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Hea 05 Acoustic performance

Number of credits available Minimum standards

Building type dependent

No

Aim

To ensure the buildings’ acoustic performance including sound insulation meet the appropriate standards for its purpose.

Assessment Criteria

This issue is split into two parts:

The following is required to demonstrate compliance :

Pre-requisite

  1. A suitably qualified acoustician (see Relevant definitions) is appointed by the client at the appropriate stage of the project to provide early advice on influencing outline design solutions to :
    1. External sources of noise impacting the chosen site
    2. Site layout and zoning of the building for good acoustics
    3. Acoustic requirements for users with special hearing and communication needs,
    4. Acoustic treatment of different zones and facades.

Acoustic performance standards

  1. The building meets the acoustic performance standards and testing requirements for the relevant building type and function areas as detailed below.
Pre-schools, schools and sixth form colleges (Three credits)

Room function

As required by relevant standard.
Criteria Achieve the performance standards required by Building Bulletin 93.
Credits 1
Testing Requirement A programme of pre-completion acoustic testing is carried out by a compliant test body to ensure that the relevant spaces (as built) achieve the required performance standards. Where testing identifies that spaces do not meet the standards, remedial works are carried out prior to handover and occupation. Testing must be carried out in line with Section 1.3 of BB93 and the ANC Good Practice Guide, Acoustic testing of Schools1ANC Good Practice Guide, Acoustic Testing of Schools, version 1.2, July 2011. Remedial works must be carried out in line with the Section 1.3 of BB93.

Room function

As required by relevant standard.
Criteria Rain noise - For roofs with a mass per unit area less than 150kg/m2(lightweight roofs) or any roofs with glazing/rooflights, calculations or laboratory data are required for teaching/learning spaces to demonstrate that the reverberant sound pressure level in these rooms are not more than 20dB above the indoor ambient noise level for the equivalent type of room given in Table 1.1 of Building Bulletin 93 during heavy rain.
Credits 1

Testing

Requirement

Installation of a specification compliant with the above criteria demonstrates compliance. No testing of the roof installation is required.
Notes For heavy weight roofs, or parts of the roof that are heavyweight, with a mass per unit area greater than 150kg/m2 (including those with sedum planting) that do not have any glazing/rooflights, calculations are not required, as such the credit can be awarded on a default basis of compliance. For the purpose of assessing the reverberant sound pressure levels on rooms beneath light weight roofs and roofs with glazing and/or roof lights the levels should be calculated using laboratory test data from measurements conducted in accordance with BS EN ISO 140-18 2BS EN ISO 140-18:2006 Acoustics. Measurement of sound insulation in buildings and of building elements. ‘Heavy’ rain noise excitation

Room function

As required by relevant standard.
Criteria All music accommodation (or multi-purpose halls in primary schools with no music accommodation) is to meet the performance levels set within BB93. Where noise levels are expected to exceed 95dBA (e.g. in the case of amplified music and/or percussion) the design team must demonstrate that the need for higher sound insulation has been designed out through careful space planning.
Credits 1

Testing

Requirement

As above where applicable. Where is it not considered applicable a justification and alternative means of compliance should be provided by the Suitably Qualified Acoustician
Notes

Whilst careful timetabling of lessons may also mitigate adverse acoustics issues, BREEAM’s focus for new construction is building performance. Timetabling is likely to change over the building’s lifetime, therefore, it cannot be used to demonstrate compliance with this criterion.

This credit can be awarded on a default basis where there is no music accommodation or a multi purpose hall proposed in the assessed building/development.

Further or Higher Education buildings (Two credits)

Room Function

As required by relevant standard.
Criteria Achieve the indoor ambient noise level criteria for secondary schools in Section 1 of Building Bulletin 93. Where appropriate indoor ambient noise levels in all non-teaching spaces i.e. spaces/rooms not covered in BB93, comply with the "good practice" criteria levels of BS 82333BS 8233:1999 Sound insulation and noise reduction for buildings - code of practice:, Tables 5 & 6. For the purposes of acoustic measurement and calculation these spaces should be considered unoccupied.
Credits 1

Testing

Requirement

A programme of pre-completion acoustic testing is carried out by a compliant test body to ensure that the relevant spaces (as built) achieve the required performance standards. Where testing identifies that spaces do not meet the standards, remedial works are carried out prior to handover and occupation. The procedures outlined in BB93 and the ANC Good Practice Guide, Acoustic testing of Schools, can be followed if/where appropriate.

