RIBA Stage 3 Acoustic Design - Swansea University Report.pdf · Swansea University Student Precinct RIBA Stage 3 Acoustic Design SI241-ARP-XX-XX-RP-Y-9075-RP027 Issue P01 | 21 October

Swansea University

Student Precinct

RIBA Stage 3 Acoustic Design

SI241-ARP-XX-XX-RP-Y-9075-RP027

Issue P01 | 21 October 2016

This report takes into account the particular

instructions and requirements of our client.

It is not intended for and should not be relied

upon by any third party and no responsibility

is undertaken to any third party.

Job number 246711-05

Ove Arup & Partners Ltd

6th Floor 3 Piccadilly Place

Manchester M1 3BN

United Kingdom

www.arup.com

SI241-ARP-XX-XX-RP-Y-9075-RP027 | Issue P01 | 21 October 2016

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R02-ISSUE.DOCX

Contents Page

Executive Summary 1

1 Introduction 3

2 Acoustic performance standards 4

2.1 BREEAM New Construction 2014 4

2.2 Relevant standards and guidance 5

3 Control of noise from building services 6

3.1 Criteria 6

3.2 Design requirements: Internal building services 7

3.3 Design requirements: Plant noise to environment 7

4 Building envelope sound insulation 8

4.1 Criteria 8

4.2 Ventilation strategy 11

4.3 Design requirements: Building envelope 11

5 Internal sound insulation 14

5.1 Criteria 14

5.2 Design requirements: Partitions and doors 15

5.3 Design requirements: Floors 16

5.4 Design requirements: Critical spaces 17

6 Acoustic finishes 21

6.1 Criteria 21

6.2 Design requirements: Acoustic finishes 21

Appendices

Appendix A

Acoustic terminology

Appendix B

Environmental noise survey

Appendix C

Acoustic performance criteria





R02-ISSUE.DOCX





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Executive Summary

Arup has been appointed to undertake acoustic design work for Phase 1 of the

Student Precinct building at Swansea University. This report sets out the design

considerations at RIBA Stage 3 (Developed Design).

The key acoustic issues are summarised below.

Sound break-out from SAC concourse

It is understood that the SAC concourse is likely to be used for noisy events.

3D acoustic modelling has been undertaken to predict levels of sound break-

out from the building to the nearby residential towers. Appropriate criteria for

limiting event noise has also been defined by Arup, based on measured noise

levels and appropriate guidance.

The current architectural design will enable regular noisy events (>30 per

year) to be held in the Concourse up to 23:00. NOTE: this is based on 150mm

acoustic louvres at high level, and minimum Rw40 glazing.

To enable noisy events to continue after 23:00, additional mitigation would be

required. This could be in the form of an acoustic limiter applied to sound

systems, or by increasing the sound insulation of the louvred openings at high

level.

High sound insulating folding partitions are required to separate the noisy

activities within SAC from Fulton House.

Sound insulation between concourse and 200-seat lecture theatre

The brief requires that the 200-seat lecture theatre should be designed to facilitate

simultaneous use with the main concourse space. Therefore, a box-in box

construction has been developed to provide very high levels of sound insulation

between the lecture theatre and surrounding spaces. The design includes:

Jack-up slab to lecture theatre

Independent inner plasterboard box with resiliently hung ceiling and no rigid

connections to outer structural box

High performance acoustic doorsets to the lobby and lecture theatre

Acoustic finishes within SAC concourse

The concourse is likely to be used for amplified speech and music, which

requires a well-controlled acoustic environment. However, there is a desire to

retain a lively feel to the space for general use. 3D acoustic modelling has

been undertaken to define a suitable scheme of acoustic finishes. Arup’s

recommendations are as follows:

All non-glazed balustrade fronts at 2nd and 3rd floor level (area equivalent to

300m2) should incorporate an acoustic finish which achieves Class B

performance (typically perforated panelling or slatted timber)





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An area of soffit equivalent to 220m2 Class B acoustic treatment (i.e.

perforated plasterboard)

Class A acoustic treatment to soffits around edge of concourse.





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1 Introduction

This report describes the acoustic design considerations at RIBA Stage 3

(Developed Design) for the proposed Student Precinct building at Swansea

University.

The information in this report relates to Phase 1 of the development. Phase 1

consists of the construction of the Student Activity Centre (SAC) and

refurbishment of certain spaces within Fulton House.

This report provides criteria and design advice on the following items:

Control of noise from building services equipment (both internal and external)

Building envelope sound insulation to control noise ingress and egress

Internal sound insulation of partitions, floors and doors

Provision of sound absorbing finishes to control reverberation and provide

optimal environments for the desired activity

Appendix A contains a glossary of specialist acoustic terminology.

Appendix B presents a summary of measured noise levels during an

environmental noise survey undertaken by Arup. The measurements have been

used to inform criteria for plant noise emissions and event noise break-out.

Appendix C contains a set of marked-up layouts which show the internal sound

insulation requirements for partitions and doors along with target ambient noise

levels for each space.

Figure 1: Student Precinct Building





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2 Acoustic performance standards

2.1 BREEAM New Construction 2014

Both the SAC and Fulton House are to be designed to achieve a BREEAM

‘Excellent’ rating for Other type buildings1. Based on the current building design,

it is considered that the following acoustic related credits should be targeted:

Credit Targeted

Hea 05: Bespoke set of performance standards

(3 credits) Yes

Pol 05: Noise attenuation Yes

Table 1: BREEAM acoustic credits

2.1.1 Hea 05: Acoustic performance

Three credits are available where “a suitably qualified acoustician (see relevant

definitions) is appointed to define a bespoke set of performance requirements for

all function areas in the building using the three acoustic principles defined in

criterion 1, setting out the performance requirements for each and the testing

regime required.”

The three acoustic principles are:

Sound insulation

Indoor ambient noise level

Reverberation times.

