EN ISO 5801:2008

SLOVENSKI STANDARD
01-april-2009
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Industrial fans - Performance testing using standardized airways (ISO 5801:2007)
Einführendes Element - Haupt-Element -rrrrr Ergänzendes Element (ISO 5801:2007)
Ventilateurs industriels - Essais aérauliques sur circuits normalisés (ISO 5801:2007)
Ta slovenski standard je istoveten z: EN ISO 5801:2008
ICS:
23.120 =UDþQLNL9HWUQLNL.OLPDWVNH Ventilators. Fans. Air-
QDSUDYH conditioners
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 5801
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2008
ICS 23.120
English Version
Industrial fans - Performance testing using standardized airways
(ISO 5801:2007 including Cor 1:2008)
Ventilateurs industriels - Essais aérauliques sur circuits
normalisés (ISO 5801:2007, Cor 1:2008 inclus)
This European Standard was approved by CEN on 2 October 2008.
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 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 Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2008 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 5801:2008: E
worldwide for CEN national Members.

Contents Page
Foreword.3

Foreword
The text of ISO 5801:2007 including Cor 1:2008 has been prepared by Technical Committee ISO/TC 117
“Industrial fans” of the International Organization for Standardization (ISO) and has been taken over as EN
ISO 5801:2008 by 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 April 2009, and conflicting national standards shall be withdrawn at the
latest by April 2009.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
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, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 5801:2007 including Cor 1:2008 has been approved by CEN as a EN ISO 5801:2008 without
any modification.
INTERNATIONAL ISO
STANDARD 5801
Second edition
2007-12-15
Industrial fans — Performance testing
using standardized airways
Ventilateurs industriels — Essais aérauliques sur circuits normalisés

Reference number
ISO 5801:2007(E)
©
ISO 2007
ISO 5801:2007(E)
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©  ISO 2007
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ii © ISO 2007 – All rights reserved

ISO 5801:2007(E)
Contents Page
Foreword. vii
Introduction . viii
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 1
4 Symbols and units. 16
4.1 Symbols . 16
4.2 Subscripts . 19
5 General. 19
6 Instruments for pressure measurement. 20
6.1 Barometers . 20
6.2 Manometers. 21
6.3 Damping of manometers. 21
6.4 Checking of manometers. 21
6.5 Position of manometers. 22
7 Determination of average pressure in an airway. 22
7.1 Methods of measurement . 22
7.2 Use of wall tappings . 22
7.3 Construction of tappings . 22
7.4 Position and connections . 23
7.5 Checks for compliance. 23
7.6 Use of Pitot-static tube. 23
8 Measurement of temperature . 24
8.1 Thermometers . 24
8.2 Thermometer location . 24
8.3 Humidity. 24
9 Measurement of rotational speed . 25
9.1 Fan shaft speed. 25
9.2 Acceptable instruments . 25
10 Determination of power input. 25
10.1 Measurement accuracy . 25
10.2 Fan shaft power . 25
10.3 Determination of fan shaft power by electrical measurement . 25
10.4 Impeller power. 26
10.5 Transmission systems . 26
11 Measurement of dimensions and determination of areas. 26
11.1 Flow-measurement devices. 26
11.2 Tolerance on dimensions . 26
11.3 Determination of cross-sectional area . 27
12 Determination of air density, humid gas constant and viscosity . 27
12.1 Density of air in the test enclosure at section x . 27
12.2 Determination of vapour pressure . 28
12.3 Determination of air viscosity . 30
13 Determination of flow rate . 31
13.1 General. 31
ISO 5801:2007(E)
13.2 In-line flowmeters (standard primary devices). 31
13.3 Traverse methods . 32
14 Calculation of test results . 34
14.1 General . 34
14.2 Units . 34
14.3 Temperature. 34
14.4 Mach number and reference conditions. 36
14.5 Fan pressure. 40
14.6 Calculation of stagnation pressure at a reference section of the fan from gauge pressure,
p , measured at a section x of the test duct . 43
ex
14.7 Inlet volume flow rate . 44
14.8 Fan air power and efficiency. 44
15 Rules for conversion of test results. 52
15.1 Laws on fan similarity. 52
15.2 Conversion rules. 54
16 Fan characteristic curves. 57
16.1 General . 57
16.2 Methods of plotting. 58
16.3 Characteristic curves at constant speed. 58
16.4 Characteristic curves at inherent speed. 58
16.5 Characteristic curves for adjustable-duty fan. 59
16.6 Complete fan characteristic curve . 60
16.7 Test for a specified duty. 61
17 Uncertainty analysis . 62
17.1 Principle . 62
17.2 Pre-test and post-test analysis. 62
17.3 Analysis procedure. 62
17.4 Propagation of uncertainties . 62
17.5 Reporting uncertainties. 63
17.6 Maximum allowable uncertainties measurement . 63
17.7 Maximum allowable uncertainty of results. 64
18 Selection of test method . 65
18.1 Classification. 65
18.2 Installation categories . 65
18.3 Test report. 65
18.4 User installations . 66
18.5 Alternative methods. 66
18.6 Duct simulation . 66
19 Installation of fan and test airways . 66
19.1 Inlets and outlets. 66
19.2 Airways. 66
19.3 Test enclosure. 67
19.4 Matching fan and airway . 67
19.5 Outlet area. 67
20 Carrying out the test . 67
20.1 Working fluid . 67
20.2 Rotational speed . 67
20.3 Steady operation . 67
20.4 Ambient conditions. 68
20.5 Pressure readings. 68
20.6 Tests for a specified duty. 68
20.7 Tests for a fan characteristic curve . 68
20.8 Operating range . 68
21 Determination of flow rate. 68
21.1 Multiple nozzle. 68
21.2 Conical or bellmouth inlet. 68
iv © ISO 2007 – All rights reserved