Room Function

As required by relevant standard.
Criteria All areas used for teaching, training and educational purposes (such as classrooms, seminar rooms and lecture theatres) achieve reverberation times compliant with Table 1.5 of BB93.
Credits 1

Testing Requirement

A programme of pre-completion acoustic testing is carried out by a compliant test body to ensure that the relevant spaces (as built) achieve the required performance standards. Where testing identifies that spaces do not meet the standards, remedial works are carried out prior to handover and occupation. The procedures outlined in BB93 and the ANC Good Practice Guide can be followed if/where appropriate

 

Healthcare Buildings (Two credits)

Room Function

As required by relevant standard.
Criteria

The values for noise intrusion from external sources in Table 1 of HTM 08-01 Acoustics Health Technical Memorandum 08-01: Acoustics, Department of Health Gateway Review, Estates & Facilities Division, 2008.4 are not exceeded. The values for internal noise from mechanical and electrical services in Table 2 of HTM 08-01 Acoustics are not exceeded.

The weighted standardized level differences measured between rooms on site are not lower than the values of the sound insulation ratings (dB DnT,w) in Table 4 of HTM 08-01:Acoustics (the values in Table 4 are determined according to the privacy requirements, noise generation of the source room and noise sensitivity of the receiving room as specified in Table 3 of HTM 08-01:Acoustics) Impact noise is controlled at source and the weighted standardised impact sound pressure level (L’nT,w) does not exceed 65dB in noise sensitive rooms

Credits 1

Testing

Requirement

A programme of pre-completion acoustic testing is carried out by a compliant test body to ensure that the relevant spaces (as built) achieve the required performance standards. Where testing identifies that spaces do not meet the standards, remedial works are carried out prior to handover and occupation. The procedures outlined in HTM 08-01 Acoustics, Chapter 7 Testing and Validation should be followed.

Notes Deviations from the values in Table 1 are acceptable only in the circumstances specified by HTM 08-01. The design team must use the recommendations specified in HTM 08-01 to justify any deviation.

Room Function

As required by relevant standard.
Criteria Sound-absorbent treatment is provided to control reverberation in rooms and circulation spaces in accordance with paragraphs 2.110 of HTM 08-01 Acoustics.
Credits 1

Testing

Requirement

None
Notes None

 

Multi-residential Buildings (Four credits)

Room Function

Individual bedrooms & self contained dwellings
Criteria Airborne sound insulation values are at least 3dB higher and impact sound insulation values are at least 3dB lower than the than the performance standards in the Building Regulations or Standards.
Credits 1

Testing

Requirement

A programme of pre-completion testing is carried out by a compliant test body based on the normal programme of testing described in the Building Regulations or Standards for every group or sub-group of dwelling-houses, flats or rooms for residential purposes; this must demonstrate that the performance standards detailed within this table are achieved.

OR

Use of constructions for all relevant building elements have been registered with and assessed and approved by Robust Details Limited (RDL) and found to achieve the performance standards required for the number of credits sought (see additional information section for further information on Robust Details).

Notes Testing should be between habitable rooms on the Ground Floor and at higher storey levels if applicable. Where there are insufficient suitable separating walls or floors in a development to carry out the number of tests specified in the appropriate Building Regulations or Standards, all of the available suitable separating walls or floors must be tested.

Room Function

Individual bedrooms & self contained dwellings
Criteria Airborne sound insulation values are at least 5dB higher and impact sound insulation values are at least 5dB lower than the than the performance standards in the Building Regulations or Standards.
Credits 3

Testing

Requirement

A programme of pre-completion testing is carried out by a compliant test body based on the normal programme of testing described in the Building Regulations or Standards for every group or sub-group of dwelling-houses, flats or rooms for residential purposes; this must demonstrate that the performance standards detailed within this table are achieved.

OR

Use of constructions for all relevant building elements have been registered with and assessed and approved by Robust Details Limited (RDL) and found to achieve the performance standards required for the number of credits sought (see additional information section for further information on Robust Details).

Notes Alternative to pre-completion testing or RDL approval includes, where separating walls or floors only occur between non-habitable rooms. In such cases, three credits can be awarded by default.

