SIST EN 13141-5:2021
(Main)Ventilation for buildings - Performance testing of components/products for residential ventilation - Part 5: Cowls, assisted cowls and roof outlet terminal devices
Ventilation for buildings - Performance testing of components/products for residential ventilation - Part 5: Cowls, assisted cowls and roof outlet terminal devices
This document specifies methods for measuring the aerodynamic and acoustic characteristics of cowls and roof outlets used in both natural and mechanical ventilation. Only those cowls and roof outlets fitted onto ducts which project above the roof surface are covered by the present standard.
Regarding the assisted cowls, only the fan assisted cowls are covered by the present standard, other types (such as injection assisted cowls) being too recent to be adequately considered for the time being.
The performance testing of the "assistance" provided by the auxiliary fan of an assisted cowl is excluded for the scope of this standard.
Lüftung von Gebäuden - Leistungsprüfung von Bauteilen/Produkten für die Lüftung von Wohnungen - Teil 5: Hauben und Dach-Fortluftdurchlässe
Diese Europäische Norm legt die Verfahren für die Messung der aerodynamischen und akustischen Kenngrößen von Hauben, Hauben mit Unterstützung und Dach-Fortluftdurchlässen fest, die in Anlagen für die natürliche und Hybridlüftung verwendet werden.
Nur Hauben, Hauben mit Unterstützung und Dach-Fortluftdurchlässe, die sowohl bei natürlicher als auch Hybridlüftung genutzt werden und die auf Luftleitungen eingebaut sind, die über die Dachoberfläche hinausragen, werden von diesem Dokument abgedeckt.
Von den Hauben mit Unterstützung sind hier nur ventilatorgestützte Hauben behandelt, da andere Arten (wie zum Beispiel Hauben mit Einblasunterstützung) noch zu neu sind, um auf angemessene Art berücksichtigt zu werden.
Dieses Dokument gilt nicht für Dach-Abluftgebläse, die nach EN 13141-4 geprüft werden.
Ventilation des bâtiments - Essais de performance des composants/produits pour la ventilation des logements - Partie 5 : Extracteurs statiques, extracteurs statiques assistés et dispositifs de sortie en toiture
Le présent document spécifie des méthodes pour mesurer les caractéristiques aérauliques et
acoustiques des extracteurs statiques, des extracteurs statiques motorisés et des dispositifs de sortie en
toiture utilisés en ventilation naturelle et en ventilation hybride.
Seuls les extracteurs statiques, les extracteurs statiques motorisés et les dispositifs de sorties en toiture
utilisés en ventilation naturelle et en ventilation hybride, et installés sur des conduits qui dépassent la
surface du toit sont couverts par le présent document.
En ce qui concerne les extracteurs statiques motorisés, seuls les extracteurs statiques motorisés
assistés d’un ventilateur sont couverts par le présent document, les autres catégories (par exemple,
extracteurs statiques motorisés à injection) sont trop récentes pour être valablement prises en compte
à ce jour.
Le présent document ne s’applique pas aux ventilateurs de rejet de toiture qui sont soumis à essai selon
l’EN 13141‐4.
Prezračevanje stavb - Preskušanje lastnosti sestavnih delov/izdelkov za prezračevanje stanovanjskih stavb - 5. del: Prezračevalne kape in odvodniki na strehah
General Information
Relations
Buy Standard
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 13141-5:2021
01-januar-2021
Nadomešča:
SIST EN 13141-5:2005
Prezračevanje stavb - Preskušanje lastnosti sestavnih delov/izdelkov za
prezračevanje stanovanjskih stavb - 5. del: Prezračevalne kape in odvodniki na
strehah
Ventilation for buildings - Performance testing of components/products for residential
ventilation - Part 5: Cowls, assisted cowls and roof outlet terminal devices
Lüftung von Gebäuden - Leistungsprüfung von Bauteilen/Produkten für die Lüftung von
Wohnungen - Teil 5: Hauben und Dach-Fortluftdurchlässe
Ventilation des bâtiments - Essais de performance des composants/produits pour la
ventilation des logements - Partie 5 : Extracteurs statiques, extracteurs statiques
assistés et dispositifs de sortie en toiture
Ta slovenski standard je istoveten z: EN 13141-5:2020
ICS:
91.140.30 Prezračevalni in klimatski Ventilation and air-
sistemi conditioning systems
SIST EN 13141-5:2021 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN 13141-5:2021
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SIST EN 13141-5:2021
EN 13141-5
EUROPEAN STANDARD
NORME EUROPÉENNE
October 2020
EUROPÄISCHE NORM
ICS 91.140.30 Supersedes EN 13141-5:2004
English Version
Ventilation for buildings - Performance testing of
components/products for residential ventilation - Part 5:
Cowls, assisted cowls and roof outlet terminal devices
Ventilation des bâtiments - Essais de performance des Lüftung von Gebäuden - Leistungsprüfung von
composants/produits pour la ventilation des Bauteilen/Produkten für die Lüftung von Wohnungen -
logements - Partie 5 : Extracteurs statiques, extracteurs Teil 5: Hauben und Dach-Fortluftdurchlässe
statiques assistés et dispositifs de sortie en toiture
This European Standard was approved by CEN on 8 June 2020.
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
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 13141-5:2020 E
worldwide for CEN national Members.
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SIST EN 13141-5:2021
EN 13141-5:2020 (E)
Contents Page
European foreword . 3
Introduction . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Symbols and abbreviated terms . 8
5 Performance testing of aerodynamic characteristics . 10
5.1 Test installation . 10
5.2 Pressure drop . 14
5.3 Suction effect of a cowl . 16
6 Performance testing of electrical characteristics. 20
6.1 Test installation . 20
6.2 Electrical power input . 20
7 Performance testing of acoustic characteristics of assisted cowl . 21
7.1 General . 21
7.2 Radiative sound power in outdoor space – L . 21
Wo
7.3 Sound power level in duct connections of the unit . 24
8 Test report . 25
8.1 General . 25
8.2 Aerodynamics characteristics . 26
8.3 Electricals characteristics . 26
8.4 Acoustics characteristics . 26
Annex A (normative) Derivation of values through the similitude law. 28
Bibliography . 29
2
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SIST EN 13141-5:2021
EN 13141-5:2020 (E)
European foreword
This document (EN 13141-5:2020) has been prepared 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 2021, and conflicting national standards shall be
withdrawn at the latest by April 2021.
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 13141-5:2004.
In addition to a number of editorial revisions, the following main changes have been made with respect
to EN 13141-5:2004:
— modification of the title and scope to add assisted cowls;
— exclusion from the scope of roof exhaust fans which are tested according to EN 13141-4;
— reorganization of the clause concerning the performance testing of aerodynamic characteristics
(now Clause 5) in order to have a more homogeneous organization and modification of all the figures
to make them more understandable;
— modification of the subclause concerning test installation for aerodynamic characteristics (now 5.1),
which includes the modification of all tests installation requirements as well as the distinction
between requirements that apply to all the tests and those that apply only to the wind tunnel use;
— modification of the volume flow rate correction (see 5.2 concerning pressure drop);
— modification of the formula used to characterize the suction effect of a cowl (see 5.3.2 concerning the
measurements and calculations);
— renaming of “Preliminary test” as “Least favourable horizontal wind approach angle for the suction
effect” (see 5.3.3.1);
— replacement of “a wind of sufficient speed to give easily measurable pressure differences” by “a wind
of 8 m/s” (see 5.3.3.1);
— removal of the two following measurements points: V = 0,5 m/s and 1,5 m/s (see 5.3.3.2);
— more precise definition of the three series of measurements to carry out (i.e. v = 0m/s,
duct
v = 4m/s and 0 m/s < v < 4 m/s) (see 5.3.3.3);
duct duct
— for additional testing (e.g. acoustics and aerodynamic) for fan assisted cowls, reference to
EN 13141-4 is replaced by reference to EN ISO 5801 and more developed information are given;
— addition of a test method for measuring the combined effect of natural wind and wind from the fan
assisted cowl;
— addition of a detailed clause concerning the test report;
— review of the entire document in order to make it more accessible regarding the changes made.
3
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SIST EN 13141-5:2021
EN 13141-5:2020 (E)
A list of all parts in the EN 13141 series, published under the general title Ventilation for buildings —
Performance testing of components/products for residential ventilation can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations 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.
4
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SIST EN 13141-5:2021
EN 13141-5:2020 (E)
Introduction
The position of this document in the field of standards for the mechanical building services is shown in
Figure 1.
Mechanical Building Services
Ventilation and air conditioning
Control systems Heating systems
systems
Mechanical and Design criteria for
Air terminal Air handling System
Ductwork natural residential the indoor Installation
devices units performance
ventilation environment
Components/product
s for residential Performance testing of Design and Performance testing
Simplified calculation
ventilation Required components/products dimensioning for and installation
methods for residential
and optional for residential residential ventilation checks for residential
ventilation systems
performance ventilation systems ventilation systems
characteristics
Part 1: Externally and internally mounted air transfer devices
Part 2: Exhaust and supply air terminal devices
Part 3: Range hoods for residential use without fan
Part 4: Fans used in residential ventilation systems
Part 5: Cowls, assisted cowls and roof outlet terminal devices
Part 6: Exhaust ventilation system packages used in a single dwelling
Part 7: Performance testing of a mechanical supply and exhaust
ventilation units (including heat recovery) for mechanical ventilation
systems intended for single family dwellings
5
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SIST EN 13141-5:2021
EN 13141-5:2020 (E)
Part 8: Performance testing of un-ducted mechanical supply and exhaust
ventilation units (including heat recovery) for mechanical ventilation
systems intended for a single room
Part 9: Externally mounted humidity controlled air transfer device
Part 10: Humidity controlled extract air terminal device
Part 11: Supply ventilation units
Figure 1 — Position of EN 13141-5 in the field of the mechanical building services
6
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SIST EN 13141-5:2021
EN 13141-5:2020 (E)
1 Scope
This document specifies methods for measuring:
— the aerodynamic characteristics of cowls, fan assisted cowls and roof outlets;
— the electrical and acoustic characteristics of fan assisted cowls.
This document is applicable to cowls, assisted cowls and roof outlets used in natural, hybrid or
mechanical ventilation and that are meant to be fitted onto ducts which project above the roof surface.
