ISO 12759-4:2019/FDAmd 1

• Status: Not Published
• ICS: 23.120 - Ventilators. Fans. Air-conditioners
• Technical Committee: ISO/TC 117 - Fans
• Drafting Committee: ISO/TC 117/WG 11 - Energy efficiency classification
• Current Stage: 5020 - FDIS ballot initiated: 2 months. Proof sent to secretariat
• Start Date: 12-Oct-2026
• Completion Date: 12-Oct-2026

• Consolidates: EN ISO 12759-4:2019/FprA1:2026 - Fans - Efficiency classification for fans - Part 4: Driven fans at maximum operating speed - Amendment 1 (ISO 12759-4:2019/FDAmd1:2026)
• Effective Date: 12-Feb-2026
• Consolidates: ISO 5976:2025 - Rare earth — Determination of loss on ignition in rare earth products — Gravimetric method
• Effective Date: 17-May-2025
• Amends: ISO 12759-4:2019 - Fans — Efficiency classification for fans — Part 4: Driven fans at maximum operating speed
• Effective Date: 03-May-2025

ISO 12759-4:2019/FDAmd 1 is an ISO amendment to Part 4 of the ISO 12759 series on fan efficiency classification. It updates how driven fans at maximum operating speed are treated, including the scope, several definitions, the installation categories used for testing, and an annex on minimum efficiency limits (MELs).

What does ISO 12759-4:2019/FDAmd 1 specify?

ISO 12759-4:2019/FDAmd 1 specifies a system for classifying the efficiency of all fan types driven by motors with an electrical input power of 0.125 kW and above. It applies to driven fans themselves, not to the complete product or installation in which the fan is fitted.

The document also points readers to related ISO 12759 parts for different efficiency-classification procedures and for applying MELs. Annex F shows how the procedures in this part can be used to set MELs.

Annex	What it covers
Annex A	Ecodesign requirements for fans driven by motors with an electrical input power between 125 W and 500 kW, including limit curves and correction factors
Annex F	How the procedures described in this document can be used to set MELs

The main clauses shown in the amendment are Clause 1 on scope, Clause 3 on definitions, and Clause 5.2 on installation categories.

What are the key requirements of ISO 12759-4:2019/FDAmd 1?

ISO 12759-4:2019/FDAmd 1 keeps the focus on driven fans and on efficiency classification at the fan level. In practice, that means the fan is assessed as a component, while the surrounding system is treated separately.

• Clause 1 limits the document to driven fans with motor input power from 0.125 kW upward. For users, this sets the boundary for which fans can be classified under this part.
• Clause 1 also separates the fan from the larger OEM product or ventilation system. In practice, a buyer or test lab should not mix system performance claims with fan-only classification.
• Clause 1 states that ISO 12759-3, ISO 12759-5 and ISO 12759-6 provide different procedures for classifying efficiency or applying a MEL. This matters because the user needs to choose the right procedure for the intended claim or regulatory route.
• Clause 1 and Annex F link the procedures to MELs, but no method is given for comparing classifications and MELs. In practice, classification and minimum-limit compliance are related but not interchangeable.
• Clause 3 revises the definition of conventional output power. This is the output basis used in the efficiency calculations, so the chosen power definition affects the result.
• Clause 3 revises the definitions connected with fan efficiency when a variable speed drive is part of the fan and motor combination. In practice, the electrical input basis changes when the drive/control arrangement is included.
• Clause 5.2 ties the installation list to ISO 5801:2017 categories A, B, C and D. This matters because the test installation category affects how the fan is set up and reported.
• Annex A gives minimum energy efficiency limit curves and correction factors for power conversion, part-load operation, and guard compensation. In practice, this tells users what must be adjusted before comparing a fan against a limit.

What terms does ISO 12759-4:2019/FDAmd 1 define?

