EN ISO 12759-4:2019

Fans - Efficiency classification for fans - Part 4: Driven fans at maximum operating speed (ISO 12759-4:2019)

This document establishes a system for the classification of fan efficiency for all fan types driven by motors of nominal rating 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 describes a number of different procedures to classify the efficiency of a fan or to apply a minimum efficiency limit (MEL). Those procedures are described in:
—     ISO 12759-3;
—     this document (ISO 12759-4);
—     ISO 12759-5;
—     ISO 12759-6.
There is no method described to compare these classifications and MEL's.

Ventilatoren - Effizienzklassifizierung für Ventilatoren - Teil 4: Angetriebene Ventilatoren bei maximaler Betriebsdrehzahl (ISO 12759-4:2019)

Diese Internationale Norm legt ein System für die Klassifizierung des Ventilator-Wirkungsgrads bei allen Ventilatortypen fest, die von einem Motor mit einer Nennleistung von mindestens 0,125 kW angetrieben werden. Dies bezieht sich nur auf angetriebene Ventilatoren, aber nicht auf das System (Endprodukt des Originalgeräteherstellers, also z. B. Kastenventilatoren und Dachventilatoren oder Lüftungsanlagen), in das diese eingebaut sind. In diesem Dokument wird eine Reihe von verschiedenen Verfahren zur Klassifizierung des Ventilator-Wirkungsgrads bzw. zur Anwendung der Mindestwirkungsgradgrenze (en: minimum efficiency limit; MEL) beschrieben. Diese Verfahren werden in den folgenden Dokumenten beschrieben:
- ISO 12759 3;
- dieses Dokument (ISO 12759 4);
- ISO 12759 5;
- ISO 12759 6.
Es wird kein Verfahren zum Vergleich dieser Klassifizierungen und MELs beschrieben.

Ventilateurs - Classification du rendement des ventilateurs - Partie 4: Ventilateurs entraînés à vitesse maximale de fonctionnement (ISO 12759-4:2019)

Le présent document établit un système de classification du rendement de tous les types de ventilateurs entraînés par des moteurs dont la puissance nominale est de 125 kW et au-delà. Il est applicable aux ventilateurs (entraînés) uniquement. Il n'est pas applicable au système dans lequel les ventilateurs sont installés (produits finis du fabricant d'équipement d'origine, par exemple, les ventilateurs en caisson, les ventilateurs de toiture ou le système de ventilation). Le présent document décrit un nombre de procédures variées permettant de classifier le rendement d'un ventilateur ou d'appliquer une limite de rendement minimale (MEL). Ces procédures sont décrites dans:
—          ISO 12759‑3;
—          le présent document (ISO 12759‑4);
—          ISO 12759‑5;
—          ISO 12759‑6.
Il n'existe pas de méthode décrite permettant de comparer ces classifications et les MEL.

Ventilatorji - Klasifikacija učinkovitosti ventilatorjev - 4. del: Ventilatorji s pogonom pri največji obratovalni hitrosti (ISO 12759-4:2019)

Ta standard določa le besedišče vilic in priključkov za pretovarjanje. Dokument ne vsebuje varnostnih zahtev za vilice in priključke za pretovarjanje. V tem dokumentu izraz priključek opisuje napravo, nameščeno na industrijski tovornjak, ki omogoča alternativni način uporabe dvižnega sistema.

General Information

• Status: Published
• Publication Date: 26-Nov-2019
• Withdrawal Date: 30-May-2020
• ICS: 23.120 - Ventilators. Fans. Air-conditioners
• Technical Committee: CEN/TC 156 - Ventilation for buildings
• Drafting Committee: CEN/TC 156 - Ventilation for buildings
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 27-Nov-2019
• Completion Date: 27-Nov-2019
• Ref Project: SIST EN ISO 12759-4:2020 - Fans - Efficiency classification for fans - Part 4: Driven fans at maximum operating speed (ISO 12759-4:2019)

Relations

• Replaces: EN ISO 12759:2015 - Fans - Efficiency classification for fans (ISO 12759:2010, including Amd 1:2013)
• Effective Date: 04-Dec-2019

