SIST EN ISO 140-5:1999

Acoustics - Measurement of sound insulation in buildings and of building elements - Part 5: Field measurements of airborne sound insulation of façade elements and façades (ISO 140-5:1998)

Migrated from Progress Sheet (TC Comment) (2000-07-10): EN ISO 140-1 and -3 to -8 are a package and have as DOW 1997-06-30 (BTS1 17/94) ++ DOW for EN ISO 140-1, -3 to -8 will be 1998-12-31 (2nd ext. - BTS1 C 16/1997) ++ SPP update 1997-12-11

Akustik - Messung der Schalldämmung in Gebäuden und von Bauteilen - Teil 5: Messung der Luftschalldämmung von Fassadenelementen und Fassaden am Bau (ISO 140-5:1998)

Dieser Teil der ISO 140 legt zwei Arten von Verfahren zur Messung der Luftschalldämmung von Außenbauteilen (Bauteil-Verfahren) bzw. von gesamten Außenwänden (Gesamt-Verfahren) fest. Die Bauteil-Verfahren dienen zur Ermittlung des Schalldämm-Maßes eines Außenbauteils (z.B. eines Fensters). Beim genaueren Bauteil-Verfahren wird ein Lautsprecher als künstliche Schallquelle verwendet. Andere Bauteil-Verfahren mit geringerer Genauigkeit verwenden den vorhandenen Verkehrslärm.

Acoustique - Mesurage de l'isolation acoustique des immeubles et des éléments de construction - Partie 5: Mesurages in situ de la transmission des bruits aériens par les éléments de façade et les façades (ISO 140-5:1998)

Akustika - Merjenje zvočne izolirnosti v stavbah in zvočne izolirnosti stavbnih elementov - 5. del: Terenska merjenja izolirnosti fasadnih elementov in fasad pred zvokom v zraku (ISO 140-5:1998)

General Information

• Status: Withdrawn
• Publication Date: 31-Oct-1999
• Withdrawal Date: 17-May-2016
• ICS: 17.140.01 - Acoustic measurements and noise abatement in general
• ICS: 91.120.20 - Acoustics in building. Sound insulation
• Technical Committee: AKU - Acoustics
• Current Stage: 9900 - Withdrawal (Adopted Project)
• Start Date: 18-May-2016
• Due Date: 10-Jun-2016
• Completion Date: 18-May-2016
• Directive: 89/106/EEC - Construction products
• Directive: TRRTP128 - Tehnična smernica TSG-1-005:2012 - Zaščita pred hrupom v stavbah
• Mandate: M/100 - Mandate to CEN/CENELEC concerning the execution of standardization work for harmonized standards on precast concrete products
• Ref Project: EN ISO 140-5:1998 - Acoustics - Measurement of sound insulation in buildings and of building elements - Part 5: Field measurements of airborne sound insulation of façade elements and façades (ISO 140-5:1998)

Relations

• Replaced By: SIST EN ISO 16283-1:2014 - Acoustics - Field measurement of sound insulation in buildings and of building elements - Part 1: Airborne sound insulation (ISO 16283-1:2014)
• Effective Date: 01-Jun-2014
• Replaced By: SIST EN ISO 16283-3:2016 - Acoustics - Field measurement of sound insulation in buildings and of building elements - Part 3: Façade sound insulation (ISO 16283-3:2016)
• Effective Date: 01-Jun-2016
• Replaced By: SIST EN ISO 16283-3:2016 - Acoustics - Field measurement of sound insulation in buildings and of building elements - Part 3: Façade sound insulation (ISO 16283-3:2016)
• Effective Date: 08-Jun-2022
• Replaced By: SIST EN ISO 16283-1:2014 - Acoustics - Field measurement of sound insulation in buildings and of building elements - Part 1: Airborne sound insulation (ISO 16283-1:2014)
• Effective Date: 08-Jun-2022

