Bui lding Bul let in 93

ACOUSTIC DESIGNOF SCHOOLS

A DESIGN GUIDE

BUILDING BULLETIN 93

Acoustic Design ofSchools

Architects and Building Branch

London : The Stationery Office

DfES Project TeamRichard Daniels Building Services Engineer, School Buildings & Design UnitAlex Freemantle Architect, Formerly of School Buildings & Design UnitMukund Patel Head of School Buildings & Design Unit

AcknowledgementsDfES would like to thank the following:

Editors:Bridget Shield, London South Bank UniversityCarl Hopkins, BRE Acoustics, Building Research Establishment Ltd (BRE)

Principal authors:Carl Hopkins & Robin Hall, BRE Acoustics, Building Research Establishment Ltd (BRE)Adrian James, Adrian James Acoustics, NorwichRaf Orlowski & Sam Wise, Arup AcousticsDavid Canning, City University

Other authors and advisors:Stephen Chiles University of BathDavid Dennis London Borough of NewhamNigel Cogger The English Cogger PartnershipJohn Miller & Theodoros Niaounakis Bickerdike Allen and PartnersLes Fothergill Building Regulations Division, Office of the

Deputy Prime MinisterGuy Shackle Barron and Smith ArchitectsJulie Dockrell Institute of Education, University of LondonMindy Hadi Building Research Establishment Ltd (BRE)Matthew Ling Formerly of Building Research Establishment Ltd (BRE)Russell Brett British Association of Teachers of the DeafRichard Vaughan National Deaf Children's SocietyRoz Comins Voice Care Network UKThomas Wulfrank Arup AcousticsDavid Coley & Andrew Mitchell Centre for Energy and the Environment, Exeter University. Derek Poole Formerly of University of Wales, College of CardiffJohn Lloyd & Tom Cecil Faber MaunsellPeter Brailey Hawksmoor Engineering Ltd.Andrew Parkin RW Gregory LLPTerry Payne Monodraught LtdWayne Aston PassiventTim Spencer Rockwool Rockfon LtdDavid Whittingham Formerly of Ecophon Ltd

Photographer: Philip Locker, Photo Graphic Design, Bolton

Design & Mac file: Malcolm Ward, Malcolm Studio, Croydon.

ISBN 0 11 271105 7

Introduction 1

Scope of Building Bulletin 93Overview of contents of Building Bulletin 93

Section 1: Specification of acoustic performance 7

1.1 Performance standards 81.1.1 Indoor ambient noise levels in unoccupied spaces1.1.2 Airborne sound insulation between spaces1.1.3 Airborne sound insulation between circulation spaces and

other spaces used by students1.1.4 Impact sound insulation of floors1.1.5 Reverberation in teaching and study spaces1.1.6 Sound absorption in corridors, entrance halls and stairwells1.1.7 Speech intelligibility in open-plan spaces

1.2 Demonstrating compliance to the Building Control Body 161.2.1 Alternative performance standards

1.3 Demonstrating compliance to the client 171.3.1 Timetabling of acoustic testing1.3.2 Remedial treatments1.3.3 Indoor ambient noise levels in unoccupied spaces1.3.4 Airborne sound insulation between spaces1.3.5 Airborne sound insulation between circulation spaces and

other spaces used by students1.3.6 Impact sound insulation1.3.7 Reverberation in teaching and study spaces1.3.8 Sound absorption in corridors, entrance halls and stairwells1.3.9 Speech intelligibility in open-plan spacesReferences

Section 2: Noise control 21

2.1 Choosing a site 212.2 Recommendations for external noise levels outside school buildings 212.3 Noise survey 222.4 Road and rail noise 232.5 Aircraft noise 232.6 Vibration 232.7 Noise barriers 242.8 Noise from schools to surrounding areas 242.9 Planning and layout 242.10 Limiting indoor ambient noise levels 252.11 Impact noise 252.12 Corridors, entrance halls and stairwells 252.13 Masking noise 262.14 Low frequency noise and hearing impaired pupils 26

References

Contents

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Section 3: Insulation from external noise 27

3.1 Roofs 273.1.1 Rain noise

3.2 External walls 283.3 Ventilation 28

3.3.1 Ventilators3.4 External windows 303.5 External doors 31

Sound insulation of the building envelope 323.6 Subjective characteristics of noise 323.7 Variation of noise incident on different facades 323.8 Calculations 323.9 Test Method 32

3.9.1 Conditions for similar constructions3.9.2 Conditions for similar sources

Sound insulation between rooms 333.10 Specification of the airborne sound insulation between rooms using Rw 33

3.10.1 Flanking details3.10.2 Examples of problematic flanking details3.10.3 Junction between ceilings and internal walls3.10.4 Flanking transmission through windows

3.11 Specification of the impact sound insulation between rooms using Ln,w 363.12 Internal walls and partitions 37

3.12.1 General principles3.12.2 Sound insulation of common constructions3.12.3 Flanking transmission3.12.4 High performance constructions flanking transmission3.12.5 Corridor walls and doors

3.13 Internal doors, glazing, windows and folding partitions 413.13.1 Doors3.13.2 Lobbies3.13.3 Folding walls and operable partitions3.13.4 Roller shutters

3.14 Floors and ceilings 453.14.1 Impact sound insulation3.14.2 Voids above suspended ceilings3.14.3 Upgrading existing wooden floors using suspended plasterboard ceilings3.14.4 Upgrading existing wooden floors using platform and ribbed floors3.14.5 Concrete floors

3.15 Design and detailing of building elements 50References

Section 4: The design of rooms for speech 53

4.1 Approach to acoustic design 534.2 Internal ambient noise levels and speech clarity 534.3 Reverberation times 544.4 Amount of acoustic absorption required 544.5 Distribution of absorbent materials 544.6 Room geometry 544.7 Classrooms 55

Contents

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4.8 Assembly halls, auditoria and lecture theatres 554.8.1 Room geometry4.8.2 Sound reinforcement

4.9 Open-plan teaching and learning areas 584.10 Practical spaces 59

4.10.1 Design and Technology spaces4.10.2 Art rooms4.10.3 Floor finishes in practical spaces

4.11 Drama rooms 604.12 Multi-purpose halls 614.13 Other large spaces 624.14 Dining areas 62

References

Section 5: The design of rooms for music 63

5.1 Aspects of acoustic design 635.2 Ambient noise 635.3 Sound insulation

5.3.1 Sound insulation between music rooms5.4 Room acoustics 64

5.4.1 Reverberation time, loudness and room volume5.4.2 Distribution of acoustic absorption5.4.3 Room geometry5.4.4 Diffusion

5.5 Types of room 675.5.1 Music classrooms5.5.2 Music classroom/recital room5.5.3 Practice rooms/group rooms5.5.4 Ensemble rooms5.5.5 Control rooms for recording5.5.6 Recording studios5.5.7 Audio equipment

5.6 Acoustic design of large halls for music performance 735.6.1 Shape and size5.6.2 Surface finishes

5.7 Design of large auditoria for music and speech 75References

Section 6: Acoustic design and equipment for pupils with specialhearing requirements 77

6.1 Children with listening difficulties 776.2 Children with hearing impairments and the acoustic environment 776.3 Hearing impairment and hearing aids 786.4 The speech signal and hearing aids 786.5 Listening demands within the classroom 796.6 Strategies developed to assist children with hearing and listening difficulties 796.7 Individual technology 80

6.7.1 Radio aids6.7.2 Auditory trainers and hard-wired systems

6.8 Whole class technology 826.8.1 Whole classroom soundfield systems6.8.2 System overview

Contents

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6.8.3 Personal soundfield systems 6.8.4 Infra red technology6.8.5 Induction loop systems6.8.6 Audio-visual equipment6.8.7 Other assistive devices

6.9 Special teaching accommodation 876.10 Beyond the classroom 89

References

Section 7: Case studies 91

7.1 Remedial work to a multi-purpose hall in a county primary school 93 7.2 An investigation into the acoustic conditions in three open-plan primary schools 977.3 Remedial work to an open-plan teaching area in a primary school 1077.4 Conversion of a design and technology space to music accommodation 1137.5 A purpose built music suite 1177.6 A junior school with resource provision for deaf children 1237.7 An all-age special school for hearing impaired children 129 7.8 Acoustic design of building envelope and classrooms at a new secondary school 1397.9 Acoustically attenuated passive stack ventilation of an extension to an inner city

secondary school 1437.10 An investigation into acoustic conditions in open-plan learning spaces in

a secondary school 147

Appendices 159

Introduction to appendices 1591 Basic concepts and units 1612 Basic principles of room acoustics 1653 Basic principles of sound insulation 1674 Classroom sound insulation sample calculations 1715 Sound insulation of the building envelope 1756 Calculation of room reverberation times 1777 Calculation of sound absorption required in corridors,

entrance halls and stairwells 1818 Equipment specifications for sound field systems in schools 1859 Noise at Work Regulations relating to teachers 19110 Example submission to Building Control Body 193

Bibliography 203

List of organisations 207

Contents

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Page

1The constructional standards for acousticsfor new school buildings, as given inSection 1 of this document, are requiredto be achieved under the BuildingRegulations. This represents a significanttightening of the regulation of acousticdesign in schools, to reflect a generalrecognition, supported by research, thatteaching and learning are acousticallydemanding activities. In particular, thereis a consensus that low ambient noiselevels are required, particularly in view ofthe requirements of the SpecialEducational Needs and Disability Act20011 for integration of children withspecial needs in mainstream schools.