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 12759-4:2020
01-februar-2020
Nadomešča:
SIST EN ISO 12759:2015
Ventilatorji - Klasifikacija učinkovitosti ventilatorjev - 4. del: Ventilatorji s pogonom
pri največji obratovalni hitrosti (ISO 12759-4:2019)
Fans - Efficiency classification for fans - Part 4: Driven fans at maximum operating speed
(ISO 12759-4:2019)
Ventilatoren - Effizienzklassifizierung für Ventilatoren - Teil 4: Angetriebene Ventilatoren
bei maximaler Betriebsdrehzahl (ISO 12759-4:2019)
Ventilateurs - Classification du rendement des ventilateurs - Partie 4: Ventilateurs
entraînés à vitesse maximale de fonctionnement (ISO 12759-4:2019)
Ta slovenski standard je istoveten z: EN ISO 12759-4:2019
ICS:
23.120 Zračniki. Vetrniki. Klimatske Ventilators. Fans. Air-
naprave conditioners
SIST EN ISO 12759-4:2020 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 12759-4:2020


EN ISO 12759-4
EUROPEAN STANDARD

NORME EUROPÉENNE

November 2019
EUROPÄISCHE NORM
ICS 23.120 Supersedes EN ISO 12759:2015
English Version

Fans - Efficiency classification for fans - Part 4: Driven fans
at maximum operating speed (ISO 12759-4:2019)
Ventilateurs - Classification du rendement des Ventilatoren - Effizienzklassifizierung für Ventilatoren
ventilateurs - Partie 4: Ventilateurs entraînés à vitesse - Teil 4: Angetriebene Ventilatoren bei maximaler
maximale de fonctionnement (ISO 12759-4:2019) Betriebsdrehzahl (ISO 12759-4:2019)
This European Standard was approved by CEN on 4 October 2019.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.





EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 12759-4:2019 E
worldwide for CEN national Members.

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SIST EN ISO 12759-4:2020
EN ISO 12759-4:2019 (E)
Contents Page
European foreword . 3

2

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SIST EN ISO 12759-4:2020
EN ISO 12759-4:2019 (E)
European foreword
This document (EN ISO 12759-4:2019) has been prepared by Technical Committee ISO/TC 117 "Fans"
in collaboration with Technical Committee CEN/TC 156 “Ventilation for buildings” the secretariat of
which is held by BSI.
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 May 2020, and conflicting national standards shall be
withdrawn at the latest by May 2020.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 12759:2015.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 12759-4:2019 has been approved by CEN as EN ISO 12759-4:2019 without any
modification.

3

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SIST EN ISO 12759-4:2020
INTERNATIONAL ISO
STANDARD 12759-4
First edition
2019-10
Fans — Efficiency classification for
fans —
Part 4:
Driven fans at maximum operating
speed
Ventilateurs — Classification du rendement des ventilateurs —
Partie 4: Ventilateurs entraînés à vitesse maximale de fonctionnement
Reference number
ISO 12759-4:2019(E)
©
ISO 2019

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ISO 12759-4:2019(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2019
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: [phone]
Fax: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved

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ISO 12759-4:2019(E)