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 140-5:1999
01-november-1999
$NXVWLND0HUMHQMH]YRþQHL]ROLUQRVWLYVWDYEDKLQ]YRþQHL]ROLUQRVWLVWDYEQLK
HOHPHQWRYGHO7HUHQVNDPHUMHQMDL]ROLUQRVWLIDVDGQLKHOHPHQWRYLQIDVDGSUHG
]YRNRPY]UDNX,62
Acoustics - Measurement of sound insulation in buildings and of building elements - Part
5: Field measurements of airborne sound insulation of façade elements and façades
(ISO 140-5:1998)
Akustik - Messung der Schalldämmung in Gebäuden und von Bauteilen - Teil 5:
Messung der Luftschalldämmung von Fassadenelementen und Fassaden am Bau (ISO
140-5:1998)
Acoustique - Mesurage de l'isolation acoustique des immeubles et des éléments de
construction - Partie 5: Mesurages in situ de la transmission des bruits aériens par les
éléments de façade et les façades (ISO 140-5:1998)
Ta slovenski standard je istoveten z: EN ISO 140-5:1998
ICS:
17.140.01 $NXVWLþQDPHUMHQMDLQ Acoustic measurements and
EODåHQMHKUXSDQDVSORãQR noise abatement in general
91.120.20 $NXVWLNDYVWDYEDK=YRþQD Acoustics in building. Sound
L]RODFLMD insulation
SIST EN ISO 140-5:1999 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 140-5:1999

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SIST EN ISO 140-5:1999

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SIST EN ISO 140-5:1999

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SIST EN ISO 140-5:1999

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SIST EN ISO 140-5:1999

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SIST EN ISO 140-5:1999
INTERNATIONAL ISO
STANDARD 140-5
Second edition
1998-08-15
Acoustics — Measurement of sound
insulation in buildings and of building
elements —
Part 5:
Field measurements of airborne sound
insulation of façade elements and façades
Acoustique — Mesurage de l’isolation acoustique des immeubles et des
éléments de construction —
Partie 5: Mesurages in situ de la transmission des bruits aériens par les
éléments de façade et les façades
A
Reference number
ISO 140-5:1998(E)

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SIST EN ISO 140-5:1999
ISO 140-5:1998(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide
federation of national standards bodies (ISO member bodies). The work of
preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which
a technical committee has been established has the right to be represented
on that committee. International organizations, governmental and non-
governmental, in liaison with ISO, also take part in the work. ISO
collaborates closely with the International Electrotechnical Commission
(IEC) on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an International
Standard requires approval by at least 75 % of the member bodies casting
a vote.
International Standard ISO 140-5 was prepared by Technical Committee
ISO/TC 43, Acoustics, Subcommittee SC 2, Building acoustics.
This second edition cancels and replaces the first edition (ISO 140-
5:1978), which has been technically revised.
ISO 140 consists of the following parts, under the general title Acoustics —
Measurement of sound insulation in buildings and of building elements:
— Part 1: Requirements of laboratory test facilities with suppressed
flanking transmission
— Part 2: Determination, verification and application of precision data
— Part 3: Laboratory measurement of airborne sound insulation of
building elements
— Part 4: Field measurements of airborne sound insulation between
rooms
— Part 5: Field measurements of airborne sound insulation of façade
elements and façades
— Part 6: Laboratory measurements of impact sound insulation of floors
©  ISO 1998
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
or utilized in any form or by any means, electronic or mechanical, including photocopying and
microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case postale 56 • CH-1211 Genève 20 • Switzerland
Internet [e-mail]
Printed in Switzerland
ii

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SIST EN ISO 140-5:1999
©
ISO ISO 140-5:1998(E)
— Part 7: Field measurements of impact sound insulation of floors
— Part 8: Laboratory measurements of the reduction of transmitted
impact noise by floor coverings on a heavyweight standard floor
— Part 9: Laboratory measurement of room-to-room airborne sound
insulation of a suspended ceiling with a plenum above it
— Part 10: Laboratory measurement of airborne sound insulation of
small building elements
Annexes A and B form an integral part of this part of ISO 140. Annexes C
to F are for information only.
iii