This document does not apply to:
— assisted cowls assisted by a device other than a fan (e.g. injection assisted cowls);
— roof exhaust fans (see EN 13141-4).
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.
EN 12792, Ventilation for buildings — Symbols, terminology and graphical symbols
EN ISO 5136, Acoustics — Determination of sound power radiated into a duct by fans and other air-moving
devices — In-duct method (ISO 5136)
EN ISO 5801:2017, Fans — Performance testing using standardized airways (ISO 5801:2017)
EN ISO 7235, Acoustics — Laboratory measurement procedures for ducted silencers and air-terminal
units — Insertion loss, flow noise and total pressure loss (ISO 7235)
EN ISO/IEC 17025:2017, General requirements for the competence of testing and calibration laboratories
(ISO/IEC 17025:2017)
ISO 13347-2, Industrial fans — Determination of fan sound power levels under standardized laboratory
conditions — Part 2: Reverberant room method
ISO 13347-3, Industrial fans — Determination of fan sound power levels under standardized laboratory
conditions — Part 3: Enveloping surface methods
ISO 13347-4, Industrial fans — Determination of fan sound power levels under standardized laboratory
conditions — Part 4: Sound intensity method
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 12792 and the following apply.
ISO and IEC maintain terminological databases for the use in standardization at the following addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO online browsing platform: available at https://www.iso.org/obp
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SIST EN 13141-5:2021
EN 13141-5:2020 (E)
3.1
cowl
exhaust air terminal device with or without moving component, intended to be fitted on top of a duct,
with aim, by creating negative pressure depending on the wind speed, to avoid reverse flow and to
increase the exhaust air flow rate in presence of wind
[SOURCE: EN 12792:2003, 92, modified – reformulation of the definition in a single sentence]
3.2
assisted cowl
cowl fitted with an auxiliary device using an energy source other than wind to compensate for lack of
suction effect
[SOURCE: EN 12792:2003, 46, modified – removal of “such as a fan and” and replacement of “pressure
difference” by “suction effect”]
3.3
fan assisted cowl
assisted cowl where the auxiliary device is a fan
3.4
roof outlet
exhaust air terminal device without moving component, intended to be fitted on top of a duct
4 Symbols and abbreviated terms
For the purposes of this document, the symbols listed in Table 1 apply.
No abbreviated terms are listed in this document.
Table 1 — Symbols
Symbol Quantity Unit
C(α,v ,v )
pressure factor —
tunnel duct
D duct diameter m
L duct length m
L sound power level dB
W
L A-weighted sound power level dB(A)
WA
L
radiated sound power in the outdoor space (including casing) dB
wo
p atmospheric pressure Pa
a
p dynamic pressure in the test duct Pa
d,duct
p
dynamic pressure in the wind tunnel Pa
d,tunnel
p static gauge pressure in the test duct Pa
s,duct
8
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SIST EN 13141-5:2021
EN 13141-5:2020 (E)
Symbol Quantity Unit
p average static gauge pressure in the wind tunnel Pa
s,tunnel
P electrical power input W
E
3
q corrected volume flow rate m /s
v,cor
3
q
measured volume flow rate m /s
v,meas
r coefficient of determination of the regression line —
v mean air speed in the test duct m/s
duct
v air speed in the wind tunnel (wind speed) m/s
tunnel
α vertical wind approach angle degree
β horizontal wind approach angle degree
∆p pressure drop Pa
∆p difference between the total pressure in the test duct Pa
cowl
approaching the cowl under test and the static pressure in the
tunnel
∆p pressure drop due to friction in the test duct between the Pa
f,duct
pressure tapping and the bottom of the cowl
ζ pressure drop coefficient —
θ temperature of the air in the test duct °C
a
3 3
ρ
density of 1 204 kg/m corresponding to the air under kg/m
ref
standard conditions (20 °C, 101 325 Pa)
3
ρ
air density in the wind tunnel kg/m
tunnel
9
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SIST EN 13141-5:2021
EN 13141-5:2020 (E)
5 Performance testing of aerodynamic characteristics
5.1 Test installation
5.1.1 General
The aerodynamic characteristics of the air terminal device shall be tested in a test installation as shown
in Figure 2. For pressure drop (see 5.2) and mechanical tests without wind (see 5.3.3.4), the wind tunnel
is not necessary. The test installation shall comprise the following:
— an adjustable air supply incorporating a flow rate measuring device with an uncertainty in
accordance with 5.1.3 (e.g. orifice plate or venturi tube conforming with EN ISO 5167-1, or other flow
meter, such as a rotameter). The air supply passes via an airtight duct;
— means to stabilize the flow and pressure upstream the test duct, e.g. airtight plenum chamber (with
a side length at least 4 times the diameter of the test duct) containing flow settling screens at the air
entry zone and a smooth outlet;
— an airtight test circular duct (test duct) to carry the air terminal device under test, of diameter D
chosen according to EN 1506:2007, Table 1 to suit the air terminal device, and with a minimum
length as given by Formula (1).
LD6⋅
(1)
In case of assisted cowl, the test installation shown in Figure 2 shall be in accordance with Category C
installation as defined in EN ISO 5801:2017, 11.5, ducted inlet and free outlet.
The test shall be performed according to the intended use of the air terminal device.
The pressure measurement point in the test duct (Figure 2, Key 6) shall be located 3D upstream of the air
terminal device (D being the diameter of the test duct).
In order to reach high pressure values, a device to increase the pressure drop in the test duct (e.g. iris)
may be used (Figure 2, Key 15). In order to reach low pressure values, a fan with flow rate adjusted device
may be used (Figure 2, Key 12).
5.1.2 Wind tunnel
Static pressure shall be measured using two pressure probes (or more) located in the working section
(see Figure 2, section A-A). The pressure probes should be situated far enough from the cowl to avoid
side effects, at each side of the wind cross section. The reference pressure is the average of the two (or
more) static pressures.
The wind speed measurement shall be made at 1 m upstream from the air terminal device and in front of
it.
During the suction effect tests, the volume flow rate in the test duct shall not exceed 2 % of the volume
flow rate from the wind tunnel.
If the tests are carried out in a confined working section as shown in Figure 2, then the cross-section area
of the working section (in projection along the axis of the wind tunnel) shall be at least 20 times the cross
section area of the cowl and duct in the wind.
If the tests are carried out using an open jet type wind tunnel, then the cross section area of the jet shall
be at least 10 times the cross-section area (in projection along the axis of the wind tunnel) of the cowl
and duct in the wind.
In order to avoid side effects from the wind tunnel, the test duct part located in the working section (see
Figure 2, section A-A) of the wind tunnel (i.e. the duct part blown by the wind) shall be at least 5 times
the duct diameter.
10
=
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SIST EN 13141-5:2021
EN 13141-5:2020 (E)
The turbulence intensity of the air inside the wind tunnel upwards from the air terminal device shall be
less than 5 %.
To simulate varying vertical wind approach angles, it shall be possible to rotate the cowl and test duct
about an axis perpendicular to the wind tunnel axis and test duct axis, the cowl remaining near the same
test point located at the wind tunnel axis to remain in the homogenous wind stream (see Figure 3).
NOTE 1 The test point represents the position of the cowl during the test.
In addition, where the test duct axis is perpendicular to the wind tunnel axis, it shall be possible to rotate
the cowl about the test duct axis to simulate varying horizontal wind approach angles (see Figure 4).
When the mounting parts which support the duct and the cowl are in the wind, they should have limited
influence from an aerodynamic point of view.
NOTE 2 No practical rules can be formulated in this document on how to limit the influence of mounting parts.
11
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SIST EN 13141-5:2021
EN 13141-5:2020 (E)
Key
1 wind tunnel 9 plenum chamber
2 location for wind speed measurement 10 air flow measuring device
3 air terminal device 11 flow straightener
4 location for static pressure measurement 12 fan with flow rate adjusting device
5 test duct 13 air supply
6 location for static pressure measurement 14 location for static pressure measurement at the
bottom of the device
7 location of sealing for preliminary suction test 15 pressure regulation device
8 flow setting screens
Figure 2 — Typical example of a test installation
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SIST EN 13141-5:2021
EN 13141-5:2020 (E)
Key
1 axis of wind tunnel 5 test duct
2 wind tunnel 6 axis of test duct
3 location for wind speed measurement 7 axis of rotation
4 homogeneous part of the wind flow
Figure 3 — Rotation to simulate varying vertical wind approach
Key
1 axis of wind tunnel 4 axis of test duct (axis of rotation)
2 wind tunnel 5 test duct
3 location for wind speed measurement
Figure 4 — Rotation to simulate varying horizontal wind approach
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SIST EN 13141-5:2021
EN 13141-5:2020 (E)
5.1.3 Maximum permissible measurement error
The maximum permissible measurement error is given in Table 2 for each quantity.
Table 2 — Maximum permissible measurement error
Quantity Maximum permissible Unit
measurement error
Wind speed ≤ 0,05 m/s
3
Air flow ≤ 0,000 3 + 0,03 × measured value m /s
Pressure ≤ 0,5 + 0,03 × measured value Pa
5.2 Pressure drop
5.2.1 General
When testing a fan assisted cowl, the auxiliary fan shall be switched-off and its blades shall not be blocked.
5.2.2 Measurements and calculations
The parameters to be measured are:
— the volume flow rate in the test duct;
— the static pressure difference between the test duct (Figure 2, key 6) and the room in which the test
is carried out (static gauge pressure);
— the atmospheric pressure;
— the temperature of the air in the test duct.
The measured volume flow rate shall be corrected if the temperature or barometric pressure are different
from the standard conditions (20 °C and 101 325 Pa), using Formula (2).
0,5 0,5
p
293,15
a
qq= ⋅⋅ (2)
v,cor v,meas
101 325 273,15 + θ
a
where
3
q is the corrected volume flow rate, in m /s;
v,cor
3
q is the measured volume flow rate, in m /s;
v,meas
p is the atmospheric pressure, in Pa;
a
θ is the temperature of the air in the test duct, in °C.
a
For each measurement, the dynamic pressure in the test duct, p , shall be calculated using
d,duct
Formula (3).
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SIST EN 13141-5:2021
EN 13141-5:2020 (E)
1
2
pv⋅ ρ ⋅ (3)
d,duct ref duct
2
where
p is the dynamic pressure in the test duct, in Pa;
d,duct
3 3
ρ is the air density, in kg/m , in this case ρ = 1 204 kg/m which corresponds to the air
ref ref
under standard condition (20°C, 101 325 Pa);
v is the mean air speed in the test duct, in m/s.
duct
with
4 ⋅ q
v,cor
v = (4)
duct
2
π ⋅ D
where
3
q is the corrected volume flow rate, in m /s;
v,cor
D is the test duct diameter, in m.