Contents  Page
Foreword .iv
Introduction .v
1  Scope . 1
2  Normative references . 1
3  Terms and definitions . 1
4  Symbols . 5
5  General information . 5
5.1 General . 5
5.2 Use of installation categories . 6
5.3 Efficiency calculation . 7
5.4 Tolerances . 8
6  Ratings. 8
6.1 General . 8
6.2 Driven fans . 8
6.3 Axial, forward curved centrifugal, radial and mixed flow driven fan efficiency grades . 9
6.4 Centrifugal backward bladed fan with and without housing driven fan efficiency grades 11
6.5 Cross flow driven fan efficiency grades .13
Annex A (normative) Examples of applying efficiency lines to driven fans .15
Annex B (informative) Compensation factors .18
Annex C (informative) The variation of fan performance between installation categories .19
Annex D (informative) Selection of fans for best efficiency .20
Annex E (informative) Explanatory note .23
Bibliography .25
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ISO 12759-4:2019(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 117, Fans.
1)
This first edition of ISO 12759-4, together with ISO 12759-1, ISO 12759-2, ISO 12759-3, ISO 12759-5
2)
and ISO 12759-6 , cancels and replaces ISO 12759:2010, which has been technically revised. It also
incorporates the Amendment ISO 12759:2010/Amd.1:2013.
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.
1) Under preparation. Stage at the time of publication: ISO/DIS 12759-5:2019.
2) Under preparation. Stage at the time of publication: ISO/CD 12759-6:2019.
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Introduction
The last decade has seen an escalation in the price and an increasing recognition of the finite life of
many of the fossil fuels currently used. There is also a belief by many that climatic change is due to
increasing levels of carbon dioxide in the atmosphere. This has led to many nations reviewing methods
of energy generation and usage.
To maintain economic growth there is therefore a need to promote energy efficiency. This requires
better selection of equipment by users and thus better design of this equipment by manufacturers.
Fans of all types are used for ventilation, air conditioning, process engineering – drying, pneumatic
conveying – combustion air supply and agriculture. Indeed, the energy use of fans has been calculated
to account for nearly 20 % of the global electricity usage.
The fan industry is global in nature, with a considerable degree of exporting and licensing. To ensure
that the definitive fan performance characteristics are common throughout the world, a series of
standards has been developed. It is the belief of the industry that there is now a need for minimum
efficiency standards to be recognised. To encourage their implementation, a classification system is
proposed which incorporates a series of efficiency bands. With improvements in technology and
manufacturing processes, the minimum efficiency levels could be reviewed and increased over time.
This document can be used by legislators or regulatory bodies for defining future energy-saving targets.
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SIST EN ISO 12759-4:2020
INTERNATIONAL STANDARD ISO 12759-4:2019(E)
Fans — Efficiency classification for fans —
Part 4:
Driven fans at maximum operating speed
1  Scope
This document establishes a system for the classification of fan efficiency for all fan types driven by
motors of nominal rating 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 describes a number of different procedures
to classify the efficiency of a fan or to apply a minimum efficiency limit (MEL). Those procedures are
described in:
— ISO 12759-3;
— this document (ISO 12759-4);
— ISO 12759-5;
— ISO 12759-6.
There is no method described to compare these classifications and MEL’s.
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 5801:2017, Fans — Performance testing using standardized airways
ISO 13348:2007, Industrial fans — Tolerances, methods of conversion and technical data presentation
3  Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
fan
rotary-bladed machine that receives mechanical energy and utilizes it by means of one or more
impellers fitted with blades to maintain a continuous flow of air or other gas passing through it and
whose work per unit mass does not normally exceed 25 kJ/kg
Note 1 to entry: Fans are defined according to their installation category, function, fluid path and operating
conditions (see ISO 13349).
[SOURCE: ISO 13349:2010, 3.1.1, — Notes to entry 1 and 3 were deleted.]
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3.2
fan size
nominal diameter of the impeller
3.3
drive
mechanism used to power the fan which includes the motor, belt, couplings, chains, transmission
and VFDs
EXAMPLE Transmission drive and motor drive.
3.4
driven fan
impeller fitted to or connected to a motor, with or without a drive mechanism, housing or means of
variable speed drive
Note 1 to entry: See Figure 1.
3.5
air
working fluid for tests with standardized airways shall be atmospheric air
[SOURCE: ISO 5801:2017, 3.1]
3.6
installation category A
installation with free inlet and free outlet with a partition
[SOURCE: ISO 13349:2010, 3.4.1, modified — References to ISO 5801 and ISO 5802 were deleted.]
3.7
installation category B
installation with free inlet and ducted outlet
[SOURCE: ISO 13349:2010, 3.4.2, modified — References to ISO 5801 and ISO 5802 were deleted.]
3.8
installation category C
installation with ducted inlet and free outlet
[SOURCE: ISO 13349:2010, 3.4.3, modified — References to ISO 5801 and ISO 5802 were deleted.]
3.9
installation category D
installation with ducted inlet and ducted outlet
[SOURCE: ISO 13349:2010, 3.4.4, modified — References to ISO 5801 and ISO 5802 were deleted.]
3.10
density at fan inlet
ρ
1
fluid density calculated from the absolute pressure and the static temperature at the fan inlet
3.11
fan pressure
p
f
difference between the stagnation pressure at the fan outlet and the stagnation pressure at the fan inlet
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ISO 12759-4:2019(E)