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SIST EN ISO 140-5:1999

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SIST EN ISO 140-5:1999
©
INTERNATIONAL STANDARD  ISO ISO 140-5:1998(E)
Acoustics — Measurement of sound insulation in buildings and of
building elements —
Part 5:
Field measurements of airborne sound insulation of façade elements
and façades
1 Scope
This part of ISO 140 specifies two series of methods (element methods and global methods) for measurement of
the airborne sound insulation of façade elements and whole façades, respectively. The element methods aim to
estimate the sound reduction index of a façade element, for example a window. The most accurate element method
uses a loudspeaker as an artificial sound source. Other, less accurate, element methods use available traffic noise.
The global methods, on the other hand, aim to estimate the outdoor/indoor sound level difference under actual
traffic conditions. The most accurate global methods use the actual traffic as sound source. In addition, a
loudspeaker may be used as an artificial sound source. An overview of the methods is given in table 1.
The element loudspeaker method yields an apparent sound reduction index which, under certain circumstances
[e.g. taking account of measurement precision (see 7.1)], can be compared with the sound reduction index
measured in laboratories in accordance with ISO 140-3 or ISO 140-10. This method is the preferred method when
the aim of the measurement is to evaluate the performance of a specified façade element in relation to its
performance in the laboratory.
The element road traffic method will serve the same purposes as the element loudspeaker method. It is particularly
useful when, for different practical reasons, the element loudspeaker method cannot be used. These two methods
will often yield slightly different results. The road traffic method tends to result in lower values of the sound reduction
index than the loudspeaker method. In annex D this road traffic method is supplemented by the corresponding
aircraft and railway traffic methods.
The global road traffic method yields the real reduction of a façade in a given place relative to a position 2 m in front
of the façade. This method is the preferred method when the aim of the measurement is to evaluate the
performance of a whole façade, including all flanking paths, in a specified position relative to nearby roads. The
result cannot be compared with that of laboratory measurements.
The global loudspeaker method yields the sound reduction of a façade relative to a position 2 m in front of the
façade. This method is particularly useful when, for different practical reasons, the real noise source cannot be
used. The result cannot be compared with that of laboratory measurements.
1

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SIST EN ISO 140-5:1999
©
ISO
ISO 140-5:1998(E)
Table 1 — Overview of the different measurement methods
No. Method Reference Result Field of application
Element
1 Element Clause 5 R¢ Preferred method to estimate the apparent
45°
loudspeaker sound reduction index of façade elements
2 Element Clause 6 Alternative to method No.1 when road traffic
R¢
tr,s
road traffic noise of sufficient level is available
3 Element Annex D R¢ Alternative to method No.1 when railway
rt,s
railway traffic (informative) traffic noise of sufficient level is available
4 Element Annex D R¢ Alternative to method No.1 when air traffic
at,s
air traffic (informative) noise of sufficient level is available
Global
5 Global Clause 5 D Alternative to methods Nos. 6, 7 and 8
ls,2m,nT
loudspeaker
D
ls,2m,n
6 Global Clause 6 D Preferred method to estimate the global
tr,2m,nT
road traffic sound insulation of a façade exposed to
D
tr,2m,n
road traffic noise
7 Global railway Annex D Preferred method to estimate the global
D
rt,2m,nT
traffic (informative) sound insulation of a façade exposed to
D
rt,2m,n
railway traffic noise
8 Global Annex D D Preferred method to estimate the global
at,2m,nT
air traffic (informative) sound insulation of a façade exposed to air
D
at,2m,n
traffic noise
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this part of
ISO 140. At the time of publication, the editions indicated were valid. All standards are subject to revision, and
parties to agreements based on this part of ISO 140 are encouraged to investigate the possibility of applying the
most recent edition of the standards indicated below. Members of IEC and ISO maintain registers of currently valid
international standards.
ISO 140-2:1991, Acoustics — Measurement of sound insulation in buildings and of building elements — Part 2:
Determination, verification and application of precision data.
ISO 140-3:1995, Acoustics — Measurement of sound insulation in buildings and of building elements — Part 3:
Laboratory measurements of airborne sound insulation of building elements.
ISO 354:1985, Acoustics — Measurement of sound absorption in a reverberation room.
ISO 717-1:1996, Acoustics — Rating of sound insulation in buildings and of building elements — Part 1: Airborne
sound insulation.
IEC 60651:1979, Sound level meters.
IEC 60804:1985, Integrating-averaging sound level meters.
IEC 60942:1991, Sound calibrators.
IEC 61260:1995, Electroacoustics — Octave band filters and fractional — Octave band filters.
2