ISO 5801:2007(E)
21.3 Orifice plate . 68
21.4 Pilot-static tube traverse (see ISO 3966 and ISO 5221). 69
22 Determination of flow rate using multiple nozzles. 69
22.1 Installation . 69
22.2 Geometric form . 69
22.3 Inlet zone . 70
22.4 Multiple-nozzle characteristics. 70
22.5 Uncertainty . 72
23 Determination of flow rate using a conical or bellmouth inlet. 73
23.1 Geometric form . 73
23.2 Screen loading . 74
23.3 Inlet zone . 75
23.4 Conical inlet performance. 75
23.5 Bellmouth inlet performance . 75
23.6 Uncertainties . 77
24 Determination of flow rate using an orifice plate . 77
24.1 Installation . 77
24.2 Orifice plate . 77
24.3 Ducts . 81
24.4 Pressure tappings. 81
24.5 Calculation of mass flow rate . 81
24.6 Reynolds number. 82
24.7 In-duct orifice with D and D/2 taps [see Figure 20 a) and ISO 5167-1]. 82
24.8 Outlet orifice with wall tappings [see Figure 20 c) and e)] . 86
25 Determination of flow rate using a Pitot-static tube traverse . 88
25.1 General. 88
25.2 Pitot-static tube. 88
25.3 Limits of air velocity . 93
25.4 Location of measurement points . 93
25.5 Determination of flow rate . 94
25.6 Flow rate coefficient . 94
25.7 Uncertainty of measurement . 95
26 Installation and setup categories. 95
26.1 Category A: free inlet and free outlet. 95
26.2 Category B: free inlet and ducted outlet . 95
26.3 Category C: ducted inlet and free outlet . 96
26.4 Category D: ducted inlet and ducted outlet . 96
26.5 Test installation type . 96
27 Flow straighteners. 96
27.1 Types of straightener . 97
27.2 Rules for use of a straightener. 98
28 Common-segment airways for ducted fan installations. 99
28.1 Common segments. 99
28.2 Common segment at fan outlet. 99
28.3 Common segment at fan inlet . 101
28.4 Outlet duct simulation. 103
28.5 Inlet duct simulation. 103
28.6 Loss allowances for standardized airways. 104
29 Standardized test chambers. 107
29.1 Test chamber. 107
29.2 Variable supply and exhaust systems. 112
29.3 Standardized inlet test chambers . 112
29.4 Standardized outlet test chambers . 115
30 Standard methods with test chambers — Category A installations . 118
30.1 Types of fan setup . 118
ISO 5801:2007(E)
30.2 Inlet-side test chambers. 118
30.3 Outlet-side test chambers . 131
31 Standard test methods with outlet-side test ducts — Category B installations . 136
31.1 Types of fan setup . 136
31.2 Outlet-side test ducts with antiswirl device . 137
31.3 Outlet chamber test ducts without antiswirl device. 149
32 Standard test methods with inlet-side test ducts or chambers — Category C installations . 156
32.1 Types of fan setup . 156
32.2 Inlet-side test ducts . 157
32.3 Inlet-side test chambers. 170
33 Standard methods with inlet- and outlet-side test ducts — Category D installations. 180
33.1 Types of fan setup . 180
33.2 Installation category B with outlet antiswirl device and with an additional inlet duct or
inlet-duct simulation . 184
33.3 Installation category B without outlet antiswirl device nor common segment, modified
with addition of an inlet duct or inlet-duct simulation . 190
33.4 Installation category C with common inlet duct, modified with the addition of an outlet
common segment with antiswirl device . 193
33.5 Installation category C, modified with the addition of an outlet-duct simulation without
antiswirl device . 197
Annex A (normative) Fan pressure and fan installation category. 205
Annex B (normative) Fan-powered roof exhaust ventilators. 209
Annex C (informative) Chamber leakage test procedure . 211
Annex D (informative) Fan outlet elbow in the case of a non-horizontal discharge axis. 217
Annex E (informative) Electrical input power consumed by a fan installation . 220
Annex F (informative) Preferred methods of performance testing. 227
Bibliography . 228

