Acoustics - Measurement of room acoustic parameters - Part 3: Open plan offices (ISO 3382-3:2022)

This document specifies a method for the measurement of room acoustic parameters in unoccupied open-plan offices. It specifies measurement procedures, the apparatus needed, the coverage required, the method for evaluating the data, and the presentation of the test report.
This document describes a group of single-number quantities indicating the room acoustic performance of an open-plan office in a condition when one person is speaking. They focus on spatial decay of speech while the quantities in ISO 3382-2 focus on temporal decay of sound.

Akustik - Messung von Parametern der Raumakustik - Teil 3: Großraumbüros (ISO 3382-3:2022)

Dieses Dokument legt ein Verfahren zur Messung von Parametern der Raumakustik in unbesetzten Großraum¬büros fest. Festgelegt werden Messverfahren, die benötigte Prüfeinrichtung, die erforderliche Messpunkt¬dichte, das Verfahren zur Bewertung der Daten und die Angabe des Prüfberichts.
Dieses Dokument beschreibt eine Gruppe von Einzahlwerten, welche die raumakustischen Eigenschaften eines Großraumbüros in einem Zustand, bei dem eine Person spricht, angeben. Schwerpunkt dieser Einzahl¬werte ist das räumliche Abklingen von Sprache, während sich die Größen in ISO 3382 2 auf das zeitliche Abklingen von Schall konzentrieren.

Acoustique - Mesurage des paramètres acoustiques des salles - Partie 3: Bureaux ouverts (ISO 3382-3:2022)

Le présent document spécifie une méthode de mesurage des paramètres acoustiques des salles dans des bureaux ouverts non occupés. Il décrit les modes opératoires de mesurage, l’appareillage nécessaire, la couverture requise, la méthode d’évaluation des données et la présentation du rapport d’essai.
Le présent document décrit un groupe de grandeurs exprimées en valeurs uniques indiquant la performance acoustique d’un bureau ouvert lorsqu’une personne parle. Ces grandeurs sont basées sur le taux de décroissance spatiale de la parole, tandis que celles de l’ISO 3382-2 concernent le taux de décroissance temporelle du son.

Akustika - Merjenje parametrov prostorske akustike - 3. del: Velike odprte pisarne (ISO 3382-3:2022)

Ta dokument določa metodo za merjenje parametrov prostorske akustike v praznih
velikih odprtih pisarnah. Določa merilne postopke, potrebne naprave, zahtevano pokritost
ter metodo za vrednotenje podatkov in predstavitev poročila o preskusu.
Ta dokument opisuje skupino enoštevilskih vrednosti, ki označujejo prostorske akustične lastnosti velike odprte pisarne, kadar v njej govori ena oseba. Osredotočajo se na prostorski razpad govora, medtem ko se vrednosti v standardu ISO 3382-2 osredotočajo na časovni razpad zvoka.

General Information

Status
Published
Publication Date
11-Jan-2022
Withdrawal Date
30-Jul-2022
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Start Date
12-Jan-2022
Completion Date
12-Jan-2022

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SLOVENSKI STANDARD
SIST EN ISO 3382-3:2022
01-april-2022
Nadomešča:
SIST EN ISO 3382-3:2012
Akustika - Merjenje parametrov prostorske akustike - 3. del: Velike odprte pisarne
(ISO 3382-3:2022)
Acoustics - Measurement of room acoustic parameters - Part 3: Open plan offices (ISO
3382-3:2022)
Akustik - Messung von Parametern der Raumakustik - Teil 3: Großraumbüros (ISO 3382
-3:2022)
Acoustique - Mesurage des paramètres acoustiques des salles - Partie 3: Bureaux
ouverts (ISO 3382-3:2022)
Ta slovenski standard je istoveten z: EN ISO 3382-3:2022
ICS:
17.140.01 Akustična merjenja in Acoustic measurements and
blaženje hrupa na splošno noise abatement in general
91.120.20 Akustika v stavbah. Zvočna Acoustics in building. Sound
izolacija insulation
SIST EN ISO 3382-3:2022 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 3382-3:2022

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SIST EN ISO 3382-3:2022


EN ISO 3382-3
EUROPEAN STANDARD

NORME EUROPÉENNE

January 2022
EUROPÄISCHE NORM
ICS 91.120.20 Supersedes EN ISO 3382-3:2012
English Version

Acoustics - Measurement of room acoustic parameters -
Part 3: Open plan offices (ISO 3382-3:2022)
Acoustique - Mesurage des paramètres acoustiques des Akustik - Messung von Parametern der Raumakustik -
salles - Partie 3: Bureaux ouverts (ISO 3382-3:2022) Teil 3: Großraumbüros (ISO 3382-3:2022)
This European Standard was approved by CEN on 17 December 2021.