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SIST EN ISO 140-5:1999
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ISO
ISO 140-5:1998(E)
3 Definitions
For the purposes of this part of ISO 140, the definitions given in ISO 140-3 and the following definitions apply.
3.1 average sound pressure level on a test surface, L : Ten times the logarithm to the base 10 of the ratio of
1,s
the surface and time average of the sound pressure squared to the square of the reference sound pressure, the
surface average being taken over the entire test surface including reflecting effects from the test specimen and
façade; it is expressed in decibels.
3.2 average sound pressure level in a room, L : Ten times the logarithm to the base 10 of the ratio of the space
2
and time average of the sound pressure squared to the square of the reference sound pressure, the space average
being taken over the entire room with the exception of those parts where the direct radiation of a sound source or
the near field of the boundaries (wall, window, etc.) is of significant influence; it is expressed in decibels.
3.3 equivalent continuous sound pressure level, L : Value of the sound pressure level of a continuous steady
eq
sound that, within the measurement time interval, has the same mean square sound pressure as the sound under
consideration, the level of which varies with time; it is expressed in decibels.
3.4 sound reduction index, R: Ten times the logarithm to the base 10 of the ratio of the sound power W incident
1
on the test specimen to the sound power W transmitted through the specimen:
2
 
W
1
=1R 0lg dB . . . (1)
W
 
2
NOTE  The expression “sound transmission loss” (TL) is also in use in English-speaking countries. It is equivalent to “sound
reduction index”.
3.5 apparent sound reduction index, R¢: Ten times the logarithm to the base 10 of the ratio of the sound power
W which is incident on the test specimen to the total sound power transmitted into the receiving room, if, in addition
1
to the sound power W radiated by the specimen, sound power W radiated by flanking elements or by other
2 3
components is significant:
 
W
1
=1R′ 0lg dB . . . (2)
WW+
 
23
3.6 apparent sound reduction index, R¢ : Measure of the airborne sound insulation of a building element when
45°
the sound source is a loudspeaker and when the angle of sound incidence is 45°. The angle of sound incidence is
the angle between the loudspeaker axis directed towards the centre of the test specimen and the normal to the
surface of the façade. The apparent sound reduction index is then calculated from equation (3):
S
� �
R¢ = L - L + 10 lg � � dB - 1,5 dB . . . (3)
45° 2
1,s
Ł ł
A
where
L is the average sound pressure level on the surface of the test specimen, as defined in 3.1;
1,s
L is the average sound pressure level in the receiving room, as defined in 3.2;
2
S is the area of the test specimen, determined as given in annex A;
A is the equivalent sound absorption area in the receiving room.
NOTE  This equation is based on the assumption that the sound is incident from one angle only, 45°, and that the sound field
in the receiving room is perfectly diffuse.
3