Room Function

Individual bedrooms & self contained dwellings
Criteria Airborne sound insulation values are at least 8dB higher and impact sound insulation values are at least 8dB lower than the than the performance standards in the Building Regulations or Standards.
Credits 4

Testing

Requirement

A programme of pre-completion testing is carried out by a compliant test body based on the normal programme of testing described in the Building Regulations or Standards for every group or sub-group of dwelling-houses, flats or rooms for residential purposes; this must demonstrate that the performance standards detailed within this table are achieved.

OR

Use of constructions for all relevant building elements have been registered with and assessed and approved by Robust Details Limited (RDL) and found to achieve the performance standards required for the number of credits sought (see additional information section for further information on Robust Details).

Notes Alternative to pre-completion testing or RDL approval includes, where the dwellings are detached. In such cases, four credits can be awarded by default

 

Office, Industrial, Retail, Prisons, Courts and other building types (Two credits)

Room Function

All room functions
Criteria Indoor ambient noise levels comply with the “good practice” criteria levels of BS8233:1999, Tables 5 & 6 (see additional information section) unless otherwise stated below. Where the room types below are present, the appropriate criteria for ambient noise levels, sound insulation and acoustic privacy must also be achieved.
Credits First credit

Testing

Requirement

A programme of pre-completion acoustic testing is carried out by a compliant test body to ensure that the relevant spaces (as built) achieve the required performance standards. Where testing identifies that spaces do not meet the standards, remedial works are carried out prior to handover and occupation.

The acoustic testing and measurement procedures in the Additional Guidance section should be followed.

Notes For the purposes of acoustic measurement and calculation these spaces should be considered unoccupied. Typical, appropriate noise levels are given in the table below (additional information section), the list is not intended to be exhaustive.

Room Function

Educational space (teaching & lecture spaces)
Criteria Achieve the indoor ambient noise level criteria outlined above for FE and HE buildings. See also the requirements below for acoustically sensitive rooms and apply if relevant.
Credits First credit

Testing

Requirement

A programme of pre-completion acoustic testing is carried out by a compliant test body to ensure that the relevant spaces (as built) achieve the required performance standards. Where testing identifies that spaces do not meet the standards, remedial works are carried out prior to handover and occupation. The procedures outlined in BB93 and the ANC Good Practice Guide, Acoustic Testing of Schools can be followed if/where appropriate.

Notes None

Room Function

Medical treatment rooms
Criteria Achieve the airborne and impact sound insulation criteria in Health Technical Memorandum 08-01.
Credits First credit

Testing

Requirement

A programme of pre-completion acoustic testing is carried out by a compliant test body to ensure that the relevant spaces (as built) achieve the required performance standards. Where testing identifies that spaces do not meet the standards, remedial works are carried out prior to handover and occupation. The procedures outlined in HTM 08-01 Acoustics, Chapter 7 Testing and Validation should be followed.

Notes None

Room Function

Acoustically sensitive rooms
Criteria

The sound insulation between acoustically sensitive rooms and other occupied areas complies with the following, where relevant:

General office type areas, section 7.6.3.1 of BS8233 , as follows, Dw + LAeq,T > 75.Where privacy is viewed to be critical by the client and/or design team, or where the room is adjacent to a noisy space such as a music room, the area should comply with an enhanced privacy index: Dw + LAeq,T > 85. Examples of rooms where this criteria may be applicable include a judges chamber that is next to another judges chamber or waiting room, a Human Resources meeting room next to an adjacent office (cellular or open plan).

Bedrooms in hotels or other residential institutions not assessed under BREEAM Multi-residential, section 7.6.2.2 of BS8233 as follows: sound insulation (DnT,w) of not less than 50 dB for partitions and floors between rooms and between rooms and corridors.

Credits First credit

Testing

Requirement

A programme of pre-completion acoustic testing is carried out by a compliant test body to ensure that the relevant spaces (as built) achieve the required performance standards. Where testing identifies that spaces do not meet the standards, remedial works are carried out prior to handover and occupation. The acoustic testing and measurement procedures in the Additional Guidance section (below) should be followed.

Notes

See Compliance notes for definition of “acoustically sensitive rooms”. Dw is the weighted sound level difference between the two spaces LAeqT is the measured indoor ambient noise level in the acoustically sensitive room (for the purposes of awarding design stage credits, the design ambient noise level can be used). The source and receive room sound pressure levels from which Dw is derived must be measured in accordance with BS EN ISO 140-4:1998 and the guidance in Annex B of Approved Document E. Measurements must be based on finished but unfurnished rooms, accounting for and including the effect of any carpets and acoustically absorbent ceilings specified.

