.4.3 Test procedure
7.9.4.3.1 Set up the air cleaner as in 6.3 (restriction and differential pressure test). Measure and
record the restriction/differential pressure of the unit at the rated flow only. Replace the later
reference primary element by a new primary element.
7.9.4.3.2 Conduct a full life efficiency and capacity test as specified in 7.5.
7.9.4.3.3 Replace the primary element with the reference one used at the start of the test. Repeat
the restriction and differential pressure test of 7.9.4.3.1. Note the result.
7.9.4.3.4 Remove the secondary element and reweigh.

Impact:
1) If the customer requests, then the test can be tested per ISO 5011:2014.
2) The lab can run ISO 5011:2020, 7.9.2 instead of ISO 5011:2014, 7.9.4. as a substitute method to
challenge the secondary.
6 Revised recommended ISO dust injector table
The revision of: ISO 5011:2020, 6.2.3
The text in ISO 5011:2014, 6.2.3 reads as follows:
Use the dust injector described in Table 1 and shown in Figures B.2 and B.3.
Table 1 — Table 1 of ISO 5011:2014 "Recommended ISO dust injectors (see Figures B.2 and B.3)"
Dust feed rate (g/min) 0 to 26 26 to 45 >45
ISO injector or ISO
Injector type ISO injector ISO Heavy-duty injector
heavy-duty injector
The specified ISO injector has been shown to feed dust satisfactorily at rates up to 45 g/min. Where
dust feed rates greater than this are required, more than one injector will have to be used. It should
be noted that the design of the system feeding test dust to the injector may affect this maximum
rate of dust feed. The maximum attainable dust feed rate should therefore be determined prior to
the dust feed/injector system being used for tests.
Injector nozzles are subject to natural erosion. Erosion may affect the distribution and delivery of
test contaminant. Therefore, it is recommended to use a design with replaceable parts.”
The text in ISO 5011:2020, 6.2.3 reads a
...