2.1.2 Pol 05: Noise attenuation

To achieve this credit (where there are, or will be, noise-sensitive areas or

buildings with 800m of the site) a noise impact assessment should be undertaken

to demonstrate that the noise level from the proposed site is a difference no

greater than +5dB during the day (07:00 to 23:00) and +3dB at night (23:00 to

07:00) compared to the background noise level.

This credit is achievable by default as the Local Authority’s noise emissions

criteria are more stringent than those of Pol 05. However, a noise impact

assessment is required to demonstrate that the proposed plant complies with

Pol 05 limits.

1 For the purposes of BREEAM assessment, Fulton House falls under the ‘Refurbishment & Fit-

out’ manual whilst the SAC falls under ‘New Construction’. The acoustic credit requirements are

the same for both.





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2.2 Relevant standards and guidance

Below is a summary of the performance standards and guidance used to inform

the acoustic design of the scheme.

Document Applies to

Building Bulletin 93: Acoustic Design of

Schools: Performance standards (2015)

All teaching and study spaces

British Council for Offices Guide to

Specification (2014)

Office spaces (where performance standard

is higher than in BB93)

BS 8233: 2014 Guidance on sound insulation

and noise reduction for buildings

Office spaces (where performance standard

is higher than in BB93)

Table 2: Summary of relevant performance standards used





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3 Control of noise from building services

3.1 Criteria

3.1.1 Internal noise control

Drivers

BREEAM Hea 05 internal noise credit

BREEAM Hea 05 sound insulation credit (through maintaining privacy)

BCO guidance for office acoustic design (where performance standard is

higher than in BB93)

Space Noise rating (NR) level target for building

services systems

Concourse / student commons <35*

Music rooms <30**

Interview / meeting rooms 30-35***

Media hub <35

Games room <40

Dance studio <35

200-seat lecture theatre <30*

Bookable rooms <35

Open-plan offices 35-38***

Single person offices 30-35***

Circulation spaces e.g. corridors <40

Toilets / changing rooms <45

*Assisted ventilation mode only

**Assumes spaces are not intended to be specialist recording facilities

***Lower limit added to maintain acoustic privacy between spaces

Table 3: Design targets for internal building services systems noise

3.1.2 External plant noise emissions

Drivers

BREEAM Pol 05 noise pollution credit

Local Authority planning conditions





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Criterion (relative

to measured

background noise

level)

Typical lowest

measured

background noise

level

Maximun noise

rating level, LAr,Tr,

from fixed plant

when measured at

nearest residential

BREEAM Pol 05 Day: +5dB

Night: +3dB

Day: 43dBLA90,1 hour

Night: 41dBLA90,15 min

Day: 48dB

Night: 44dB

Swansea City

Council noise policy -5dB 41dBLA90,15 min 36dB

Table 4: Design noise limits at Horton House / Penmaen House for fixed plant external

noise emissions

It can be seen from the table above that the Local Authority criterion for plant

noise is more onerous than the BREEAM Pol 05 criteria. This is based on a

current background noise level at Penmaen House and Horton House.

3.2 Design requirements: Internal building services

Table 3 details the internal noise level limits for building services equipment in

order to achieve the indoor ambient noise limits set by BB93 (see Table 5). Fans

and attenuators will need to be selected to meet the noise limits in Table 3 with

the mechanical ventilation system operating at normal design duty. Normal duty is

assumed to include normal heating and cooling of internal heat loads.

If additional cooling is required during peak summer time, in spaces with

mechanical ventilation noise having a boost facility which is occupant controlled,

limits can be increased by 5dB noise levels in any space (excluding a plant room)

but should not be higher than 55dB(A).

3.3 Design requirements: Plant noise to environment

The current proposal is for a plant room on the 3rd floor, housing air handling

units (AHUs), extract fans, chillers, pumps and other equipment. Outside air will

be drawn in through louvres on the north façade of the building. Air will be

exhausted at roof level.

The combined noise level from all plant operating simultaneously at normal

design duty shall be attenuated to achieve a rating level of 36dBLAr,Tr at 1m from

the nearest residential building (Horton House) which is approximately 50m from

the north façade of the SAC. This level is considered to be achievable with

reasonable mitigation measures.

Attenuation measures will be designed by the mechanical engineer and reviewed

by Arup Acoustics at the next design stage.





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4 Building envelope sound insulation

4.1 Criteria

4.1.1 Noise break-in

Drivers


BREEAM Hea 05 sound insulation credit (through maintaining privacy)

Concourse / Student Commons <40

Music rooms <35*

Interview / Meeting rooms 35-40**

Media hub <40

Games room <45

Dance studio <40

200-seat lecture theatre <35

Bookable rooms <40

Open-plan offices 35-40**

Single person offices 35-40**

Circulation spaces e.g. corridors <45

Toilets / Changing rooms <50

*Assumes spaces are not intended to be specialist recording facilities

**Lower limit added to maintain acoustic privacy between spaces

Table 5: Design targets for internal ambient noise levels

4.1.2 Noise break-out

It is understood that the central circulation space within the SAC building is to be

used for a variety of activities at different times of the day. Proposed activities to

take place within the SAC concourse include:

a social hub during daytime periods which has a relaxing retail type feel;

evening presentation mode which is to include amplified speech presentations,

and

a bar/nightclub type space for night time student activity and bar facilities.

Noise breaking out from the SAC during these activities must be controlled to

meet local authority planning criteria.

Drivers

Local Authority planning conditions

Suitable guidance on event noise





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Arup has consulted the local pollution control division at Swansea City Council

which has provided the following advice on the control of entertainment noise.

“The proposed development includes bars/clubs. Such premises are inherently

noisy and are likely to provide amplified music or some form of amplified

entertainment. Therefore it is essential that the proposed units are constructed

appropriately to contain entertainment noise and should ensure that excessive

noise does not adversely affect current occupiers of properties in the vicinity.