To increase the ambient noise level, where privacy is required or the ambient targets include a minimum as well as maximum limit, an artificial sound source or sound masking system may be required. Any artificial sound source or sound masking system should be installed and in operation at the time of the acoustic testing to demonstrate compliance.

Room Function

Rooms/areas used for speech or performance, including public speaking
Criteria Achieve reverberation times compliant with Table 8 of BS8233 1999. In addition, or alternatively, if relevant to assessed building; classrooms, seminar rooms and lecture theatres achieve reverberation times compliant with Table 1.5 of BB93
Credits Second credit (note: credit not dependant on first credit being achieved)

Testing

Requirement

A programme of pre-completion acoustic testing is carried out by a compliant test body to ensure that the relevant spaces (as built) achieve the required performance standards. Where testing identifies that spaces do not meet the standards, remedial works are carried out prior to handover and occupation. The acoustic testing and measurement procedures in the Additional Guidance section (below) should be followed.

Notes Where the reverberation time required by the relevant standard is not appropriate for the type of space/building assessed, the acoustician must confirm why this is the case. In addition the acoustician must set alternative appropriate reverberation times and provide these to demonstrate compliance.

Compliance Notes

Ref

Terms

Description

CN1 

Shell only Where it is not possible to define the type of office space due to the speculative nature of the development, i.e. open plan or cellular, it must be assumed that it will be open plan with an occupancy rate of 1 person per 10m2.

Assessments of buildings that are not fully fitted do not need to assess the criteria associated with sound insulation of acoustically sensitive rooms.

CN2 

Building types without areas “used for speech” Where a building type (other than education, healthcare, multi-residential types) does not have areas “used for speech”, it does not need to comply with the relevant reverberation criteria. In these instances, the two available credits can be awarded where the building complies with the indoor ambient noise level and, if relevant, sound insulation criteria.

CN3 

BB93 relaxation of requirements for schools in Northern Ireland The Department for Education Northern Ireland (DENI) issued a note to designers in November 2006 detailing relaxations in compliance with BB93. The relaxations were made to facilitate the particular design requirements for new schools in Northern Ireland (as recommended in the various DENI Building Handbooks). Subsequently, where an assessed school in Northern Ireland has cited the note and applied the relaxation of BB93 requirements, they are not prevented from achieving the available BREEAM credits provided, in all other respects, the building complies with BB93 (and the above BREEAM requirements).

CN4 

BB93 alternative performance standards BB93 recognises alternative standards and details what is required should these be used within the building project, where appropriate this approach may also be used to demonstrate compliance with BREEAM criteria.

CN5 

Acoustically sensitive rooms Where the term ‘acoustically sensitive rooms’ is referenced in this BREEAM issue, it refers to any room/space the design team or client deems to be acoustically sensitive for the purposes of privacy which may include the following types of space/rooms (where specified);
  1. Cellular offices,
  2. Meeting/interview/consulting/treatment rooms

In addition;

  1. Court buildings: Witness/consultation rooms and Judges’/magistrates’ chambers and jury retiring rooms.
  2. Prison buildings: Care/listener suites, Official visit rooms, ‘Closed visits’ rooms.
  3. Educational buildings/spaces: rooms for teaching and learning i.e. classrooms, lecture theatres.
  4. Rooms used for public speaking or seminars
  5. Any other room/space the design team or client deems to be acoustically sensitive for the purposes of privacy.

CN6 

Unoccupied spaces Where the term ‘unoccupied space’ is referenced in this BREEAM issue it refers to the nature of the space for the purpose of carrying acoustic calculations or measurements i.e. such measurements must be carried when the space is unoccupied and therefore devoid of sources of noise.

CN7 

Multi-residential developments with CSH assessed dwellings Building’s with self-contained dwellings also being assessed under the Code for Sustainable Homes (CSH), the following applies:

The number of credits achieved for the self-contained dwellings assessed under the CSH issue Hea 2 (Sound Insulation) can also be applied to this issue of the Multi-residential assessment for those dwellings. Other residential and non-residential areas, not forming part of a self-contained dwelling, must meet the above requirements in order for this credit to be awarded.

CN8 

Robust Details It must be noted that the Robust Details scheme is not applicable in the assessment of forms of construction which fall into the categories of material change of use or rooms for residential purposes. (Refer to additional Guidance section for more detail/definition of Robust Details.)

