Acoustics - Recommended practice for the design of low-noise workplaces containing machinery - Part 2: Noise control measures (ISO 11690-2:2020)

This document deals with the technical aspects of noise control in workplaces. The various technical
measures are stated, the related acoustical quantities described, the magnitude of noise reduction
discussed, and the verification methods outlined.
This document deals only with audible sound.

Akustik - Richtlinien für die Gestaltung lärmarmer maschinenbestückter Arbeitsstätten - Teil 2: Lärmminderungsmaßnahmen (ISO 11690-2:2020)

Dieses Dokument befasst sich mit technischen Gesichtspunkten des Schallschutzes in Arbeitsstätten. Es werden die verschiedenen technischen Maßnahmen angegeben, die entsprechenden akustischen Größen beschrieben, das Ausmaß der Lärmminderung diskutiert und die Nachprüfverfahren grob beschrieben.
Dieses Dokument befasst sich ausschließlich mit Hörschall.

Acoustique - Pratique recommandée pour la conception de lieux de travail à bruit réduit contenant des machines - Partie 2: Moyens de maîtrise du bruit (ISO 11690-2:2020)

Akustika - Priporočena praksa za oblikovanje tihih delovnih mest - 2. del: Ukrepi za obvladovanje hrupa (ISO 11690-2:2020)

General Information

Status
Published
Technical Committee
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
18-Nov-2020
Completion Date
18-Nov-2020

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SLOVENSKI STANDARD
SIST EN ISO 11690-2:2021
01-marec-2021
Nadomešča:
SIST EN ISO 11690-2:1997

Akustika - Priporočena praksa za oblikovanje tihih delovnih mest - 2. del: Ukrepi

za obvladovanje hrupa (ISO 11690-2:2020)

Acoustics - Recommended practice for the design of low-noise workplaces containing

machinery - Part 2: Noise control measures (ISO 11690-2:2020)

Akustik - Richtlinien für die Gestaltung lärmarmer maschinenbestückter Arbeitsstätten -

Teil 2: Lärmminderungsmaßnahmen (ISO 11690-2:2020)

Acoustique - Pratique recommandée pour la conception de lieux de travail à bruit réduit

contenant des machines - Partie 2: Moyens de maîtrise du bruit (ISO 11690-2:2020)

Ta slovenski standard je istoveten z: EN ISO 11690-2:2020
ICS:
13.140 Vpliv hrupa na ljudi Noise with respect to human
beings
17.140.20 Emisija hrupa naprav in Noise emitted by machines
opreme and equipment
SIST EN ISO 11690-2:2021 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 11690-2:2021
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SIST EN ISO 11690-2:2021
EN ISO 11690-2
EUROPEAN STANDARD
NORME EUROPÉENNE
November 2020
EUROPÄISCHE NORM
ICS 13.140 Supersedes EN ISO 11690-2:1996
English Version
Acoustics - Recommended practice for the design of low-
noise workplaces containing machinery - Part 2: Noise
control measures (ISO 11690-2:2020)

Acoustique - Pratique recommandée pour la Akustik - Richtlinien für die Gestaltung lärmarmer

conception de lieux de travail à bruit réduit contenant maschinenbestückter Arbeitsstätten - Teil 2:

des machines - Partie 2: Moyens de maîtrise du bruit Lärmminderungsmaßnahmen (ISO 11690-2:2020)

(ISO 11690-2:2020)
This European Standard was approved by CEN on 17 October 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 ISO 11690-2:2020 E

worldwide for CEN national Members.
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SIST EN ISO 11690-2:2021
EN ISO 11690-2:2020 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

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SIST EN ISO 11690-2:2021
EN ISO 11690-2:2020 (E)
European foreword

This document (EN ISO 11690-2:2020) has been prepared by Technical Committee ISO/TC 43

"Acoustics" in collaboration with Technical Committee CEN/TC 211 “Acoustics” the secretariat of which

is held by DIN.

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 May 2021, and conflicting national standards shall be

withdrawn at the latest by May 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 ISO 11690-2:1996.