Noise control measures should be incorporated into the design stage of the

development. Information and a schedule of the noise control measures to be

employed, together with the relevant standards of control that will be adopted,

shall be required by condition to be submitted to and agreed by the local planning

authority prior to commencing construction.”

Although the city council advice does not specifically mention a limiting noise

level for the control of entertainment noise a number of guidance papers have

been published with regard to this issue.

The following documents have been used as the basis for suggesting appropriate

noise criteria:

Institute of Acoustics (IoA) - Good Practice on the Control of Noise from

Pubs and Clubs

Defra research report NANR 163 - Noise from Pubs and Clubs Phase II

The Noise Council – Code of Practice on Environmental Noise Control at

Concerts (1995)

Based upon the documents above, it is considered that the following limits

represent a suitable design standard in order to protect the nearest noise sensitive

building with respect to amplified music/entertainment noise:





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Venue Suggested Regulation

Scenario A: Once a year event continuing

up to 23:00

LAeq,15mins (EN1) should not exceed 75dB, 1m from the

exposed facade of nearby properties

Scenario B: Entertainment < 30 times/year

up to 23:00

LAeq,5mins (EN1) should not exceed LA90 (WEN2) by more than

5dB, 1m from the exposed facade of nearby properties

Scenario C: Entertainment > 30 times/year

up to 23:00

LAeq,5min (EN) should be 5dB or more below the representative

background LA90 (WEN), 1m from the exposed facade of

nearby properties

Scenario D: Entertainment > once/week or

continues beyond 2300hrs.

LAeq,5min (EN) should be 10dB or more below the representative

background LA90 (WEN), 1m from the exposed facade of

nearby properties. (Subject to a lower limit of 30dB LAeq,5min).

AND

Entertainment noise levels in the 63 and 125Hz octave bands

should be 3dB or more below the L90 background noise levels

within the nearest apartment bedrooms. Subject to a lower

limit of 47dB at 63Hz and 41dB at 125Hz.

Notes:

1. EN entertainment noise

2. WEN without entertainment noise

Table 6: Suggested criteria for limiting event noise, based on number/time of events

4.1.3 Rain impact noise

Drivers


BCO guidance

In spaces used for teaching and study, levels of rain noise during heavy rain

(when calculated using laboratory sound intensity test data with ‘heavy’ rain

excitation as defined in BS EN ISO 140-182) should not be more than 25dB above

the appropriate ambient noise level for the space.

BCO guidance states that, for office spaces, rain noise should be controlled so it

does not exceed 60dBLAeq during heavy rainfall.

Room function Internal ambient noise level,

dB LAeq,30min

Maximum noise level due to

rain impact noise, dB LAeq

Concourse 40 65

Office 35-40 60

Table 7: Design limits for rain impact noise

2 Acoustics. Measurement of sound insulation in buildings and of building elements. Laboratory

measurement of sound generated by rainfall on building elements (2006)





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4.2 Ventilation strategy

It is proposed that the SAC concourse will be naturally ventilated. Air will be

supplied under the seating areas via underground ducts, and will extract via high-

level louvres in the rooflights. The louvres will incorporate axial fans for use

during times of high occupancy.

All other occupied spaces will be mechanically ventilated.

4.3 Design requirements: Building envelope

Appendix B presents a summary of measured noise levels during an

environmental noise survey undertaken by Arup. The measurements have been

used to inform criteria for plant noise emissions and event noise.

Measured noise levels around the site are not high enough to influence the façade

design in terms of noise ingress. The acoustic performance of the façade will be

driven by controlling noise break-out from the main space.

3D environmental noise modelling has been undertaken to predict the levels of

sound breaking out of the building envelope to the nearby student accommodation

during a noisy event.

4.3.1 Assessment of current design

Various façade elements were identified as acoustic ‘weak spots’ and were

included in the model with the following minimum sound reduction indices (SRI)

chosen to be representative of the current design.

The glazed areas below refer only to parts of the façade which are open to the

SAC concourse (for example, the glazing to the dance studio was not included as

it is not directly open to the concourse).

Area of building envelope Rw Octave band sound reduction, R

63 125 250 500 1k 2k 4k 8k

North façade glazing

8.4mm lam / 16mm AG /

8mm

38 24 24 26 34 45 44 50 50

East façade glazing


8mm

38 24 24 26 34 45 44 50 50

South façade glazing


8mm

38 24 24 26 34 45 44 50 50

Rooflights


8mm

38 24 24 26 34 45 44 50 50

Lightweight roof

Steel profiled deck, insulation

above

27 12 18 19 23 25 31 41 50





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Area of building envelope Rw Octave band sound reduction, R

63 125 250 500 1k 2k 4k 8k

Louvres

150mm deep acoustic louvres 15 6 6 8 10 14 18 16 15

Table 8: Minimum sound reduction performance of façade elements, dB

An average sound pressure level inside the SAC concourse of 104dB(A) was used

for the predictions. This is considered typical of a club night or rock concert.

Resultant noise levels were assessed for two locations representative of the worst-

affected residential windows within the Horton and Penmaen accommodation

blocks. Total predicted noise levels at each location are shown in Table 9.

Receiver location Predicted event noise level, dBLeq (free field)

(A) 63 125 250 500 1k 2k 4k 8k

Top of Penmaen House, R1 39 57 48 41 36 32 22 13 -1

Top of Horton House, R2 40 55 47 41 37 35 27 20 9

Table 9: Predicted noise levels at worst-affected residential windows

Against a current background at the residences of 41dBLA90, the current design

therefore is predicted to satisfy Scenarios A, B and C in Table 6. This suggests

that, with no changes to the architectural design and incorporating acoustic

louvres, it would be reasonable to hold over 30 events per year which run up

to 23:00.