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SIST EN ISO 140-5:1999
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ISO 140-5:1998(E)
3.7 apparent sound reduction index, R¢ : Measure of the airborne sound insulation of a building element when
tr,s
the sound source is traffic noise and the outside microphone position is on the test surface. The apparent sound
reduction index is then calculated from equation (4):
S
� �
R¢ = L - L + 10 lg dB - 3 dB . . . (4)
� �
tr,s eq,1,s eq,2
Ł ł
A
where
L is the average value of the equivalent continuous sound pressure level on the surface of the test
eq,1,s
specimen including reflecting effects from the test specimen and façade;
L is the average value of the equivalent continuous sound pressure level in the receiving room;
eq,2
S and A are as given in 3.6.
3.8 level difference, D : Difference, in decibels, between the outdoor sound pressure level 2 m in front of the
2m
façade, L , and the space and time averaged sound pressure level, L , in the receiving room:
1,2m 2
D = L - L . . . (5)
2m 1,2m 2
NOTE  If traffic noise is used as the sound source, the notation is D . If a loudspeaker is used, it is D .
tr,2m ls,2m
3.9 standardized level difference, D : Level difference, in decibels, corresponding to a reference value of the
2m,nT
reverberation time in the receiving room:
� T �
= + 10 lg dB . . . (6)
D D � �
2m,nT 2m
T
Ł ł
0
where T = 0,5 s.
0
NOTE  If traffic noise is used as the sound source, the notation is D . If a loudspeaker is used, it is D .
tr,2m,nT ls,2m,nT
3.10 normalized level difference, D : Level difference, in decibels, corresponding to the reference absorption
2m,n
area in the receiving room:
A
D = D - 10 lg dB . . . (7)
2m,n 2m
A
0
2
where A = 10 m .
0
NOTE  If traffic noise is used as the sound source, the notation is D . If a loudspeaker is used, it is D .
tr,2m,n ls,2m,n
4 Equipment
4.1 General
The microphone shall have a maximum diameter of 13 mm.
The sound pressure level measurement equipment shall meet the requirements of a class 0 or 1 instrument
according to IEC 60651 or IEC 60804. The measurement chain shall be calibrated by using a class 1 or better
acoustical calibrator according to IEC 60942.
The one-third-octave band filters and, if relevant, the octave band filters shall meet the requirements of IEC 61260.
The reverberation time measurement equipment shall meet the requirements of ISO 354.
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ISO 140-5:1998(E)
4.2 Loudspeaker
The directivity of the loudspeaker in a free field shall be such that the local differences in the sound pressure level in
each frequency band of interest are less than 5 dB, measured on an imaginary surface of the same size and
orientation as the test specimen.
NOTE  If the loudspeaker method is adapted to large test specimens, i.e. specimens where one dimension exceeds 5 m,
differences up to 10 dB can be accepted. This should then be reported in the measurement report.
5 Measurement with loudspeaker noise
5.1 General
Two methods, the element and the global loudspeaker method, are described.
The element loudspeaker method will yield an estimate of the apparent sound reduction index which, under
specified circumstances, can be compared with the sound reduction index for the corresponding façade elements
obtained in laboratories.
The global loudspeaker method will quantify the airborne sound insulation of a whole façade or even a whole
building in a specified situation. This result cannot be compared with laboratory measurements.
5.2 Principle
The loudspeaker is placed in one or more positions outside the building at a distance d from the façade, with the
angle of sound incidence equal to (45 ± 5)° (see figure 1).
The average sound pressure level is determined either directly on the test specimen (the element method) or 2 m in
front of the façade (the global method), as well as in the receiving room. The apparent sound reduction index R¢
45°
or the level difference D is calculated.
ls,2m
Key
1  Normal to the façade
2  Vertical plane
3  Horizontal plane
4  Loudspeaker
Figure 1 — Geometry of the loudspeaker method
5

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SIST EN ISO 140-5:1999
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ISO 140-5:1998(E)
5.3 Generation of sound field
The sound field generated shall be steady and have a continuous spectrum in the frequency range considered. If
the measurements are made in one-third-octave bands, frequency bands with centre frequencies from at least
100 Hz to 3 150 Hz, preferably from 50 Hz to 5 000 Hz, shall be used. If the measurements are made in octave
bands, frequency bands with centre frequencies from at least 125 Hz to 2 000 Hz, preferably from 63 Hz to
4 000 Hz, shall be used. In addition, the differences between the sound power levels in the one-third-octave bands
belonging to an octave band shall not be greater than 6 dB in the 125 Hz octave band, 5 dB in the 250 Hz band, and
4 dB in bands of higher centre frequencies.
In all relevant frequency bands, the sound power level of the sound source shall be high enough to give a sound
pressure level in the receiving room that exceeds the background noise level by at least 6 dB.
5.4 Position of the loudspeaker
Choose the position of the loudspeaker and the distance d to the façade so that the variation of the sound pressure
level on the test specimen is minimized. This implies that the sound source is preferably placed on the ground.
Alternatively, place the sound source as high above the ground as is possible in practice.
The distance r from the sound source to the centre of the test specimen shall be at least 5 m (d > 3,5 m) for the
element loudspeaker method, and at least 7 m (d > 5 m) for the global loudspeaker method. The angle of the sound
incidence shall be (45±5)°(see figure 1).
5.5 Measurements in the receiving room
5.5.1 General
Obtain the average sound pressure level in the receiving room by using a single microphone moved from position to
position, or by an array of fixed microphones, or by a continuously moving or oscillating microphone. The sound
pressure levels at the different microphone positions shall be averaged on an energy basis for all sound source
positions. In addition, determine the background noise level L .
b
5.5.2 Microphone positions
As a minimum, five microphone positions shall be used in each room to obtain the average sound pressure level of
each sound field. These positions shall be distributed within the maximum permitted space throughout each room,
spaced uniformly.
The following separating distances are minimum values and should be exceeded where possible:
— 0,7 m between microphone positions;
— 0,5 m between any microphone position and room boundaries or objects in the room;
— 1,0 m between any microphone position and the sound source.
When using a moving microphone, the sweep radius shall be at least 0,7 m. The plane of the traverse shall be
°
inclined in order to cover a large portion of the permitted room space and shall not lie in any plane within 10 of a
room surface. The duration of a traverse period shall be not less than 15 s.
5.5.3 Corrections for background noise
Measure background noise levels to ensure that the observations in the receiving room are not affected by
extraneous sound, such as noise from outside the test room, electrical noise in the receiving system, or electrical
cross-talk between the source and receiving systems.
The background level should be at least 6 dB (and preferably more than 10 dB) below the level of the signal and
background noise combined. If the difference in levels is smaller than 10 dB but greater than 6 dB, calculate
corrections to the signal level according to equation (8):
6