3.12
mass flow rate
q
m
mean value, over time, of the mass of air which passes through the specified airway cross-section per
unit of time
3.13
inlet volume flow rate
q
v1
mass flow rate at the inlet divided by the corresponding mean value, over time, of the average density
at the inlet
3.14
fan work per unit mass
W
m
increase in mechanical energy per unit mass of fluid passing through the fan
3.15
compressibility coefficient
k
p
ratio of the mechanical work done by the fan on the air to the work that would be done on an
incompressible fluid with the same mass flow, inlet density and pressure ratio
3.16
fan air power
P
u
conventional output power which is the product of the mass flow rate and the fan work per unit mass,
or the product of the inlet volume flow rate, the compressibility coefficient and the fan pressure
3.17
fan static air power
P
us
conventional output power which is the product of the mass flow rate and the fan work per unit mass,
or the product of the inlet volume flow rate, the compressibility coefficient and the fan pressure
3.18
impeller power
P
r
mechanical power supplied to the fan impeller
[SOURCE: ISO 5801:2017, 3.45]
3.19
fan shaft power
P
a
mechanical power supplied to the fan shaft
[SOURCE: ISO 5801:2017, 3.46, modified — Note 1 to entry was deleted.]
3.20
motor output power
P
o
shaft power output of the motor or other prime mover
[SOURCE: ISO 5801:2017, 3.47]
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3.21
motor input power
P
e
electrical input power supplied at the terminals of an electric motor drive without a variable speed drive
[SOURCE: ISO 5801:2017, 3.48]
3.22
drive/control electrical input power
P
ed
power supplied by electrical mains or equivalent energy supply to a motor system
3.23
fan impeller efficiency
η
r
fan air power divided by the impeller power
[SOURCE: ISO 5801:2017, 3.50, modified — References to quantities and formula deleted.]
3.24
fan shaft efficiency
η
a
fan air power divided by the fan shaft power
[SOURCE: ISO 5801:2017, 3.51, modified — References to quantities and formula deleted.]
3.25
overall efficiency for a fan without a variable speed drive
η
e
fan air power divided by the motor input power for the fan and motor without a variable speed drive
Note 1 to entry: The efficiency should be referred to the installation category, see Figure 2 and ISO 13349.
Note 2 to entry: For the purposes of this document efficiency should be expressed as a proportion of unity. To
obtain a percentage value multiply the efficiency result by 100.
Note 3 to entry: The motor input power as defined in 3.21.
3.26
overall efficiency for a fan with a variable speed drive
η
ed
fan air power divided by the motor input power for the fan and motor combination with a variable
speed drive
Note 1 to entry: The efficiency should be referred to the installation category, see Figure 2 and ISO 13349.
Note 2 to entry: For the purposes of this document efficiency should be expressed as a proportion of unity. To
obtain a percentage value multiply the efficiency result by 100.
Note 3 to entry: The motor input power as defined in 3.22.
3.27
overall static efficiency for a fan without a variable speed drive
η
es
fan static air power divided by the motor input power for the fan and motor without a variable speed drive
3.28
overall static efficiency for a fan with a variable speed drive
η
esd
fan static air power divided by the motor input power for the fan and motor combination with a variable
speed drive
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3.29
optimum efficiency
η
opt
maximum efficiency achieved on the fan air characteristic with all operational parameters, except the
air system resistance, being fixed
3.30
fan motor efficiency grade
FMEG
efficiency grade for a driven fan
Note 1 to entry: The definitions given in 3.25 to 3.28 shall apply.
4  Symbols
Symbol Term Unit
k compressibility coefficient
p
N grade number
G
P fan shaft power W
a
P motor input power W
e
P drive/control electrical input power W
ed
P motor output power W
o
P impeller power W
r
P fan air power W
u
P fan static air power W
us
p atmospheric pressure Pa
a
p dynamic pressure at a point Pa
d
p fan pressure Pa
f
p fan static pressure Pa
sf
p absolute stagnation pressure at a point Pa
sg
q mass flow rate kg/s
m
3
q inlet volume flow rate m /s
v1
W fan work per unit mass J/kg
m
η fan shaft efficiency Expressed as a decimal
a
η overall efficiency Expressed as a decimal
e
η overall efficiency for a fan with VSD Expressed as a decimal
ed
η overall static efficiency Expressed as a decimal
es
η overall static efficiency for a fan with VSD Expressed as a decimal
esd
η optimum efficiency Expressed as a decimal
opt
η fan impeller efficiency Expressed as a decimal
r
3
ρ density at fan inlet kg/m
1
NOTE Efficiency in percent (%) divided by 100 equals the efficiency expressed as a decimal.
5  General information
5.1  General
Fans range from the purpose-built single fan to the series-produced certified ranges manufactured in
large quantities. A fan may be a motor attached to a drive system attached to an impeller within an