4.3.2 Additional measures required

If the aspiration is to hold weekly events, or events past 23:00 (Scenario D), then

additional mitigation measures will be required to limit break-out noise to the

following:

Overall (A-weighted) levels at residential façade no more than 34dBLAeq

before 23:00 and 31dBLAeq after 23:00

Levels in 63Hz and 125Hz octave bands within residential rooms no more

than 47dBLeq and 41dBLeq respectively

Figure 2 below shows the noise level broken down by building element. It can be

seen that the louvres are the dominant source of sound break-out.

Furthermore, the dominant component of sound break-out is at low frequency;

predominantly between 50-160Hz. Therefore, reducing source noise levels at low

frequencies should help to achieve both the overall and octave-band criteria.





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Figure 2: Noise level contributions at receiver 2 (Penmaen) broken down by building area

The following options are proposed to achieve the criteria and enable events to

run past 23:00 on a weekly basis:

Acoustic limiter: to limit overall sound levels within the SAC concourse to

99dBLAeq before 23:00, and 96dBLAeq after 23:00. Additionally, to limit sound

to 100dB in any octave band. (Note this will have an effect on the subjective

impression of the event by audience)

OR

Additional sound insulation of louvres: Incorporate attenuation to increase

the overall sound insulation of the louvred openings to Rw22. Additionally,

they should provide a minimum transmission loss of 14dB at 63Hz, and 11dB

at 125Hz

Attenuation could be incorporated in the form of deeper louvres (although this is

unlikely to provide the low frequency performance needed) or a labyrinth plenum

at high level.

Alternatively, a combination of sound level limiting and additional sound

insulation could be used.





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5 Internal sound insulation

5.1 Criteria

Drivers

BREEAM Hea 05 sound insulation credit

BCO guidance for office acoustic design

5.1.1 Airborne and impact sound insulation

The criteria below are given in terms of DnT,w and LnT,w, which are measureable on

site.

Key adjacency Minimum airborne

sound insulation DnT,w

Maximum impact sound

pressure level LnT,w

Interview Interview 40 60

Bookable Bookable 40 60

VC room VC room 50 60

Music room Music room 55 n/a

Interview Meeting 40 60

Music room Games room 55 n/a

Media hub Games room 55 n/a

Dance studio 400-seat

lecture theatre 55 60

Dance studio Music rooms 55 55

Concourse 200-seat lecture

theatre 75* 60

200-seat lecture theatre

Bookable rooms 75* n/a

*Based on desire for simultaneous use of lecture theatre during noisy event in concourse

Table 10: Design limits for airborne and impact sound insulation

5.1.2 Flanking sound transmission

Sound insulation between vertical and horizontal adjacencies can be significantly

compromised by noise flanking along common elements between rooms. Typical

areas where this can occur are;

Along the inner leaf of external facades where the inner plasterboard layers

are continuous between adjacencies,

Across a raised access floor where partitions are built from the top of the

raised access floor,

Across lightweight ceilings where ceilings are common between rooms and

separating partitions stop at ceiling level,





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Horizontally and vertically through mullions and transoms of curtain wall

systems, and

Vertically along the slab edge detail

Where a sound insulation performance of DnT,w45 or above is required, partitions

should be built from the structural slab to the soffit.

Vertical and horizontal façade flanking details will be further developed during

the next stage of the project to ensure that appropriate sound insulation levels are

maintained. For performance of DnT,w50 and 60, the measures will include

multiple layers of mass and sealing.

Table 11 below details the minimum required façade flanking sound insulation

values required to maintain the appropriate sound insulation between spaces.

Key adjacency Minimum flanking sound transmission Dnf,w

Interview Interview

Interview Meeting

Bookable Bookable

45

VC room VC room 50

Music room Music room

Music room Games room

Dance studio 400-seat lecture theatre

Dance studio Music rooms

60

Table 11: Design limits for flanking sound transmission

5.2 Design requirements: Partitions and doors

5.2.1 General

Sound insulation ratings for internal partitions, doors and glazed screens are

provided in Arup Acoustics’ marked up AAc-SI drawing series. These can be

found in Appendix C. Where applicable, ratings are based on meeting the on-site

sound insulation criteria provided above.

Partition, door and glazing performances are provided in terms of the sound

reduction index (Rw), which is a laboratory measure of the sound insulation

performance of a partition.

Typically, on-site level differences (see section 5.1.1) will be 4-7dB lower than

the Rw value of a partition depending on the size and type of partition, control of

flanking noise and quality of workmanship.

5.2.2 Typical partition constructions

Table 12 details typical partition constructions which can achieve the

recommended sound reduction values. Appropriate flanking and penetration

details should also be selected to ensure the partitions meet the required on-site

values.





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Rw Description Image

40

1 x 15mm plasterboard each side of a 70mm

metal stud with 25 mm glass fibre/mineral wool in cavity (total width 100 mm)

100 mm block (minimum density 1400 kg/m3) plastered/rendered 12 mm one side

45

2 x 12.5 mm plasterboard each side of a 70

mm metal stud (total width 122 mm) both sides

115 mm brickwork plastered/rendered 12 mm

both sides

100 mm block (minimum density 1400 kg/m3) plastered/rendered 12 mm both sides

50

2 x 12.5 mm plasterboard each side of a 70

mm metal stud with 50 mm glass/mineral wool in cavity (total width 122 mm)

225 mm brickwork plastered/rendered 12 mm

both sides

140 mm block (minimum density 1400 kg/m3) plastered/rendered 12 mm both sides

55

2 x 12.5 mm plasterboard each side of a

staggered 60 mm metal stud in a 72 mm

channel with 50 mm glass fibre/mineral wool in cavity (total width 122 mm)

100 mm block (minimum density 1800

kg/m3) with 12 mm plaster on one side and 1

x 15 mm plasterboard on metal frame with 50

mm cavity lined with glass fibre/mineral wool

Table 12: Typical partition constructions

5.3 Design requirements: Floors

Generally, floors will be 300mm thick reinforced concrete. This will provide

sufficient levels of airborne and impact sound insulation between floors, with the

exception of the critical spaces covered in Section 5.4.