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
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 3382-3:2022 E
worldwide for CEN national Members.

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SIST EN ISO 3382-3:2022
EN ISO 3382-3:2022 (E)
Contents Page
European foreword . 3

2

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SIST EN ISO 3382-3:2022
EN ISO 3382-3:2022 (E)
European foreword
This document (EN ISO 3382-3:2022) has been prepared by Technical Committee ISO/TC 43
"Acoustics" in collaboration with Technical Committee CEN/TC 126 “Acoustic properties of building
elements and of buildings” the secretariat of which is held by AFNOR.
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 July 2022, and conflicting national standards shall be
withdrawn at the latest by July 2022.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 3382-3:2012.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 3382-3:2022 has been approved by CEN as EN ISO 3382-3:2022 without any
modification.


3

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SIST EN ISO 3382-3:2022

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SIST EN ISO 3382-3:2022
INTERNATIONAL ISO
STANDARD 3382-3
Second edition
2022-01
Acoustics — Measurement of room
acoustic parameters —
Part 3:
Open plan offices
Acoustique — Mesurage des paramètres acoustiques des salles —
Partie 3: Bureaux ouverts
Reference number
ISO 3382-3:2022(E)
© ISO 2022

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SIST EN ISO 3382-3:2022
ISO 3382-3:2022(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
  © ISO 2022 – All rights reserved

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SIST EN ISO 3382-3:2022
ISO 3382-3:2022(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Measurement conditions . 3
4.1 Equipment . 3
4.2 Measurement procedure . 3
4.2.1 Measurement conditions . 3
4.2.2 Acoustic zones and measurement paths . 3
4.2.3 Source and microphone positions . . 4
4.2.4 Measured quantities . 5
5 Determination of single-number values . 5
5.1 Spectrum of normal speech . 5
5.2 Spatial decay rate of speech . . 5
5.2.1 Conventional method . 5
5.2.2 Impulse response method . 8
5.3 Speech level at 4 m distance . 8
5.4 Background noise level . 9
5.5 Speech transmission index . 9
5.6 Comfort distance and distraction distance . 10
5.7 Typical single-number values . . 10
6 Precision .10
7 Test report .10
Annex A (informative) Psychological reasoning of distraction distance .12
Annex B (informative) Alternative methods for determining the spatial decay rate .13
Annex C (informative) Examples of typical single-number values .15
Annex D (informative) Precision .16
Bibliography .17
iii
© ISO 2022 – All rights reserved

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SIST EN ISO 3382-3:2022
ISO 3382-3:2022(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 43, Acoustics, Subcommittee SC 2,
Building acoustics, in collaboration with the European Committee for Standardization (CEN) Technical
Committee CEN/TC 126, Acoustic properties of building products and buildings, in accordance with the
Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
This second edition cancels and replaces the first edition (ISO 3382-3:2012), which has been technically
revised. The main changes compared to the previous edition are as follows:
— new single-number quantity, comfort distance, added, and privacy distance removed;
— sole use of omnidirectional sound source in all measurement phases emphasized;
— definitions (Clause 3), measurement conditions (Clause 4), and determination of single-number
values (Clause 5) clarified;
— use of impulse response method better described and a new Annex B added;
— Clause 6 “Precision” and an informative Annex D were added;
— STI is determined in conformity with IEC 60268-16 using weighting factors α and β for male gender;
A list of all parts in the ISO 3382 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
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SIST EN ISO 3382-3:2022
ISO 3382-3:2022(E)
Introduction
Open-plan office is a large and open office space where large number of occupants can simultaneously
work in well-defined workstations. Both flexible offices and activity-based offices often involve spaces
that resemble open-plan offices. Open working areas, which can be considered as open-plan offices, can
also be found in many libraries, hospital wards, industrial workplaces, and schools.
Noise and lack of speech privacy are among the largest contributors to environmental dissatisfaction
[1]
in open-plan offices . Colleagues’ speech is the main source of office noise. Inadequate room acoustic
design of the office is one reason to the perception of noise and lack of speech privacy. Distraction due
to colleagues’ speech weakens the ability to concentrate and reduces work performance, especially in
tasks requiring cognitive resources. Insufficient speech privacy prevents confidential conversations.
[2]
Several experimental studies suggest that distraction can be reduced by reducing speech intelligibility
[3]
. A large field survey supports that reduced speech intelligibility is associated with reduced noise
[4]
disturbance . According to Reference [4], many of the single-number quantities described in this
standard are associated with the perceived noise disturbance in open-plan offices.
The outcomes of this method describe the acoustic performance of the open-plan office in a standardized
[5]
condition where a single occupant is speaking with normal speech effort . The background sound
caused by building appliances or sound masking system is considered in the measurements. The
measurements are conducted in an unoccupied open-plan office because the method concerns
the permanent building properties and stable room acoustic conditions as well as ISO 3382-1 and
ISO 3382-2. The activity sound caused by the occupants does not belong to the scope of this standard,
although the level of activity sound can be significantly larger than the level of background sound.
The method uses omnidirectional sound source to provide reproducible results between measurement
operators. Furthermore, the speaking direction of occupant in the office workstation is not always
known nor constant in time. The use of directional sound sources would lead into different results
between measurement operators due to different choices of source direction and source directivities.
Room acoustic quality can be affected by the amount and positioning of wall and ceiling sound
absorption materials, room geometry, workstations, screens, other furniture, floor coverings, and
background sound level (e.g., masking sound). Presentation of acoustic design guidelines is beyond
the scope of this document because literature gives sufficient advice how to reach good room acoustic
[5][6][7]
quality .
v
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SIST EN ISO 3382-3:2022

