EN ISO 5801:2017/A1:2025

Fans - Performance testing using standardized airways - Amendment 1 (ISO 5801:2017/Amd 1:2025)

Ventilatoren - Leistungsmessung auf genormten Prüfständen - Änderung 1 (ISO 5801:2017/Amd 1:2025)

Ventilateurs - Essais aérauliques sur circuits normalisés - Amendement 1 (ISO 5801:2017/Amd 1:2025)

Ventilatorji - Preskušanje lastnosti na standardiziranih merilnih progah - Dopolnilo A1 (ISO 5801:2017/Amd 1:2025)

General Information

• Status: Published
• Publication Date: 21-Jan-2025
• ICS: 23.120 - Ventilators. Fans. Air-conditioners
• Technical Committee: CEN/TC 156 - Ventilation for buildings
• Drafting Committee: CEN/TC 156/WG 17 - Fans
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 22-Jan-2025
• Completion Date: 22-Jan-2025
• Ref Project: SIST EN ISO 5801:2018/A1:2025 - Fans - Performance testing using standardized airways - Amendment 1 (ISO 5801:2017/Amd 1:2025)

Relations

• Amends: EN ISO 5801:2017 - Fans - Performance testing using standardized airways (ISO 5801:2017)
• Effective Date: 15-Nov-2023

Overview

EN ISO 5801:2017/A1:2025 is Amendment 1 to the international CEN-adopted standard ISO 5801:2017, titled Fans - Performance testing using standardized airways. Approved January 2025, this amendment updates definitions, test procedures, calculation methods and uncertainty reporting for aerodynamic performance testing of fans in standardized test ducts (airways). It is published by CEN in collaboration with ISO/TC 117 (Fans) and CEN/TC 156 (Ventilation for buildings).

Key topics and technical requirements

• Revised definitions and symbols: updates to hydraulic diameter, hydraulic mean depth and isentropic exponent; the perimeter symbol is clarified (E).
• “Blow through” verification test: clarified procedure and acceptance criteria for settling means (measurement plane at 0.1 Dh downstream; velocity uniformity threshold: max ≤ 2 m/s or ≤ 125% of average).
• Fan air power calculations: two approved methods
  • Polytropic method for compressible flow (detailed formulae and polytropic exponent calculation).
  • Simplified method for reference velocities v ≤ 65 m/s (simplified expressions and guidance when impeller power is not measured).
• Static air power and efficiencies: updated formulas for fan static air power and related efficiency computations, with specific guidance for low-speed (v ≤ 65 m/s) conditions.
• Measurement uncertainty & reporting:
  • Updated propagation and reporting rules (RSS combination of Type A and Type B elements; return to standard uncertainty).
  • Test report must state test value, expanded uncertainty and confidence level (~95%).
  • Maximum allowable expanded uncertainties for individual parameters (examples): ambient pressure 0.2%, ambient temperature 0.2%, gauge/differential pressure 1.4%, rotational frequency 0.5%, power input 2%.
  • Maximum allowable uncertainties for results (examples): fan air power 2.5%, fan impeller efficiency 3.2%, fan flow rate 2.0%, fan pressure 1.4%.
• Annex updates:
  • Nozzle installation, geometry and surface-waviness tolerances for standardized airways.
  • Guidance on measuring motor input power with VFDs (annex F) due to harmonic and measurement challenges.

Applications and users

This amendment is essential for:

• Independent test laboratories performing standardized fan performance testing and certification.
• Fan and HVAC manufacturers verifying aerodynamic performance, efficiency and compliance.
• R&D and test engineers developing fan designs and system integrations.
• Certification bodies and regulators requiring traceable test methods and uncertainty documentation.

Practical uses include performance verification, efficiency benchmarking, selection of fans for ventilation and air-conditioning systems, and compliance testing under national CEN implementations.

Related standards

• ISO 5801:2017 (base standard)
• CEN adoption: EN ISO 5801:2017/A1:2025
• Associated documents: ISO/IEC Directives, ISO 5168 (uncertainty/measurement), ISO 5802 (measurement point arrangements)

Keywords: fans, performance testing, standardized airways, fan air power, polytropic exponent, hydraulic diameter, measurement uncertainty, nozzle calibration, VFD motor input.

Standards Content (Sample)