Schedule of Evidence

Ref Design stage
Post-construction stage
All Professional report/study and calculations from the acoustician.

Letter of appointment or other confirmation demonstrating when the acoustician was appointed.

Relevant section/clauses of the building specification or contract and/or formal letter from the project team regarding commitments

Professional field report/study and calculations from the acoustician post construction.

Evidence, such as a formal letter from the acoustician or their test report confirming that they meet BREEAM’s definition of a suitably qualified acoustician.

A letter from the design team or principal contractor confirming that any and all required remedial works have been carried out in accordance with the acoustician’s recommendations.

Multi- Residential only Where pre-completion testing will be carried out a letter from the developer confirming the intent to:
  1. Meet the relevant sound insulation performance levels
  2. Use a Compliant Test Body to complete testing

Where Robust Details will be used;

  1. Confirmation that the Robust Details chosen will achieve the required performance standards for sound insulation (as applicable)
  2. Confirmation that the relevant plots are registered with RDL (the Purchase Statement)
Either
  1. Copies of the sound insulation field test results and/or a letter of confirmation that the required sound insulation performance standards as detailed in the assessment criteria have been achieved AND
  2. Evidence that the tests have been carried out by a Compliant Test Body

OR

  1. Completed Robust Details Ltd Compliance Certificate signed by the developer for all relevant constructions relating to the plots being assessed