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5.4 Design requirements: Critical spaces

5.4.1 SAC concourse to Fulton House concourse

When high levels of entertainment noise are created in the concourse of the SAC

folding partitions with high levels of sound insulation will be closed between the

two spaces. This enables performance type events to take place within the

concourse of the SAC whilst enabling quiet conditions to be maintained within

Fulton house. Partitions similar to http://skyfold.com/ should be installed in the

locations indicated in drawing AAC-SI-00 in Appendix C.

5.4.2 200-seat lecture theatre

The brief for the 200-seat lecture theatre is to provide a flexible space which can

be used simultaneously with a noisy event occurring in the SAC concourse. Due

to the proximity of the two spaces, this level of flexibility requires very high

levels of sound insulation.

The proposed design is based on an average sound level of 104dBLAeq in the SAC

concourse with significant low frequency content. This corresponds to a sound

level which could reasonably be expected during a club night or rock concert.

Corresponding noise levels in the lecture theatre should not exceed 30dBLAeq3

.

Noise transmission should not be noticeable or distracting.

Figure 4 shows a diagrammatic section through the lecture theatre and lobby, and

describes the key sound insulation measures which should be taken. Key measures

to note are as follows:

Lecture theatre

Minimum 100mm jack-up slab on resilient bearings supported off structural

box

Plasterboard walls built off jack-up slab. Minimum surface mass 28kg/m2 (2x

15mm dense boards). Built to underside of structural box with resilient head

details

Plasterboard ceiling on resilient hangers suspended from structural box.

Minimum 200mm cavity, with 50mm mineral wool in cavity. Minimum

surface mass of boards 28kg/m2 (2x 15mm dense boards)

Attenuated penetrations through structural box for the air supply from the

AHU

Minimum 200mm cavity between inner box and lobby, with 50mm mineral

wool in cavity.

Lobby

3 Based on an internal noise limit of 35dBLAeq (as per BB93) with 5dB contingency for building

services / other noise sources

http://skyfold.com/





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Plasterboard walls built off structural box. Minimum surface mass 28kg/m2

(2x 12.5mm medium boards). Built to underside of structural box with

resilient head details

Standard metal framed suspended ceiling. Minimum 200mm cavity with

50mm mineral wool in cavity.

Below lecture theatre

Sound insulating ceiling (e.g. Armstrong Perla dB) with minimum sound

reduction of Rw40

Both sets of doors to the lecture theatre should be high performance acoustic

doorsets, with minimum sound reduction of Rw40.

A typical product which can achieve this is a Huet Club 39 timber doorset

(http://www.huet-doors.co.uk/products/acoustic-rated-doorsets/club-39).

To achieve this performance, the doors will require recessed seals to the head and

jambs, and drop-down threshold seals.

5.4.3 400 seat lecture theatre

A high level of sound insulation is required between the 2nd floor lecture theatre

and the dance studio below to facilitate flexible, simultaneous use of both spaces.

Proposed sound insulation measures are as follows:

>100mm precast concrete seat rake, structure supported on resilient pads

130/70mm composite deck

Suspended ceiling to dance studio consisting of 2 layers of 12.5mm medium

density plasterboard on a metal frame system

5.4.4 Music rooms

Figure 3 shows the required measures to achieve suitable level of sound insulation

between music rooms.

The resiliently hung mass barrier ceiling is predominantly to control impact noise

from the dance studios above.

http://www.huet-doors.co.uk/products/acoustic-rated-doorsets/club-39





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Figure 3: Section showing acoustic principles for music rooms




J:\MANCHESTER\PROJECTS\246711-00 SWANSEA UNIVERSITY-STUDENT FACING CENTRE\4_INTERNAL_PROJECT_DATA_DESIGN\4_08_REPORTS\STAGE 3\246711-05 R02-ISSUE.DOCX

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Figure 4: Diagrammatic section showing acoustic principles of 200-seat box-in-box lecture theatre





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6 Acoustic finishes

6.1 Criteria

Drivers

BREEAM Hea 05 reverberation credit

BCO guidance for office acoustic design

Reverberation time (RT) is a measure of how long sound takes to decay in a

space. Generally speaking, a shorter RT is an indicator of better speech

intelligibility, reduced noise build-up and increased acoustic comfort.

Reverberation can be controlled through the addition of sound-absorbing finishes.

The criteria below have been chosen where necessary to satisfy BB93 guidance on

spaces used for teaching and learning. In other spaces, suitable reverberation times

have been chosen to complement the intended use of the space.

Room Reverberation time target, Tmf (s)

Concourse / Student Commons ≤1.2

Music rooms ≤0.6

Interview / Meeting / Bookable rooms ≤0.8

Media hub ≤0.8

Dance studio ≤1.2

200-seat lecture theatre ≤0.8

Open-plan offices ≤0.8

Single person offices ≤0.8

Table 13: Design limits for mid-frequency reverberation time

6.2 Design requirements: Acoustic finishes

6.2.1 SAC concourse

The table below sets out the considerations relating to reverberation time for each

intended use of the concourse space.





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Intended use Acoustic considerations

Conference space (including amplified and

natural speech)

Low RT is preferable. If RT is too long,

speech will become muddy and possibly

unintelligible at larger distances from the

sound source

Event space (including amplified music)

Low RT is preferable. High RT could lead to

excessive loudness/harshness/muddiness of

sound.

Circulation space Mid RT is preferable. RT too low could lead

to space feeling ‘dead’

Table 14: Acoustic considerations for SAC concourse

Taking into account the above, the acoustic environment in the SAC concourse

should be balanced between providing a controlled environment for speech and

music, and providing a lively environment for students to circulate and socialise.

An RT of 1.2s has been suggested, which is consistent with BB93 guidance for

atrium spaces used for teaching and learning.