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impeller casing, if so supplemented by a volume control such as a variable speed control or guide vanes
(driven fan), see Figure 1.
The variation in design has led to efficiency being defined in a number of ways to suit the demands of
the fan type and the market place.
Key
1 electrical input power P
ed
a
2 variable speed device loss (heat)
3 motor losses (heat)
4 belt losses (heat)
5 bearing losses (heat)
6 impeller and casing aerodynamic losses (heat)
7 volume flow and pressure P (air power)
u
a
The variable speed device might or might not be fitted. See Clause 6.
Figure 1 — Example of a driven fan showing power losses
5.2  Use of installation categories
Fan efficiency ratings are frequently specific to each standardised installation category.
When a fan is designed for a single installation category, its rated efficiency grade shall refer to that
particular installation category, and this shall be clearly identified.
When a fan is suitable for use with different installation categories, the fan efficiency grade shall be
based on the efficiency ratings referring to the most suitable installation category.
To determine the operating point of the fan, four installation categories are considered, see Figure 2.
For details of the required test methods refer to the following subclauses of ISO 5801:
— category A installations – ISO 5801:2017, 6.1;
— category B installations – ISO 5801:2017, 6.2;
— category C installations – ISO 5801:2017, 6.3;
— category D installations – ISO 5801:2017, 6.4.
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The standardised installation category used for rating the fan shall be clearly stated (see Annex C).
The motor input power and motor output power shall be measured or determined using methods given
in ISO 5801.
Installation category E is not included in this document.
Figure 2 — Installation categories
5.3  Efficiency calculation
See ISO 5801:2017, 15.2.
For driven fans, where the input power can be determined, the overall efficiency is given by Formula (1)
for fans without a variable speed drive and Formula (2) for fans with variable speed drives.
η =PP/ (1)
eu e
or
η =PP/ (2)
ed ued
The overall static efficiency can be calculated by substituting the static air power into Formulae (1) and
(2) so that the overall static efficiency is given by Formula (3) for fans without a variable speed drive
and Formula (4) for fans with variable speed drives.
η =PP/ (3)
es us e
or
η =PP/ (4)
esdused
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5.4  Tolerances
At each stage of the fan design and manufacturing cycle, including conversion from prototype
performance data or calculation, and fabrication and testing of a purpose-designed fan, finite
uncertainties will prevail and acceptance tolerances shall be applied.
Any test for fan performance is subject to error, and the range within which these testing errors
may be expected to lie is defined numerically as the uncertainty of measurement. In addition, the
true performance of the fan (if it could be ascertained) would be found to differ from that of another
nominally identical fan, owing to inevitable variations in manufacture. The expected range of this
manufacturing variation shall be added to the uncertainty of measurement to determine the minimum
tolerance required for a performance specification.
For the purposes of this document the tolerances given in ISO 13348:2007, Clauses 5 and 6, shall apply.
6  Ratings
6.1  General
The variation of fan type and drive option leads to efficiency being derived in different ways. For
grading purposes, the efficiency for driven fans has been defined as a function of motor input power.
The following is a guide to the optimum efficiency (best efficiency point) levels that are achievable by the
fan types addressed by this document. The minimum levels of acceptability are dependent on consultation
between regulators and manufacturers’ representatives or local legislation where this exists.
The efficiency grade for a fan is based on its performance characteristics at maximum permissible
rotational speed to obtain its best efficiency point.
Further information on the subject of fan efficiency can be found in Annexes D and E.
6.2  Driven fans
The efficiency grades for driven fans are shown in Figures 3, 4 and 5. The variation of optimum
efficiency and fan motor efficiency grade (FMEG) is shown as a function of input power and design.
In cases where a volume control device is necessary, a variable speed drive is the best option, as it is the
most efficient method for adjustment to different operating points. Other options for volume control
such as guide vanes or control valves are less efficient.
The FMEG (e.g. FMEG55) of a given fan at its best efficiency point at full speed shall be the value
calculated according to Annex A, for the relevant input power.
The curves of FMEGs are based on impeller and motor combinations. If a control device is used then the
efficiency data can be revised by the correction values for controls in
...