Unfortunately, a large number ofclassrooms in the UK currently sufferfrom poor acoustics. The most seriousacoustic problems are due to noisetransfer between rooms and/or excessivereverberation in rooms. There are manyreasons for the poor acoustics, for example: The acoustics of the stock of oldVictorian schools are often unsuitable formodern teaching methods. Modern constructions do not alwaysprovide adequate sound insulation andmay need special treatment. Open plan, or semi-open plan layouts,designed to accommodate a number ofdifferent activities, are areas wherebackground noise and sound intrusionoften cause problems. The acoustics of multi-purpose rooms,such as halls, have to be suitable for avariety of activities, for example music(which requires a long reverberationtime) and speech (which requires shorterreverberation times).

Many activities, such as music anddesign technology lessons, can be noisyand will cause problems if there isinadequate sound insulation betweenareas for these activities and thoserequiring quieter conditions.

Poor acoustic conditions in theclassroom increase the strain on teachersvoices as most teachers find it difficult tocope with high noise levels. This oftenleads to voice problems due to prolongeduse of the voice and the need to shout tokeep control. Recent surveys in the UKand elsewhere show that teachers form adisproportionate percentage of voice clinicpatients.

Historically, there have been a numberof factors preventing good acoustic designand this Building Bulletin addresses theseissues. Before 2003, Part E of the BuildingRegulations did not apply to schools. Itnow includes schools within its scope. Although the constructional standardsfor schools previously quoted BuildingBulletin 87[2] as the standard foracoustics in schools, many designers wereunaware of the requirements of BB87 andthe standards were rarely enforced. Thesestandards have been updated to reflectcurrent research and the relevantrequirements of the DisabilityDiscrimination Act, and are included inthe compliance section, Section 1, of thisbulletin. The pressure on finances has meant inthe past that acoustics came low on thelist of design priorities. The acousticdesign will now have a higher priority as itwill be subject to building control

Introduction

1. Now incorporated asSection IV of the DisabilityDiscrimination Act[1]

Building Bulletin 93 aims to: provide a regulatory framework for the acoustic design of schools in support

of the Building Regulations give supporting advice and recommendations for planning and design of

schools provide a comprehensive guide for architects, acousticians, building control

officers, building services engineers, clients, and others involved in the design of new school buildings.

2approval procedures. There has been little guidance availablein the past on how to achieve the rightbalance of acoustics in the complex anddynamic environment of a school.Architects and designers have had adifficult time finding information to makedesign easy and, in particular, to helpthem choose the correct target values ofappropriate parameters.

Overall, Building Bulletin 93recommends a structured approach toacoustic design at each stage of theplanning and design process, as shown inthe table below.

Introduction

A structured approach to acoustic design at each stage of the planning and design process

Feasibility/Sketch Design Selection of the site Noise survey to establish external noise levels Orientation of buildings Massing and form of the buildings Consideration of need for external noise barriers using the buildings, fences and screens and

landscape features Preliminary calculation of sound insulation provided by building envelope including the effect of

ventilation openings

Detailed Design Determine appropriate noise levels and reverberation times for the various activities and room types

Consider the special educational needs of the pupils Consider the design of music, drama and other specialist spaces separately from that of

normal classrooms as the design criteria are very different. Provide the necessary faade sound insulation whilst providing adequate ventilation,

particularly in the case of spaces such as classrooms and science laboratories which require high ventilation rates

Architectural/acoustic zoning: plan the disposition of 'quiet' and 'noisy' spaces, separating them wherever possible by distance, external areas or neutral 'buffer' spaces such as storerooms or corridors

Consider sound insulation separately from other aspects of room acoustics using walls, floors and partitions to provide adequate sound insulation

Design the acoustics of the rooms by considering their volume and shape, and the acoustic properties of their surfaces

Specify the acoustic performance of doors, windows and ventilation openings Specify any amplification systems

Building Control Approval Submit plans, including specific details of the acoustic design, for approval by Building Control Body

3SCOPE of Building Bulletin 93

Section 1 of Building Bulletin 93supersedes Section A of Building Bulletin87[2] as the constructional standard foracoustics for new school buildings.

In addition, Part E of the BuildingRegulations includes schools within itsscope and Approved Document E[3]

gives the following guidance: In theSecretary of States view the normal way ofsatisfying Requirement E4 will be to meetthe values for sound insulation,reverberation time and internal ambientnoise which are given in Section 1 ofBuilding Bulletin 93 The Acoustic Designof Schools, produced by DfES.

The requirements of Section 1 cameinto force on 1st July 2003, at the sametime as those contained in the newApproved Document Part E[3], insupport of the Building Regulations.

Requirement E4 from Part E ofSchedule 1 to The Building Regulations2000 (as amended) states that:

Each room or other space in a schoolbuilding shall be designed and constructedin such a way that it has the acousticconditions and the insulation againstdisturbance by noise appropriate to itsintended use.

The Education (School Premises)Regulations 1999, SI 1999 No.2 whichapplies to both new and existing schoolbuildings, contains a similar statement: Each room or other space in a schoolbuilding shall have the acoustic conditionsand the insulation against disturbance bynoise appropriate to its normal use.

Compliance with the acousticperformance standards specified inSection 1 will satisfy both regulations fornew schools.

Although Building Regulations do notapply to all alteration and refurbishmentwork, it is desirable that such work shouldconsider acoustics and incorporateupgrading of the acoustics as appropriate.(In the case of existing buildings, theBuilding Regulations apply only tomaterial alterations as defined inRegulations 3 and 4.) Although it wouldbe uneconomic to upgrade all existingschool buildings to the same standards as

new school buildings, where there is aneed for upgrading the acousticperformance of an existing building orwhen refurbishment is happening forother reasons, then the designer shouldaim to meet the acoustic performancegiven in Section 1 of BB93 to satisfy theSchool Premises Regulations and theDisability Discrimination Act.

The exemption of Local EducationAuthority (LEA) maintained schools fromthe Building Regulations has ended. Newschool buildings, including extensions toexisting school buildings and new schoolsformed by change of use of otherbuildings, are now included in theBuilding Regulations and may be subjectto detailed design checks and on-siteinspections by Building Control Bodies.

The Building Regulations and hencethe requirements of BB93 only apply inEngland and Wales. They apply to bothLEA maintained schools and independentschools.

Temporary buildings are exempt fromthe Building Regulations. Temporarybuildings are defined in Schedule 2 to theBuilding Regulations as those which arenot intended to remain in place for longerthan 28 days. What are commonly calledtemporary buildings in schools are classedas prefabricated buildings and arenormally subject to the same BuildingRegulations requirements as other typesof building. Additional guidance is givenin Clause 0.6 of Approved DocumentE[3]. A building that is created bydismantling, transporting and re-erectingthe sub-assemblies on the same premises,or is constructed from sub-assembliesobtained from other premises or fromstock manufactured before 1st July 2003,would normally be considered to meet therequirements for schools if it satisfies therelevant provisions relating to acousticstandards set out in the 1997 edition ofBuilding Bulletin 87[2].

The extension of Part E of Schedule 1to the Building Regulations 2000 (asamended by SI 2002/2871) to schoolsapplies to teaching and learning spaces.Therefore the performance standards in

Introduction

4Introduction

the tables in Section 1 are required forcompliance with Part E for all teachingand learning spaces. Part E of theBuilding Regulations is not intended tocover the acoustic conditions inadministration and ancillary spaces not usedfor teaching and learning except in as far asthey affect conditions in neighbouringteaching and learning spaces. Thereforeconsideration needs to be given toadjoining areas, such as corridors, whichmight have doors, ventilators, or glazingseparating them from a teaching orlearning space. The performance standardsgiven in the tables for administration andancillary spaces are for guidance only.

Rooms used for nursery andadult/community education within schoolcomplexes are also covered by Part E. PartE does not apply to nursery schools whichare not part of a school, sixth form collegeswhich have not been established as schools,and Universities or Colleges of Furtherand Higher Education2. However, manyof the acoustic specifications are desirableand can be used as a guide to the designof these buildings. The standards areparticularly appropriate for nurseryschools as figures are quoted for nurseryspaces within primary schools.

The Disability Discrimination Act

1995[1], as amended by the SpecialEducational Needs and Disability Act2001, places a duty on all schools andLEAs to plan to increase over time theaccessibility of schools for disabled pupilsand to implement their plans. Schools andLEAs are required to provide: increased access for disabled pupils tothe school curriculum. This coversteaching and learning and the widercurriculum of the school such as after-school clubs, leisure and culturalactivities. improved access to the physicalenvironment of schools, includingphysical aids to assist education. Thisincludes acoustic improvements and aidsfor hearing impaired pupils.

When alterations affect the acoustics ofa space then improvement of the acousticsto promote better access for children withspecial needs, including hearingimpairments, should be considered. Approved Document M: 1999 Accessand facilities for disabled people, insupport of the Building Regulations[4]

includes requirements for access forchildren with special needs. See also BS8300: 2001 Design of buildings and theirapproaches to meet the needs of disabledpeople[5].

2. Part E of the Building Regulations quotes the definition of school given in Section 4 of the1996 Education Act. In the case of sixth form colleges Section 4 of the 1996 Act should be readin conjunction with Section 2 of the same Act, in particular subsections (2), (2A) and (4) whichdeal with the definition of secondary education.

If a sixth form college is established as a school under the 1998 School Standards andFramework Act then it will be classed as a school under Section 4 of the 1996 Education Act andPart E of the Building Regulations on acoustics will apply. Only one sixth form college has beenestablished in this way up until now.

Therefore, most sixth form colleges are institutions in the Further Education sector and notschools, and Part E of the Building Regulations will not apply.