It is recommended to adopt a strategy as follows:

Provide the bulk of sound-absorbing finishes at high level (2F and above) to

control RT

Keep the ground floor area relatively free of sound-absorbing finishes to

provide a lively atmosphere at low level

Based on 3D acoustic modelling of the space, the following recommended

amounts and performances of sound absorbing finishes should be incorporated to

achieve the design target:

Minimum Class B sound absorbing treatment to 100% of solid (non-glazed)

balustrade fronts at 2F and 3F floor level

Class A sound absorbing treatment to 100% of soffits around edge of

concourse at all levels

Minimum Class B sound absorbing treatment to at least 200m2 of ceiling area

Figure 5 and Figure 6 present views from the 3D acoustic model, demonstrating

the recommended acoustic finishes strategy.





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Figure 5: 3D concourse view showing recommended placement of absorption (looking

towards Taliesin)

Figure 6: 3D concourse view showing recommended placement of absorption (looking

towards Taliesin)

Class B sound

absorbing treatment to

balustrades at 2F and

3F level

Class A sound absorbing

treatment to soffits

around concourse edge

(all levels)





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6.2.2 200 seat lecture theatre

The design brief for the 200-seat lecture theatre is to provide a flexible space

which may be used as a cinema, small performance venue and as a lecture theatre.

To achieve a suitable environment, the following scheme of acoustic finishes is

recommended:

Rear wall: Area equivalent to 50% (17m2) Class A sound absorber

Rear soffit: Area equivalent to 100% (70m2) Class A sound absorber)

Mid and front soffit: Reflective i.e. plasterboard

Side walls: Faceted/profiled finish to diffuse sound

Floor: Carpeted on seat rake

Figure 7: Section view showing recommended acoustic finishes for 200-seat lecture

theatre

6.2.3 Music rooms

Class A sound absorbing treatment to 50% of ceiling area

2m2 Class A sound absorbing panels to one or two walls

Ideally carpeted

6.2.4 Media hub

Class C sound absorbing treatment to ceiling

Ideally carpeted





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6.2.5 Student Commons / Bar / Café

Class A sound absorbing treatment to soffit areas (to control noise spill

to/from SAC concourse)

6.2.6 Dance studio

Area equivalent to 50% ceiling area Class A sound absorbing treatment

Class A acoustic treatment on at least one wall, ideally above 2m height.

Typically panels or heavy drapes

6.2.7 Interview / Bookable / Meeting rooms

Area equivalent to 60% ceiling area Class A sound absorbing treatment

Appendix A

Acoustic terminology





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Page A1

Decibel (dB)

The ratio of sound pressures which we can hear is a ratio of 106:1 (one

million:one). For convenience, therefore, a logarithmic measurement scale is used.

The resulting parameter is called the ‘sound pressure level’ (Lp) and the associated

measurement unit is the decibel (dB). As the decibel is a logarithmic ratio, the

laws of logarithmic addition and subtraction apply.

dB(A)

The unit used to define a weighted sound pressure level, which correlates well

with the subjective response to sound. The ‘A’ weighting follows the frequency

response of the human ear, which is less sensitive to low and very high

frequencies than it is to those in the range 500Hz to 4kHz.

In some statistical descriptors the ‘A’ weighting forms part of a subscript, such as

LA10, LA90, and LAeq for the ‘A’ weighted equivalent continuous noise level.

Equivalent continuous sound level

An index for assessment for overall noise exposure is the equivalent continuous

sound level, Leq. This is a notional steady level which would, over a given period

of time, deliver the same sound energy as the actual time-varying sound over the

same period. Hence fluctuating levels can be described in terms of a single figure

level.

Frequency

Frequency is the rate of repetition of a sound wave. The subjective equivalent in

music is pitch. The unit of frequency is the hertz (Hz), which is identical to cycles

per second. A 1000Hz is often denoted as 1kHz, eg 2kHz = 2000Hz. Human

hearing ranges approximately from 20Hz to 20kHz. For design purposes the

octave bands between 63Hz to 8kHz are generally used. The most commonly used

frequency bands are octave bands, in which the mid frequency of each band is

twice that of the band below it. For more detailed analysis, each octave band may

be split into three one-third octave bands or in some cases, narrow frequency

bands.

Impact sound pressure level, L’nT,w

The impact sound insulation of floors is evaluated by measuring the sound

pressure level in the receiving room resulting from a standard tapping machine

placed on the floor of the source room. The measured values, in each of the third-

octave bands from 100Hz to 3150Hz, are adjusted to allow for the acoustic of the

receiving room and compared with a standard reference curve, in accordance with

the procedure defined in BS EN ISO 717-2: 2013 to obtain the single figure

weighted standardised impact sound pressure level, L’nT,w.





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Page A2

Where there are no flanking routes to modify the performance the results are

described by LnT,w.

The improvement in impact sound insulation provided by a floor finish is the

∆Lnw, which is the measured improvement in Lnw achieved by a floor finish when

placed on a 200mm depth reference concrete slab.

Noise rating (NR) curves

Noise rating (NR) curves are a set of internationally-agreed octave band sound

pressure level curves, based on the concept of equal loudness. The curves are

mathematically derived and defined in BS 8233 and commonly used to define

building services noise limits. The NR value of a noise is obtained by plotting the

octave band spectrum on the set of standard curves. The highest value curve

which is reached by the spectrum is the NR value. Shown below is a plant noise

spectrum that is equivalent to NR70.

Reverberation time (RT60)

The time in seconds taken for a sound within a space to decay by 60dB after the

sound source has stopped. The RT is an important indicator of the subjective

acoustic within a space.

Sound level difference (D)

The sound insulation required between two spaces may be determined by the

sound level difference needed between them. A single figure descriptor, the

NR85

NR80

NR75

NR70

NR65

NR60

NR55

NR50

40

45

50

55

60

65

70

75

80

85

90

63 125 250 500 1k 2k 4k 8k

Sou

nd

Pre

ssu

re L

evel

, d

B r

e 2*10

-5P

a

Octave Band Centre Frequency, Hz





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Page A3

weighted sound level difference, Dw, is sometimes used (see BS EN ISO 717-1).