SLOVENSKI STANDARD
oSIST prEN ISO 12759-4:2018
01-julij-2018
9HQWLODWRUML.ODVLILNDFLMDXþLQNRYLWRVWLYHQWLODWRUMHYGHO9HQWLODWRUMLVSRJRQRP
SULQDMYHþMLREUDWRYDOQLKLWURVWL,62',6
Fans - Efficiency classification for fans - Part 4: Driven fans at maximum operating speed
(ISO/DIS 12759-4:2018)
Ventilatoren - Effizienzklassifizierung für Ventilatoren (ISO/DIS 12759-4:2018)
Ventilateurs - Classification du rendement des ventilateurs - Partie 4: Ventilateurs
entraînés à vitesse maximale de fonctionnement (ISO/DIS 12759-4:2018)
Ta slovenski standard je istoveten z: prEN ISO 12759-4
ICS:
23.120 =UDþQLNL9HWUQLNL.OLPDWVNH Ventilators. Fans. Air-
QDSUDYH conditioners
oSIST prEN ISO 12759-4:2018 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN ISO 12759-4:2018

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oSIST prEN ISO 12759-4:2018
DRAFT INTERNATIONAL STANDARD
ISO/DIS 12759-4
ISO/TC 117 Secretariat: BSI
Voting begins on: Voting terminates on:
2018-05-09 2018-08-01
Fans — Efficiency classification for fans —
Part 4:
Driven fans at maximum operating speed
Ventilateurs — Classification du rendement des ventilateurs —
Partie 4: Titre manque
ICS: 23.120
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 12759-4:2018(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 2018

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oSIST prEN ISO 12759-4:2018
ISO/DIS 12759-4:2018(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2018
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: [phone]
Fax: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved

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oSIST prEN ISO 12759-4:2018
ISO/DIS 12759-4:2018(E)

Contents  Page
Foreword .iv
Introduction .v
1  Scope . 1
2  Normative references . 1
3  Terms and definitions. . 1
4  Units and symbols . 4
5  General. . 5
5.1 Use of installation categories . 6
5.2 Efficiency calculation . 7
5.2.1  . 7
5.3 Tolerances . 8
6  Ratings. . 8
6.1 Driven fans . 8
Annex A (normative) Examples of applying efficiency lines to driven fans .15
Annex B (informative) Compensation factors .17
Annex C (informative) The variation of fan performance between installation categories .18
Annex D (informative) Selection of fans for best efficiency. .19
Annex E (informative) Explanatory note .22
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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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International
Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies
casting a vote.
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.
ISO 12759 was prepared by Technical Committee ISO/TC 117, Fans, Subcommittee SC , .
This second/third/. edition cancels and replaces the first/second/. edition (), [clause(s) / subclause(s)
/ table(s) / figure(s) / annex(es)] of which [has / have] been technically revised.
iv © ISO 2018 – All rights reserved