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SIST EN ISO 3382-3:2022
INTERNATIONAL STANDARD ISO 3382-3:2022(E)
Acoustics — Measurement of room acoustic parameters —
Part 3:
Open plan offices
1 Scope
This document specifies a method for the measurement of room acoustic parameters in unoccupied
open-plan offices. It specifies measurement procedures, the apparatus needed, the coverage required,
the method for evaluating the data, and the presentation of the test report.
This document describes a group of single-number quantities indicating the room acoustic performance
of an open-plan office in a condition when one person is speaking. They focus on spatial decay of speech
while the quantities in ISO 3382-2 focus on temporal decay of sound.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 3382-1, Acoustics — Measurement of room acoustic parameters — Part 1: Performance spaces
IEC 60268-16, Sound system equipment — Part 16: Objective rating of speech intelligibility by speech
transmission index
IEC 60942, Electroacoustics — Sound calibrators
IEC 61260, Electroacoustics — Octave-band and fractional-octave-band filters
IEC 61672-1, Electroacoustics — Sound level meters — Part 1: Specifications
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
omnidirectional sound source
OSS
sound source which radiates sound evenly to all directions
1
© ISO 2022 – All rights reserved

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SIST EN ISO 3382-3:2022
ISO 3382-3:2022(E)
3.2
spatial decay rate of speech
D
2,S
rate of spatial decay of A-weighted sound pressure level (SPL) of speech per distance doubling in
decibels
Note 1 to entry: D describes how fast the A-weighted SPL of speech attenuates in the open-plan office when the
2,S
distance to OSS increases. Large value means strong room acoustic attenuation. In free field, D = 6 dB.
2,S
3.3
speech level at 4 m distance
L
p,A,S,4m
A-weighted SPL of speech in decibels at the distance of 4,0 m from the middle point of the OSS
Note 1 to entry: Distance between nearby workstations is usually less than 4,0 m. Small value means strong
room acoustic attenuation near the OSS.
3.4
comfort distance
r
C
shortest distance from the middle point of the OSS where the A-weighted SPL of speech is lower than
45 dB
Note 1 to entry: Comfort distance reduces with increasing D and decreasing L .
2,S p,A,S,4m
3.5
background noise level
L
p,B
unweighted SPL of background noise in decibels at the workstations along the measurement path
during working hours when occupants are absent
3.6
speech transmission index
STI
quantity describing the transmission quality of speech from speaker to listener
Note 1 to entry: STI is based on IEC 60268-16.
3.7
distraction distance
r
D
shortest distance from the middle point of the OSS where the STI is lower than 0,50
Note 1 to entry: Distraction distance reduces with decreasing r and increasing L . Smaller values are associated
C p,B
with higher levels of speech privacy. Annex A gives a psychological reasoning of distraction distance.
3.8
workstation
furniture ensemble containing at least one chair and one table having a minimum size of 70 cm x 70 cm
Note 1 to entry: Workstation can also contain other components, such as table-mounted or floor-mounted
screens, storage units, display units, or luminaires.
3.9
sound masking system
centralized or networked electronic system used to produce spatially constant background sound in
the workstation area
2
  © ISO 2022 – All rights reserved