For each measurement, the pressure drop shall be calculated using Formula (5).
p p + p (5)
s,duct d,duct
where
Δp is the pressure drop, in Pa;
p is the static gauge pressure in the test duct, in Pa;
s,duct
p is the dynamic pressure in the test duct, in Pa.
d,duct
NOTE In this calculation method of the pressure drop, it is assumed that the thermal gravity effect (stack effect
in the test duct) is negligible.
5.2.3 Test method
The test shall be carried out by varying the flow rate through the air terminal device to give static pressure
differences of 5 Pa, 10 Pa, 20 Pa and 50 Pa with a tolerance of ± 1 Pa, between the test duct and the room
in which the test is carried out.
5.2.4 Analysis of results
It shall be checked whether the pressure drop can be expressed with a single pressure drop coefficient,
ζ, as given by Formula (6).
∆=pp ζ⋅ (6)
d,duct
To that effect, a linear regression line intercepting the point (p = 0; ΔP = 0) shall be searched through
d,duct
the obtained couples (p ; Δp) using an appropriate least squares method. For the regression line and
d,duct
2
Formula (6) to be valid in terms of this document, the coefficient of determination (r ) of the regression
line shall be ≥ 0,98. With a valid regression line, the pressure drop coefficient, ζ, equals the slope of the
line.
15
∆=
=
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SIST EN 13141-5:2021
EN 13141-5:2020 (E)
5.3 Suction effect of a cowl
5.3.1 General
In use, the cowl performance will combine both the suction effect due to the wind and the pressure drop
due to the air flowing through the cowl. The tests methods described in 5.3.3.2 and 5.3.3.3 measure the
performance of the cowl when these two effects are combined.
The test method described in 5.3.3.4 is used to characterize the effect of the fan for fan assisted cowls in
the absence of wind.
In use, when the auxiliary fan of an assisted cowl is switched on, the assisted cowl performance combines
both the suction effect due to the wind and due to the fan. The test described in 5.3.3.5 characterizes the
performance of the assisted cowl when these two effects are combined.
When testing a fan assisted cowl for tests without fan, the auxiliary fan shall be switched off and its blades
shall not be blocked.
The electric supply of the assisted cowl shall respond to the manufacturer specifications.
All tests shall be performed using the same cowl as in 5.2.
5.3.2 Measurements and calculations
The following parameters shall be measured:
— wind speed;
— air flow in test duct;
— static gauge pressure in test duct (Figure 2, Key 6);
— static gauge pressure in wind tunnel (Figure 2, Key 4);
— horizontal and vertical wind approach angles (see Figure 3 and Figure 4);
— atmospheric pressure;
— air temperature in the test duct.
The dynamic pressure of the wind, p , is calculated with the air speed measured at point 2 (see
d,tunnel
Figure 2) using Formula (7).
1
2
pv⋅ ρ ⋅ (7)
d,tunnel tunnel tunnel
2
where
p is the dynamic pressure in the wind tunnel, in Pa;
d,tunnel
3
ρ
is the air density in the wind tunnel, in kg/m ;
tunnel
v is the wind speed, in m/s.
tunnel
The difference between the total pressure in the test duct approaching the cowl and the static pressure
in the wind tunnel is calculated using Formula (8).
16
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SIST EN 13141-5:2021
EN 13141-5:2020 (E)
∆−pp= ∆p + p − p (8)
cowl d,duct f,duct s,,duct s tunnel
where
Δp is the difference between the total pressure in the test duct approaching the cowl under
cowl
test and the static pressure in the tunnel, in Pa;
Δp is the pressure drop due to friction in th
...
SLOVENSKI STANDARD
SIST EN 13141-5:2021
01-januar-2021
Nadomešča:
SIST EN 13141-5:2005
Prezračevanje stavb - Preskušanje lastnosti sestavnih delov/izdelkov za
prezračevanje stanovanjskih stavb - 5. del: Prezračevalne kape in strešni iztoki na
strehah
Ventilation for buildings - Performance testing of components/products for residential
ventilation - Part 5: Cowls, assisted cowls and roof outlet terminal devices
Lüftung von Gebäuden - Leistungsprüfung von Bauteilen/Produkten für die Lüftung von
Wohnungen - Teil 5: Hauben und Dach-Fortluftdurchlässe
Ventilation des bâtiments - Essais de performance des composants/produits pour la
ventilation des logements - Partie 5 : Extracteurs statiques, extracteurs statiques
assistés et dispositifs de sortie en toiture
Ta slovenski standard je istoveten z: EN 13141-5:2020
ICS:
91.140.30 Prezračevalni in klimatski Ventilation and air-
sistemi conditioning systems
SIST EN 13141-5:2021 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN 13141-5:2021
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SIST EN 13141-5:2021
EN 13141-5
EUROPEAN STANDARD
NORME EUROPÉENNE
October 2020
EUROPÄISCHE NORM
ICS 91.140.30 Supersedes EN 13141-5:2004
English Version
Ventilation for buildings - Performance testing of
components/products for residential ventilation - Part 5:
Cowls, assisted cowls and roof outlet terminal devices
Ventilation des bâtiments - Essais de performance des Lüftung von Gebäuden - Leistungsprüfung von
composants/produits pour la ventilation des Bauteilen/Produkten für die Lüftung von Wohnungen -
logements - Partie 5 : Extracteurs statiques, extracteurs Teil 5: Hauben und Dach-Fortluftdurchlässe
statiques assistés et dispositifs de sortie en toiture
This European Standard was approved by CEN on 8 June 2020.
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
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 13141-5:2020 E
worldwide for CEN national Members.
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SIST EN 13141-5:2021
EN 13141-5:2020 (E)
Contents Page
European foreword . 3
Introduction . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Symbols and abbreviated terms . 8
5 Performance testing of aerodynamic characteristics . 10
5.1 Test installation . 10
5.2 Pressure drop . 14
5.3 Suction effect of a cowl . 16
6 Performance testing of electrical characteristics. 20
6.1 Test installation . 20
6.2 Electrical power input . 20
7 Performance testing of acoustic characteristics of assisted cowl . 21
7.1 General . 21
7.2 Radiative sound power in outdoor space – L . 21
Wo
7.3 Sound power level in duct connections of the unit . 24
8 Test report . 25
8.1 General . 25
8.2 Aerodynamics characteristics . 26
8.3 Electricals characteristics . 26
8.4 Acoustics characteristics . 26
Annex A (normative) Derivation of values through the similitude law. 28
Bibliography . 29
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SIST EN 13141-5:2021
EN 13141-5:2020 (E)
European foreword
This document (EN 13141-5:2020) has been prepared 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 2021, and conflicting national standards shall be
withdrawn at the latest by April 2021.
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 13141-5:2004.
In addition to a number of editorial revisions, the following main changes have been made with respect
to EN 13141-5:2004:
— modification of the title and scope to add assisted cowls;
— exclusion from the scope of roof exhaust fans which are tested according to EN 13141-4;
— reorganization of the clause concerning the performance testing of aerodynamic characteristics
(now Clause 5) in order to have a more homogeneous organization and modification of all the figures
to make them more understandable;
— modification of the subclause concerning test installation for aerodynamic characteristics (now 5.1),
which includes the modification of all tests installation requirements as well as the distinction
between requirements that apply to all the tests and those that apply only to the wind tunnel use;
— modification of the volume flow rate correction (see 5.2 concerning pressure drop);
— modification of the formula used to characterize the suction effect of a cowl (see 5.3.2 concerning the
measurements and calculations);
— renaming of “Preliminary test” as “Least favourable horizontal wind approach angle for the suction
effect” (see 5.3.3.1);
— replacement of “a wind of sufficient speed to give easily measurable pressure differences” by “a wind
of 8 m/s” (see 5.3.3.1);
— removal of the two following measurements points: V = 0,5 m/s and 1,5 m/s (see 5.3.3.2);
— more precise definition of the three series of measurements to carry out (i.e. v = 0m/s,
duct
v = 4m/s and 0 m/s < v < 4 m/s) (see 5.3.3.3);
duct duct
— for additional testing (e.g. acoustics and aerodynamic) for fan assisted cowls, reference to
EN 13141-4 is replaced by reference to EN ISO 5801 and more developed information are given;
— addition of a test method for measuring the combined effect of natural wind and wind from the fan
assisted cowl;
— addition of a detailed clause concerning the test report;
— review of the entire document in order to make it more accessible regarding the changes made.
3
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SIST EN 13141-5:2021
EN 13141-5:2020 (E)
A list of all parts in the EN 13141 series, published under the general title Ventilation for buildings —
Performance testing of components/products for residential ventilation can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations 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.
4
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SIST EN 13141-5:2021
EN 13141-5:2020 (E)
Introduction
The position of this document in the field of standards for the mechanical building services is shown in
Figure 1.
Mechanical Building Services
Ventilation and air conditioning
Control systems Heating systems
systems
Mechanical and Design criteria for
Air terminal Air handling System
Ductwork natural residential the indoor Installation
devices units performance
ventilation environment
Components/product
s for residential Performance testing of Design and Performance testing
Simplified calculation
ventilation Required components/products dimensioning for and installation
methods for residential
and optional for residential residential ventilation checks for residential
ventilation systems
performance ventilation systems ventilation systems
characteristics
Part 1: Externally and internally mounted air transfer devices
Part 2: Exhaust and supply air terminal devices
Part 3: Range hoods for residential use without fan
Part 4: Fans used in residential ventilation systems
Part 5: Cowls, assisted cowls and roof outlet terminal devices
Part 6: Exhaust ventilation system packages used in a single dwelling
Part 7: Performance testing of a mechanical supply and exhaust
ventilation units (including heat recovery) for mechanical ventilation
systems intended for single family dwellings
5
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SIST EN 13141-5:2021
EN 13141-5:2020 (E)
Part 8: Performance testing of un-ducted mechanical supply and exhaust
ventilation units (including heat recovery) for mechanical ventilation
systems intended for a single room
Part 9: Externally mounted humidity controlled air transfer device
Part 10: Humidity controlled extract air terminal device
Part 11: Supply ventilation units
Figure 1 — Position of EN 13141-5 in the field of the mechanical building services
6
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SIST EN 13141-5:2021
EN 13141-5:2020 (E)
1 Scope
This document specifies methods for measuring:
— the aerodynamic characteristics of cowls, fan assisted cowls and roof outlets;
— the electrical and acoustic characteristics of fan assisted cowls.