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Introduction
The last decade has seen not only an escalation in the price, but also an increasing recognition of the
finite life of many of the fossil fuels currently used. There is also a belief by many that climatic change
is due to an increase of carbon dioxide in the atmosphere. This has lead to many nations reviewing
methods of energy generation and usage.
To maintain economic growth there is therefore a need to promote energy efficiency. This requires better
selection of equipment by users and therefore better design of this equipment by its manufacturers.
Fans of all types are used for ventilation and air conditioning, for process engineering – drying,
pneumatic conveying, and combustion air supply and for agriculture etc. Indeed, the energy usage by
fans has been calculated to be nearly 20% of the worldwide usage.
The fan industry is of a global nature, with a considerable degree of exporting and licensing. To ensure
that the definition fan performance characteristics are common throughout the world a series of
standards have been developed, it is the belief of the industry that there is now a need for minimum
efficiency standards to be recognised. To encourage their implementation, a classification system is
proposed which incorporates a series of efficiency bands. With improvements in technology and
manufacturing processes the minimum efficiency levels may be reviewed and increased in time
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oSIST prEN ISO 12759-4:2018
DRAFT INTERNATIONAL STANDARD ISO/DIS 12759-4:2018(E)
Fans — Efficiency classification for fans —
Part 4:
Driven fans at maximum operating speed
1  Scope
This international standard deals with the classification of fan efficiency for all fan types driven by
motors of nominal rating 0.125kW and above. This standard may be used by legislators or regulatory
bodies for defining future energy saving targets. This applies to the fan (driven) only but not to the
system (finished Original Equipment Manufacturer’s product, e.g. box fans and roof fans or ventilation
system) in which it is installed.
2  Normative references
The following referenced documents are indispensable for the application 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 5801, Fans — Performance testing using standardized airways
ISO 13348, Industrial fans — Tolerances, methods of conversion and technical data presentation
ISO 13349, Fans — Vocabulary and definitions of categories
IEC 60034-2-1, Rotating electrical machines — Part 2-1: Standard methods for determining losses and
efficiency from tests (excluding machines for traction vehicles)
IEC 60034-30, Rotating electrical machines — Part 30: Efficiency classes of single speed, three phase, cage
induction motors
3  Terms and definitions.
See tables 6 and 7 of ISO 13349 and associated formulae in ISO 5801 and clause 5 of this international
standard.
For the purposes of this International Standard, the following definitions apply.
3.1
fan
a rotary bladed machine which receives mechanical energy and utilizes it by means of one or more
impellers fitted with blades to maintain a continuous flow of air or other gas passing through it and
whose work per unit mass does not normally exceed 25 kJ/kg
Note 1 to entry: Fans are defined according to their installation category, function, fluid path and operating
conditions (see ISO 13349).
3.2
fan size
fan size is the nominal diameter of the impeller.
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3.3
drives (transmission and motor)
any mechanism used to power the fan including the motor, belts, couplings, chains, transmission,
VFDs, etc.
3.4
driven fan
an impeller fitted to or connected to a motor, with or without the following, a drive mechanism, a
housing, a means of variable speed drive, figure 1.
3.5
air
in this International Standard, an abbreviation for the expression "air or other gas"
3.6
standard air
3
by convention, air with a density of 1.2 kg/m
3.7
fan installation categories according to the arrangement of ducting
for details of all installation categories see figure 2 and ISO 13349.
3.7.1
installation category A
installation with free inlet and free outlet
3.7.2
installation category B
installation with free inlet and ducted outlet
3.7.3
installation category C
installation with ducted inlet and free outlet
3.7.4
installation category D
installation with ducted inlet and ducted outlet
3.8
average density at fan inlet
ρ
1
fluid density calculated from the absolute pressure and the static temperature at the fan inlet.
3.9
atmospheric pressure
p
a
pressure, measured with respect to absolute zero pressure, which is exerted at a point at rest relative
to the air around it.
3.10
fan pressure
p
f
difference between the stagnation pressure at the fan outlet and the stagnation pressure at the fan inlet.
3.11
fan static pressure
p
sf
conventional quantity defined as the fan pressure minus the fan dynamic pressure corrected by the
Mach factor.
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3.12
absolute stagnation pressure at a point
p
sg
absolute pressure which would be measured at a point in a flowing gas if it were brought to rest via an
isentropic process.
3.13
conventional dynamic pressure at a section
p
d
dynamic pressure calculated from the average velocity and the average density of the air at the specified
airway cross-section.
3.14
mass flow rate
q
m
mean value, over time, of the mass of air which passes through the specified airway cross-section per
unit of time
3.15
inlet volume flow rate
q
v1
mass flow rate at the inlet divided by the corresponding mean value, over time, of the average density
at the inlet
3.16
fan work per unit mass
W
m
increase in mechanical energy per unit mass of fluid passing through the fan
3.17
compressibility coefficient
k
p
ratio of the mechanical work done by the fan on the air to the work that would be done on an
incompressible fluid with the same mass flow, inlet density and pressure ratio.
3.18
fan air power
P
u
conventional output power which is the product of the mass flow rate and the fan work per unit mass,
or the product of the inlet volume flow rate, the compressibility coefficient and the fan pressure.
3.19
impeller power
P
r
mechanical power supplied to the fan impeller
3.20
fan shaft power
P
a
mechanical power supplied to the fan shaft
3.21
motor output power
P
o
shaft power output of the motor or other prime mover
3.22
motor input power
P
e
Electrical power supplied at the terminals of an electric motor drive
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3.23
drive/control electrical input power
P
ed
The power supplied by electrical mains or equivalent energy supply to a motor system.
3.24