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SIST EN ISO 3382-3:2022
ISO 3382-3:2022(E)
4 Measurement conditions
4.1 Equipment
4.1.1 Sound source, OSS shall be used in all measurements. The requirements given in ISO 3382-1
for the OSS within 125 Hz to 4 000 Hz shall be fulfilled for measurements to be in accordance with this
document.
NOTE There are no requirements for the 8 000 Hz octave band.
4.1.2 Microphone, SPLs in each octave band and at each microphone position shall be measured
using a sound level meter meeting the requirements of IEC 61672-1, class 1. The microphone shall be
omnidirectional considering any supplementary equipment connected to it.
4.1.3 Analyser, the octave-band filters of the analyser or analysis software shall comply with
IEC 61260. If the signal is recorded, the recording device shall have the characteristics described in
ISO 3382-1.
4.1.4 Calibrator, the acoustical sensitivity of the measurement system shall be checked using a
sound calibrator that complies with IEC 60942. This is done both before and after each measurement
series. The results of the calibration checks shall be documented. A difference of more than 0,5 dB
between calibration checks shall be an argument to repeat measurements. It is recommended that the
calibration is checked when batteries of the measurement equipment or open-plan office is changed.
4.2 Measurement procedure
4.2.1 Measurement conditions
Measurements can be conducted in open-plan offices of any kind and with any configuration of ceiling
absorbers, wall absorbers, sound masking systems, floor coverings, fixed partitions, workstations,
screens, storage units, and other furniture, whether they are fixed or mobile. The results are valid only
to the specified configuration which prevails during the measurement. Therefore, it is mandatory to
report the abovementioned configurations along with the measurement results.
Background noise means all continuous or non-transient sounds, which are present during normal
working hours and are not caused by the occupants. Such sounds are, e.g., heating, ventilation, and
air conditioning (HVAC) devices, environmental noise caused by sources outside the building, and
electronic sound masking system.
The HVAC devices shall operate on the same power as during typical working hours. If the office is
equipped with a sound masking system, it shall be switched on during the measurement. Sound
masking shall operate at the same level and with the same spectrum as during typical working hours.
Adaptive masking systems can be tested separately for minimum and maximum levels. Appliances
such as refrigerators, printers, coffee machines, radios, and video projectors shall be shut down if they
increase the background noise level in any measurement position. Windows and balcony doors shall
be closed. Occupants shall not be present in the workstations involving measurement positions or OSS.
If the table heights are electrically adjustable, the tabletop height shall be set to (75 ± 5) cm from
the floor corresponding to the tabletop height of a sitting occupant. The setting shall be made in the
workstations located along the measurement path and in the workstation containing the OSS.
4.2.2 Acoustic zones and measurement paths
Acoustic zone means an area in the open-plan office, where the absorption treatment, room height, and
workstation layout are similar. Open-plan office can contain one or several acoustic zones. If the open-
plan office contains two or more acoustic zones, the measurements should be conducted in each of
them. Separate results are reported for each acoustic zone, where measurements have been conducted.
3
© ISO 2022 – All rights reserved

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SIST EN ISO 3382-3:2022
ISO 3382-3:2022(E)
At least two separate measurement paths shall be used per acoustic zone. If only one measurement path
is possible in a zone, measurements shall be conducted in both directions along this measurement path.
4.2.3 Source and microphone positions
The measurements shall be conducted along a straightest possible path which crosses over
workstations, as shown in Figure 1.
Key
1 straight measurement path
2 non-straight measurement path
Figure 1 — Example of a straight and a non-straight measurement path in an open-plan office,
where workstations and other furniture are present
(position of the OSS is in the end of a path)
If the acoustic zone contains high piece of furniture (such as screens, dividers, or storage units being
higher than 1,20 m) between workstations, the measurement path should be chosen in such a way that
there is such a high piece of furniture between the OSS and the first measurement position.
The OSS is located at the workstation at the end of the path. The OSS shall be located at the position of
a sitting occupant’s head in a workstation. The middle point of the OSS shall be at the height of 1,20 m
above the floor. The distance between the middle point of the OSS and a nearest table shall be at least
0,40 m. The distance between the middle point of the OSS and nearest wall of the room shall be at least
1,00 m. Discrepancy from this requirement shall be mentioned in the report.
All workstations along the measurement path shall be measured and considered in the analysis. The
number of measurement positions on a path shall be at least four. In other words, measurements
according to this standard are only possible if measurement path involves at least five consecutive
workstations. The preferred number of successive measurement positions on the path is six to ten.
Measurement positions locating farther than 16 m from OSS are not necessary, but they can facilitate
the determination of r , if it is larger than 16 m.
D
The reference position shall be located at the distance of 1,00 m from the middle point of the OSS without
any separating obstacles, such as a screen, between the OSS and the microphone. The reference position
can locate in another direction than the measurement path if an obstacle prevents the abovementioned
condition. The reference position is not a measurement position affecting the reported single-number
values. It enables a post check of the actual sound power level of the OSS. The value at the reference
position can be shown in spatial decay curves of both A-weighted SPL of speech and STI to provide
additional information about the acoustic conditions at short conversation distance.
4
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SIST EN ISO 3382-3:2022
ISO 3382-3:2022(E)
The actual measurement positions, which affect the reported single-number values, shall be located at
workstations along the measurement path at the position of a sitting occupant’s head, which is 1,20 m
above the floor. Standing occupant is not considered in this document. The distance of the microphone
positions shall be at least 1,00 m from the nearest wall of the room. Discrepancy from this requirement
shall be mentioned in the report. Chairs are moved away from the workstations of the measurement
path during the measurements. The first measurement position shall be located at the workstation
nearest to the OSS.
It is possible that the measurements need to be conducted in an unfurnished open-plan office, where the
workstations and other furniture are absent, but the room surfaces and building services are otherwise
finished. This is necessary when the acoustic target values concern the unfurnished open-plan offi
...