Additionally, the term DnTw may be used, which has been standardised to a

reverberation time of 0.5s.

Sound power level

The sound power level (Lw) of a source is a measure of the total acoustic power

radiated by a source. The sound power level is an intrinsic characteristic of a

source (analogous to its volume or mass), which is not affected by the

environment within which the source is located.

Sound pressure level

The sound power emitted by a source results in pressure fluctuations in the air,

which are heard as sound.

The sound pressure level (Lp) is 10 times the logarithm of the ratio of the

measured sound pressure (detected by a microphone) to the reference level of 2 x

10-5Pa (the threshold of hearing).

Thus Lp (dB) = 10 log (P1/Pref)2 where Pref, the lowest pressure detectable by the

ear, is 0.00002 pascals (ie 2x10-5 Pa).

The threshold of hearing is 0dB, while the threshold of pain is approximately

120dB. Normal speech is approximately 60dBLA and a change of 3dB is only just

detectable. A change of 10dB is subjectively twice, or half, as loud.

Sound reduction index (R)

The sound reduction index (or transmission loss) of a building element is a

measure of the loss of sound through the material, ie its attenuation properties. It

is a property of the component, unlike the sound level difference which is affected

by the common area between the rooms and the acoustic of the receiving room.

The weighted sound reduction index, Rw, is a single figure description of sound

reduction index which is defined in BS EN ISO 717-1: 2013. The Rw is calculated

from measurements in an acoustic laboratory. Sound insulation ratings derived

from site (which are invariably lower than the laboratory figures) are referred to as

the R’w ratings.

Statistical noise levels

For levels of noise that vary widely with time, for example road traffic noise, it is

necessary to employ an index which allows for this variation. The L10, the level

exceeded for 10% of the time period under consideration, and can be used for the

assessment of road traffic noise (note that LAeq is used in BS 8233 for assessing

traffic noise). The L90, the level exceeded for 90% of the time, has been adopted

to represent the background noise level. The L1, the level exceeded for 1% of the

time, is representative of the maximum levels recorded during the sample period.

A weighted statistical noise levels are denoted LA10, dBLA90 etc. The reference

time period (T) is normally included, eg dBLA10, 5min or dBLA90, 8hr.

Appendix B

Environmental noise survey





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Page B1

B1 Measurement locations

Figure B 1: Location of noise measurements during environmental noise survey





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Page B2

B2 Results summary

Location ref Associated

façade

Measured noise levels, dB

LAeq,5min LA1,5min LAmax,5min

R2 SAC, south 55 64 68

R3 SAC, north 46-49 53-57 56-64

R4 SAC, east 49-53 54-63 60-67

R5 Fulton House,

south 58-61 65-67 69-76

R6 Fulton House,

west 61-65 71-77 74-82

Table B 1: Measured noise levels at existing and proposed building facades

Time period Average background noise level, dBLA90,T

A-weighted 63Hz 125Hz

Day (07:00-23:00)

T = 1 hour 44 50 48

Night (07:00-23:00)

T = 15 minutes 41 48 47

Table B 2: Minimum average background noise levels over 7-day period at location R1.