In the case of a new sixth form college it will be necessary to contact the LEA to enquire if thesixth form college has been established as a school or as an Institute of Further Education.

5Introduction

Section 1: Specification of AcousticPerformance consists of three parts.

Section 1.1 gives the performancestandards for new school buildings tocomply with the Building Regulations. These provide a good minimum standardfor school design. However, on occasionhigher standards will be necessary.

Section 1.2 sets out the preferredmeans of demonstrating compliance tothe Building Control Body.

Section 1.3 gives the testsrecommended to be conducted as part ofthe building contract.

Section 2: Noise Control describes howto conduct a site survey and to plan theschool to control noise. It also includesrecommendations on maximum externalnoise levels applying to playing fields,recreational areas and areas used forformal and informal outdoor teaching.External levels are not covered byBuilding Regulations but are taken intoconsideration in planning decisions bylocal authorities[6].

Section 3: Sound Insulation gives detailedguidance on constructions to meet theperformance standards for soundinsulation specified in Section 1.1.

Section 4: The Design of Rooms forSpeech and Section 5: The Design ofRooms for Music give guidance onvarious aspects of acoustic design relevantto schools.

Section 6: Acoustic Design andEquipment for Pupils with SpecialHearing Requirements discusses designappropriate for pupils with hearingimpairments and special hearingrequirements. It discusses the necessaryacoustic performance of spaces anddescribes the range of aids available tohelp these pupils.

Section 7 contains 10 case studiesillustrating some of the most importantaspects of acoustic design of schools.

Appendix 1 defines the basic concepts andtechnical terms used in the Bulletin.

Appendices 2 and 3 describe the basicprinciples of room acoustics and soundinsulation.

Appendices 4 to 7 give examples ofcalculations of sound insulation,reverberation time and absorption.

Appendix 8 gives equipment specificationsfor sound field systems to guide thosewho need to specify this type of equipment.

Appendix 9 gives an overview of theNoise at Work Regulations as they relateto teachers.

Appendix 10 gives an example of asubmission for approval by a BuildingControl Body.

The DfES acoustics websitewww.teachernet.gov.uk/acoustics containsfurther reference material which expandson the source material for acousticiansand designers. For example, it links to aspreadsheet which can be used to calculatethe sound insulation of the buildingenvelope and the reverberation time ofinternal rooms. The website will beregularly updated with new information,discussion papers and case studies. Thewebsite also contains complete downloadsof BB93.

Overview of contents of Building Bulletin 93

6References[1] Disability Discrimination Act (1995) Part IVwww.hmso.gov.uk[2] Building Bulletin 87, Guidelines forEnvironmental Design in Schools (Revision of Design Note 17), The Stationery Office, 1997. ISBN 011 271013 1. (Now superseded by2003 version of BB87, which excludesacoustics, and is available onwww.teachernet.gov.uk/energy)[3] Approved Document E Resistance to thepassage of sound. Stationery Office, 2003. ISBN 0 11 753 642 3. www.odpm.gov.uk[4] Approved Document M:1999 Access andfacilities for disabled people, in support of theBuilding Regulations, Stationery Office, 1999 ISBN 0 11 753469. To be replaced shortly byApproved Document M, Access to and use ofbuildings.www.odpm.gov.uk [5] BS 8300: 2001 Design of buildings andtheir approaches to meet the needs of disabledpeople, Code of Practice. [6] PPG 24, Planning Policy Guidance: Planningand Noise, Department of the Environment, TheStationery Office, September 1994. To bereplaced by revised Planning Policy documents.

Introduction

The normal way of satisfyingRequirement E4 of The BuildingRegulations is to demonstrate that all theperformance standards in Section 1.1, asappropriate, have been met.

Section 1.2 sets out the preferredmeans for demonstrating compliance ofthe design to the Building Control Body.

Section 1.3 describes acoustic tests thatcan be used to demonstrate compliancewith the performance standards in Section1.1. It is strongly recommended that theclient require acoustic testing to becarried out as part of the buildingcontract, because testing of the completed

construction is the best practical means ofensuring that it achieves the design intent.

In all but the simplest of projects it isadvisable to appoint a suitably qualifiedacoustic consultant1 at an early stage ofthe project, before the outline design hasbeen decided. This will prevent simplemistakes which can be costly to design outat a later stage. An acoustic consultant willnormally be needed to check the designdetails and on-site construction, and tocarry out acoustic tests to confirm thatthe building achieves the requiredacoustic performance.

7

Contents1.1 Performance standards 9

1.1.1 Indoor ambient noise levels in unoccupied spaces 91.1.2 Airborne sound insulation between spaces 121.1.3 Airborne sound insulation between circulation spaces and

other spaces used by students 121.1.4 Impact sound insulation of floors 131.1.5 Reverberation in teaching and study spaces 141.1.6 Sound absorption in corridors, entrance halls and stairwells 151.1.7 Speech intelligibility in open-plan spaces 16

1.2 Demonstrating compliance to the Building Control Body 171.2.1 Alternative performance standards 17

1.3 Demonstrating compliance to the client 181.3.1 Timetabling of acoustic testing 181.3.2 Remedial treatments 181.3.3 Indoor ambient noise levels in unoccupied spaces 181.3.4 Airborne sound insulation between spaces 181.3.5 Airborne sound insulation between circulation spaces and

other spaces used by students 181.3.6 Impact sound insulation 181.3.7 Reverberation in teaching and study spaces 181.3.8 Sound absorption in corridors, entrance halls and stairwells 191.3.9 Speech intelligibility in open-plan spaces 19References 19

Specification of acoustic performance 1Section 1 of Building Bulletin 93 sets the performance standards for theacoustics of new buildings, and describes the normal means of demonstrating

compliance with The Building Regulations.

1 The primary professionalbody for acoustics in theUK is the Institute ofAcoustics. An experiencedprofessional acousticianwho is competent to beresponsible for theacoustic design of schoolbuildings would normally bea corporate member of theInstitute of Acoustics.

SE

CT

ION

1.1 Performance standardsThe overall objective of the performancestandards in Section 1.1 is to provideacoustic conditions in schools that (a)facilitate clear communication of speechbetween teacher and student, andbetween students, and (b) do notinterfere with study activities.

Performance standards on thefollowing topics are specified in thissection to achieve this objective: indoor ambient noise levels airborne sound insulation betweenspaces airborne sound insulation betweencorridors or stairwells and other spaces impact sound insulation of floors reverberation in teaching and studyspaces sound absorption in corridors, entrancehalls and stairwells speech intelligibility in open-planspaces.

All spaces should meet theperformance standards defined in Tables1.1, 1.2, 1.3, 1.4 and 1.5 for indoorambient noise level, airborne and impactsound insulation, and reverberation time.Open-plan spaces should additionallymeet the performance standard for speechintelligibility in Table 1.6.

The notes accompanying Tables 1.1,1.2, 1.3 and 1.5 contain additionalguidance that should be considered whendesigning the spaces to meet theperformance standards in these tables.Although good practice, this guidancewill not be enforced under the BuildingRegulations.

1.1.1. Indoor ambient noise levels inunoccupied spacesThe objective is to provide suitableindoor ambient noise levels (a) for clearcommunication of speech betweenteacher and student, and betweenstudents and (b) for study activities.

The indoor ambient noise levelincludes noise contributions from: external sources outside the schoolpremises (including, but not limited to,noise from road, rail and air traffic,industrial and commercial premises) building services (eg ventilation system,

plant, etc). If a room is naturallyventilated, the ventilators or windowsshould be assumed to be open as requiredto provide adequate ventilation. If a roomis mechanically ventilated, the plantshould be assumed to be running at itsmaximum operating duty.

The indoor ambient noise levelexcludes noise contributions from: teaching activities within the schoolpremises, including noise from staff,students and equipment within thebuilding or in the playground. Noisetransmitted from adjacent spaces isaddressed by the airborne and impactsound insulation requirements. equipment used in the space (egmachine tools, CNC machines, dust andfume extract equipment, compressors,computers, overhead projectors, fumecupboards). However, these noise sourcesshould be considered in the designprocess. rain noise. However, it is essential that

8

NOTES ON TABLE 1.11 Research indicates that teaching can bedisrupted by individual noisy events such asaircraft flyovers, even where the noise level isbelow the limits in Table 1.1. For roomsidentified in Table 1.1 having limits of 35 dB orless the noise level should not regularly exceed55 dB LA1,30min.2 Acoustic considerations of open-plan areasare complex and are discussed in Section1.1.7 and Section 4. 3 Studios require specialised acousticenvironments and the noise limits for these willvary with the size, intended use and type ofroom. In some cases noise limits below 30 dB LAeq may be required, and separatelimits for different types of noise may beappropriate; specialist advice should be sought.4 Halls are often multi-functional spaces(especially in primary schools) used foractivities such as dining, PE, drama, music,assembly, and performing plays and concerts.In such multi-functional spaces the designershould design to the lowest indoor ambientnoise level for which the space is likely to beused. For large halls used for formal drama andmusic performance lower noise levels thanthose in Table 1.1 are preferable, and levels of25 dB LAeq,30min may be appropriate. In thesecases specialist advice should be sought.