SLOVENSKI STANDARD
oSIST prEN ISO 3382-3:2021
01-marec-2021
Akustika - Merjenje parametrov prostorske akustike - 3. del: Velike odprte pisarne
(ISO/DIS 3382-3:2021)
Acoustics - Measurement of room acoustic parameters - Part 3: Open plan offices
(ISO/DIS 3382-3:2021)
Akustik - Messung von Parametern der Raumakustik - Teil 3: Großraumbüros (ISO/DIS
3382-3:2021)
Acoustique - Mesurage des paramètres acoustiques des salles - Partie 3: Bureaux
ouverts (ISO/DIS 3382-3:2021)
Ta slovenski standard je istoveten z: prEN ISO 3382-3
ICS:
17.140.01 Akustična merjenja in Acoustic measurements and
blaženje hrupa na splošno noise abatement in general
91.120.20 Akustika v stavbah. Zvočna Acoustics in building. Sound
izolacija insulation
oSIST prEN ISO 3382-3:2021 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
oSIST prEN ISO 3382-3:2021

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oSIST prEN ISO 3382-3:2021
DRAFT INTERNATIONAL STANDARD
ISO/DIS 3382-3
ISO/TC 43/SC 2 Secretariat: DIN
Voting begins on: Voting terminates on:
2021-01-29 2021-04-23
Acoustics — Measurement of room acoustic parameters —
Part 3:
Open plan offices
Acoustique — Mesurage des paramètres acoustiques des salles —
Partie 3: Bureaux ouverts
ICS: 91.120.20
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
BEING ACCEPTABLE FOR INDUSTRIAL,
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Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Measurement conditions . 3
4.1 Equipment . 3
4.2 Measurement procedure . 3
4.2.1 Measurement conditions . 3
4.2.2 Room acoustic zones . 3
4.2.3 Source and microphone positions . 4
4.2.4 Measurement quantities . 5
5 Determination of single-number quantities . 6
5.1 Spectrum of normal speech . 6
5.2 Spatial decay rate of speech . 6
5.2.1 Conventional method . 6
5.2.2 Impulse response method . 8
5.3 Speech level at 4 m distance . 8
5.4 Background noise . 9
5.5 Speech Transmission Index . 9
5.6 Comfort and distraction distances .10
5.7 Typical values of single-number quantities .11
6 Precision .11
7 Test report .11
Annex A (informative) Psychological reasoning of distraction distance .13
Annex B (informative) Alternative methods for determining the spatial decay rate .14
Annex C (informative) Examples of typical values of the single-number quantities .16
Annex D (informative) Accuracy .17
Bibliography .18
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Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee [or Project Committee] ISO/TC 43, Acoustics,
Subcommittee SC 2, Building acoustics.
This second edition cancels and replaces the first edition (ISO 3382-3:2012), which has been technically
revised. The main changes compared to the previous edition are as follows:
— new single-number quantity, comfort distance, added, and privacy distance removed;
— use of omnidirectional sound source emphasized;
— measurement conditions (Clause 4) have been clarified;
— determination of single-number quantities (Clause 5) clarified;
— use of impulse response method better described and a new Annex added;
— new Clause 6 Precision and a new informative Annex Accuracy added;
— STI is determined in conformance of IEC 20268-16 using weighting factors α and β for male gender;
A list of all parts in the ISO 3382 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
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Introduction
Noise and lack of speech privacy are among the most dissatisfactory environmental factors in open-
plan offices [1]. Colleagues’ speech is the main source of office noise. Inadequate room acoustic design
of the office is one reason to the perception of noise and lack of speech privacy. Distraction due to
colleagues’ speech weakens the ability to concentrate and reduces productivity, especially in tasks
requiring cognitive resources. Insufficient speech privacy prevents confidential conversations. Several
experimental studies suggest that distraction can be reduced by reducing speech intelligibility [2,3].
A large field survey supports that reduced speech intelligibility is associated with reduced noise
disturbance [4].
This part of ISO 3382 specifies a measurement method, which results in a group of single-number
quantities indicating the room acoustic performance of an open-plan office in a condition when one
person is speaking. They focus on spatial decay of speech while quantities in part 2 of this standard
focus on temporal decay of sound.
The concept "open-plan offices" covers large office spaces where large number of occupants can work in
well-defined workstations. A large share of flexible offices and activity-based offices belong to the open-
plan office concept of this standard. Open-plan offices can also be found in libraries, hospital wards,
industrial workplaces, and schools. According to [4], many of the single-number quantities provided by
this standard are associated with the perceived noise disturbance in open-plan offices.
Room acoustic quality can be affected by the amount and positioning of absorption materials, room
geometry, workstations, screens, other furniture, and background noise level, i.e. sound masking.
Current literature gives good advice how the room acoustics should be designed to reach good room
acoustic quality as it is defined in this standard [5,6,7].
The method describes the acoustic performance of the open-plan office in a standardized condition
where a single occupant is speaking with normal speech effort. The background noise caused by
building appliances or electronic masking sound is considered. The measurements are conducted in
an unoccupied open-plan office because the method concerns the permanent building properties and
stable room acoustic conditions as well as parts 1 and 2 of this standard. The actual noise conditions
during use of the space do not belong to the scope of this standard. Although the activity noise caused
by occupants can be significantly larger than the background noise from building appliances or sound
masking, activity noise is beyond the scope of this standard. Presentation of acoustic design guidelines
is also beyond the scope of this part of ISO 3382-3.
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DRAFT INTERNATIONAL STANDARD ISO/DIS 3382-3:2021(E)
Acoustics — Measurement of room acoustic parameters —
Part 3:
Open plan offices
1 Scope
This document specifies methods for the measurement of room acoustic parameters in unoccupied