• Conventional output power - the output basis used for fan efficiency, expressed from mass flow rate and fan static work, or from inlet volume flow rate, compressibility coefficient and fan static pressure.
• Fan air power - the air-side power used in the efficiency expressions for fans with a variable speed drive.
• Fan static air power - the static-air-side power used in the efficiency expressions for fans with a variable speed drive.
• Drive/control electrical input power - the electrical input power used for the fan and motor combination when a variable speed drive is involved.
• Minimum efficiency limit (MEL) - the minimum efficiency level a fan is expected to meet when the document’s procedures are applied.
• Best efficiency point - the operating point used in Annex A for the power input used in the limit formulae.
• Guard compensation - a correction applied when a fan has a permanently fitted protective guard with a small opening.
• Category A, B, C and D installations - the ISO 5801 installation categories used to identify the test arrangement.

Who uses ISO 12759-4:2019/FDAmd 1?

ISO 12759-4:2019/FDAmd 1 is used by fan manufacturers, test laboratories, conformity assessment bodies, and regulatory or ecodesign teams. It is also relevant to HVAC designers, quality managers, and buyers who need to compare fan efficiency claims on a common basis.

In practice, users apply it to classify fans, choose the correct test installation category, calculate efficiency with the right power basis, and assess whether a fan meets a MEL or an ecodesign limit.

What changed in ISO 12759-4:2019/FDAmd 1 from the previous edition?

ISO 12759-4:2019/FDAmd 1 amends ISO 12759-4:2019 by replacing the scope text, revising the definitions at 3.17, 3.26 and 3.28, updating the list in 5.2, and adding Annex F. It also adds informative Annex A content on ecodesign requirements and a bibliography reference to Commission Regulation (EU) 2024/1834.

Which standards are used with ISO 12759-4:2019/FDAmd 1?

• ISO 5801:2017 - supplies the installation categories A, B, C and D used in Clause 5.2.
• ISO 13857:2019 - defines the opening dimension e used for guard compensation in Annex A.
• ISO 12759-3 - named as a companion part that provides procedures for classifying fan efficiency or applying a MEL.
• ISO 12759-5 - named as a companion part that provides procedures for classifying fan efficiency or applying a MEL.
• ISO 12759-6 - named as a companion part that provides procedures for classifying fan efficiency or applying a MEL.
• Commission Regulation (EU) 2024/1834 - the ecodesign regulation discussed in Annex A and listed in the bibliography.

What does the ISO 12759-4:2019/FDAmd 1 document contain?

ISO 12759-4:2019/FDAmd 1 contains the amended scope, revised definitions, and an updated installation-category list. It also contains informative Annex A with formula-based minimum energy efficiency limits and correction factors.

Annex A covers the treatment of power conversion losses, part-load operation for fans with variable speed drives, and guard compensation for protected fans. The annex also shows how the opening size e is used when a protective guard is present.

The document adds Annex F to connect the classification procedures with MEL setting. That makes the amendment useful both for testing and for ecodesign or procurement decisions where a minimum efficiency threshold is needed.

FINAL DRAFT
Amendment
ISO 12759-4:2019/
FDAM 1
ISO/TC 117
Fans — Efficiency classification for
Secretariat: BSI
fans —
Voting begins on:
2026-10-12
Part 4:
Driven fans at maximum operating
Voting terminates on:
2026-12-07
speed
AMENDMENT 1
Ventilateurs — Classification du rendement des ventilateurs —
Partie 4: Ventilateurs entraînés à vitesse maximale de
fonctionnement
AMENDEMENT 1
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 SUPPOR TING DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/CEN PARALLEL PROCESSING LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
ISO 12759-4:2019/FDAM 1:2026(en) © ISO 2026

FINAL DRAFT
ISO 12759-4:2019/FDAM 1:2026(en)
Amendment
ISO 12759-4:2019/
FDAM 1
ISO/TC 117
Fans — Efficiency classification for
Secretariat: BSI
fans —
Voting begins on:
Part 4:
Driven fans at maximum operating
Voting terminates on:
speed
AMENDMENT 1
Ventilateurs — Classification du rendement des ventilateurs —
Partie 4: Ventilateurs entraînés à vitesse maximale de
fonctionnement
AMENDEMENT 1
© ISO 2026
All rights reserved.
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
This ISO publication is protected by copyright and is owned by ISO and/or its licensors.
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
The content of this ISO publication is provided under licence, not sold. Use is subject to the applicable licence terms issued by ISO,
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
an ISO member body, or an authorized third-party distributor.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
Except as required for implementation or expressly permitted by a separate licence, no part of this ISO publication may be
ISO/CEN PARALLEL PROCESSING
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
reproduced, distributed, modified, used, or made available in any form or by any means – electronic or mechanical, including
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
photocopying, scanning, recording, or posting on internal or external digital platforms. TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
Any use beyond the scope of the granted rights is prohibited and may result in legal action.
MADE IN NATIONAL REGULATIONS.
ISO copyright office
CP 401 • CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
Reference number
ISO 12759-4:2019/FDAM 1:2026(en) © ISO 2026