This document is applicable to cowls, assisted cowls and roof outlets used in natural, hybrid or
mechanical ventilation and that are meant to be fitted onto ducts which project above the roof surface.
This document does not apply to:
— assisted cowls assisted by a device other than a fan (e.g. injection assisted cowls);
— roof exhaust fans (see EN 13141-4).
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.
EN 12792, Ventilation for buildings — Symbols, terminology and graphical symbols
EN ISO 5136, Acoustics — Determination of sound power radiated into a duct by fans and other air-moving
devices — In-duct method (ISO 5136)
EN ISO 5801:2017, Fans — Performance testing using standardized airways (ISO 5801:2017)
EN ISO 7235, Acoustics — Laboratory measurement procedures for ducted silencers and air-terminal
units — Insertion loss, flow noise and total pressure loss (ISO 7235)
EN ISO/IEC 17025:2017, General requirements for the competence of testing and calibration laboratories
(ISO/IEC 17025:2017)
ISO 13347-2, Industrial fans — Determination of fan sound power levels under standardized laboratory
conditions — Part 2: Reverberant room method
ISO 13347-3, Industrial fans — Determination of fan sound power levels under standardized laboratory
conditions — Part 3: Enveloping surface methods
ISO 13347-4, Industrial fans — Determination of fan sound power levels under standardized laboratory
conditions — Part 4: Sound intensity method
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 12792 and the following apply.
ISO and IEC maintain terminological databases for the use in standardization at the following addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO online browsing platform: available at https://www.iso.org/obp
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SIST EN 13141-5:2021
EN 13141-5:2020 (E)
3.1
cowl
exhaust air terminal device with or without moving component, intended to be fitted on top of a duct,
with aim, by creating negative pressure depending on the wind speed, to avoid reverse flow and to
increase the exhaust air flow rate in presence of wind
[SOURCE: EN 12792:2003, 92, modified – reformulation of the definition in a single sentence]
3.2
assisted cowl
cowl fitted with an auxiliary device using an energy source other than wind to compensate for lack of
suction effect
[SOURCE: EN 12792:2003, 46, modified – removal of “such as a fan and” and replacement of “pressure
difference” by “suction effect”]
3.3
fan assisted cowl
assisted cowl where the auxiliary device is a fan
3.4
roof outlet
exhaust air terminal device without moving component, intended to be fitted on top of a duct
4 Symbols and abbreviated terms
For the purposes of this document, the symbols listed in Table 1 apply.
No abbreviated terms are listed in this document.
Table 1 — Symbols
Symbol Quantity Unit
C(α,v ,v )
pressure factor —
tunnel duct
D duct diameter m
L duct length m
L sound power level dB
W
L A-weighted sound power level dB(A)
WA
L
radiated sound power in the outdoor space (including casing) dB
wo
p atmospheric pressure Pa
a
p dynamic pressure in the test duct Pa
d,duct
p
dynamic pressure in the wind tunnel Pa
d,tunnel
p static gauge pressure in the test duct Pa
s,duct
8
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SIST EN 13141-5:2021
EN 13141-5:2020 (E)
Symbol Quantity Unit
p average static gauge pressure in the wind tunnel Pa
s,tunnel
P electrical power input W
E
3
q corrected volume flow rate m /s
v,cor
3
q
measured volume flow rate m /s
v,meas
r coefficient of determination of the regression line —
v mean air speed in the test duct m/s
duct
v air speed in the wind tunnel (wind speed) m/s
tunnel
α vertical wind approach angle degree
β horizontal wind approach angle degree
∆p pressure drop Pa
∆p difference between the total pressure in the test duct Pa
cowl
approaching the cowl under test and the static pressure in the
tunnel
∆p pressure drop due to friction in the test duct between the Pa
f,duct
pressure tapping and the bottom of the cowl
ζ pressure drop coefficient —
θ temperature of the air in the test duct °C
a
3 3
ρ
density of 1 204 kg/m corresponding to the air under kg/m
ref
standard conditions (20 °C, 101 325 Pa)
3
ρ
air density in the wind tunnel kg/m
tunnel
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SIST EN 13141-5:2021
EN 13141-5:2020 (E)
5 Performance testing of aerodynamic characteristics
5.1 Test installation
5.1.1 General
The aerodynamic characteristics of the air terminal device shall be tested in a test installation as shown
in Figure 2. For pressure drop (see 5.2) and mechanical tests without wind (see 5.3.3.4), the wind tunnel
is not necessary. The test installation shall comprise the following:
— an adjustable air supply incorporating a flow rate measuring device with an uncertainty in
accordance with 5.1.3 (e.g. orifice plate or venturi tube conforming with EN ISO 5167-1, or other flow
meter, such as a rotameter). The air supply passes via an airtight duct;
— means to stabilize the flow and pressure upstream the test duct, e.g. airtight plenum chamber (with
a side length at least 4 times the diameter of the test duct) containing flow settling screens at the air
entry zone and a smooth outlet;
— an airtight test circular duct (test duct) to carry the air terminal device under test, of diameter D
chosen according to EN 1506:2007, Table 1 to suit the air terminal device, and with a minimum
length as given by Formula (1).
LD6⋅
(1)
In case of assisted cowl, the test installation shown in Figure 2 shall be in accordance with Category C
installation as defined in EN ISO 5801:2017, 11.5, ducted inlet and free outlet.
The test shall be performed according to the intended use of the air terminal device.
The pressure measurement point in the test duct (Figure 2, Key 6) shall be located 3D upstream of the air
terminal device (D being the diameter of the test duct).
In order to reach high pressure values, a device to increase the pressure drop in the test duct (e.g. iris)
may be used (Figure 2, Key 15). In order to reach low pressure values, a fan with flow rate adjusted device
may be used (Figure 2, Key 12).
5.1.2 Wind tunnel
Static pressure shall be measured using two pressure probes (or more) located in the working section
(see Figure 2, section A-A). The pressure probes should be situated far enough from the cowl to avoid
side effects, at each side of the wind cross section. The reference pressure is the average of the two (or
more) static pressures.
The wind speed measurement shall be made at 1 m upstream from the air terminal device and in front of
it.
During the suction effect tests, the volume flow rate in the test duct shall not exceed 2 % of the volume
flow rate from the wind tunnel.
If the tests are carried out in a confined working section as shown in Figure 2, then the cross-section area
of the working section (in projection along the axis of the wind tunnel) shall be at least 20 times the cross
section area of the cowl and duct in the wind.
If the tests are carried out using an open jet type wind tunnel, then the cross section area of the jet shall
be at least 10 times the cross-section area (in projection along the axis of the wind tunnel) of the cowl
and duct in the wind.
In order to avoid side effects from the wind tunnel, the test duct part located in the working section (see
Figure 2, section A-A) of the wind tunnel (i.e. the duct part blown by the wind) shall be at least 5 times
the duct diameter.
10
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EN 13141-5:2020 (E)
The turbulence intensity of the air inside the wind tunnel upwards from the air terminal device shall be
less than 5 %.
To simulate varying vertical wind approach angles, it shall be possible to rotate the cowl and test duct
about an axis perpendicular to the wind tunnel axis and test duct axis, the cowl remaining near the same
test point located at the wind tunnel axis to remain in the homogenous wind stream (see Figure 3).
NOTE 1 The test point represents the position of the cowl during the test.
In addition, where the test duct axis is perpendicular to the wind tunnel axis, it shall be possible to rotate
the cowl about the test duct axis to simulate varying horizontal wind approach angles (see Figure 4).
When the mounting parts which support the duct and the cowl are in the wind, they should have limited
influence from an aerodynamic point of view.
NOTE 2 No practical rules can be formulated in this document on how to limit the influence of mounting parts.
11
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Key
1 wind tunnel 9 plenum chamber
2 location for wind speed measurement 10 air flow measuring device
3 air terminal device 11 flow straightener
4 location for static pressure measurement 12 fan with flow rate adjusting device
5 test duct 13 air supply
6 location for static pressure measurement 14 location for static pressure measurement at the
bottom of the device
7 location of sealing for preliminary suction test 15 pressure regulation device
8 flow setting screens
Figure 2 — Typical example of a test installation
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SIST EN 13141-5:2021
EN 13141-5:2020 (E)
Key
1 axis of wind tunnel 5 test duct
2 wind tunnel 6 axis of test duct
3 location for wind speed measurement 7 axis of rotation
4 homogeneous part of the wind flow
Figure 3 — Rotation to simulate varying vertical wind approach
Key
1 axis of wind tunnel 4 axis of test duct (axis of rotation)
2 wind tunnel 5 test duct
3 location for wind speed measurement
Figure 4 — Rotation to simulate varying horizontal wind approach
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EN 13141-5:2020 (E)
5.1.3 Maximum permissible measurement error
The maximum permissible measurement error is given in Table 2 for each quantity.
Table 2 — Maximum permissible measurement error
Quantity Maximum permissible Unit
measurement error
Wind speed ≤ 0,05 m/s
3
Air flow ≤ 0,000 3 + 0,03 × measured value m /s
Pressure ≤ 0,5 + 0,03 × measured value Pa
5.2 Pressure drop
5.2.1 General
When testing a fan assisted cowl, the auxiliary fan shall be switched-off and its blades shall not be blocked.
5.2.2 Measurements and calculations
The parameters to be measured are:
— the volume flow rate in the test duct;
— the static pressure difference between the test duct (Figure 2, key 6) and the room in which the test
is carried out (static gauge pressure);
— the atmospheric pressure;
— the temperature of the air in the test duct.
The measured volume flow rate shall be corrected if the temperature or barometric pressure are different
from the standard conditions (20 °C and 101 325 Pa), using Formula (2).
0,5 0,5
p
293,15
a
qq= ⋅⋅ (2)
v,cor v,meas
101 325 273,15 + θ
a
where
3
q is the corrected volume flow rate, in m /s;
v,cor
3
q is the measured volume flow rate, in m /s;
v,meas
p is the atmospheric pressure, in Pa;
a
θ is the temperature of the air in the test duct, in °C.
a
For each measurement, the dynamic pressure in the test duct, p , shall be calculated using
d,duct
Formula (3).