Specification of acoustic performance1

9Table 1.1: Performance standardsfor indoor ambient noise levels - upperlimits for the indoor ambient noiselevel, LAeq,30min

Type of room

Nursery school playroomsNursery school quiet roomsPrimary school: classrooms, class bases, generalteaching areas, small group roomsSecondary school: classrooms, general teaching areas,seminar rooms, tutorial rooms, language laboratoriesOpen-plan2

Teaching areasResource areasMusicMusic classroomSmall practice/group roomEnsemble room Performance/recital roomRecording studio3

Control room for recordingLecture rooms Small (fewer than 50 people)Large (more than 50 people)Classrooms designed specifically for use by hearingimpaired students (including speech therapy rooms)Study room (individual study, withdrawal, remedialwork, teacher preparation)LibrariesQuiet study areasResource areasScience laboratoriesDrama studiosDesign and Technology Resistant materials, CADCAM areas Electronics/control, textiles, food,

graphics, design/resource areasArt roomsAssembly halls4, multi-purpose halls4 (drama, PE,audio/visual presentations, assembly, occasional music) Audio-visual, video conference roomsAtria, circulation spaces used by studentsIndoor sports hallDance studioGymnasiumSwimming poolInterviewing/counselling rooms, medical rooms Dining roomsAncillary spaces Kitchens*

Offices*, staff rooms*Corridors*, stairwells*Coats and changing areas*Toilets*

Room classification for the purpose ofairborne sound insulation in Table 1.2

Activity noise(Source room)HighLow

Average

Average

AverageAverage

Very highVery highVery highVery highVery highHigh

AverageAverage

Average

Low

LowAverageAverageHigh

High

AverageAverage

HighAverageAverageHighHighHighHighLowHighHighAverageAverage - HighHighAverage

Noise tolerance(Receiving room)LowLow

Low

Low

MediumMedium

LowLowVery lowVery lowVery lowLow

LowVery low

Very low

Low

LowMediumMediumVery low

High

MediumMedium

LowLowMediumMediumMediumMediumHighLowHighHighMediumHighHighHigh

Upper limit for theindoor ambientnoise levelLAeq,30min (dB)

351

351

351

351

401

401

351

351

301

301

301

351

351

301

301

351

351

4040301

40

4040

351

351

4540404050351

455040454550

1Specification of acoustic performance

* Part E of Schedule 1 to the Building Regulations 2000 (as amended by SI 2002/2871) applies to teaching and learning spaces and is not intended to coveradministration and ancillary spaces (see under Scope in the Introduction). For theseareas the performance standards are for guidance only.

10

this noise is considered in the design oflightweight roofs and roof lights as it cansignificantly increase the indoor ambientnoise level (see the design guidance inSection 3.1.1). It is intended that aperformance standard for rain noise willbe introduced in a future edition ofBB93. To satisfy this edition of BB93 itshould be demonstrated to the BuildingControl Body that the roof has beendesigned to minimise rain noise (seeSection 1.2).

Table 1.1 contains the required upperlimits for the indoor ambient noise levelsfor each type of unoccupied space. Thenoise levels in Table 1.1 are specified interms of LAeq,30min. This is an averagenoise level over 30 minutes, as explainedin Appendix 1. The specified levels referto the highest equivalent continuous A-weighted sound pressure level,

LAeq,30min, likely to occur during normalteaching hours. The levels due to externalsources will depend on weatherconditions (eg wind direction) and localactivities. High noise levels due toexceptional events may be disregarded.

The indoor ambient noise levels inTable 1.1 apply to finished butunoccupied and unfurnished spaces.

Tonal and intermittent noises aregenerally more disruptive than othertypes of noise at the same level. Noisefrom plant, machinery and equipment innoisesensitive rooms should therefore beconstant in nature and should not containany significant tonal or intermittentcharacteristics. Noise from buildingservices which is discontinuous, tonal, orimpulsive (ie noise which can bedistracting) should be reduced to a level atleast 5 dB below the specified maximum.

Minimum DnT (Tmf,max),w (dB) Activity noise in source room (see Table 1.1)

Low Average High Very high

High 30 35 45 55

Medium 35 40 50 55

Low 40 45 55 55

Very low 45 50 55 60

Noi

se t

oler

ance

in

rec

eivi

ng r

oom

(see

Tab

le 1

.1)

Table 1.2: Performancestandards for airbornesound insulation betweenspaces - minimum weightedBB93 standardized leveldifference, DnT (Tmf,max),w

NOTES ON TABLE 1.21 Each value in the table is the minimum required to comply with the Building Regulations. A valueof 55 dB DnT (Tmf,max),w between two music practice rooms will not mean that the music will beinaudible between the rooms; in many cases, particularly if brass or percussion instruments areplayed, a higher value is desirable. 2 Where values greater than 55 dB DnT (Tmf,max),w are required it is advisable to separate the roomsusing acoustically less sensitive areas such as corridors and storerooms. Where this is not possible,high performance constructions are likely to be required and specialist advice should be sought.3 It is recommended that music rooms should not be placed adjacent to design and technologyspaces or art rooms.4 These values of DnT (Tmf,max),w include the effect of glazing, doors and other weaknesses inthe partition. In general, normal (non-acoustic) doors provide much less sound insulation than thesurrounding walls and reduce the overall DnT (Tmf,max),w of the wall considerably, particularly forvalues above 35 dB DnT (Tmf,max),w. Therefore, doors should not generally be installed inpartitions between rooms requiring values above 35 dB DnT (Tmf,max),w unless acoustic doors,door lobbies, or double doors with an airspace are used. This is not normally a problem as roomsare usually accessed via corridors or circulation spaces so that there are at least two doorsbetween noise-sensitive rooms. For more guidance see Section 3.

Specification of acoustic performance1

11

In rooms with very low noise tolerance,including music rooms, studios androoms used for formal music and dramaperformance, any audible intermittentnoise source of this type is likely to causeproblems and specialist advice should besought.

1.1.2. Airborne sound insulationbetween spaces The objective is to attenuate airbornesound transmitted between spacesthrough walls and floors.

Table 1.2 contains the requiredminimum airborne sound insulationvalues between rooms. These values aredefined by the activity noise in the sourceroom and the noise tolerance in thereceiving room. The activity noise andnoise tolerance for each type of room aregiven in Table 1.1. The airborne soundinsulation is quoted in terms of theweighted BB93 standardized leveldifference, DnT (Tmf,max),w, between tworooms.

The BB93 standardized leveldifference, DnT (Tmf,max), is the leveldifference, in decibels, corresponding to aBB93 reference value of the reverberationtime in the receiving room:

DnT(Tmf,max) = D+10 lg dB

whereD is the level difference (dB)

T is the reverberation time in thereceiving room (s)Tmf,max is the reference reverberationtime equal to the upper limit of thereverberation time, Tmf, given in Table1.5 for the type of receiving room. Thisreference reverberation time shall be usedfor all frequency bands.

The BB93 standardized leveldifference, DnT (Tmf,max),w, is measuredin accordance with BS EN ISO 140-4:1998[1] in octave or one-third octavebands, the results are weighted andexpressed as a single-number quantity,DnT (Tmf,max),w, in accordance with BSEN ISO 717-1:1997[2].

The prediction and measurement ofDnT (Tmf,max),w between two roomsmust be carried out in both directions asits value depends upon the volume of thereceiving room, see the example below.

1.1.3 Airborne sound insulationbetween circulation spaces and otherspaces used by studentsThe objective is to attenuate airbornesound transmitted between circulationspaces (eg corridors, stairwells) and otherspaces used by students.

Table 1.3 contains the requiredminimum airborne sound insulation forthe separating wall construction, anydoorset in the wall and any ventilators inthe wall. The airborne sound insulationfor walls and doorsets is quoted in terms

Example to determine the performance standards for airborne sound insulation between a music classroom and asecondary school general teaching area.

From the music classroom (source room) to the general teaching area (receiving room): Table 1.1 shows that music classrooms have very high activity levels and that general teaching areas have lowtolerance. Table 1.2 shows that at least 55 dB DnT (0.8s),w is required.

From the general teaching area (source room) to the music classroom (receiving room): Table 1.1 shows that general teaching areas have average activity levels and that music classrooms have low tolerance.Table 1.2 shows that at least 45 dB DnT (1.0s),w is required.

In this example the requirement to control noise from the music classroom to the general teaching area is more stringent.

The construction should be designed to achieve at least 55 dB DnT (0.8s),w from the music classroom (source room) tothe general teaching area (receiving room), and at least 45 dB DnT (1.0s),w from the general teaching area (source room)to the music classroom (receiving room).

1Specification of acoustic performance

TTmf,max

of the weighted sound reduction index,Rw, which is measured in the laboratory.The airborne sound insulation forventilators is quoted in terms of theweighted element-normalized leveldifference, Dn,e,w. The performancestandard for ventilators is quoted in termsof Dn,e,w 10lgN where N is the numberof ventilators with airborne soundinsulation Dn,e,w.

The weighted sound reduction index ismeasured in accordance with BS EN ISO140-3:1995[3] and rated in accordancewith BS EN ISO 717-1:1997[2].

The weighted element-normalized leveldifference is measured in accordance withBS EN 20140-10:1992[4] and rated inaccordance with BS EN ISO 717-1:1997[2].

Table 1.3 excludes: service corridors adjacent to spaces thatare not used by students lobby corridors leading only to spacesused by students that have a hightolerance to noise as defined in Table 1.1.

The performance standard is set using

12

Type of space used by students Minimum Rw (dB) MinimumDn,e,w 10lgN

Wall including Doorset1 (dB)any glazing

All spaces except music rooms 40 30 39

Music rooms2 45 35 453

Table 1.3: Performancestandards for airbornesound insulation betweencirculation spaces andother spaces used bystudents - minimum soundreduction index, Rw andminimum Dn,e,w 10lgN(laboratory measurements}

a laboratory measurement because of thedifficulty in accurately measuring theairborne sound insulation between roomsand corridors, or rooms and stairwells inthe field. Therefore it is crucial that theairborne sound insulation of the walland/or doorset is not compromised byflanking sound transmission, eg soundtransmission across the junction betweenthe ceiling and the corridor wall (seeguidance in Section 3.10.3).