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 11690-2:2020 has been approved by CEN as EN ISO 11690-2:2020 without any

modification.
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SIST EN ISO 11690-2:2021
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SIST EN ISO 11690-2:2021
INTERNATIONAL ISO
STANDARD 11690-2
Second edition
2020-10
Acoustics — Recommended practice
for the design of low-noise workplaces
containing machinery —
Part 2:
Noise control measures
Acoustique — Pratique recommandée pour la conception de lieux de
travail à bruit réduit contenant des machines —
Partie 2: Moyens de maîtrise du bruit
Reference number
ISO 11690-2:2020(E)
ISO 2020
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SIST EN ISO 11690-2:2021
ISO 11690-2:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

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 2020 – All rights reserved
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SIST EN ISO 11690-2:2021
ISO 11690-2:2020(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Technical aspects of noise control...................................................................................................................................................... 1

5 Noise control at source................................................................................................................................................................................... 3

5.1 General ........................................................................................................................................................................................................... 3

5.2 Noise control at source by design ........................................................................................................................................... 3

5.3 Information on noise emission ................................................................................................................................................. 4

5.4 Use of low-noise machines ........................................................................................................................................................... 4

5.5 Modification or replacement of machine components ........................................................................................ 7

5.6 Low noise working and production technologies .................................................................................................... 8

5.7 Maintenance of machines and noise control devices............................................................................................. 8

6 Noise control on the transmission path ....................................................................................................................................... 8

6.1 Noise control by means of a proper spatial arrangement of the noise sources .............................. 8

6.2 Use of noise control devices ........................................................................................................................................................ 8

6.3 Noise control by use of sound-absorbing materials ............................................................................................... 8

6.4 Sound propagation in structures and noise control measures ..................................................................11

7 Noise control at the work station .....................................................................................................................................................11

8 Verification methods .....................................................................................................................................................................................12

8.1 General ........................................................................................................................................................................................................12

8.2 Sound sources .......................................................................................................................................................................................12

8.3 Noise control devices......................................................................................................................................................................12

8.4 Workroom ................................................................................................................................................................................................12

8.5 Specified positions, work stations.......................................................................................................................................12

9 New technologies ..............................................................................................................................................................................................13

Annex A (informative) Modification or replacement of machine components .....................................................14

Annex B (informative) Arrangement of sound sources ..................................................................................................................16

Annex C (informative) Enclosures ........................................................................................................................................................................17

Annex D (informative) Silencers ............................................................................................................................................................................20

Annex E (informative) Noise barriers and screens in rooms ...................................................................................................21

Annex F (informative) Acoustical treatment of surfaces ..............................................................................................................22

Annex G (informative) Structure-borne sound insulation ..........................................................................................................24

Annex H (informative) Airborne sound insulation of partitions .........................................................................................25

Annex I (informative) Noise control at the work station ..............................................................................................................26

Annex J (informative) Example of a new technology ........................................................................................................................27

Bibliography .............................................................................................................................................................................................................................29

© ISO 2020 – All rights reserved iii
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SIST EN ISO 11690-2:2021
ISO 11690-2:2020(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/

is o/ f or ewor d . ht m l .

This document was prepared by Technical Committee ISO/TC 43, Acoustics, Subcommittee SC 1, Noise,

in collaboration with the European Committee for Standardization (CEN) Technical Committee CEN/

TC 211, Acoustics, in accordance with the Agreement on technical cooperation between ISO and CEN

(Vienna Agreement).

This second edition cancels and replaces the first edition (ISO 11690-2:1996), of which it constitutes a

minor revision. The changes compared to the previous edition are editorial.
A list of all parts in the ISO 11690 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 © ISO 2020 – All rights reserved
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SIST EN ISO 11690-2:2021
ISO 11690-2:2020(E)
Introduction

Several standards specify methods for measurement and/or evaluation of noise. The final objective of

the ISO 11690 series is noise reduction.

A number of noise control measures are offered. However, in order to be effective, the most appropriate

noise control measure(s) should be chosen for a given situation.

It is important when non-acoustic engineers are involved in noise control practice for these engineers

to have a basic knowledge of noise emission and propagation characteristics and to understand the

basic principles of noise control.

To assist in the development of noise control in the workplace, it is essential that the information

contained in these recommended practices is disseminated through International Standards.

In order to reduce noise as a hazard in the workplace, individual countries have produced national

legislation. Generally, such national legislation requires noise control measures to be carried out in

order to achieve the lowest reasonable levels of noise emission, noise immission and noise exposure,

taking into account:
— known available measures;
— the state of the art regarding technical progress;
— the treatment of noise at source;
— appropriate planning, procurement and installation of machines and equipment.

This document, together with the two other parts in the series, outlines procedures to be considered

when dealing with noise control at workplaces, within workrooms and in the open. These recommended

practices give in relatively simple terms the basic information necessary for all parties involved in noise

control in workplaces and in the design of low-noise workplaces to promote the understanding of the

desired noise control requirements.