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EN 13141-5:2020 (E)
1
2
pv⋅ ρ ⋅ (3)
d,duct ref duct
2
where
p is the dynamic pressure in the test duct, in Pa;
d,duct
3 3
ρ is the air density, in kg/m , in this case ρ = 1 204 kg/m which corresponds to the air
ref ref
under standard condition (20°C, 101 325 Pa);
v is the mean air speed in the test duct, in m/s.
duct
with
4 ⋅ q
v,cor
v = (4)
duct
2
π ⋅ D
where
3
q is the corrected volume flow rate, in m /s;
v,cor
D is the test duct diameter, in m.
For each measurement, the pressure drop shall be calculated using Formula (5).
p p + p (5)
s,duct d,duct
where
Δp is the pressure drop, in Pa;
p is the static gauge pressure in the test duct, in Pa;
s,duct
p is the dynamic pressure in the test duct, in Pa.
d,duct
NOTE In this calculation method of the pressure drop, it is assumed that the thermal gravity effect (stack effect
in the test duct) is negligible.
5.2.3 Test method
The test shall be carried out by varying the flow rate through the air terminal device to give static pressure
differences of 5 Pa, 10 Pa, 20 Pa and 50 Pa with a tolerance of ± 1 Pa, between the test duct and the room
in which the test is carried out.
5.2.4 Analysis of results
It shall be checked whether the pressure drop can be expressed with a single pressure drop coefficient,
ζ, as given by Formula (6).
∆=pp ζ⋅ (6)
d,duct
To that effect, a linear regression line intercepting the point (p = 0; ΔP = 0) shall be searched through
d,duct
the obtained couples (p ; Δp) using an appropriate least squares method. For the regression line and
d,duct
2
Formula (6) to be valid in terms of this document, the coefficient of determination (r ) of the regression
line shall be ≥ 0,98. With a valid regression line, the pressure drop coefficient, ζ, equals the slope of the
line.
15
∆=
=
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EN 13141-5:2020 (E)
5.3 Suction effect of a cowl
5.3.1 General
In use, the cowl performance will combine both the suction effect due to the wind and the pressure drop
due to the air flowing through the cowl. The tests methods described in 5.3.3.2 and 5.3.3.3 measure the
performance of the cowl when these two effects are combined.
The test method described in 5.3.3.4 is used to characterize the effect of the fan for fan assisted cowls in
the absence of wind.
In use, when the auxiliary fan of an assisted cowl is switched on, the assisted cowl performance combines
both the suction effect due to the wind and due to the fan. The test described in 5.3.3.5 characterizes the
performance of the assisted cowl when these two effects are combined.
When testing a fan assisted cowl for tests without fan, the auxiliary fan shall be switched off and its blades
shall not be blocked.
The electric supply of the assisted cowl shall respond to the manufacturer specifications.
All tests shall be performed using the same cowl as in 5.2.
5.3.2 Measurements and calculations
The following parameters shall be measured:
— wind speed;
— air flow in test duct;
— static gauge pressure in test duct (Figure 2, Key 6);
— static gauge pressure in wind tunnel (Figure 2, Key 4);
— horizontal and vertical wind approach angles (see Figure 3 and Figure 4);
— atmospheric pressure;
— air temperature in the test duct.
The dynamic pressure of the wind, p , is calculated with the air speed measured at point 2 (see
d,tunnel
Figure 2) using Formula (7).
1
2
pv⋅ ρ ⋅ (7)
d,tunnel tunnel tunnel
2
where
p is the dynamic pressure in the wind tunnel, in Pa;
d,tunnel
3
ρ
is the air density in the wind tunnel, in kg/m ;
tunnel
v is the wind speed, in m/s.
tunnel
The difference between the total pressure in the test duct approaching the cowl and the static pressure
in the wind tunnel is calculated using Formula (8).
16
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EN 13141-5:2020 (E)
∆−pp= ∆p + p − p (8)
cowl d,duct f,duct s,,duct s tunnel
where
Δp is the difference between the total pressure in the test duct approaching the cowl under
cowl
test and the static pressure in the tunnel, in Pa;
Δp is the pressure drop due to friction
...
SLOVENSKI STANDARD
oSIST prEN 13141-5:2019
01-junij-2019
Prezračevanje stavb - Preskušanje lastnosti sestavnih delov/izdelkov za
prezračevanje stanovanjskih stavb - 5. del: Prezračevalne kape in strešni iztoki na
strehah
Ventilation for buildings - Performance testing of components/products for residential
ventilation - Part 5: Cowls and roof outlet terminal devices
Lüftung von Gebäuden - Leistungsprüfung von Bauteilen/Produkten für die Lüftung von
Wohnungen - Teil 5: Hauben und Dach-Fortluftdurchlässe
Ventilation des bâtiments - Essais de performance des composants/produits pour la
ventilation des logements - Partie 5 : Extracteurs statiques et dispositifs de sortie en
toiture
Ta slovenski standard je istoveten z: prEN 13141-5
ICS:
91.140.30 Prezračevalni in klimatski Ventilation and air-
sistemi conditioning systems
oSIST prEN 13141-5:2019 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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oSIST prEN 13141-5:2019
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oSIST prEN 13141-5:2019
DRAFT
EUROPEAN STANDARD
prEN 13141-5
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2019
ICS 91.140.30 Will supersede EN 13141-5:2004
English Version
Ventilation for buildings - Performance testing of
components/products for residential ventilation - Part 5:
Cowls and roof outlet terminal devices
Ventilation des bâtiments - Essais de performance des Lüftung von Gebäuden - Leistungsprüfung von
composants/produits pour la ventilation des Bauteilen/Produkten für die Lüftung von Wohnungen -
logements - Partie 5 : Extracteurs statiques et Teil 5: Hauben und Dach-Fortluftdurchlässe
dispositifs de sortie en toiture
This draft European Standard is submitted to CEN members for second enquiry. It has been drawn up by the Technical
Committee CEN/TC 156.
If this draft becomes a European Standard, 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.
This draft European Standard was established by CEN 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.
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.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.
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. prEN 13141-5:2019 E
worldwide for CEN national Members.
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oSIST prEN 13141-5:2019
prEN 13141-5:2019 (E)
Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Symbols and abbreviations . 7
5 Performance testing of aerodynamic characteristics . 9
5.1 Test installation . 9
5.1.1 General . 9
5.1.2 Wind tunnel . 9
5.1.3 Maximum permissible measurement error . 13
5.2 Pressure drop . 13
5.2.1 General . 13
5.2.2 Measurements and calculations . 13
5.2.3 Test method . 14
5.2.4 Analysis of results . 14
5.3 Suction effect of a cowl . 15
5.3.1 General . 15
5.3.2 Measurements and calculations . 15
5.3.3 Test method . 16
5.3.3.1 Least favorable horizontal wind approach angle for the suction effect. 16
5.3.3.2 Effect of the flow rate . 17
5.3.3.3 Effect of the vertical wind approach angle . 17
5.3.3.4 Mechanical effect without wind for fan assisted cowl . 18
5.3.3.5 Combination of mechanical and wind effects for fan assisted cowl . 18
6 Performance testing of electrical characteristics. 19
6.1 Test installation . 19
6.2 Electrical power input . 19
6.2.1 General . 19
6.2.2 Measurement . 19
6.2.3 Test method . 19
6.2.4 Analysis of results . 19
7 Performance testing of acoustic characteristics of assisted cowl . 19
7.1 General . 19
7.2 Radiative sound power in outdoor space – L . 20
Wo
7.2.1 General . 20
7.2.2 Test Installation . 20
7.2.3 Reverberant room method . 20
7.2.3.1 Anechoic or semi-anechoic room method . 21
7.2.3.2 Free field method . 22
7.2.4 Measurements . 22
7.3 Sound power level in duct connections of the unit . 23
7.3.1 General . 23
7.3.2 Test Installation . 23
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8 Test report . 24
8.1 General . 24
8.2 Aerodynamics characteristics . 24
8.3 Electricals characteristics. 24
8.4 Acoustics characteristics . 25
Annex A (normative) Derivation of values through the similitude law . 26
A.1 Similitude law . 26
A.2 Example of application . 26
Bibliography . 27
3
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European foreword
This document (prEN 13141-5:2019) has been prepared by Technical Committee CEN/TC 156
“Ventilation for buildings”, the secretariat of which is held by BSI.
This document is currently submitted to the second CEN Enquiry.
This document will supersede EN 13141-5:2004.
A list of all parts in the EN 13141 series, published under the general title Ventilation for buildings —
Performance testing of components/products for residential ventilation can be found on the CEN website.
In addition to a number of editorial revisions, the following main changes have been made with respect
to EN 13141-5:2004:
— modification of the title and scope to add assisted cowls;
— exclusion from the scope of roof exhaust fan which are tested according to EN 13141-4;
— reorganization of the clause concerning the performance testing of aerodynamic characteristics
(now Clause 5) in order to have a more homogeneous organization and modification of all the figures
to make them more understandable;
— modification of the subclause concerning test installation for aerodynamic characteristics (now 5.1),
which includes the modification of all tests installation requirements as well as the distinction
between requirements that apply to all the tests and those that apply only to the wind tunnel use;
— modification of the volume flow rate correction (see 5.2 concerning pressure drop);
— modification of the formula used to characterize the suction effect of a cowl (see 5.3.2 concerning the
measurements and calculations);
— renaming of “Preliminary test” as “Least favourable horizontal wind approach angle for the suction
effect” (see 5.3.3.1);
— replacement of “a wind of sufficient speed to give easily measurable pressure differences“ by “a wind
of 8 m/s” (see 5.3.3.1);
— removal of the two following measurements points: V = 0,5 m/s and 1,5 m/s (see 5.3.3.2);
— more precise definition of the three series of measurements to carry out (i.e. v = 0m/s,
duct
v = 4m/s and 0 m/s < v < 4 m/s) (see 5.3.3.3);
duct duct
— for additional testing (e.g. acoustics and aerodynamic) for fan assisted cowls, reference to EN 13141-
4 is replaced by reference to EN ISO 5801 and more developed information are given;
— addition of a test method for measuring the combined effect of natural wind and wind from the fan
assisted cowl;
— addition of a detailed clause concerning the test report;
— review of the entire document in order to make it more accessible regarding the changes made.