Additional Information

Relevant definitions

Building Bulletin 93 revision (schools)
BB93 is under revision (as of March 2010) and may change its title to Guidelines for acoustic design of schools to include criteria for refurbishment and conversion work as well as new build.
Building Regulations/Standards
For England and Wales – Approved Document E 2003 edition, with amendments 2004 – Resistance to sound, for Northern Ireland – DOE Technical Booklet G - Sound, for Scotland – Technical Handbook Section 5 - Noise
Compliant Test Body
A Compliant Test Body is defined as :
  1. Organisations having UKAS accreditation to the appropriate scope, or who are accredited by a member of the International Accreditation Forum (IAF - www.iaf.nu) to the appropriate scope OR
  2. Organisations or individuals registered with the Association of Noise Consultants (ANC) Registration Scheme OR
  3. Organisations who can provide evidence that they follow the relevant principles of BS EN ISO 17024 (Conformity assessment - General requirements for bodies operating certification of persons)4ISO/IEC 17024:2003 Conformity assessment - General requirements for bodies operating certification of persons in relation to BREEAM requirements.
Groups and Sub-groups
As defined in the Building Regulations for England and Wales Approved Document E: Resistance to the Passage of sound, section 1 (paragraphs 1.11 – 1.17). For example, flats and study bedrooms are usually considered as two separate groups, and if there are significant differences in construction type then the groups will need to be broken down into sub groups. In addition to this, where there are steps or staggers greater than 300mm between dwellings, dwellings without steps/staggers should be treated as a different sub-group to those with step/staggers. This is because the presence of steps/staggers is likely to improve performance.
Habitable rooms
For the purpose of this issue, habitable rooms include any room where individuals will sit or lie down and require a reasonably quiet environmental to concentrate or rest. Such rooms are bedrooms, living rooms, dining rooms, studies as well as kitchen-dining and kitchen-living rooms.
Material change of use
is where there is a change in the purpose for which or the circumstance in which a building is used e.g. where a building has been converted from a non dwelling (school, church etc.) to a dwelling.
Multiple occupancy offices
Office space that is not cellular in nature i.e. it is open-planned, and designed to accommodate more than two desk spaces/workstations.
Non-habitable rooms
For the purpose of this issue, non-habitable rooms include any room that is not considered as defined above, such as kitchens, bathrooms, toilets, hallways, garages and laundry rooms.
Occupied spaces
Refer to BREEAM issue Hea 01 and note that for Hea 05 there is a specific, unrelated, definition of 'unoccupied' with reference to acoustic testing and measurement, see Compliance notes for details.
Robust Details
Robust Details (RDs) are construction solutions that provide an alternative to pre-completion sound insulation testing as a method of complying with Requirements E1 of Approved Document E (2003 edition) of the Building Regulations (England and Wales). The relevant plots on a development must be registered with RDL and built in accordance with the RD specification. To give a reasonable level of assurance that these details will achieve the required minimum standards, RDL carry out random inspections during construction and random sound insulation tests after construction. A Robust Detail is deemed to be approved for BREEAM (Multi-residential building) credits only when it achieves a specified performance level as assessed by RDL. Robust Details can only be used in relation to assessment for new build dwellings and cannot be used to assess the performance of construction details in rooms for residential purposes or material change of use.
Room for residential purposes
is defined within the Building Regulations for England and Wales Approved Document E as a room, or a suite of rooms which is not a dwelling-house or a flat and which is used by one or more persons to live and sleep and includes a room in a hostel, hotel, a boarding house, a hall of residence or a residential home, whether or not the room is separated from or arranged in a cluster group with other rooms, but does not include a room in hospital, or other similar establishment, used for patient accommodation.
Specified performance level
Robust Details are approved for credits under the Code for Sustainable Homes (CSH), where the specified performance levels set out below are met. Construction types that meet these levels are listed on the Robust Details website www.robustdetails.com on the CSH page. Where assessing self contained dwellings in multi-residential buildings that are not defined as material change of use or rooms for residential purposes, Robust Details that meet the specified performance level as set out below can also comply with the credit criteria for self contained units in multi-residential buildings and reference must be made to the CSH page on the Robust Details website:
    Mature Robust Details (published for over 12 months and at least 100 test results) – regular assessment based on the 90th percentile of results from the last 100 site tests
    Low use Robust Detail (published for over 12 months but fewer than 100 test results) – initial assessment based on the first 30 tests needed to qualify for the Robust Details scheme and the site tests available, and reviewed regularly as new test results become available, until it becomes a mature Robust Detail or is rejected.
    New Robust Detail (published for less than 12 months and fewer than 100 test results) – initial assessment based on the first 30 tests needed to qualify for the Robust Details scheme, and reviewed regularly as new test results become available, until it becomes a mature Robust Detail or is rejected.
It should be noted that not all RDs will necessarily achieve the performance levels required to achieve multi-residential credits. If in doubt, please check the list of currently approved details with RDL directly at www.robustdetails.com or on 0870 240 8210.
Suitably qualified acoustician
An individual who holds a recognised acoustic qualification and membership of an appropriate professional body. The primary professional body for acoustics in the UK is the Institute of Acoustics. An individual achieving all the following items can be considered to be “suitably qualified” for the purposes of a BREEAM assessment:
    Holds a degree, PhD or equivalent qualification in acoustics/sound testing.
    Has a minimum of three years relevant experience (within the last five years). Such experience must clearly demonstrate a practical understanding of factors affecting acoustics in relation to construction and the built environment; including, acting in an advisory capacity to provide recommendations for suitable acoustic performance levels and mitigation measures.
Where a suitably qualified acoustician is verifying the acoustic measurements/calculations carried out by another acoustician who does not meet the SQA requirements, they must, as a minimum, have read and reviewed the report and confirm in writing that they have found it to:
    represent sound industry practice
    be appropriate given the building assessed and scope of works proposed
    avoid invalid, biased and exaggerated recommendations.
Additionally, written confirmation from the third party verifier that they comply with the definition of a Suitably Qualified Acoustician is required.
Single occupancy offices
Cellular office space designed to accommodate one or two desk spaces/workstations (typically no greater than 10m2).
Weighted standardized level differences (DnT,w)
HTM 08-01 defines this as the ‘unit for rating airborne sound insulation on site’.
Weighted standardised impact sound pressure level (L'nT,w)
HTM 08-01 defines this as the ‘unit for rating impact airborne sound insulation on site’.

Checklists and Tables

Table 8 A selection of good practice indoor ambient noise levels from table 5 and 6 of BS8233:1999

Function of area Indoor ambient noise level*
Single occupancy offices 40dB LAeq,T
Multiple occupancy offices 40-50dB LAeq,T
Meeting rooms 35-40 dB LAeq,T
General spaces (staffrooms, restrooms) 40dB LAeq,T
Spaces designed for speech e.g. seminar/lecture rooms 35dB LAeq,T
Informal café/canteen areas 50 dB LAeq,T
Catering kitchens 50 dB LAeq,T
Restaurant areas 40-55dB LAeq,T
Manual workshops 55 dB LAeq,T
Courtrooms with no public address 30dB LAeq,T
Courtrooms with public address 40dB LAeq,T
Consulting/treatment rooms 35dB LAeq,T
Sound recording studios 30dB LAeq,T
Bars 40-45dB LAeq,T
Laboratories 40 dB LAeq,T
Lecture theatre/seminar room 35dB LAeq,T
Concert hall/theatre/auditoria 30dB LAeq,T
Bedrooms 35dB LAeq,T
Library areas 40-50 LAeq,T
Open visit areas (Prisons) 45 LAeq,T
* Where ranges of noise levels are specified where privacy is not deemed by the final occupier to be an issue, it is acceptable to disregard the lower limit of the range and consider the noise level criteria to be lower than or equal to the upper limit of the range.