vi © ISO 2007 – All rights reserved

ISO 5801:2007(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.
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 5801 was prepared by Technical Committee ISO/TC 117, Industrial fans.
This second edition cancels and replaces the first edition (ISO 5801:1997), which has been technically revised.

ISO 5801:2007(E)
Introduction
This International Standard is the result of almost 30 years of discussion, comparative testing and detailed
analyses by leading specialists from the fan industry and research organizations throughout the world.
It was demonstrated many years ago that the codes for fan performance testing established in different
countries do not always lead to the same results.
The need for an International Standard has been evident for some time and Technical Committee ISO/TC 117
started its work in 1963. Important progress has been achieved over the years and, although the International
Standard itself was not yet published, the successive revisions of various national standards led to much
better agreement among them.
It has now become possible to complete this International Standard by agreement on certain essential points.
It must be borne in mind that the test equipment, especially for large fans, is very expensive and it was
necessary to include in this International Standard many setups from various national codes in order to
authorize their future use. This explains the sheer volume of this document.
Essential features of this International Standard are as follows:
a) Categories of installation
Since the connection of a duct to a fan outlet and/or inlet modifies its performance, it has been agreed that
four standard installation categories should be recognized (see 18.2).
A fan adaptable to more than one installation category will have more than one standardized performance
characteristic. Users should select the installation category closest to their application.
b) Common parts
The differences obtained by testing the same fan according to various test codes depend chiefly on the flow
pattern at the fan outlet and, while often minor, can be of substantial significance. There is general agreement
that it is essential that all standardized test airways to be used with fans have portions in common adjacent to
the fan inlet and/or outlet sufficient to ensure consistent determination of fan pressure.
Geometric variations of these common segments are strictly limited.
However, conventional agreement has been achieved for some particular situations:
1) For fans where the outlet swirl is less than 15°, i.e. centrifugal, cross-flow or vane-axial fans, it is
possible to use a simplified outlet duct without straightener when discharging to the atmosphere or to
a measuring chamber. If there is any doubt about the degree of swirl, then a test should be
performed to establish how much is present.
2) For large fans (outlet diameter exceeding 800 mm), it may be difficult to carry out the tests with
standardized common airways at the outlet including a straightener. In this case, by mutual
agreement between the parties concerned, the fan performance may be measured using a duct of
length 3D on the outlet side. Results obtained in this way may differ to some extent from those
obtained using the normal category D installation, especially if the fan produces a large swirl.
Establishment of a possible value of differences, is still a subject of research.
viii © ISO 2007 – All rights reserved

ISO 5801:2007(E)
c) Calculations
Fan pressure is defined as the difference between the stagnation pressure at the outlet of the fan and the
stagnation pressure at the inlet of the fan. The compressibility of air must be taken into account when high
accuracy is required. However, simplified methods may be used when the reference Mach number does not
exceed 0,15.
A method for calculating the stagnation pressure and the fluid or static pressure in a reference section of the
fan, which stemmed from the work of the ad hoc group of Subcommittee 1 of ISO/TC 117, is given in Annex C.
Three methods are proposed for calculation of the fan power output and efficiency. All three methods give
very similar results (difference of a few parts per thousand for pressure ratios equal to 1,3).
d) Flow rate measurement
Determination of flow rate has been completely separated from the determination of fan pressure. A number
of standardized methods may be used.