The purpose of the ISO 11690 series is to bridge the gap between existing literature on noise control and

the practical implementation of noise control measures. In principle, the series applies to all workplaces

and its main functions are:

— to provide simple, brief information on some aspects of noise control in workplaces;

— to act as a guide to help in the understanding of requirements in standards, directives, textbooks,

manuals, reports and other specialized technical documents;

— to provide assistance in decision making when assessing the various measures available.

The ISO 11690 series should be useful to persons such as plant personnel, health and safety officers,

engineers, managers, staff in planning and purchasing departments, architects and suppliers of plants,

machines and equipment. However, the above-mentioned parties should keep in mind that adherence

to the recommendations of the ISO 11690 series is not all that is necessary to create a safe workplace.

The effects of noise on health, well-being and human activity are many. By giving guidelines for noise

control strategies and measures, the ISO 11690 series aims at a reduction of the impact of noise on

human beings at workplaces. Assessment of the impact of noise on human beings is dealt with in other

documents.
© ISO 2020 – All rights reserved v
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SIST EN ISO 11690-2:2021
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SIST EN ISO 11690-2:2021
INTERNATIONAL STANDARD ISO 11690-2:2020(E)
Acoustics — Recommended practice for the design of low-
noise workplaces containing machinery —
Part 2:
Noise control measures
1 Scope

This document deals with the technical aspects of noise control in workplaces. The various technical

measures are stated, the related acoustical quantities described, the magnitude of noise reduction

discussed, and the verification methods outlined.
This document deals only with audible sound.
2 Normative references

The following documents are referred to in the text in such 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 11690-1:2020, Acoustics — Recommended practice for the design of low-noise workplaces containing

machinery — Part 1: Noise control strategies
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 11690-1 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/
4 Technical aspects of noise control

Noise reduction measures can be applied at source (emission), between the source and the receiver

(transmission path), and at the work station (receiver) (see Figure 1).

When dealing with the noise emission of a machine, an installation or a production process, etc., all

possible noise reduction measures should be considered (see Clause 5 and ISO 11690-1). To determine

whether noise emission is the lowest level feasible, it is necessary to consider noise emission quantities;

these are given in the noise emission declaration (see ISO 11690-1:2020, Clause 8) or determined by

measurements (carried out in compliance with the relevant standard).

An assessment of noise control devices such as enclosures, partial enclosures, barriers and screens,

silencers, etc. can be carried out by using, for example, the insertion loss data (see 6.2).

The acoustic quality of workrooms and buildings is assessed with reference to the sound insulation

regarding airborne and structure-borne sound (see 6.4), and that of workrooms with reference to

sound propagation parameters (see 6.3).
© ISO 2020 – All rights reserved 1
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SIST EN ISO 11690-2:2021
ISO 11690-2:2020(E)

The overall effectiveness of noise control measures is determined from the noise immission values at

the work stations.

Generally, people located at a work station or in the vicinity of a machine are affected by the direct noise

emitted by the machine. Therefore, to reduce noise in the workplace, the most effective solution is to

reduce noise at source (primary measures). Additional measures on the transmission paths (secondary

measures) may be impractical because they hinder the work task and the production process. When

assessing the state of noise reduction technology, low noise emission of sound sources is therefore

given high priority with regard to occupational safety.

The basic aspects of noise control (see also ISO 11690-1) are illustrated in Figure 1. These are reviewed

in Clauses 5 to 7.
Figure 1 — Basic aspects of noise control

In order to minimize noise at the workplace, all noise control measures should be considered (see

Figure 2).
Figure 2 — Steps for the implementation of noise control measures

Noise control is most effective if it is carried out when planning, modifying, changing existing

machinery or equipment, or when acquiring new machinery or equipment in plants, workrooms and

buildings. From the outset, all parties involved (see ISO 11690-1:2020, Clause 6) and, in particular,

the noise experts, should take part in the process. Noise control measures are most effective if they

are integrated at the design stage of machines, production processes, workrooms and tasks (see

ISO 11690-1:2020, Clause 7). Machine operation, material transport, safety technology, ergonomics and

environmental protection should also be considered at that stage.
2 © ISO 2020 – All rights reserved
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SIST EN ISO 11690-2:2021
ISO 11690-2:2020(E)
5 Noise control at source
5.1 General

The measures described in this clause deal with the reduction of noise generated by working processes

and machines. They should be implemented at the design stage because retrospective measures can

affect operational requirements and are generally more expensive. However, they are also recommended

for existing noise sources, when practicable.

Control of noise at its source in workplaces deals in particular with the noise reduction of existing

machines, the development and selection of low noise working processes and production technologies,

the replacement of machine parts and the assessment of the results obtained.