4
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Introduction
The position of this document in the field of standards for the mechanical building services is shown in
Figure 1.
Figure 1 — Position of EN 13141-5 in the field of the mechanical building services
5
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1 Scope
This document specifies methods for measuring:
— the aerodynamic characteristics of cowls, fan assisted cowls and roof outlets;
— the electrical and acoustic characteristics of fan assisted cowls.
This document is applicable to cowls, assisted cowls and roof outlets used in natural, hybrid or
mechanical ventilation and that are meant to be fitted onto ducts which project above the roof surface.
This document does not apply to:
— assisted cowls assisted by a device other than a fan (e.g. injection assisted cowls);
— roof exhaust fans (see EN 13141-4).
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.
EN 1506:2007, Ventilation for buildings — Sheet metal air ducts and fittings with circular cross-section —
Dimensions
EN 12792, Ventilation for buildings — Symbols, terminology and graphical symbols
EN ISO 5136, Acoustics — Determination of sound power radiated into a duct by fans and other air-moving
devices — In-duct method (ISO 5136)
EN ISO 5801:2017, Industrial fans — Performance testing using standardized airways (ISO 5801)
EN ISO 7235, Acoustics — Laboratory measurement procedures for ducted silencers and air-terminal
units — Insertion loss, flow noise and total pressure loss (ISO 7235)
ISO 13347-2, Industrial fans — Determination of fan sound power levels under standardized laboratory
conditions — Part 2: Reverberant room method
ISO 13347-3, Industrial fans — Determination of fan sound power levels under standardized laboratory
conditions — Part 3: Enveloping surface methods
ISO 13347-4, Industrial fans — Determination of fan sound power levels under standardized laboratory
conditions — Part 4: Sound intensity method
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3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 12792 and the following apply.
ISO and IEC maintain terminological databases for the use in standardization at the following addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO online browsing platform: available at http://www.iso.org/obp
3.1
cowl
air terminal device with or without moving component, intended to be fitted on top of an exhaust duct,
with aim, by creating negative pressure depending of the wind speed, to avoid reverse flow and to
increase the extracted flow rate in presence of wind
[SOURCE: EN 12792:2003, 92, modified – reformulation of the definition in a single sentence]
3.2
assisted cowl
cowl fitted with an auxiliary device using an energy source other than wind to compensate for lack of
suction effect
[SOURCE: EN 12792:2003, 46, modified – removal of “such as a fan and” and replacement of “pressure
difference” by “suction effect”]
3.3
fan assisted cowl
assisted cowl where the auxiliary device is a fan
3.4
roof outlet
air terminal device without moving component, intended to be fitted on top of an exhaust duct
4 Symbols and abbreviations
For the purposes of this document, symbols listed in Table 1 apply.
Table 1 — Symbols and abbreviated terms
Symbol Quantity Unit
C(α,v ,v ) pressure factor —
tunnel duct
D duct diameter m
L duct length m
L sound power level dB
W
L A-weighted sound power level dB(A)
WA
L radiated sound power in the outdoor space (including casing) dB
wo
p atmospheric pressure Pa
a
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Symbol Quantity Unit
p dynamic pressure in the test duct Pa
d,duct
p dynamic pressure in the wind tunnel Pa
d,tunnel
p static gauge pressure in the test duct Pa
s,duct
p
average static gauge pressure in the wind tunnel Pa
s,tunnel
P electrical power input W
E
3
q corrected volume flow rate
m /s
v,cor
3
q
measured volume flow rate
m /s
v,meas
r coefficient of determination of the regression line —
v mean air speed in the test duct m/s
duct
v air speed in the wind tunnel (wind speed) m/s
tunnel
α vertical wind approach angle degree
β horizontal wind approach angle degree
∆p pressure drop Pa
∆p difference between the total pressure in the test duct Pa
cowl
approaching the cowl under test and the static pressure in the
tunnel
∆p pressure drop due to friction in the test duct between the Pa
f,duct
pressure tapping and the bottom of the cowl
ζ pressure drop coefficient —
θ temperature of the air in the test duct °C
a
3 3
ρ
density of 1 204 kg/m corresponding to the air under kg/m
ref
standard conditions (20 °C, 101 325 Pa)
3
ρ
air density in the wind tunnel
kg/m
tunnel
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5 Performance testing of aerodynamic characteristics
5.1 Test installation
5.1.1 General
The aerodynamic characteristics of the air terminal device shall be tested in a test installation as shown
in Figure 2. For pressure drop (see 5.2) and mechanical tests without wind (see 5.3.3.4), the wind tunnel
is not necessary. The test installation shall comprise the following:
— an adjustable air supply incorporating a flow rate measuring device with an uncertainty in
accordance with 5.1.3 (e.g. orifice plate or venturi tube conforming with EN ISO 5167-1, or other flow
meter, such as a rotameter). The air supply passes via an airtight duct;
— means to stabilize the flow and pressure upstream the test duct, e.g. airtight plenum chamber (with
a side length at least 4 times the diameter of the test duct) containing flow settling screens at the air
entry zone and a smooth outlet;
— an airtight test circular duct (test duct) to carry the air terminal device under test, of diameter D
chosen according to EN 1506:2007, Table 1 to suit the air terminal device, and with a minimum
length as given by Formula (1).
LD6⋅
(1)
In case of assisted cowl, the test installation shown in Figure 2 shall be in accordance with Category C
installation as defined in EN ISO 5801:2017, 11.5, ducted inlet and free outlet.
The test shall be performed according to the intended use of the air terminal device.
The pressure measurement point in the test duct (Figure 2, Key 6) shall be located 3D upstream of the air
terminal device (D being the diameter of the test duct).
In order to reach high pressure values, a device to increase the pressure drop in the test duct (e.g. iris)
may be used (Figure 2, Key 15). In order to reach low pressure values, a fan with flow rate adjusted device
may be used (Figure 2, Key 12).
5.1.2 Wind tunnel
Static pressure shall be measured using two pressure probes (or more) located in the working section
(see Figure 2, section A-A). The pressure probes should be situated far enough from the cowl to avoid
side effects, at each side of the wind cross section. The reference pressure is the average of the two (or
more) static pressures.
The wind speed measurement shall be made at 1 m upstream from the air terminal device and in front of
it.
During the suction effect tests, the volume flow rate in the test duct shall not exceed 2 % of the volume
flow rate from the wind tunnel.
If the tests are carried out in a confined working section as shown in Figure 2, then the cross-section area
of the working section (in projection along the axis of the wind tunnel) shall be at least 20 times the cross
section area of the cowl and duct in the wind.
If the tests are carried out using an open jet type wind tunnel, then the cross section area of the jet shall
be at least 10 times the cross-section area (in projection along the axis of the wind tunnel) of the cowl
and duct in the wind.
In order to avoid side effects from the wind tunnel, the test duct part located in the working section (see
Figure 2, section A-A) of the wind tunnel (i.e. the duct part blown by the wind) shall be at least 5 times
the duct diameter.
9
=
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The turbulence intensity of the air inside the wind tunnel upwards from the air terminal device shall be
less than 5 %.
To simulate varying vertical wind approach angles, it shall be possible to rotate the cowl and test duct
about an axis perpendicular to the wind tunnel axis and test duct axis, the cowl remaining near the same
test point located at the wind tunnel axis to remain in the homogenous wind stream (see Figure 3).
NOTE 1 The test point represents the position of the cowl during the test.
In addition, where the test duct axis is perpendicular to the wind tunnel axis, it shall be possible to rotate
the cowl about the test duct axis to simulate varying horizontal wind approach angles (see Figure 4).
When the mounting parts which support the duct and the cowl are in the wind, they should have limited
influence from an aerodynamic point of view.
NOTE 2 No practical rules can be formulated in this document on how to limit the influence of mounting parts.
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Key
1 wind tunnel 9 plenum chamber
2 location for wind speed measurement 10 air flow measuring device
3 air terminal device 11 flow straightener
4 location for static pressure measurement 12 fan with flow rate adjusting device
5 test duct 13 air supply
6 location for static pressure measurement 14 location for static pressure at the bottom of the
device
7 location of sealing for preliminary suction test 15 pressure regulation device
8 flow setting screens
Figure 2 — Typical example of a test installation
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Key
1 axis of wind tunnel 5 test duct
2 wind tunnel 6 axis of test duct
3 location for wind speed measurement 7 axis of rotation
4 homogeneous part of the wind flow
Figure 3 — Rotation to simulate varying vertical wind approach
Key
1 wind tunnel 3 test duct
2 location for wind speed measurement 4 axis of test duct (axis of rotation)
Figure 4 — Rotation to simulate varying horizontal wind approach
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5.1.3 Maximum permissible measurement error
The maximum permissible measurement error is given in Table 2 for each quantity.
Table 2 — Maximum permissible measurement error
Quantity Maximum permissible Unit
measurement error
Wind speed ≤ 0,05 m/s
3
Air flow ≤ 0,000 3 + 0,03 × measured value
m /s
Pressure ≤ 0,5 + 0,03 × measured value Pa
5.2 Pressure drop
5.2.1 General
When testing a fan assisted cowl, the auxiliary fan shall be switched-off and its blades shall not be blocked.
5.2.2 Measurements and calculations
The parameters to be measured are:
— the volume flow rate in the test duct;
— the static pressure difference between the test duct (Figure 2, key 6) and the room in which the test
is carried out (static gauge pressure);
— the atmospheric pressure;
— the temperature of the air in the test duct.
The measured volume flow rate shall be corrected if the temperature or barometric pressure are different
from the standard conditions (20 °C and 101 325 Pa), using Formula (2).
0,5 05
p
293,15
a
qq=
v,cor v,meas
101 325 273,15 + θ
a
(2)
where
3
q
is the corrected volume flow rate, in m /s;
v,cor
3
q
is the measured volume flow rate, in m /s;
v,meas
p
is the atmospheric pressure, in Pa;
a
θ is the temperature of the air in the test duct, in °C.
a
For each measurement, the dynamic pressure in the test duct, p , shall be calculated using
d,duct
Formula (3).