INTERNATIONAL STANDARD ISO 5801:2007(E)

Industrial fans — Performance testing using standardized
airways
1 Scope
This International Standard deals with the determination of the performance of industrial fans of all types
except those designed solely for air circulation, e.g. ceiling fans and table fans.
Estimates of uncertainty of measurement are provided and rules for the conversion, within specified limits, of
test results for changes in speed, gas handled and, in the case of model tests, size, are given.
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 3966, Measurement of fluid flow in closed conduits — Velocity area method using Pitot static tubes
ISO 5167-1, Measurement of fluid flow by means of pressure differential devices inserted in circular cross-
section conduits running full — Part 1: General principles and requirements
ISO 5168, Measurement of fluid flow — Procedures for the evaluation of uncertainties
ISO 5221, Air distribution and air diffusion — Rules to methods of measuring air flow rate in an air handling
duct
IEC 60034-2:1972, Rotating electrical machines — Part 2: Methods for determining losses and efficiency of
rotating electrical machinery from tests (excluding machines for traction vehicles)
IEC 60051-2, Direct acting indicating analogue electrical measuring instruments and their accessories —
Part 2: Special requirements for ammeters and voltmeters
IEC 60051-3, Direct acting indicating analogue electrical measuring instruments and their accessories —
Part 3: Special requirements for wattmeters and varmeters
IEC 60051-4, Direct acting indicating analogue electrical measuring instruments and their accessories —
Part 4: Special requirements for frequency meters
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 5168 and the following apply.
NOTE All the symbols used in this International Standard are listed with their units in Clause 4.
ISO 5801:2007(E)
3.1
area of the conduit section
A
x
area of the conduit at section x
3.2
fan inlet area
A
surface plane bounded by the upstream extremity of the air-moving device
NOTE Fan inlet area is, by convention, taken as the gross area in the inlet plane inside the casing.
3.3
fan outlet area
A
surface plane bounded by the downstream extremity of the air-moving device
NOTE Fan outlet area is, by convention, taken as the gross area in the outlet plane inside the casing.
3.4
temperature
T
air or fluid temperature measured by a temperature sensor
NOTE Temperature is expressed in degrees Celsius.
3.5
absolute temperature
Q
thermodynamic temperature
Θ = T + 273,15
NOTE In this document, Q represents the absolute temperature in kelvin and T the temperature in degrees Celsius.
3.6
specific gas constant
R
for an ideal dry gas, the equation of state is written
p
= RΘ
ρ
−1 −1
NOTE For dry air, R = 287 J·kg ·K .
3.7
isentropic exponent
k
for an ideal gas and an isentropic process
c
p
κ==γ
c
V
p
= constant
κ
r
NOTE For atmospheric air, k = 1,4.
2 © ISO 2007 – All rights reserved

ISO 5801:2007(E)
3.8
specific heat capacity at constant pressure
c
p
for an ideal gas
k
cR=
p
k − 1
NOTE Specific heat capacity is normally expressed in joules per (kilogram kelvin).
3.9
specific heat capacity at constant volume
c
V
for an ideal gas
cR=
V
κ −1
NOTE Specific heat capacity is normally expressed in joules per (kilogram kelvin).
3.10
compressibility factor
Z
NOTE 1 For an ideal gas, Z = 1.
NOTE 2 For a real gas,
p
Z =
ρRΘ
where
Z is a function of the ratios p/p and Θ/Θ where:

c c
p is the critical pressure of the gas;
c
Θ is the critical temperature of the gas.
c
3.11
stagnation temperature at a point
Q
sg
absolute temperature which exists at an isentropic stagnation point for ideal gas flow without addition of
energy or heat
NOTE 1 The stagnation temperature is constant along an airway and, for an inlet duct, is equal to the absolute ambient
temperature in the test enclosure.
NOTE 2 Stagnation temperature is expressed in degrees Celsius.
NOTE 3 For Mach numbers less than 0,122 obtained for standard air with duct velocities less than 40 m/s, the
stagnation temperature is virtually the same as the total temperature.
3.12
fluid temperature at a point
static temperature at a point
Q
absolute temperature registered by a thermal sensor moving at the fluid velocity
ISO 5801:2007(E)
NOTE 1 For real gas flow
v
ΘΘ=−
sg
2c
p
where v is the fluid velocity, in metres per second, at a point.
NOTE 2 These temperatures are expressed in degrees Celsius.
NOTE 3 In a duct, when the velocity increases, the static temperature decr
...