The effectiveness of noise control at its source is based on measurements and is assessed by

comparison with the noise emission data, for example, provided by the supplier/manufacturer (see

ISO 11690-1:2020, Clause 8).
5.2 Noise control at source by design

When machine noise (or noise from technical production equipment) is considered, two types of noise

generation should be distinguished: fluid dynamic noise generation (gas and/or liquid) and mechanical

generation.

Fluid dynamic noise arises from temporary fluctuations in pressure and velocity of fluids. Examples

are combustion processes, fans, blow-out openings and hydraulic systems.

Mechanically-generated noise is caused by vibrations of machine components that are excited by

dynamic forces which are generated, for example, by impacts or out-of-balance masses. The vibrations

are transmitted to noise-radiating surfaces, such as machine casing, workpieces, etc. Examples are

tooth-wheel gears, electric motors, hammers, shakers and mechanical presses (see Figure 3).

Key
1 excitation
2 machine
3 transmission
4 radiation
Figure 3 — Generation process of mechanical noise

In order to control noise at its source, the noise-generation mechanism should be taken into account.

© ISO 2020 – All rights reserved 3
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SIST EN ISO 11690-2:2021
ISO 11690-2:2020(E)
Examples of reduction of fluid dynamic noise are the following:

a) reduction of periodical pressure fluctuations at the excitation source (e.g. in-line hydraulic

dampers);
b) reduction of flow velocities (e.g. speed-controlled fans);

c) avoidance of sudden changes in pressure (e.g. graduated vs abrupt transitions in HVAC ducting);

d) effective design of through-flow components (e.g. design layouts that do not put obstacles

immediately in front of air movers).
Examples of reduction of mechanically-generated noise are the following:

e) reduction of exciting dynamic forces (e.g. by means of elastic layers to extend the impulse duration

of impacts);

f) reduction of the vibrational velocity of the machine structure at the excitation point for a given

dynamic force [e.g. by means of stiffeners or additional masses (inertia blocks)];

g) reduction of the vibration (structure-borne sound) transmission from the excitation point to the

sound-radiating surfaces [e.g. by using elastic elements and materials with high internal damping

(cast iron)];

h) reduction of the sound radiated by a vibrating structure, for example by use of

— thin walls with ribs instead of thick stiff walls,
— damping layers on thin metal sheets,
— perforated metal sheets (provided noise insulation is not required);

i) sound-insulating wrappings or thick-walled structures (thin damped metal sheets near the

radiating surface).

Further information on reducing noise at its source can be found in ISO/TR 11688-1 and ISO/TR 11688-2.

5.3 Information on noise emission

In addition to the information on noise emission given by suppliers/manufacturers in technical

documentation (see ISO 11690-1:2020, Clause 8), there may be measures specific to industrial sectors.

Information on such measures can be found in databases, professional magazines, trade association

journals, etc.

For some machine families, there are lists of noise emission data obtained under specified operating

conditions. These lists can help purchasers select low-noise machines/equipment (see ISO 11690-1:2020,

Annex A).
5.4 Use of low-noise machines

In some circumstances, rather than implementing costly retrospective noise control measures, it is

feasible to replace a noisy unit in a plant with a low-noise one (see Table 1).
4 © ISO 2020 – All rights reserved
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SIST EN ISO 11690-2:2021
ISO 11690-2:2020(E)
Table 1 — Examples of alternative processes with lower noise
High-noise processes Low-noise processes
Percussion riveting Compression and roll riveting
Drive by compressed air or internal combustion engine Electrical drive

Cutting or making holes in, for example, stone or con- Use of machines that can be fitted with drills or circular

crete by the use of pneumatic or internal combustion saw blades equipped with diamond teeth

percussive machines
Heading in the die Tapering/full-forward extrusion
Push cutting Pull cutting
Flow drying Radiation drying
Plasma oxygen cutting Plasma cutting under water
Cutting shock, punching Laser-beam cutting
Conventional TIG/TAG welding TIG/TAG shielded arc welding
Flame-hardening Laser-beam hardening
Fastening with rivets Pressure fixing
Stroke forming Hydraulic pressing
Spot welding Seam welding

NOTE 1 A change of the material and/or form of the component under manufacture may allow the use of low-noise

production processes.
NOTE 2 This list is by no means exhaustive.

There are also noisy operations which are not connected with fixed machines, for example from the use

of hand-held tools. These can often be the dominating noise sources in a workroom. If care is taken in

selecting the tools or the working arrangement (e.g. sound-deadened hammers, cushioned work tables,

low-noise grinding discs,
...

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