open-plan offices. It specifies measurement procedures, the apparatus needed, the coverage required,
the method for evaluating the data, and the presentation of the test report.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 3382-1, Acoustics — Measurement of room acoustic parameters — Part 1: Performance spaces
ISO 3740, Acoustics — Determination of sound power levels of noise sources — Guidelines for the use of
basic standards
IEC 60268-16:2011, Sound system equipment — Part 16: Objective rating of speech intelligibility by speech
transmission index
IEC 60942, Electroacoustics — Sound calibrators
IEC 61260, Electroacoustics — Octave-band and fractional-octave-band filters
IEC 61672-1, Electroacoustics — Sound level meters — Part 1: Specifications
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
Omnidirectional sound source
OSS
a sound source which radiates sound evenly to all directions.
3.2
spatial distribution of the A-weighted SPL of speech
curve which shows how the A-weighted sound pressure level (SPL) decreases as a function of the
distance from the middle point of the OSS emitting noise with the sound power level of normal speech
within 125 Hz to 8 000 Hz.
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3.3
spatial decay rate of speech
D
2,S
rate of spatial decay of A-weighted SPL of speech per distance doubling in decibels
Note 1 to entry: The quantity describes how fast the A-weighted SPL of speech attenuates in the open-plan office.
Large value means strong overall room acoustic attenuation. In free field, D = 6 dB.
2,S
3.4
Speech level at 4 m distance
L
p,A,S,4m
nominal A-weighted SPL in decibels at the distance of 4,0 m from the middle point of the OSS emitting
noise with the sound power level of normal speech within 125 Hz to 8 000 Hz
Note 1 to entry: The quantity describes the A-weighted SPL of speech at a distance within which the nearest
workstation is nearly always located. Small value means strong room acoustic attenuation near the OSS.
3.5
comfort distance
r
C
distance from the speaker in meters where the A-weighted SPL of speech falls below 45 dB when the
OSS is emitting noise with the sound power level of normal speech within 125 Hz to 8 000 Hz
Note 1 to entry: Comfort distance reduces with increasing D2,S and decreasing Lp,A,S,4m.
3.6
background noise level
L
p,B
unweighted mean SPL of background noise in decibels present at the workstations along the
measurement path during working hours when occupants are absent
Note 1 to entry: Background noise is measured in octave bands within 125 Hz to 8 000 Hz.
3.7
speech transmission index
STI
a proportional number representing the transmission quality of speech. STI has a value between 0.00
and 1.00.
[SOURCE: IEC 60268-16:2011]
Note 1 to entry: The value of STI is associated with subjective speech intelligibility.
3.8
spatial distribution of the speech transmission index
curve which shows how the STI decreases as a function of the distance from the OSS.
3.9
distraction distance
r
D
distance from the OSS in meters where the STI falls below 0,50.
Note 1 to entry: to entry. Distraction distance reduces with decreasing r and increasing L . Small value
C p,B
indicates high speech privacy. When the speaker is located beyond the distraction distance from the occupant,
occupant’s work performance is expected to be better than at shorter distances (see Annex A).
3.10
Workstation
Workstation is a furniture ensemble containing one ergonomically adjustable chair and a working table
having a minimum floor area of 70x70 cm. The height of tabletop can be adjusted to a height of 75
cm from the floor. Workstation can contain also other components, such as screen(s), storage unit(s),
display units, or luminaire.
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4 Measurement conditions
4.1 Equipment
4.1.1 Sound source. Omnidirectional sound source (abbreviated by OSS) shall be used in all
measurements. This source type is used since occupants in an open-plan office do not speak in an exactly
fixed direction. The requirements given in ISO 3382-1 for the OSS within 125 – 4000 Hz shall be fulfilled
for measurements to be in accordance with this part of ISO 3382.
NOTE There are no requirements for the 8 000 Hz octave band.
4.1.2 Microphone. SPLs in each octave band and at each microphone position shall be measured
using a sound level meter meeting the requirements of IEC 61672-1, class 1. The microphone shall be
omnidirectional considering any supplementary equipment connected to it.
4.1.3 Analyzer. The octave-band filters of the analyzer or analyzer software shall comply with
IEC 61260. If the signal is recorded, e.g., by using analogue or digital recorders for off-line processing, it
shall be ensured that the whole instrumentation complies with the above-mentioned requirements.
4.1.4 Calibrator. Before and after each measurement series, the acoustical sensitivity of the
measurement system shall be checked using a sound calibrator that complies with IEC 60942. The results
of the calibration checks shall be documented. A difference of more than 0,5 dB between calibration
checks shall be a cause to repeat measurements. It is recommended that the calibration be checked
whenever batteries or open-plan office are changed.
4.2 Measurement procedure
4.2.1 Measurement conditions
Measurements can be conducted in open-plan offices of any kind and with any configuration of ceiling
absorbers, wall absorbers, sound masking systems, floor coverings, fixed partitions, workstations,
screens, storage units, and other furniture, whether they are fixed or mobile. The results are valid only
to the specified configuration which prevails during the measurement. Therefore, it is important to
carefully report these factors along with the measurement results.
Background noise means all stationary sounds, which are present during normal working hours
and are not caused by the occupants. Such sounds are e.g. heating, ventilation, and air conditioning
(HVAC) devices, environmental noise caused by sources outside the building, or an electronic sound-
masking system.
The HVAC devices shall operate on the same power as during typical working hours. If the office is
equipped with a sound-masking system, it shall be switched on during the measurement. Sound