ii
ISO 12759-4:2019/FDAM 1:2026(en)
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 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 cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
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 117, Fans, in collaboration with the European
Committee for Standardization (CEN) Technical Committee CEN/TC 156, Ventilation for buildings,  in
accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
A list of all parts in the ISO 12759 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.

iii
ISO 12759-4:2019/FDAM 1:2026(en)
Fans — Efficiency classification for fans —
Part 4:
Driven fans at maximum operating speed
AMENDMENT 1
Clause 1 Scope,
Replace the Scope text with the following:
This document establishes a system for the classification of fan efficiency for all fan types driven by
motors with an electrical input power of 0,125 kW and above. It applies to driven fans only, but not to
the system (finished original equipment manufacturer’s product, for example box fans and roof fans or
ventilation system) in which they might be installed. This document, as well as IS
...

ISO 12759-4:2019/FDAMFDAmd 1:2026(en)
ISO/TC 117
Secretariat: BSI
Date: 2026-07-1609-28
Fans – — Efficiency classification for fans —
Part 4:
Driven fans at maximum operating speed
AMENDMENT 1
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© Ventilateurs — Classification du rendement des ventilateurs —
Partie 4: Ventilateurs entraînés à vitesse maximale de fonctionnement
AMENDEMENT 1
FDIS stage
ThiThiThis drs drs drafafaft is t is t is submitted tsubmitted tsubmitted tooo a a a p p parallel arallel arallel vovovote in ISOte in ISOte in ISO, CE, CE, CEN.N.N.

ISO 12759-4:2019/FDAMFDAmd 1:2026(en)
© ISO 2026
All rights reserved. Unless otherwise specified,
This ISO publication is protected by copyright and is owned by ISO and/or its licensors.
The content of this ISO publication is provided under licence, not sold. Use is subject to the applicable licence terms issued
by ISO, an ISO member body, or an authorized third-party distributor.
Except as required in the context of its for implementation or expressly permitted by a separate licence, no part of this
ISO publication may be reproduced or utilized otherwise, distributed, modified, used, or made available in any form or
by any means, – electronic or mechanical, including photocopying, scanning, recording, or posting on internal or external
digital platforms.
Any use beyond 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 countryscope of the requestergranted rights is prohibited and may
result in legal action.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
Email: [e-mail]
Website: www.iso.orgwww.iso.org
Published in Switzerland
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 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 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 cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents.www.iso.org/patents. ISO shall not be held responsible for identifying any or all such
patent rights.
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.htmlwww.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 117, Fans, in collaboration with the European
Committee for Standardization (CEN) Technical Committee CEN/TC 156, Ventilation for buildings, in
accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
A list of all parts in the ISO 12759 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.htmlwww.iso.org/members.html.
iv © ISO #### 2026 – All rights reserved
iv
ISO 12759-4:2019/FDAM 1:2026(en)
Fans – — Efficiency classification for fans
—
Part 4:
Driven fans at maximum operating speed

AMENDMENT 1
Clause 1 Scope,
Replace the Scope text with the following:
This document establishes a system for the classification of fan efficiency for all fan types driven by motors
with an electrical input power of 0,125 kW and above. It applies to driven fans only, but not to the system
(finished original equipment manufacturer’s product, for example box fans and roof fans or ventilation
system) in which they might be installed. This document, as well as ISO 12759-3, ISO 12759-5 and ISO 12759-
6, describe a number of different procedures to classify the efficiency of a fan or to apply a minimum efficiency
limit (MEL).
Annex F shows how procedures described in this document can be used to set MELs.
There is no method described to compare these classifications and MELs.
NOTE 1 The electrical input power is at the fan’s optimum efficiency
3.17
Replace the textdefinition with the following:
conv
...