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SIST EN ISO 140-5:1999
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ISO
ISO 140-5:1998(E)
LL/10 /10
sb b
L=10 lg 10 - 10 dB . . . (8)
()
where
L is the adjusted signal level, in decibels;
L is the level of signal and background noise combined, in decibels;
sb
L is the background noise level, in decibels.
b
If the difference in levels is less than or equal to 6 dB in any of the frequency bands, use the correction 1,3 dB,
corresponding to a difference of 6 dB. In that case indicate D , D or R¢ values in the measurement report so that it
n nT
is clear that the reported values are the limit of measurement [see i) of clause 9].
5.5.4 Measurement of reverberation time and evaluation of the equivalent sound absorption area
The correction term in equation (6) containing the equivalent sound absorption area is evaluated from the
reverberation time measured in accordance with ISO 354 and determined using Sabine's formula:
01, 6 V
A = . . . (9)
T
where
A is the equivalent absorption area, in square metres;
V is the receiving room volume, in cubic metres;
T is the reverberation time in the receiving room, in seconds.
Following ISO 354, begin the evaluation of the reverberation time from the decay curve about 0,1 s after the sound
source has been switched off, or from a sound pressure level a few decibels lower than that at the beginning of the
decay. Use a range neither less than 20 dB nor so large that the observed decay cannot be approximated by a
straight line. The bottom of this range shall be at least 10 dB above the background noise level.
The minimum number of decay measurements required for each frequency band is six. At least one loudspeaker
position and three microphone positions with two readings in each case shall be used.
Moving microphones which meet the requirements of 6.3.2 may be used, but the traverse time shall be not less than
30 s.
NOTE  If the reverberation time is extremely short (e.g. shorter than about 0,4 s), a moving microphone may be problematical.
5.6 Element loudspeaker method
5.6.1 Test requirements
If the purpose of the measurement is to obtain results as comparable as possible to those of laboratory
measurements, carry out the following steps:
a) verify that the façade element under test is in accordance with the specified construction and is properly
mounted according to the manufacturer's instructions;
b) estimate the sound reduction index of the façade to ensure that the sound transmission through the wall
surrounding the test specimen does not contribute significantly to the sound pressure level in the receiving
room.
If the purpose of the measurement is to compare the sound insulation of a window with the results of laboratory
measurements, verify in addition that the area of the test opening is representative of that of the laboratories and
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ISO 140-5:1998(E)
that the niche opening and the window position in the niche do not deviate from the requirements given in
ISO 140-3.
Annex C outlines some examples for carrying out these checks. In case of doubt about unacceptably high sound
transmission through the wall surrounding the test specimen, the procedure described in annex B shall be carried
out.
5.6.2 Measurements on the outer surface of the façade element
Determine the average sound pressure level L on the test surface. Carry out the measurements either with the
1,s
microphone fastened directly on the actual test specimen with its axis parallel to the plane of the façade and
directed upwards or downwards, or with its axis pointing in the direction normal to the test specimen. The distance
from the test specimen to the centre of the microphone membrane shall be 10 mm or shorter, depending on the
diameter of the microphone, if the axis of the microphone is parallel to the test surface, and 3 mm or shorter if the
axis is normal to the test surface. If fastened, the microphone shall be fastened to the test specimen with a strong,
adhesive tape. Equip the microphone with a hemispherical windscreen (see figure 2).
If simultaneous measurements are carried out outdoors and indoors, only microphone types which, including