masking shall operate at the same level and with the same spectrum as during typical working hours.
Adaptive masking systems should be tested separately for minimum and maximum levels. Appliances
such as refrigerators, printers, coffee machines, radios, and video projectors shall be shut down if they
increase the background noise in any measurement position. Windows and balcony doors shall be
closed. All measurements shall be conducted when the occupants are absent. Only the measurement
technician can be present in the open-plan office.
If the table heights are electrically adjustable, the tabletop height is set to 75±5 cm from the floor in the
workstations located along the measurement path.
4.2.2 Room acoustic zones
If the open-plan offices can contain two or more zones where the absorption treatments and/or
furniture layouts are different, the measurements shall be conducted in each zone and the reported
single-number quantities are determined for each zone separately.
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At least two separate measurement paths shall be used per open-plan office zone. If only one
measurement path is possible, measurements shall be conducted in both directions along the same
measurement path.
4.2.3 Source and microphone positions
The measurements shall be conducted along a straightest possible path which crosses over
workstations, as shown in Figure 1.
If the zone contains regular furniture (usually screen or storage unit) between workstations, the
measurement path should be chosen in such a way that there is an obstacle between the OSS and the
first measurement position.
The OSS is located at the workstation at one end of the path. The OSS shall be located at the position of
a sitting occupant’s head in a workstation. The middle point of the OSS shall be at the height of 1,2 m
above the floor. The position of the OSS shall be at least 0,4 m from the nearest table and at least 1,0 m
from walls and other reflecting surfaces.
All workstations shall be measured along the measurement path and considered in the analysis. The
number of measurement positions on a path shall be at least 4. In other words, measurements according
to this standard are only possible if measurement path involves at least five consecutive workstations.
The preferred number of successive measurement positions on the path is 6 to 10.
The reference position shall be located at the distance of 1,0 m from the middle point of the OSS without
any separating obstacles, such as a screen, between the OSS and the microphone. The reference position
needs not to locate in the direction of the measurement path if an obstacle prevents the abovementioned
condition. The reference position enables a post check of the actual sound power level of the OSS.
Although the position is not utilized in the determination of the single-number quantities, the result
can be shown in spatial decay curves of both A-weighted SPL of speech and STI to provide additional
information about the acoustic conditions at short conversation distance.
The actual measurement positions, which affect the reported single-number quantities, shall locate in
workstations along the measurement path at the position of a sitting occupant’s head at the height of
1,2 m above the floor. The second measurement position shall locate in the workstation nearest to the
OSS. Standing occupants are not considered in this part of ISO 3382. The position of microphone shall
be at least 0,4 m from tables and at least 1,0 m from walls and other reflecting surfaces.
Even if electric tables enable working in standing position, both OSS and microphones shall be installed
at a height of 1.20 m height from the floor.
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Key
A straight measurement path
B non-straight measurement path
Figure 1 — Example of a straight and a non-straight measurement path in an open-plan office,
where workstations and other furniture are present. Position of the OSS is in the end of a path.
If the measurements are conducted in an open-plan office where the workstations and other furniture
have not yet been installed, the number of measurement positions and positions of both OSS and
microphone shall the same as above. The measurement positions shall be chosen using typical mutual
workstation distances. The measurement positions could be located, e.g., at distances 1,0 m, 2,5 m,
5,0 m, 7,5 m, 10,0 m, 12,5 m, 15,0 m, and 17,5 m from the OSS.
4.2.4 Measurement quantities
At every measurement position, four measurements or determinations are made:
— distance to the OSS disregarding the obstacles, r;
— unweighted SPL of wide-band noise caused by the OSS, L ;
p,oss
— unweighted SPL of background noise, L ;
p,B
— STI;
The accuracy of distance measurement shall be less than 0,10 m. Distances should be based on physical
measurements on site. A laser distance meter is preferred. If the distance cannot be measured due to
e.g. obstacles on measurement path, and the distances must be based on layout drawings, the accuracy
of these drawings (open-plan office dimensions, furniture positions) shall be confirmed by physical
measurements on site.
The distance means the straight distance from the midpoint of the OSS to the midpoint of the
microphone.
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L and L are measured in octave bands within 125 Hz to 8 000 Hz. The integration time shall be at
p,oss p,B
least 10 s.
NOTE Integration times longer than 10 s are needed for transient background noise, e.g. traffic noise.
5 Determination of single-number quantities
5.1 Spectrum of normal speech
The sound power level (SWL) of normal effort speech is used. The octave band values represent normal
effort unisex speech (average of female and male speech). The octave band SPL at a distance of 1,0 m
from the middle point of the OSS in the free field (L ) is presented in Table 1. The SWL of normal
p,S,1m,ff
effort speech is related to the SPL of speech at the distance of 1,0 m in free field by L = L + 11 dB.
W,S p,S,1m,ff
Since the OSS is used in all measurements, the SPL at the distance of 1,0 m from the OSS represent the
average sound radiation in all directions from the OSS.
Table 1 — The unweighted SPL of directional and omnidirectional speech at a distance of 1,0 m
from the speaker in free field and the corresponding SWL of speech. A-weighting is needed in
formula (5).