SLOVENSKI STANDARD
01-marec-2025
Ventilatorji - Preskušanje lastnosti na standardiziranih merilnih progah - Dopolnilo
A1 (ISO 5801:2017/Amd 1:2025)
Fans - Performance testing using standardized airways - Amendment 1 (ISO
5801:2017/Amd 1:2025)
Ventilatoren - Leistungsmessung auf genormten Prüfständen - Änderung 1 (ISO
5801:2017/Amd 1:2025)
Ventilateurs - Essais aérauliques sur circuits normalisés - Amendement 1 (ISO
5801:2017/Amd 1:2025)
Ta slovenski standard je istoveten z: EN ISO 5801:2017/A1:2025
ICS:
23.120 Zračniki. Vetrniki. Klimatske Ventilators. Fans. Air-
naprave conditioners
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 5801:2017/A1
EUROPEAN STANDARD
NORME EUROPÉENNE
January 2025
EUROPÄISCHE NORM
ICS 23.120
English Version
Fans - Performance testing using standardized airways -
Amendment 1 (ISO 5801:2017/Amd 1:2025)
Ventilateurs - Essais aérauliques sur circuits Ventilatoren - Leistungsmessung auf genormten
normalisés - Amendement 1 (ISO 5801:2017/Amd Prüfständen - Änderung 1 (ISO 5801:2017/Amd
1:2025) 1:2025)
This amendment A1 modifies the European Standard EN ISO 5801:2017; it was approved by CEN on 7 January 2025.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for inclusion of
this amendment into the relevant 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 amendment 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
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 5801:2017/A1:2025 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 5801:2017/A1:2025) 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 Amendment to the European Standard EN ISO 5801:2017 shall be given the status of a national
standard, either by publication of an identical text or by endorsement, at the latest by July 2025, and
conflicting national standards shall be withdrawn at the latest by July 2025.
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 5801:2017/Amd 1:2025 has been approved by CEN as EN ISO 5801:2017/A1:2025
without any modification.
International
Standard
ISO 5801
Third edition
Fans — Performance testing using
2017-09
standardized airways
AMENDMENT 1
AMENDMENT 1
2025-01
Ventilateurs — Essais aérauliques sur circuits normalisés
AMENDEMENT 1
Reference number
ISO 5801:2017/Amd.1:2025(en) © ISO 2025

ISO 5801:2017/Amd.1:2025(en)
© 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: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
ISO 5801:2017/Amd.1:2025(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).
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 5801:2017/Amd.1:2025(en)
Fans — Performance testing using standardized airways
AMENDMENT 1
Clause 3
Replace definitions 3.8, 3.9 and 3.15 with the following.
3.8
hydraulic diameter
D
h
four times the cross-sectional area (3.5) divided by the perimeter (E) which encloses the area
4A
D =
h
E
3.9
hydraulic mean depth
H
h
cross-sectional area (3.5) divided by the perimeter (E) which encloses the area
A
H =
h
E
3.15
isentropic exponent
κ
ratio of the specific heat at constant pressure (3.13) to the specific heat at constant volume (3.14)
c
p
κ =
c
V
4.1  Symbols and abbreviated terms
Replace the symbol P with the following

E
Perimeter 3.8 and 3.9 m
Change the definition reference for Polytropic exponent to 15.1.9.2
n Polytropic exponent 15.1.9.2 —
n
Delete the Perimeter P with missing subscript (Line after Fan air power)

ISO 5801:2017/Amd.1:2025(en)
9.3.3  Blow through verification test
Add quotation marks for "Blow through" in the subclause title and replace the content of 9.3.3. with the
following.
9.3.3   “Blow through” verification test
This test evaluates the ability of the airflow settling means to provide a substantially uniform airflow ahead
of a measurement plane. For this test, equally spaced measurement points are located in a plane 0,1D
h
downstream of the settling means. The number of measurement points shall be in accordance with ISO 5802.
a) Nozzle wall: for tests of settling means upstream of the nozzle wall, the auxiliary fan should be set at its
maximum flow rate, the entire nozzle array that induces the most distorted flow shall be open and the
inlet shall be unrestricted so that the inlet area shall be equal to the largest area allowed by the cross-
sectional area.
b) Test fan: for tests of settling means upstream of the test fan, the auxiliary fan shall be set at its maximum
flow rate, half of the nozzle array that induces the most distorted flow shall be open and the outlet shall
be open so that the outlet area shall be equal to the largest area allowed by the cross-sectional area.
The flow velocities shall be measured and the average determined. If the maximum velocity is less than 2 m/s
or if the maximum velocity value does not exceed 125 % of the average, the settling screens are acceptable.

15.1.5  Simplified sets of formulae, which can be used for v ≤65 m/s
2⋅ref
Replace the first sentence with the following
As for reference air velocities v not greater than 65 m/s, the temperature ratio θθ/ does not exceed
2.ref sgxx
1,008 and the Mach factor f does not exceed 1,010 (see Annex P), simplified formulae can be used.
Mx
15.1.9.1  General
Replace the content of 15.1.9.1 with the following.
The fan air power can be written as Formula (47):
Pq=⋅y (47)
ufm
There are two methods to calculate the air power:
— the first (15.1.9.2) derived from polytropic change of state to take into account the influence of air
compressibility;
— the other one (15.1.9.3) for the simplified sets of formulae (v ≤ 65 m/s).
2.ref
If fan impeller power, P , is not measured and cannot be determined from known component efficiencies
r
such as a calibrated motor, the method in 15.1.9.3 shall be used.
NOTE In instances where there exists a strongly non-adiabatic machine, such as high-pressure fans and blowers
(where the fan pressure p exceeds 10 000 Pa), or systems with a notable temperature disparity between the machine
f
and the surrounding environment()
...