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1
2
pv= ρ
d,duct ref duct
2
(3)
where
p is the dynamic pressure in the test duct, in Pa;
d,duct
3 3
ρ
is the air density, in kg/m , in this case ρ = 1 204 kg/m which corresponds to the air
ref
ref
under standard condition (20°C, 101 325 Pa);
v is the mean air speed in the test duct, in m/s.
duct
with
4 q
v,cor
v =
duct
2
πD
(4)
where
3
q
is the corrected volume flow rate, in m /s;
v,cor
D is the test duct diameter, in m.
For each measurement, the pressure drop shall be calculated using Formula (5).
p p + p
s,duct d,duct
(5)
where
Δp is the pressure drop, in Pa;
p is the static gauge pressure in the test duct, in Pa;
s,duct
p is the dynamic pressure in the test duct, in Pa.
d,duct
NOTE In this calculation method of the pressure drop, it is assumed that the thermal gravity effect (stack effect
in the test duct) is negligible.
5.2.3 Test method
The test shall be carried out by varying the flow rate through the air terminal device to give static pressure
differences of 5 Pa, 10 Pa, 20 Pa and 50 Pa with a tolerance of ± 1 Pa, between the test duct and the room
in which the test is carried out.
5.2.4 Analysis of results
It shall be checked whether the pressure drop can be expressed with a single pressure drop coefficient,
ζ, as given by Formula (6).
∆=pp ζ
d,duct
(6)
To that effect, a linear regression line intercepting the point (p = 0; ΔP = 0) shall be searched through
d,duct
the obtained couples (p ; Δp) using an appropriate least squares method. For the regression line and
d,duct
2
Formula (6) to be valid in terms of this document, the coefficient of determination (r ) of the regression
line shall be ≥ 0,98. With a valid regression line, the pressure drop coefficient, ζ, equals the slope of the
line.
14
∆=
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5.3 Suction effect of a cowl
5.3.1 General
In use, the cowl performance will combine both the suction effect due to the wind and the pressure drop
due to the air flowing through the cowl. The tests methods described in 5.3.3.2 and 5.3.3.3 measure the
performance of the cowl when these two effects are combined.
The test method described in 5.3.3.4 is used to characterize the effect of the fan for fan assisted cowls in
the absence of wind.
In use, when the auxiliary fan of an assisted cowl is switched on, the assisted cowl performance combines
both the suction effect due to the wind and due to the fan. The test described in 5.3.3.5 characterizes the
performance of the cowl when these two effects are combined.
When testing a fan assisted cowl for tests without fan, the auxiliary
...
SLOVENSKI STANDARD
oSIST prEN 13141-5:2017
01-november-2017
3UH]UDþHYDQMHVWDYE3UHVNXãDQMHODVWQRVWLVHVWDYQLKGHORYL]GHONRY]D
SUH]UDþHYDQMHVWDQRYDQMVNLKVWDYEGHO 3UH]UDþHYDOQHNDSHLQVWUHãQLL]WRNLQD
VWUHKDK
Ventilation for buildings - Performance testing of components/products for residential
ventilation - Part 5: Cowls and roof outlet terminal devices
Lüftung von Gebäuden - Leistungsprüfung von Bauteilen/Produkten für die Lüftung von
Wohnungen - Teil 5: Hauben und Dach-Fortluftdurchlässe
Ventilation des bâtiments - Essais de performance des composants/produits pour la
ventilation des logements - Partie 5 : Extracteurs statiques et dispositifs de sortie en
toiture
Ta slovenski standard je istoveten z: prEN 13141-5
ICS:
91.140.30 3UH]UDþHYDOQLLQNOLPDWVNL Ventilation and air-
VLVWHPL conditioning systems
oSIST prEN 13141-5:2017 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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oSIST prEN 13141-5:2017
DRAFT
EUROPEAN STANDARD
prEN 13141-5
NORME EUROPÉENNE
EUROPÄISCHE NORM
September 2017
ICS 91.140.30 Will supersede EN 13141-5:2004
English Version
Ventilation for buildings - Performance testing of
components/products for residential ventilation - Part 5:
Cowls and roof outlet terminal devices
Ventilation des bâtiments - Essais de performance des Lüftung von Gebäuden - Leistungsprüfung von
composants/produits pour la ventilation des Bauteilen/Produkten für die Lüftung von Wohnungen -
logements - Partie 5 : Extracteurs statiques et Teil 5: Hauben und Dach-Fortluftdurchlässe
dispositifs de sortie en toiture
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 156.
If this draft becomes a European Standard, 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.
This draft European Standard was established by CEN 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.
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.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2017 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 13141-5:2017 E
worldwide for CEN national Members.
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Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Symbols and abbreviations . 7
5 Performance testing of aerodynamic characteristics . 9
5.1 Test installation . 9
5.1.1 General . 9
5.1.2 General information on wind effect . 9
5.2 Measurement conditions and uncertainties . 12
5.3 Pressure drop . 12
5.3.1 Test procedure . 12
5.3.2 Analysis of results . 12
5.4 Suction effect of a cowl . 13
5.4.1 General . 13
5.4.2 Preliminary measurement . 13
5.4.3 Preliminary test . 14
5.4.4 Test procedure . 14
5.4.4.1 General . 14
5.4.4.2 Test of the flow rate effect . 14
5.4.4.3 Test for wind effect . 15
5.4.5 Analysis of results . 15
5.5 Mechanical effect for assisted cowl . 15
5.5.1 Test procedure without wind . 15
5.5.2 Analysis of results . 16
5.6 Combined effect of natural wind and wind from the fan for assisted cowl . 16
5.6.1 General . 16
5.6.2 Preliminary test . 17
5.6.3 Test procedure . 17
5.6.4 Analysis of results . 17
6 Performance testing of electrical characteristics. 17
6.1 Test installation . 17
6.2 Measurement conditions and uncertainties . 17
6.3 Electrical power input for assisted cowl . 18
6.3.1 Test procedure . 18
6.3.2 Analysis of results . 18
7 Performance testing of acoustic characteristics of assisted cowl . 18
7.1 General . 18
7.2 Radiative sound power in outdoor space – L . 19
Wo
7.2.1 General . 19
7.2.2 Test Installation . 19
7.2.3 Reverberant room method . 19
7.2.3.1 Anechoic or semi-anechoic room method . 19
2
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7.2.3.2 Free field method . 20
7.2.4 Measurements . 20
7.3 Sound power level in duct connections of the unit . 21
7.3.1 General . 21
7.3.2 Test Installation . 21
8 Test report . 22
8.1 General . 22
8.2 Aerodynamics characteristics . 22
8.3 Electricals characteristics. 23
8.4 Acoustics characteristics . 23
Annex A (normative) Derivation of values through the similitude law . 24
Bibliography . 25
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oSIST prEN 13141-5:2017
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European foreword
This document (prEN 13141-5:2017) has been prepared by Technical Committee CEN/TC 156
“Ventilation for buildings”, the secretariat of which is held by BSI.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 13141-5:2004.
A list of all parts in the EN 13141 series, published under the general title Ventilation for buildings —
Performance testing of components/products for residential ventilation can be found on the CEN website.
In addition to a number of editorial revisions, the following main changes have been made with respect
to EN 13141-5:2004:
— modification of the title and scope to add assisted cowls;
— in the scope, replacement of term “hybrid ventilation” by “mechanical ventilation”;
— exclusion from the scope of roof exhaust fan which are tested according to EN 13141-4;
— correction of the formula used to compute the volume flow rate;
— in 5.4 (suction effect of cowl), for the preliminary test, use of a wind of 8 m/s instead of “a wind of
sufficient speed to give easily measurable pressure differences“;
— in 5.4 (suction effect of cowl), for the testing of the flow rate effect, removal of the two following
measurements points: V = 0,5 m/s and 1,5 m/s;
— in 5.4 (suction effect of cowl), for the test for wind effect (see 5.4.4.3), more precise definition of the
three series of measurements to carry out (i.e. V = 0m/s, V = 4m/s and 0 m/s < V < 4 m/s);
— for additional testing (e.g. acoustics and aerodynamic) for fan assisted cowls, reference to
EN 13141-4 is replaced by reference to EN ISO 5801 and more developed information are given;
— addition of a test method for measuring the combined effect of natural wind and wind from the fan
assisted cowl;
— addition of a detailed clause concerning the test report;
— review of the entire document in order to make it more accessible regarding the changes made.
4
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Introduction
The position of this document in the field of standards for the mechanical building services is shown in
Figure 1.
Figure 1 — Position of EN 13141-5 in the field of the mechanical building services
5
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1 Scope
This document specifies methods for measuring the aerodynamic and acoustic characteristics of cowls,
assisted cowls and roof outlets used in both natural and hybrid ventilation.
Only cowls, assisted cowls and roof outlets used in both natural and hybrid ventilation and fitted onto
ducts which project above the roof surface are covered by this document.
Regarding the assisted cowls, only the fan assisted cowls are covered by this document, other types (e.g.
injection assisted cowls) being too recent to be adequately considered for the time being.
This document does not apply to roof exhaust fan which are tested according to EN 13141-4.
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.
EN 1506:2007, Ventilation for buildings - Sheet metal air ducts and fittings with circular cross-section -
Dimensions
EN 12792, Ventilation for buildings - Symbols, terminology and graphical symbols
EN ISO 5136, Acoustics - Determination of sound power radiated into a duct by fans and other air-moving
devices - In-duct method (ISO 5136)
EN ISO 5801, Industrial fans - Performance testing using standardized airways (ISO 5801)
EN ISO 7235, Acoustics - Laboratory measurement procedures for ducted silencers and air-terminal units -
Insertion loss, flow noise and total pressure loss (ISO 7235)
ISO 13347-2, Industrial fans — Determination of fan sound power levels under standardized laboratory
conditions — Part 2: Reverberant room method
ISO 13347-3, Industrial fans — Determination of fan sound power levels under standardized laboratory
conditions — Part 3: Enveloping surface methods
ISO 13347-4, Industrial fans — Determination of fan sound power levels under standardized laboratory
conditions — Part 4: Sound intensity method
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 12792 and the following apply.
ISO and IEC maintain terminological databases for the use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO online browsing platform: available at http://www.iso.org/obp
3.1
cowl
air terminal device with or without moving component, intended to be fitted on top of an exhaust duct,
with aim, by creating negative pressure depending of the wind speed, to avoid reverse flow and to
increase the extracted flow rate in presence of wind
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3.2
assisted cowl
cowl fitted with an auxiliary device using an energy source other than wind to compensate for lack of
suction effect
3.3
fan assisted cowl
assisted cowl where the auxiliary device is a fan
3.4
roof outlet
air terminal device used for mechanical ventilation systems
3.5
pressure factor
ratio of the measured pressure difference to the dynamic pressure of the wind at a given vertical wind
approach angle
Note 1 to entry: The pressure factor represents the measure of the suction effect due to the wind.