1.1.4. Impact sound insulation offloorsThe objective is to attenuate impactsound (eg footsteps) transmitted intospaces via the floor.

Table 1.4 contains the recommendedmaximum weighted BB93 standardizedimpact sound pressure level, LnT (Tmf,max),w, for receiving rooms ofdifferent types and uses.

The BB93 standardized impact soundpressure level, LnT (Tmf,max), is theimpact sound pressure level in decibelscorresponding to a BB93 reference valueof the reverberation time in the receivingroom:

LnT(Tmf,max) = Li 10 lg dB

whereL i is the impact sound pressure level (dB)T is the reverberation time in thereceiving room (s)Tmf,max is the reference reverberationtime equal to the upper limit of thereverberation time, Tmf , given in Table1.5 for the type of receiving room. Thisreference reverberation time shall be usedfor all frequency bands.

The BB93 standardized impact soundpressure level, LnT (Tmf,max), is measured

NOTES ON TABLE 1.31 The Rw ratings are for the doorset alone.Manufacturers sometimes provide doorsetsound insulation data as a combined rating forthe wall and doorset where the Rw refers to theperformance of an 10 m2 high-performancewall containing the doorset. This is notappropriate as it gives higher figures than theRw of the doorset itself. However, withknowledge of the wall and doorset areas theRw of the doorset can be calculated from thesetest results. 2 Special design advice is recommended.3 Wherever possible, ventilators should not beinstalled between music rooms and circulationspaces.

Specification of acoustic performance1

TTmf,max

13

Type of room(receiving room)

Nursery school playroomsNursery school quiet roomsPrimary school: classrooms, class bases, general teaching areas, small group roomsSecondary school: classrooms, general teachingareas, seminar rooms, tutorial rooms, language laboratoriesOpen-planTeaching areasResource areasMusicMusic classroomSmall practice/group roomEnsemble room Performance/recital roomRecording studioControl room for recordingLecture roomsSmall (fewer than 50 people)Large (more than 50 people)Classrooms designed specifically for use by hearingimpaired students (including speech therapy rooms)Study room (individual study,withdrawal, remedial work,teacher preparation)LibrariesScience laboratoriesDrama studiosDesign and Technology Resistant materials, CADCAM areas Electronics/control, textiles, food,

graphics, design/resource areasArt roomsAssembly halls, multi-purpose halls (drama, PE, audio/visual presentations, assembly,occasional music) Audio-visual, video conference roomsAtria, circulation spaces used by studentsIndoor sports hallGymnasiumDance studioSwimming poolInterviewing/counselling rooms, medical rooms Dining roomsAncillary spaces Kitchens*

Offices*, staff rooms*Corridors*, stairwells*Coats and changing areas*Toilets*

Maximum weightedBB93 standardizedimpact soundpressure level LnT (Tmf,max),w (dB)

6560

60

60

6060

555555555555

6055

55

60606555

65

6060

6060656565606560656565656565

Table 1.4: Performance standards for impact sound insulation of floors -maximum weighted BB93 standardized impact sound pressure level LnT (Tmf,max),w

in accordance with BS EN ISO 140-7:1998[5] in octave or one-third octavebands, the results are weighted andexpressed as a single-number quantity,LnT (Tmf,max),w, in accordance with BS EN ISO 717-2:1997[6].

Impact sound insulation should bedesigned and measured for floors withouta soft covering (eg carpet, foam backedvinyl) except in the case of concretestructural floor bases where the softcovering is an integral part of the floor.

1.1.5. Reverberation in teaching andstudy spaces The objective is to provide suitablereverberation times for (a) clearcommunication of speech betweenteacher and student, and betweenstudents, in teaching and study spaces and(b) music teaching and performance.

Table 1.5 contains the required mid-frequency reverberation times for roomswhich are finished but unoccupied andunfurnished. The reverberation time isquoted in terms of the mid-frequencyreverberation time, Tmf , the arithmeticaverage of the reverberation times in the500 Hz, 1 kHz and 2 kHz octave bands.

Sound absorption from pinboards andnoticeboards can change when they arecovered up or painted. Absorptioncoefficients for pinboards and noticeboardsused in design calculations should be forfully covered or painted boards, asappropriate. If these data are not availablethen the absorption coefficient for theboard area used in the design calculationshould be the absorption coefficient ofthe wall to which the board is attached.

* Part E of Schedule 1 to the BuildingRegulations 2000 (as amended by SI 2002/2871) applies to teaching andlearning spaces and is not intended to coveradministration and ancillary spaces (see underScope in the Introduction). For these areas theperformance standards are for guidance only.

1Specification of acoustic performance

14

1.1.6. Sound absorption in corridors,entrance halls and stairwellsThe objective is to absorb sound incorridors, entrance halls and stairwells sothat it does not interfere with teachingand study activities in adjacent rooms.

The requirement is to provideadditional sound absorption in corridors,entrance halls and stairwells. The amountof additional absorption should becalculated according to ApprovedDocument E[7], Section 7. This describestwo calculation methods, A and B, forcontrolling reverberation in the commoninternal parts of domestic buildings. Oneof these methods should be used todetermine the amount of absorptionrequired in corridors, entrance halls andstairwells in schools. (See samplecalculations using calculation methods Aand B in Appendix 7.)

Sound absorption from pinboards andnoticeboards can change when they arecovered up or painted. Absorptioncoefficients for pinboards andnoticeboards used in design calculationsshould be for fully covered or paintedboards, as appropriate. If these data arenot available then the absorption

Type of roomNursery school playroomsNursery school quiet roomsPrimary school: classrooms, class bases, generalteaching areas, small group roomsSecondary school: classrooms, general teachingareas, seminar rooms, tutorial rooms, language laboratoriesOpen-planTeaching areasResource areasMusicMusic classroomSmall practice/group roomEnsemble room Performance/recital room3

Recording studioControl room for recordingLecture rooms3

Small (fewer than 50 people)Large (more than 50 people)Classrooms designed specifically for use by hearingimpaired students (including speech therapy rooms)Study room (individual study,withdrawal, remedial work, teacher preparation)LibrariesScience laboratoriesDrama studiosDesign and Technology Resistant materials, CADCAM areas Electronics/control, textiles, food,

graphics, design/resource areasArt roomsAssembly halls, multi-purpose halls (drama, PE,audio/visual presentations, assembly, occasional music)2,3

Audio-visual, video conference roomsAtria, circulation spaces used by studentsIndoor sports hallGymnasiumDance studioSwimming poolInterviewing/counselling rooms, medical rooms Dining roomsAncillary spacesKitchens*Offices*, staff rooms*Corridors, stairwellsCoats and changing areas*Toilets*

Tmf1 (seconds)

15

coefficient for the board area used in thedesign calculation should be theabsorption coefficient of the wall to whichthe board is attached.

1.1.7 Speech intelligibility in open-plan spaces The objective is to provide clearcommunication of speech between teacherand student, and between students, inopen-plan teaching and study spaces.

For enclosed teaching and study spacesit is possible to achieve good speechintelligibility through specification of theindoor ambient noise level, soundinsulation and reverberation time. Open-plan spaces require extra specification asthey are significantly more complexacoustic spaces. The main issue is that thenoise from different groups of peoplefunctioning independently in the spacesignificantly increases the backgroundnoise level, thus decreasing speechintelligibility.

Open-plan spaces are generallydesigned for high flexibility in terms ofthe layout of teaching and study spaces.In addition, the layout is rarely finalisedbefore the school is operational. Thisincreases the complexity of assessingspeech intelligibility in the open-planspace. Therefore, at an early stage in thedesign, the designer should establish theexpected open-plan layout and activityplan with the client. The open-plan layout should include: the positions at which the teacher willgive oral presentations to groups ofstudents the seating plan for the students andteachers in each learning base the learning base areas.The activity plan should include: the number of teachers giving oralpresentations to groups of students at anyone time the number of students engaged indiscussion at any one time the number of people walking throughthe open-plan space (eg along corridorsand walkways) during teaching and studyperiods any machinery (eg engraving machines,CNC machines, dust and fume extract

equipment, computers, printers, AVA)operating in the open-plan space.

The expected open-plan layout andactivity plan should be agreed as the basison which compliance with BB93 can bedemonstrated to the Building ControlBody.

The activity plan should be used toestablish the overall noise level due to thecombination of the indoor ambient noiselevel, all activities in the open-plan space(including teaching and study), andtransmitted noise from adjacent spaces. Acomputer prediction model should beused to calculate the Speech TransmissionIndex (STI)[8] in the open-plan space,using the overall noise level as thebackground noise level. Other methods ofestimating STI may also be applicable.

The performance standard for speechintelligibility in open-plan spaces isdescribed in terms of the SpeechTransmission Index in Table 1.6. Thecalculated value of STI should be between0.60 and 1.00, which gives an STI ratingof either good or excellent. Thisperformance standard applies to speechtransmitted from teacher to student,student to teacher and student to student.