Calculation procedures

Testing, measurement and calculation procedures

Where specific guidance on testing, measurement and calculation is not stated in the criteria table above for the relevant building type, or within the relevant standard/guidance referenced, the following procedures can be followed by the acoustician when measuring or calculating the levels required to demonstrate compliance with this BREEAM issue.

Measurements of sound insulation (airborne and impact) should be made in accordance with the relevant part of BS EN ISO 140 series, or the successor to these standards. For measurements of reverberation time, the relevant principles of BS EN ISO 354:2003 should be used and the guidance provided in BS EN ISO 140-7:1998 should be followed in respect of the number of source and microphone positions, and decay measurements. For measurements of ambient noise, when no specific guidance is available, the following procedures should be used:

  1. Noise from both internal sources (e.g. mechanical ventilation systems, plant noise, noise making systems) and external sources (e.g. traffic noise transmitted via the building façade) should be included, and, where windows are openable as part of the ventilation strategy, these should be assumed to be open for the purposes of calculations and open for measurements. If openable windows are not part of the background/permanent ventilation strategy, then these should be assumed to be closed for the purposes of calculation and closed for measurements.
  2. Noise from occupants and office equipment (e.g. computers) should not be included in the measurements.
  3. Measurements should be made in at least four rooms in which noise levels can be expected to be greatest either because they are on the noisiest façade or because they are on a naturally ventilated façade.
  4. Where different ventilation strategies are used, measurements should be conducted in rooms utilising each strategy. Otherwise, measurements should be made in rooms on the noisiest façade.
  5. T in LAeq,T is taken as the duration of the normal working day (typically 8 hours between 09.00 and 17.00).
  6. Measurements need not be made over a period of 8 hours if a shorter measurement period can be used. In this case, measurements should be made when external noise levels are representative of normal conditions throughout the day.
  7. Measurement periods less than 30 minutes may give representative values for indoor ambient noise levels and may be utilized where this is the case. However measurement periods shorter than 5 minutes should not be used.
  8. Measurements should be taken in a minimum of 3 locations in rooms at a height of 1.2 m above the floor level and at least 1 m away from any surface.
  9. Where relevant, measurement of airborne sound insulation between teaching spaces should be conducted between one in four pairs of adjacent rooms (or teaching spaces) of each room type or performance requirement category and construction type.
  10. Where relevant, measurement of impact sound pressure level should be conducted in one in four teaching spaces (separated from rooms above) of each room type or performance requirement category and construction type.
  11. The measured level of ambient noise should be used to determine compliance with the criteria for acoustically sensitive rooms. If at the time of acoustic commissioning it is not possible to measure ambient noise levels in the absence of construction or other extraneous noise sources that will not be present when the building is complete, then, for mechanical services the lower level of 35 dB, LAeq or the lowest design limit for the acoustically sensitive space should be used.

The above is intended as guidance for undertaking acoustic testing/measurement to demonstrate compliance with the performance requirements in BREEAM. If the acoustician has felt it necessary to deviate from the above procedures, they should provide a reason for doing so and confirm that the alternative procedures are adequate for demonstrating that the building meets the acoustic performance requirements.

Other information

NR curves

Noise assessments based on NR curves are often used by building services consultants to predict internal noise levels due to mechanical ventilation systems. However, the BREEAM requirement uses the indoor ambient noise level, LAeq,T which includes external noise transmitted via the façade as well as internal noise such as that from mechanical ventilation systems. In the absence of strong low frequency noise, LAeq,T can be estimated from the NR value using the following formula: LAeq,T NR + 6 dB. Therefore, if the NR value is known, but not the sound pressure levels in the individual frequency bands, an estimate for the indoor ambient noise level LAeq,T can still be determined from the NR value for the building services noise. The LAeq,T for the external noise transmitted via the façade must then be combined with the LAeq,T for the building services.
The sound insulation between acoustically sensitive rooms and other occupied areas complies with section 7.6.3.1 of BS8233 , as follows, Dw + LAeq,T > 75.

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