3.6
test voltage
voltage to be used for supplying the motorised cowl during the testing
4 Symbols and abbreviations
For the purposes of this document, symbols listed in Table 1 apply.
Table 1 — Symbols and abbreviated terms
Symbol Quantity Unit
C pressure factor —
(anglex°)
D duct diameter —
e roughness of the duct —
L duct length —
L sound power level dB
W
L A-weighted sound power level dB(A)
WA
L radiated sound power in the outdoor space —
wo
(including casing)
n air flow exponent —
p ambient pressure Pa
a
p dynamic pressure Pa
d
p dynamic pressure in the duct Pa
dyn,duct
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Symbol Quantity Unit
p dynamic pressure of the wind Pa
dw
P electrical power input W
E
P maximum electrical power input W
E,max
p fan pressure Pa
f
p static fan pressure Pa
fs
p static pressure difference Pa
s,ext
p p (measured) corrected for the pressure drop of the Pa
14 6
duct measured before the cowl set up
3 3
q volume flow rate dm /s or m /s or
v
3
l/s or m /h
3 3
q corrected volume flow rate dm /s or m /s or
v,cor
3
l/s or m /h
3 3
q measured volume flow rate dm /s or m /s or
v,m
3
l/s or m /h
q maximum air volume flow —
vmax
3 3
q air volume flow m /s or l/s or m /h
vref
v air speed in the test duct —
∆p total pressure difference Pa
Δp dynamic pressure difference Pa
d
∆p static pressure difference Pa
s
θ ambient temperature °C
a
ρ air density in the test duct —
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5 Performance testing of aerodynamic characteristics
5.1 Test installation
5.1.1 General
The pressure drop characteristics of the cowl, assisted cowl or roof outlet shall be tested in a test
installation such as is shown in Figure 2 but without the wind tunnel. For other characteristics, the wind
tunnel is required. The test installation shall comprise the following:
— an adjustable air supply incorporating an air flow rate measuring device with an uncertainty in
accordance with 5.1.2 (e.g. orifice plate or venturi tube conforming with EN ISO 5167-1, or other
flow meter, such as a rotameter). The air supply passes via an airtight duct;
— means to stabilize the flow and pressure upstream the test duct, e.g. airtight plenum chamber (with
a side length at least 4 times the smallest diameter of the test duct) containing flow settling screens
at the air entry zone and a smooth outlet;
— an airtight test circular duct to carry the cowl or roof outlet under test, of diameter D chosen
according to EN 1506:2007, Table 1 to suit this cowl or roof outlet, and of length given by
Formula (1).
(1)
LD6⋅
In case of assisted cowl, the test installation shown in Figure 2 shall be in accordance with Category C
installation as defined in EN ISO 5801, ducted inlet and free outlet.
The test shall be performed according to the intended use of the cowls, assisted cowls or roof outlet.
The air flow measurement shall be located at the extract side.
5.1.2 General information on wind effect
The suction effect characteristics of the cowl shall be tested in a test installation such as shown in
Figure 2 and described in 5.1.1. For the suction effect test, the wind tunnel is required.
Static pressure shall be measured using two pressure probes (or more) located in the working section
situated far enough from the cowl, at each side of the wind cross section. The reference pressure is the
pneumatic average of the two static pressure ambiences.
If the tests are carried out in a confined working section as shown in Figure 2, then the cross-section
area of the working section (in projection along the axis of the wind tunnel) shall be at least 20 times
the cross section area of the cowl and duct in the wind.
If the tests are carried out using an open jet type wind tunnel, then the cross section area of the jet shall
be at least 10 times the cross-section area (in projection along the axis of the wind tunnel) of the cowl
and duct in the wind.
Because of the interactions between the duct wake and the aerodynamic behaviours of the cowl, the
duct length blown by the wind is more than 5 times duct diameter. Moreover, the duct surface in the
wind shall present a certain roughness (this can be achieved, for example, by using squared ribs with
e/D > 0,01).
The turbulence intensity of the wind shall be less than 5 %.
To simulate varying vertical wind approach angles, it shall be possible to rotate the cowl and test duct
about an axis perpendicular to the wind tunnel axis and test duct axis, the cowl remaining near the
same test point located at the wind tunnel axis to remain in the homogenous wind stream (see
Figure 3).
NOTE The test point represents the position of the cowl during the test.
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In addition, where the test duct axis is perpendicular to the wind tunnel axis, it shall be possible to
rotate the cowl about the test duct axis to simulate varying horizontal wind approach angles (see
Figure 4).
When the mounting parts which support the duct and the cowl are in the wind, they shall be far from
the cowl and transparent from an aerodynamic point of view. Ensure that the approach angles are
maintained during the wind-blowing.
Key
1 wind tunnel 8 flow setting screens
2 wind velocity 9 plenum chamber
3 cowl 10 flow measuring device
4 pressure sensor in the wind 11 flow straightener
5 test duct 12 fan with flow rate adjusting device
6 static pressure measurement device 13 air supply
7 sealed for preliminary suction test 14 calculated static pressure at the bottom of the device
Figure 2 — Typical example of a test installation
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Key
1 axis of tunnel 5 test duct
2 wind tunnel 6 axis of test duct
3 wind velocity 7 axis of rotation
4 homogeneous part of the wind flow
Figure 3 — Rotation to simulate varying vertical wind approach
Key
1 wind tunnel
2 wind velocity
3 test duct
4 axis of rotation
Figure 4 — Rotation to simulate varying horizontal wind approach
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5.2 Measurement conditions and uncertainties
The wind speed measurement shall be made at 1 m from the tested device and the uncertainty of the
wind speed measurement shall be < 0,05 m/s (see Figure 2, Key 2).
During the suction effect tests, the air volume flow rate in the test duct shall not exceed 2 % of the air
volume flow rate from the wind tunnel.
The uncertainty of measurement is given in Table 2.
Table 2 — Uncertainty of measurement for air transfer devices
Measurement Uncertainty Unit
3
Air flow < 0,3 + 0,03 × measured value dm /s
Pressure < 0,5 + 0,03 × measured value Pa
5.3 Pressure drop
5.3.1 Test procedure
When testing a fan assisted cowl, the auxiliary fan shall be switched-off.
The test shall be carried out by varying the air flow rate through the cowl to give static pressure
differences between the test duct and the room in which the test is carried out, of 5 Pa, 10 Pa, 20 Pa and
50 Pa. The wind tunnel is not required.
The parameters to be measured are:
— air volume flow rate through the cowl;
— total pressure difference between the test duct and the room in which the test is carried out. The
pressure tapping in the test duct shall be 3D upstream of the cowl or roof outlet under test (D being
the smallest diameter of the test duct). The total pressure in the duct is calculated by measuring the
static pressure and the averaged air velocity in the duct (the volume flow rate divided by the duct
area).
The environmental conditions existing during the tests such as temperature and air pressure shall be
recorded.
5.3.2 Analysis of results
The measured result shall be corrected if temperature and barometric pressure are different from the
standard conditions (20 °C and 101 325 Pa), using Formula (2).
21n−
11−−nn
-6
17,,1 + 0 048 ⋅⋅θ 10
p ( )
293,15
a
a
qq= ⋅⋅ ⋅ (2)
v,cor v,m
-6
101 325 273,15 + θ
18,06 ⋅ 10
a
where
3
q is the corrected volume flow rate, in dm /s;
v,cor
3
q is the measured volume flow rate, in dm /s;
v,m
p is the ambient pressure, in Pa;
a
θ is the ambient temperature, in °C;
a
n is the air flow exponent.
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For each measurement, the pressure drop coefficient, ζ, shall be calculated using Formula (3) and
Formula (4).
∆p
(3)
ζ =
p
d
1
2
(4)
pv= ⋅⋅ρ
d
2
where
∆p is the total pressure difference between the test duct and the room in which the test is
carried out;
v is the air speed in the test duct;
ρ is the air density in the test duct.
5.4 Suction effect of a cowl
5.4.1 General
In use, the cowl performance will combine both the suction effect due to the wind and the pressure
drop due to the air flowing through the cowl. The following tests measure the performance of the cowl
when these two effects are combined.
5.4.2 Preliminary measurement
The following parameters shall be measured:
— difference between the total pressure in the test duct approaching the cowl and the static pressure
in the wind tunnel. The total pressure in the test duct is calculated with the measured static
pressure and the averaged air velocity in the duct. Static pressure difference shall be corrected
using Formula (5).
∆pp − p (5)
s 14 4
where
∆p is the static pressure difference;
s
p is p corrected for the pressure drop of the duct measured before the cowl set up (see
14 6
Figure 2).
The dynamic pressure of the wind, p , is calculated with the velocity measured at key 2 (see Figure 2)
dw
using Formula (6). Difference of velocity between the key 2 and the test point shall be included in the
final calculation.
1
2
p ⋅ ρ ⋅ U +∆p (6)
dw a 2 d
2
where
p is the dynamic pressure of the wind;
dw
Δp is the dynamic pressure difference between the test point and key 2 (see Figure 2).
d
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— horizontal and vertical wind approach angles.
The pressure tapping in the test duct, Figure 2, Key 6, shall be 3D upstream of the cowl under test
(D being the smallest diameter of the test duct).
5.4.3 Preliminary test
The aim of the preliminary test is to select the horizontal wind approach angle corresponding to the
least favourable condition for the suction effect (see Figure 4).
A set of measurements shall be made with the test duct sealed at the plenum chamber end and fixed
with its axis perpendicular to the wind tunnel axis. A wind of 8 m/s shall be used.
The cowl shall be rotated about the test duct axis, and the static pressure difference between the test
duct and the wind tunnel shall be measured for wind angle steps of 15°.
The tests in 5.2.3 to 5.2.5 shall be carried out at the angle about the test duct axis which results in the
smallest pressure difference (i.e. the least favourable suction effect).
5.4.4 Test procedure
5.4.4.1 General
When testing fan assisted cowl, the auxiliary fan shall be switch-off.
5.4.4.2 Test of the flow rate effect
a) Test with “horizontal” wind 8 m/s
— set
...
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