The performance standard in Table 1.6is intended to ensure that open-planspaces in schools are only built whensuited to the activity plan and layout.With some activity plans, room layoutsand open-plan designs it will not bepossible to achieve this performancestandard. At this point in the designprocess the decision to introduce anopen-plan space into the school should bethoroughly re-assessed. If, after re-assessment, there is still a need for theopen-plan space, then the inclusion ofoperable walls between learning basesshould be considered. These operablewalls will form classrooms and be subjectto the airborne sound insulationrequirements in Table 1.2. It is notappropriate to simply adjust the activity

Room type

Open-plan teaching and study spaces

Speech Transmission Index (STI)

>0.60

Table 1.6: Performancestandard for speechintelligibility in open-planspaces SpeechTransmission Index (STI)

1Specification of acoustic performance

16

plan until the performance standard forspeech intelligibility is met.

Computer prediction software capableof simulating an impulse response shouldbe used to create a three-dimensionalgeometric model of the space, comprisingsurfaces with scattering coefficients andindividually assigned absorptioncoefficients for each frequency band. Themodel should allow for the location andorientation of single and multiple sourceswith user-defined sound power levels anddirectivity. (See guidance on computerprediction models on the DfES acousticswebsite www.teachernet.gov.uk/acoustics.)

Assumptions to be made in theassessment of speech intelligibility are: for students, when seated, the headheight (for listening or speaking) is 0.8 mfor nursery schools, 1.0 m for primaryschools and 1.2 m for secondary schools for students, when standing, the headheight (for listening or speaking) is 1.0 mfor nursery schools, 1.2 m for primaryschools and 1.65 m for secondary schools for teachers, when seated, the headheight (for listening or speaking) is 1.2 m for teachers, when standing, the headheight (for listening or speaking) is 1.65 m the background noise level is the overallnoise level due to all activities (includingteaching and study) in the open-plan space.

1.2 Demonstrating compliance tothe Building Control BodyThe preferred means of demonstratingcompliance to the Building Control Bodyis to submit a set of plans, constructiondetails, material specifications, andcalculations, as appropriate for each areaof the school which is covered byRequirement E4 of the BuildingRegulations.The plans should identify: the highest estimate for the indoorambient noise level, LAeq,30min, in eachspace and the appropriate upper limitfrom Table 1.1 the estimated weighted BB93standardized level difference, DnT (Tmf,max),w, between spaces and theappropriate minimum value from Table 1.2 the proposed values of Rw for partitionwalls and for doors, Dn,e,w 10lgN for

ventilators between circulation spaces andother spaces used by students, and theappropriate minimum values from Table 1.3 the estimated weighted BB93standardized impact sound pressure level,LnT (Tmf,max),w, of floors above spacesand the appropriate maximum valuesfrom Table 1.4 the estimated value of mid frequencyreverberation time Tmf in each space andthe appropriate range of values fromTable 1.5 the proposed absorption treatments incorridors, entrance halls and stairwells for open plan spaces, the estimatedrange of STI values for speechcommunication from teacher to student,student to teacher and student to student.

The supporting information shouldinclude: construction details and materialspecifications for the external buildingenvelope construction details and materialspecifications for all wall and floorconstructions, including all flankingdetails calculations of the sound insulationDnT (Tmf,max),w and LnT (Tmf,max),w calculations of reverberation times inteaching and study spaces calculations of the absorption area tobe applied in corridors, entrance halls andstairwells measurements and/or calculationsdemonstrating how rain noise has beencontrolled sound insulation test reports(laboratory and/or field) sound absorption test reports(laboratory) activity plan and layout for open-planspaces.

An example of a submission to aBuilding Control Body, with explanatorynotes, is contained in Appendix 10.

1.2.1 Alternative performancestandardsIn some circumstances alternativeperformance standards may beappropriate for specific areas withinindividual schools for particular

Specification of acoustic performance1

educational, environmental or health andsafety reasons. In these cases, thefollowing information should be providedto the Building Control Body: a written report by a specialist acousticconsultant, clearly identifying (a) all areasof non-compliance with BB93performance standards (b) the proposedalternative performance standards and (c)the technical basis upon which thesealternative performance standards havebeen chosen written confirmation from theeducational provider (eg school or LocalEducation Authority) of areas of non-compliance, together with the justificationfor the need and suitability of thealternative performance standards in eachspace.

1.3 Demonstrating compliance tothe clientTo ensure that the performance standardsare met, it is recommended that the clientshould include a requirement for acoustictesting in the building contract.

The design calculations submitted tothe Building Control Body demonstrateonly that the construction has thepotential to meet the performancestandards in Section 1.1. In practice, theperformance of the construction isstrongly influenced by workmanship onsite. If the design calculations anddetailing are correct, the most likelycauses of failure to meet the performancestandards will be poor workmanship,product substitution and design changeson site. Therefore, acoustic testing isrecommended.

The DfES acoustics website(www.teachernet.gov.uk/acoustics) will beused to encourage manufacturers andothers to disseminate acoustic test resultsalongside construction details forconstructions that consistently satisfy theperformance standards.

1.3.1 Timetabling of acoustic testingTimetabling of acoustic testing isimportant because any test that results ina failure to satisfy the performancestandards will require remedial work torectify the failure and potential design

changes to other parts of the building.For this reason it is desirable, wherepossible, to complete a sample set ofrooms in the school for advance testing.

1.3.2 Remedial treatmentsWhere the cause of failure is attributed tothe construction, other rooms that havenot been tested may also fail to meet theperformance standards. Therefore,remedial treatment may be needed inrooms other than those in which the testswere conducted. The efficacy of anyremedial treatment should be assessedthrough additional testing.

1.3.3 Indoor ambient noise levels inunoccupied spaces To demonstrate compliance with thevalues in Table 1.1, measurements ofindoor ambient noise levels should betaken in at least one in four roomsintended for teaching and/or studypurposes, and should include rooms onthe noisiest faade. These rooms shouldbe finished and unoccupied but may beeither furnished or unfurnished.Measurements should be made whenexternal noise levels are representative ofconditions during normal schooloperation.

During measurements, the followingshould apply: Building services (eg ventilation system,plant) should be in use during themeasurement period. For mechanically ventilated rooms, theplant should be running at its maximumdesign duty. For naturally ventilated rooms, theventilators or windows should be open asrequired to provide adequate ventilation. There should be no more than oneperson present in the room. (The valuesin Table 1.1 allow for one person to bepresent in the room during the test) There should be dry weatherconditions outside.

Measurements of LAeq,T should bemade at least 1 m from any surface of theroom and at 1.2 m above floor level in atleast three positions that are normallyoccupied during teaching or studyperiods. A sound level meter complying

17

1Specification of acoustic performance

with BS EN 60804:2001 (IEC60804:2001)[9] should be used. Furtherinformation on noise measurementtechniques is available in the Associationof Noise Consultants Guidelines on NoiseMeasurement in Buildings[10].

Where there is negligible change innoise level over a teaching period,measurements of LAeq,T over a timeperiod much shorter than 30 minutes (egLAeq,5min) can give a good indication ofwhether the performance standard interms of LAeq,30min is likely to be met.However, if there are significant variationsin noise level, for example due tointermittent noise events such as aircraftor railways, measurements should betaken over a typical 30 minute period inthe school day.

1.3.4 Airborne sound insulationbetween spaces To demonstrate compliance with thevalues in Table 1.2, measurements ofairborne sound insulation should be takenbetween vertically and horizontallyadjacent rooms where the receiving roomis intended for teaching and/or studypurposes. At least one in four roomsintended for teaching and study purposesshould be tested. Measurements shouldbe taken in the direction with the morestringent airborne sound insulationrequirement.

During measurements, the ventilatorsor windows should be open as required toprovide adequate ventilation in both thesource room and the receiving room.

Measurements should be made inaccordance with BS EN ISO 140-4:1998[1] and the additional guidance inApproved Document E[7] Annex B,paragraphs B2.3 B2.8. Performanceshould be rated in accordance with BSEN ISO 717-1:1997[2].

1.3.5 Airborne sound insulationbetween circulation spaces and otherspaces used by studentsIt is not intended that field measurementsshould be taken between circulationspaces and other spaces used by students.Laboratory data for the wall, doorsets (ifany) and ventilators (if any) should be

presented as evidence of compliance withthe values in Table 1.3.

1.3.6 Impact sound insulation To demonstrate compliance with thevalues in Table 1.4, measurements ofimpact sound insulation should be takenbetween vertically adjacent rooms, wherethe receiving room is intended forteaching and study purposes. At least onein four teaching/study rooms below aseparating floor should be tested.

Measurements should be made inaccordance with BS EN ISO 140-7:1998[5]. Performance should be ratedin accordance with BS EN ISO 717-2:1997[6].

Impact sound insulation should bemeasured on floors without a softcovering (eg carpet, foam backed vinyl),except in the case of concrete structuralfloor bases where the soft covering is anintegral part of the floor.

1.3.7 Reverberation in teaching andstudy spacesTo demonstrate compliance with thevalues in Table 1.5, measurements ofreverberation time should be taken in atleast one in four rooms intended forteaching and study purposes.

One person may be present in theroom during the measurement.

Depending upon the completionsequence for spaces within the school, itmay be possible to reduce themeasurement effort by utilisingmeasurements of reverberation time thatare required as part of airborne or impactsound insulation measurements. For thisreason, two measurement methods,described below, are proposed for themeasurement of reverberation time. Forthe purpose of demonstrating compliance,either method can be used to assesswhether the performance standards havebeen met. If one method demonstratescompliance with the performancestandard and the other demonstratesfailure, then the performance standardshould be considered to have been met.Measurement method 1: Measurementsshould be made in accordance with eitherlow coverage or normal coverage

18

Specification of acoustic performance1

measurements described in BS EN ISO3382:2000[11].Measurement method 2: Reverberationtime measurements should be made inaccordance with BS EN ISO 140-4:1998[1] (airborne sound insulation) orBS EN ISO 140-7:1998[5] (impact soundinsulation) in octave bands.