cables, have been shown not to affect the sound insulation of the test specimen should be used if the microphone is
fastened to the test specimen.
Choose between three and ten measurement positions depending on the difference in the sound pressure levels
between the positions. Distribute the measurement positions evenly but asymmetrically on the measurement
surface. It is recommended to begin with three measurement positions (n=3). If the difference in the sound pressure
level between two positions in one frequency is more than n, increase the number of measurement positions up to
ten. If the test specimen is mounted in a recess of the façade, always choose ten measurement positions. If the
difference in the sound pressure levels between the measurement positions is more than 10 dB, this shall be stated
in the measurement report.
As an alternative to several fixed positions, a scanning microphone is allowed provided that the distance to the
façade element can be kept constant and provided that the background noise is kept at least 10 dB below the signal
level.
Average the n positions as given by equation (10):
L /10 L /10 L /10
L = 10 lg(10 1 + 10 2 + . + 10 n ) - 10 lg(n) dB . . . (10)
1,s
where L , L ,., L are the sound pressure levels in positions 1,2,., n.
1 2 n
NOTE  The differences in the sound pressure levels depend among other things on the height h above the ground, recesses,
balconies and the position of the test specimen.
Figure 2 — Flush-mounted microphone
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SIST EN ISO 140-5:1999
©
ISO
ISO 140-5:1998(E)
5.7 Global loudspeaker method
5.7.1 Test requirements
There are no special requirements.
5.7.2 Measurements in front of the façade
Place the microphone on the outside of the façade, in the middle. The distance shall be:
a) (2,0 ± 0,2) m from the plane of the façade, or
b) 1,0 m from a balustrade or other similar protrusion.
The height of the microphone shall be 1,5 m above the floor of the receiving room.
If the main part of the façade is a sloping construction such as a roof, choose the position not nearer to the roof than
the projected part of the vertical part of the façade. If the room considered has more than one outside wall or is very
large, see 5.7.3. Denote the measured sound pressure level L .
1,2m
NOTE  Because of uncontrolled interference effects, systematic errors will occur, particularly at low frequencies.
5.7.3 Large rooms or façades comprising more than one outside wall
If the room is very large or if it has more than one outside wall, it is normally not possible to measure with one
source position only. In those cases, use several source positions, each in full compliance with 5.4. The number of
positions is given by the directional characteristics of the loudspeaker and the area of the façade (see 4.2).
5.7.4 Calculation of measurement results
If several source positions have been used, calculate the level difference for each position and average them
according to equation (11):
1
� �
-D /10
i
D = -10 lg 10 dB . . . (11)
� �
ls,2m �
Ł ł
n
where
n is the number of source positions;
D is the level difference for each source-receiver combination.
i
6 Measurements with road traffic
6.1 General
Two methods, the element and the global road traffic method, are described. The corresponding methods for
railway and air traffic noise are described in annex D.
The element road traffic method will yield an estimate of the apparent sound reduction index which, under specified
circumstances, can be compared with the corresponding sound reduction index obtained in laboratories.
NOTE  Due to background noise, this method is normally limited to measuring R¢ < 40 dB.
w
The global road traffic method will quantify the airborne sound insulation of a whole façade or even a whole building
in a specified situation. This result cannot be compared with the sound reduction index obtained in a laboratory.
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SIST EN ISO 140-5:1999
©
ISO
ISO 140-5:1998(E)
6.2 Principle
If the sound is incident on the test specimen from different directions and with varying intensity (e.g. traffic noise in
busy streets), the sound reduction index or the level difference is obtained from the equivalent sound pressure
levels measured as a function of frequency on both sides of t
...