Appendix C

Acoustic performance criteria

A1

Do not scale

A B C D E F G H I J K L M N

1

2

3

4

5

6

7

8

9

10

O P

Rev Date By Chkd Appd

Client Project Title

© Arup

Scale at A1

Suitability

Name

Arup Job No

Role

Rev

Drawing Title

07/0

9/2

016 1

4:2

5:2

4

1 : 200

Student PrecinctSwansea University,Singleton Park Campus,Swansea

Swansea University

70277

AAC-SI-0

Games RoomStudent Commons

78.14 m²Student LoungeStudent Commons

269.73 m²

ReprographicsRetail

43.67 m²

Retail 2Retail

40.79 m²

Retail 1Retail

41.93 m²

Core 2Circulation

44.39 m²

Retail 3Retail

64.99 m²

Retail 4Retail

63.35 m²

Cafe/BarCatering

111.96 m²Lounge/Bar

Student Commons

133.22 m²

Core 1Circulation

41.12 m²

ReceptionMy Uni Hub

30.80 m²

Waiting & Hot DeskMy Uni Hub

77.12 m²

Furniture StoreStore

40.06 m²

ChangingMedia

50.96 m²

Cash OfficeMy Uni Hub

16.40 m²

Lobby 2Circulation

6.60 m²

WC 2WC

17.07 m²

WC 1WC

19.60 m²

Dis WC 2

Dis ChMedia

6.00 m²

Lift 2Circulation

6.47 m²

Lift 1Circulation

5.33 m²

SAC ConcourseCirculation

859.64 m²

Circula

tion

Circula

tion

28.9

0 m

²

IT Hub

ElecPlant

3.39 m²

Mech

MechPlant

6.05 m²

Elec Mech

IT Hub

Mech

Main

Main IncomingPlant

3.02 m² Media HubMedia

56.25 m²

Music 1Media

15.90 m²

Music 2Media

15.92 m²

Music 3Media

15.90 m²

Music StoreMedia

8.59 m²

8 User MeetingMy Uni Hub

23.68 m²

Int 1

Sec Int 1 Sec Int 2

Int 2 Int 3 Int 4

Int 7

WaitingMy Uni Hub

55.88 m²

8 User MeetingMy Uni Hub

24.63 m²

Int 8

Int 5 Int 6

Int 7 Int 8

Retail 9Informal Dining

55.28 m²

SU SupportStudents Union Facilities

100.18 m²

FH Core 3Circulation

78.30 m²

Retail ShopRetail

234.94 m²


36.31 m²

Retail 11Retail

66.49 m²

Riser

CirculationCirculation

36.37 m²

Retail 10Retail

79.16 m²

Retail 8Informal Dining

43.04 m²Retail 7

Informal Dining

43.52 m²Retail 6

Informal Dining

43.58 m²Retail 5

Informal Dining

54.64 m²

Catering KitchensKitchen

284.26 m²

Fulton House ConcourseCirculation

443.00 m²

Student CommonsSocial Space

107.64 m² CirculationCirculation

53.20 m²

Student CommonsSocial Space

108.69 m²

WC3WC

66.50 m²


36.63 m²

WC3WC

38.47 m²

Lobby 1Circulation

36.40 m²University Bookshop

Retail

122.22 m²

Riser


33.95 m²


25.70 m²

Catering OfficesKitchen

116.24 m²

F.1 F.2 F.3F.4 F.5 F.6 F.7 F.8 F.9 F.10 F.11 F.12

F.A

F.B

F.C

F.D

F.E

F.F

F.G

F.H

F.I

F.J

F.K

F.L

F.M

F.N

F.H1

F.J1

F.E1

F.C1

F.B1

SA.1 SA.3 SA.4 SA.5 SA.6 SA.7 SA.9

SA.A

SA.B

SA.C

SA.G

SA.J

SA.K

SA.D

SA.H

SA.2 SA.8 SA.10

SA.F

SA.E

40

40

40

40404040

45

40

40

45

40 40 40

50

40 4045

35

35

35

35

50

45

50

40 40 40

45

45 45

45

45

45

45

45 45

Stage 3 Acoustic PerformanceRequirements - Ground Floor

246711 1

For information

35

35

35

3535

35

30

40

35

30

30

3030

30 30

30

3030303030

3030

30

30

35

35

35 35

-01

30

30

30 30

Twin frame partitions required - Seereport section 5.4.3 for details

Weighted soundreduction index, dB Rw

40

45

50

55

65

Partitions

Glazing

40

45

Door Rw, dB 35

Internal ambient noiselevel, dBLAeq

35

High performancefolding partition>Rw60

A1

Do not scale

A B C D E F G H I J K L M N

1

2

3

4

5

6

7

8

9

10

O P

Rev Date By Chkd Appd

Client Project Title

© Arup

Scale at A1

Suitability

Name

Arup Job No

Role

Rev

Drawing Title

07/0

9/2

016 1

4:2

5:2

4

1 : 200

Student PrecinctSwansea University,Singleton Park Campus,Swansea

Swansea University

70277

AAC-SI-01

UP

Catering

StaffAccessOnly

Core 1Circulation

42.54 m²

Core 2Circulation

43.57 m²

Student Rep HubStudents Union Facilities

64.48 m²6 User Office

Venue Waiting/LoungeStudent Commons

137.29 m²

200 Seat VenueStudent Commons

115.16 m²

WC 2WC

17.02 m²

Dis WC 2

WC 1WC

21.56 m²

Lobby 2Circulation

6.60 m²

StaffAccessOnly

Balcony Terrace

Balcony Terrace

First Floor CirculationCirculation

332.67 m²

ReceptionStudents Union Facilities

44.75 m²

12 U

ser

Open P

lan O

ffic

eS

tudents

Unio

n F

acili

ties

50.9

3 m

²

Int 2Int 1 Int 3

WaitingStudents Union Facilities

23.47 m²

22 User Open Plan OfficeStudents Union Facilities

135.89 m²

Cash Office

IT Hub

Elec Mech

Bookable

Room

Large MeetingStudents Union Facilities

72.92 m²

Flexi BookableStudents Union Facilities

30.90 m² Bookable Room

Mech

Mech

Mech

IT HubElec

Dance StudioMedia

281.27 m²Student CommonsStudent Commons

140.51 m²

Informal DiningCatering

93.30 m²

WC3WC

135.87 m²


57.85 m²

Open Access ICT SuiteLearning Commons

228.40 m²


44.04 m²

Board RoomUniversity Facilities

67.19 m²

Riser

20 User Open Plan OfficeAcademic Services

129.46 m²8 User Meeting Room

Academic Services

33.26 m²

Existing stair accessCirculation

23.91 m²

StoreCore

7.77 m²


55.91 m²

2 User Meeting RoomAcademic Services

13.06 m²


29.45 m²

StoreCore

6.49 m²


13.06 m²


18.14 m²

Riser


39.63 m²

Cafe Kitchen / StoreKitchen

75.58 m²

Coffee ShopInformal Dining

117.75 m²

Informal DiningCatering

79.17 m²

Social SpaceStudent Commons

117.14 m²

Riser


36.71 m²

Bookable RoomLearning Commons

67.20 m²

Learning CommonsLearning Commons

718.22 m²

F.1 F.2 F.3F.4 F.5 F.6 F.7 F.8 F.9 F.10 F.11 F.12

F.A

F.B

F.C

F.D

F.E

F.F

F.G

F.H

F.I

F.J

F.K

F.L

F.M

F.N

F.H1

F.J1

F.E1

F.C1

F.B1

SA.1 SA.3 SA.4 SA.5 SA.6 SA.7 SA.9

SA.A

SA.B

SA.C

SA.G

SA.J

SA.K

SA.D

SA.H

SA.2 SA.8 SA.10

SA.F

SA.E

Social SpaceStudent Commons

93.25 m²

4040

40

45

40404040

45

40

40

40

40

40

35

45

50

45

45

50

246711 1

For information

Specialist box-in-box construction - seereport section 5.4.1 for details

35

35

35

30

30

30

30

30

30

30

35

3535

40

40

40

40

35

35

35

35

35

35

3030

30

30

30

30

Stage 3 Acoustic PerformanceRequirements - First Floor

Weighted soundreduction index, dB Rw

40

45

50

55

65

Partitions

Glazing

40

45

Door Rw, dB 35

Internal ambient noiselevel, dBLAeq

35

30

Documents

RIBA Stage 3 Acoustic Design - Swansea University Report.pdf · Swansea University Student Precinct RIBA Stage 3 Acoustic Design SI241-ARP-XX-XX-RP-Y-9075-RP027 Issue P01 | 21 October