1.3.8 Sound absorption in corridors,entrance halls and stairwellsIt is not intended that field measurementsof reverberation time should be taken incorridors, entrance halls and stairwells.

1.3.9 Speech intelligibility in open-plan spacesTo demonstrate compliance with thevalues in Table 1.6, measurements of theSpeech Transmission Index (STI) shouldbe taken in at least one in ten studentpositions in the open-plan spaces.

Measurements should be made inaccordance with BS EN 60268-16:1998[8].

Measurements should be made usingthe following heights for listening orspeaking: to represent seated students, a headheight of 0.8 m for nursery schools, 1.0 mfor primary schools and 1.2 m forsecondary schools to represent standing students, a headheight of 1.0 m for nursery schools, 1.2 mfor primary schools and 1.65 m forsecondary schools to represent seated teachers, a headheight of 1.2 m to represent standing teachers, a headheight of 1.65 m.

Simulation of the estimated occupancynoise should be carried out in the STImeasurement. This noise level will havebeen established at the design stage (seeSection 1.1.7) and is defined as the noiselevel due to the combination of theindoor ambient noise level, all activities inthe open-plan space (including teachingand study), and transmitted noise fromadjacent spaces.

References[1] BS EN ISO 140-4:1998 Acoustics Measurement of sound insulation in buildingsand of building elements. Part 4. Fieldmeasurements of airborne sound insulationbetween rooms.[2] BS EN ISO 717-1:1997 Acoustics Ratingof sound insulation in buildings and of buildingelements. Part 1. Airborne sound insulation.[3] BS EN ISO 140-3:1995 Acoustics Measurement of sound insulation in buildingsand of building elements. Part 3. Laboratorymeasurement of airborne sound insulation ofbuilding elements.[4] BS EN 20140-10:1992 Acoustics Measurement of sound insulation in buildingsand of building elements. Part 10. Laboratorymeasurement of airborne sound insulation ofsmall building elements.[5] BS EN ISO 140-7:1998 Acoustics Measurement of sound insulation in buildingsand of building elements. Part 7. Fieldmeasurements of impact sound insulation offloors.[6] BS EN ISO 717-2:1997 Acoustics Ratingof sound insulation in buildings and of buildingelements. Part 2. Impact sound insulation.[7] Approved Document E Resistance to thepassage of sound. Stationery Office 2003. ISBN 0 11 753 642 3.www.odpm.gov.uk[8] BS EN 60268-16:1998 Sound systemequipment Part 16: Objective rating ofspeech intelligibility by speech transmissionindex.[9] BS EN 60804:2001 (IEC 60804:2001)Integrating-averaging sound level meters.[10] Guidelines on Noise Measurement inBuildings, Part 1: Noise from Building Servicesand Part 2: Noise from External Sources.Association of Noise Consultants.[11] BS EN ISO 3382:2000 Acoustics Measurement of the reverberation time ofrooms with reference to other acousticalparameters.

19

1Specification of acoustic performance

20

21

2.1 Choosing a siteThe acoustic design of a school starts withthe selection of the site, a noise survey ofthe site and planning the layout of theschool buildings.

Economic sites for new schools witheasy access to transport often suffer fromtraffic noise and pollution. In the past,schools have sometimes been built onsites which would not normally have beenconsidered suitable for housing. This hasbeen in part because schools have notalways been recognised as requiringparticularly high environmental standards,and in part because there has been lessformal control or regulation of noiselevels in schools than for housing.

Where school sites are adjacent to busyroads they will require the use ofintelligent design, zoning, noise screeningand, if necessary, sound insulatingbuilding envelopes together withmechanical ventilation or acousticallydesigned passive ventilation.

Many of the acoustic problems inexisting schools derive directly from theschools location in a noisy area. Forexisting schools, noise from road traffic isa common problem, but in some areasnoise from railways and aircraft isintrusive[1]. Noise from industrial andleisure sources is a less frequent problemand can normally be dealt with at sourceby the Local Authority using their powersunder the Environmental Pollution Act.

2.2 Recommendations for externalnoise levels outside school buildingsAlthough Requirement E4 does not applyto external noise, the followingrecommendations are considered goodpractice for providing good acoustic

conditions outside school buildings.For new schools, 60 dB LAeq,30min

should be regarded as an upper limit forexternal noise at the boundary of externalpremises used for formal and informaloutdoor teaching, and recreational areas.

Under some circumstances it is possibleto meet the specified indoor ambientnoise levels on sites where external noiselevels are as high as 70 dB LAeq,30min butthis will require considerable buildingenvelope sound insulation, screening orbarriers.

Noise levels in unoccupiedplaygrounds, playing fields and otheroutdoor areas should not exceed 55 dBLAeq,30min and there should be at leastone area suitable for outdoor teachingactivities where noise levels are below 50 dB LAeq,30min. If this is not possibledue to a lack of suitably quiet sites,acoustic screening should be used toreduce noise levels in these areas as muchas practicable, and an assessment ofpredicted noise levels and of options forreducing these should be carried out.

Playgrounds, outdoor recreation areasand playing fields are generally consideredto be of relatively low sensitivity to noise,and indeed playing fields may be used asbuffer zones to separate school buildingsfrom busy roads where necessary.However, where used for teaching, forexample sports lessons, outdoor ambientnoise levels have a significant impact oncommunication in an environment whichis already acoustically less favourable thanmost classrooms. Ideally, noise levels onunoccupied playing fields used forteaching sport should not exceed 50 dBLAeq,30min. If this is not possible at alllocations, there should be at least one area

Noise control 2Section 2 gives recommendations and guidance concerning noise control,starting with the choice of a site and the control of external noise. Local

government planning policy will be influenced by the recommendations onmaximum external noise levels in playing fields and other external areas usedby the school. Section 2 also includes discussion of the means of controlling

indoor ambient noise.

SE

CT

ION

22

at which noise levels are below 50 dBLAeq,30min so that some outdoorteaching is possible.

Acoustic screening from fences, wallsor buildings may be used to protectplaygrounds from noise. At positions nearthe screen, traffic noise can be reduced byup to 10 dB(A).

All external noise levels in this sectionapply to measurements made atapproximately head height and at least 3 mfrom any reflecting surface other than theground.

2.3 Noise surveyFigure 2.1 shows typical external andinternal sources of noise which can affectnoise levels inside a school.

In order to satisfy the limits for theindoor ambient noise levels in Table 1.1,it is necessary to know the external noiselevel so that the building envelope can bedesigned with the appropriate soundinsulation.

The external noise level should beestablished by carrying out a noisemeasurement survey. (Note that a briefsurvey is advisable even if the site appearsto be quiet, in case there are noisy eventsat certain times of the day.) Themeasurements should be taken duringFigure 2.1: Typical

sources of noise

PLANTROOM NOISEAND VIBRATION

NOISYCORRIDORS

NOISE VIA OPEN WINDOWS

WEATHER& RAIN NOISE

BREAK-OUT/BREAK-INOF DUCTBORNE

NOISE

DUCTBORNE NOISE

PLUMBING NOISE

DUCTBORNE NOISE FAN

TRAFFIC NOISEAND VIBRATION

PLAYGROUNDNOISE

NOISE THROUGHDOORS & WALLS

AIRCRAFT NOISE

typical school hours and include noisyevents (eg road traffic at peak hours,worst case runway usage in the case ofairports, etc). The measurements mustalso take account of the weatherconditions. For long-distance propagationof noise, the measured level is affected bywind gradients, temperature gradients andturbulence. With wind, the noise level isgenerally increased downwind or reducedupwind. (Note that temperatureinversions can radically change noisepropagation, but tend to occur only atnight-time, outside school hours.)

A noise measurement survey mustinclude octave or one-third octavefrequency band levels. This is because theattenuation of sound, for example by asound insulating wall or noise barrier,depends upon the frequency of sound. Ingeneral materials and barriers are lesseffective at controlling low frequencynoise than mid and high frequency noise.Although overall noise levels andperformance standards can be quoted asoverall A-weighted levels, calculationsmust be carried out in octave or one-thirdoctave bands (see Appendix 1) and theresults converted into overall A-weightedlevels.

In addition to the noise measurement

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Barrier

Soundsource Receiver

Ground

ab

c

Path difference = a + b c

Figure 2.2: Attenuationby a noise barrier as afunction of path difference

2000 Hz

1000 Hz500 Hz

250 Hz

125 Hz

30

25

20

15

10

5

0 0.5 1.0 1.5 2.0

Path difference, m

Atte

nuat

ion,

dB

survey, consideration should be given topredicting the potential increases in noiselevels due to future developments (egincreases in traffic flows, new transportschemes, changes in flight paths). Thelocal highway authority should be able toadvise on whether significant changes inroad traffic noise are expected in thefuture. This is likely to be relevant fordevelopments near new or recentlyimproved roads. Where road traffic noiselevels are likely to increase, it is reasonableto base the sound insulation requirementson the best estimate of noise levels in 15years time. Similar information is likely tobe available from railway operators, andairports. The prediction[2,3] of futureexternal noise levels should be carried outby an acoustic consultant.

If the noise measurement survey showsthat the ambient external noise levels onthe site are below 45 dB LAeq,30min, andprediction work shows that they willremain below 45 dB LAeq,30min in thefuture, no special measures are likely to benecessary to protect the buildings orplaying fields from external noise.