fan efficiency definitions.
3.24.1
fan impeller efficiency
η
r
fan air power divided by the impeller power P
r
3.24.2
fan shaft efficiency
η
a
fan air power divided by the fan shaft power.
3.24.3
overall efficiency (fan and motor)
η
e
fan air power divided by the motor input power for the fan and motor combination.
Note 1 to entry: The efficiency should be referred to the installation category, see figure 2 and ISO 13349.
Note 2 to entry: For the purposes of this standard efficiency should be expressed as a proportion of unity. To
obtain a % value multiply the efficiency result by 100.
Note 3 to entry: The motor input power as defined in section 3.23 or 3.24 dependant on electrical drive.
3.24.4
overall static efficiency (fan and motor)
η
es
fan static air power divided by the motor input power for the fan and motor combination.
3.25
optimum efficiency
η
opt
maximum efficiency achieved on the fan air characteristic with all operational parameters, except the
air system resistance, being fixed
3.26

fan efficiency grade
3.26.1
fan motor efficiency grade (FMEG)
the efficiency grade for a driven fan.
Note 1 to entry: The definitions given in 3.24.3 shall apply.
4  Units and symbols
The following primary units and symbols for the parameters listed shall be used.
Symbol Term Unit
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3
ρ average density at fan inlet kg/m
1
p Atmospheric pressure Pa
a
p Fan pressure Pa
f
p Absolute stagnation pressure at a point Pa
sg
p Fan static pressure Pa
sf
p Dynamic pressure at a point Pa
d
q Mass flow rate kg/s
m
3
q Inlet volume flow rate m /s
v1
W Fan work per unit mass J/kg
m
k Compressibility coefficient
p
P Fan air power W
u
P Impeller power W
r
P Fan shaft power W
a
P Motor input power W
e
P Motor output power W
o
P Drive/ control electrical input power W
ed
η Fan impeller efficiency Expressed as a decimal
r
η Fan shaft efficiency Expressed as a decimal
a
η Overall efficiency Expressed as a decimal
e
η Overall static efficiency Expressed as a decimal
es
η Optimum efficiency Expressed as a decimal
opt
NOTE Efficiency in percent, (%), divided by 100 equals the efficiency expressed as a decimal.
5  General.
Fans range from the purpose built single fan to the series produced certified ranges manufactured in
large quantities. A fan may be a motor attached to a drive system attached to an impeller within an
impeller casing, if so supplemented by a volume control such as a variable speed control or guide vanes,
(driven fan) figure 1.
The variation in design has led to efficiency being defined in a number of ways to suit the demands of
the fan type and the market place.
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Key
1 Electrical input power P
ed
2 Variable speed device loss (heat)*
3 Motor losses (heat)
4 Belt losses (heat)
5 Bearing losses (heat)
6 Impeller and casing aerodynamic losses (heat)
7 Volume flow and pressure Pu (Air Power)
8 Electrical input power P
ed
NOTE The variable speed device may or may not be fitted. See section 6.
Figure 1 — An example of a driven fan showing power losses.
5.1  Use of installation categories
Fan efficiency ratings are frequently specific for each standardised installation category.
When a fan is designed for a single installation category, its rated efficiency grade shall refer to that
particular installation category, and this shall be clearly identified.
When a fan is suitable for use with different installation categories, the fan efficiency grade shall be
based on the efficiency ratings referring to the most suitable installation category.
To determine the operating point of the fan, four installation categories are considered, see figure 2. For
details of test methods refer to ISO 5801:2017 and the following sections contained therein;
Category A installations – Section 6.1
Category B installations – Section 6.2
Category C installations – Section 6.3
Category D installations – Section 6.4
The standardised installation category used for rating the fan must be clearly stated. (See appendix C).
6 © ISO 2018 – All rights reserved

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The motor input power and motor output power may be measured or determined using methods given
in ISO 5801.
Installation category E is not included in this standard.
Figure 2 — Installation categories.
5.2  Efficiency calculation
See ISO 5801, clause 15.8.1.4
5.2.1
For driven fans, where the input power can be determined, the overall efficiency is given by:
η =P / P (1)
e u e
or
η =P / P (2)
e u ed
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5.3  Tolerances
At each stage of th
...