Band No. Frequency SPL of speech SPL of speech SWL of speech A-weighting
 directional omnidirectional
i f L L L A
p,S,1m,ff p,S,1m,ff W,S
Hz dB re 20 μPa dB re 20 μPa dB re 1 pW dB
1 125 51,2 49,9 60,9 -16,1
2 250 57,2 54,3 65,3 -8,6
3 500 59,8 58,0 69,0 -3,2
4 1 000 53,5 52,0 63,0 0,0
5 2 000 48,8 44,8 55,8 1,2
6 4 000 43,8 38,8 49,8 1,0
7 8 000 38,6 33,5 44,5 -1,1
A-weighted 59,5 57,4 68,4

NOTE The SPL of directional speech within 250–8000 Hz is based on ANSI S3.5 [8]. The value at 125 Hz has
been chosen to be 6 dB under the SPL at 250 Hz. The SPL of omnidirectional speech is derived in [9] assuming the
directivity pattern of speech reported in [10]. Both directional and omnidirectional sources produce the same SWL.
5.2 Spatial decay rate of speech
5.2.1 Conventional method
Conventional method is based on the measurements of SPL produced by a calibrated OSS (abbreviated
by “oss” in related subindex). The SWL of the OSS producing wide-band noise shall be sufficiently high
in each octave band so that the SPL
...

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