2.4 Road and rail noiseSources of road and rail noise requireindividual assessment because of theircharacteristics.

Road traffic noise is a function of trafficflow, percentage of heavy goods vehicles,traffic speed gradient (rate of acceleration),road surface and propagation path of thenoise.

Rail noise is a function of train type, number, speed, rail type and propagationpath of the noise.

In general it is advisable to locate aschool at least 100 m away from busyroads and railways, but in towns and citiesthis is often not possible. However, theuse of distance alone is a relativelyineffective way to reduce noise. Simplerules of thumb are that the noise levelfrom a busy road increases by 3 dB(A) fora doubling of the traffic flow anddecreases by 3 dB(A) for a doubling ofdistance from the road (over hardground).

2.5 Aircraft noiseWhere a school is to be located in an areaaffected by aircraft noise, special measuresare necessary and an acoustic consultantshould be appointed.

2.6 VibrationRailways, plant and heavy vehicles close toa school can lead to vibration within theschool buildings. This vibration can re-radiate as audible noise, even when thevibration itself is not perceptible asshaking in the building. The propagationof vibration depends on groundconditions but in general when planning anew school building it is advisable for thenoise survey to include vibrationmeasurements when there is a railwaywithin 30 m of a building, or a road withsignificant HGV traffic within 20 m. Inthese cases airborne noise is also likely tobe a problem.

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2.7 Noise barriersNoise barriers are much more effectivethan distance in reducing noise from roador rail traffic. In its simplest form a noisebarrier can be a continuous close-boardedwooden fence, with a mass of not lessthan 12 kg/m2. There is relatively littlepoint in increasing the weight of thebarrier beyond this because a significantproportion of the noise passes over thetop (or round the ends) of the barrier.

The attenuation of a barrier is afunction of the path difference, that is theextra distance that the sound has to travelto pass over the top of the barrier, seeFigure 2.2. Barriers are less effective atreducing low frequency noise than midand high frequency noise. Hence, tocalculate the effectiveness of a noisebarrier it is necessary to know the sourcenoise levels in octave or one-third octavebands (see Appendix 1).

Hedges or single trees (or rows oftrees) do not in themselves make effectivenoise barriers. A common and effectivesolution is a wooden fence to act as anoise barrier, located within a band oftrees to create an acceptable visual effect.

Barriers can also be formed by otherbuildings or by landscaping using earthbunds, see Figure 2.3. The pathdifference, and hence the attenuation, will

be affected by whether the road or railwayis in a cutting or on an embankment.

2.8 Noise from schools tosurrounding areasNoise from schools to the surroundingarea can also be a problem, andconsideration should be given to nearbyresidential and other noise-sensitivedevelopments which could be disturbedby noise from playgrounds, playing fields,music rooms and halls used for eventssuch as after school concerts and discos.The local planning authority will normallyconsider this in assessing any planningapplication for new schools or extensionsto existing premises.

The effect of playground noise onchildren inside parts of the school nearthe playground should also be consideredas part of the design.

2.9 Planning and layoutAmong the most common problemsfound in schools is noise transfer betweenrooms. To a large extent this can bedesigned out without resort to very highperformance sound insulating walls orfloors, but by good planning and zoningof the building at the earliest stages ofdesign. At this stage it is possible toidentify noise-sensitive areas and to

POORNo acoustical shieldingfrom landscaping

BETTERShielding from embankment would beimproved by a fence within the trees

BESTEarth bund acts as acoustic barrier, plantingacts as visual barrier

Figure 2.3: Traffic noisebarriers

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Otherclassroom

Store Store

Store

Store

StoreGroupRoom

GroupRoom

GroupRoom

GroupRoom

GroupRoom

GroupRoom

Musicclassroom

Musicclassroom

StaffBase

GroupRoom

Instrumentstore

EnsembleRoom

Recording/ControlRoom

To otherdepartments

Corridorcreatesacoustic

separation

Easyaccess tosupportspaces

Storesprovide

acousticbuffer

Acoustic separationfor ensemble room and

group rooms

Store

Store

GroupRoom

Fig 2.4: Planning acousticbuffer zones

separate these from noisy areas usingbuffer zones such as storerooms,corridors or less sensitive rooms, or bylocating buildings a suitable distanceapart. See Figure 2.4 for an example ofroom layout in a music department usingbuffer zones.

When considering external noise suchas that from roads, it is sensible to locatenoise-sensitive rooms, such as classrooms,away from the source.

Tables 1.1 and 1.2 give the requiredmaximum indoor ambient noise levels andthe minimum sound insulation levelsbetween rooms. The performancestandards in these tables should be usedin the early planning stages of a project todetermine (a) the layout of the school (b) the constructions needed to providesound insulation and (c) the compatibilityof school activities in adjacent rooms.

2.10 Limiting indoor ambient noiselevelsThe total indoor ambient noise level isdetermined by combining the noise levelsfrom all the known sources. The indoorambient noise level due to externalsources such as traffic must be added tothe noise from mechanical ventilation,heating systems, lighting and otherbuilding services. Unless care is taken,these individual sources can be loudenough to cause disturbance, particularlyin spaces where low indoor ambient noiselevels are required.

It should be noted that noise levels indB or dB(A) cannot be simply addedtogether. For example, two noise levels of40 dB(A) when combined will produce alevel of 43 dB(A). The addition of noiselevels is explained in Appendix 1.

2.11 Impact noise Impact noise within a space from footfallson balconies, stairs and circulation routes,or from movement of furniture or otherclass activities, can be a significantdistraction to teaching and learning.

Carpets and other soft yet resilientfloor finishes such as resilient backed vinylor rubber type flooring materials can beuseful in limiting this impact noise withina space. However, carpets may be difficult

to clean and are sometimes not usedbecause of their effect on indoor airquality and resultant health implications.

Resilient feet can also be fitted tofurniture to reduce impact noise within aspace.

2.12 Corridors, entrance halls andstairwellsNoise in corridors, entrance halls andstairwells can cause disturbance toneighbouring classrooms and otherteaching spaces. It is therefore importantthat reverberation in corridors, entrancehalls and stairwells is kept as low as

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possible in order to minimise noise levelsin these areas. The requirement is toprovide sound absorption in accordancewith Section 1.1.6. To satisfy thisrequirement, corridors outside classroomstypically need acoustically absorbentceilings and/or wall finishes. Carpets andother soft floor finishes can also help toreduce reverberation and the noise fromfootfalls. However, as discussed in Section2.11, the use of carpets may not beappropriate in all schools.

2.13 Masking noiseThe audibility and intrusiveness of noisefrom other areas (break-in noise) is afunction of both the level of the break-innoise and the noise level in the roomunder consideration (the receiving room).If the ambient noise level in the receivingroom is unnecessarily low, break-in noisewill be more audible. Hence where roomsare mechanically ventilated, the noisefrom the ventilation system can be usedto mask the noise from activities inneighbouring rooms. In these casesventilation noise should not be more than5 dB below the maximum ambient noiselevels listed in Table 1.1. For this type ofmasking to work it is important to ensurethat the ventilation noise follows a specificmasking noise curve and has no tonal orintermittent characteristics. Specialistacoustic advice is required before usingbuilding services noise for masking.

Other possible sources of maskingnoise are fan convectors, electric lightingcircuits, and constant levels of road trafficnoise, for example from distant arterialroads. However it should be noted thatthe noise from some sources (eg fans andother mechanical equipment) may causeannoyance to individuals, particularlyhearing impaired people, in somecircumstances. Also, some buildingservices systems may only operate atcertain times of the year.

2.14 Low frequency noise andhearing impaired pupilsMany hearing impaired pupils make useof low frequencies below 500 Hz toobtain information from speech.Therefore, for hearing impaired pupils tobe included in classes with pupils havingnormal hearing, special care should betaken to minimise low frequency indoorambient noise levels. Given the prevalenceof infections leading to temporary hearingloss, it is advisable to minimise lowfrequency indoor ambient noise levels inall classrooms, especially those used byyounger pupils.

The indoor ambient noise levels inTable 1.1 are given in terms ofLAeq,30min which is an A-weighted noiselevel. This is a convenient and widely-used parameter but is not a goodindicator of low frequency noise. Toassess indoor noise there are other ratingsystems in use which address lowfrequency noise but these are beyond thescope of this document. In cases wherelow frequency noise is likely to be aproblem, specialist advice from anacoustics consultant should be sought.Such cases include schools exposed tohigh levels of external noise (in excess of60 dB LAeq,30min, see Section 2.2),where sound insulation may reduce highfrequency noise while leavingcomparatively high levels of lowfrequency noise.

More information is given in CIBSEGuide B5 Noise and Vibration Controlfor HVAC.[4]

References [1] B Shield, J Dockrell, R Jeffery and I Tachmatzidis. The effects of noise on theattainments and cognitive performance ofprimary school children. Department of Health,2002.[2] Calculation of road traffic noise (CRTN),Department of Transport, The StationeryOffice, 1988.[3] Calculation of railway noise (CRN),(Supplement 1), Department of Transport, The Stationery Office, 1995.[4] CIBSE Guide B5, Noise and vibrationcontrol for HVAC, CIBSE, 2002ISBN 1 903287 2 51.

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General principles of sound insulation and typical constructions are discussed inthis section. Space does not allow all details for each type of construction to be

shown. Many such details are illustrated and discussed in greater detail inApproved Document E[1]. Further guidance and illustrations are also available in

Sound Control for Homes[2] and in manufacturers literature for proprietarymaterials and systems.

Sound insulation 3

SE

CT

ION

3.1 RoofsThe sound insulation of a pitched roofdepends upon the mass of the ceiling andthe roof layers and the presence of asound absorbing