Acoustics Case Studies
Whether it’s acoustic consultancy, monitoring or vibration mitigation, our case studies are an independent demonstration of successful solutions across a broad range of sectors.
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Specialist Emergency Care Hospital, Cramlington
Acoustics case study
Specialist Emergency Care Hospital, Cramlington
Background
The hospital is the result of 10 years’ work led by clinical teams at Northumbria Healthcare and is specifically dedicated to emergency care, having A&E consultants physically on site 24/7, as well as specialists in a range of conditions. The facility has cost £75 million to build; a further £15 million for specialised equipment and £5 million to improve surrounding roads. It has 210 acute beds spread across seven specialist wards.
The project is the first of its kind in the UK and is set to become a flagship model for emergency care. Its unusual “fractal” shape is highly innovative in terms of its look, its construction and in the patient care that it enables; the circular emergency ward layout allows clinical staff faster access to patients in need of urgent care and assistance. The location for the site was a key factor for the success of the project. The Specialist Emergency Care Hospital has to be in the perfect geographical location to deliver the vision. Excellent transport links are essential, and it was these transport links which dictated the pioneering acoustic / ventilation design solution on this project.
Challenge
There are many studies on the impact of noise on health and wellbeing and its effect upon patient recovery from critical injury. We knew that getting the noise environment right was vital in creating the best possible healing environment. The planning process demanded a rigorous environmental assessment of the impact of the hospital at each of the possible sites, and conversely the likely impact of the various site locations on the hospital. SRL identified early in the process that the preferred site had significant noise-related issues; resolving these fundamentally affected the intended design of the hospital, and a carefully designed solution was needed to stay within budget.
The nearby A189 is a busy road which creates noise levels high enough to preclude a fully naturally ventilated solution. Aircraft noise was also a major issue, with the site directly underneath the final approach and early take-off flight paths to Newcastle International Airport. SRL’s in-depth analysis of the site soon revealed that openable windows would give unacceptable noise levels within the hospital and that to meet the appropriate guidance within HTM08-01 would require a radical change to the ventilation method previously envisaged. Alternative methods of ventilation design and their acoustic implications were considered in parallel with the planning application process. So important were the noise issues that the requirements for the internal acoustic environment became part of the planning conditions.
Solution
SRL Technical Services assessed a range of options in terms of window and ventilation panels, many of which created other notable design and operational issues. Acoustically-treated “trickle” vents became the clear leader as the best option. These needed to be as small as possible whilst delivering the maximum airflow. We worked with the ventilation engineers to determine exactly what the airflow requirements were. This required detailed analysis, the results of which formed an essential part of our combined solution.
We showed that using high-performance acoustic vents would enable the required airflow into the room and achieve the target noise criteria. We selected and specified the most appropriate vent units given all the constraints. The architect and planners approved the selection but felt that the units impaired the visual impact of the building. This was largely overcome by building them in to the glass units rather than having them separate to the windows.SRL is proud of its contribution to the creation of an efficient acoustic and ventilation design which satisfies all the technical and environmental requirements. During the planning process our evidence, both written and at the inquiry, was a key part of the decision to award planning consent. Without this solution the project is likely to have been refused planning permission and it would then have experienced substantial delays whilst another site was sought.
The project was Highly Commended at the 2015 Building Better Healthcare Awards for the Best Acute Hospital, and was shortlisted at the 2015 IHEEM awards for Project of The Year.
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Travelodge London Docklands Central
Acoustics case study
Travelodge London Docklands Central
Background
John Sisk & Son Ltd. (Sisk) constructed a new Travelodge (London Docklands Central) very close to an existing Travelodge (London Docklands), which was to be sold, demolished, and turned into a new data centre.
Challenge
The new hotel is situated next to a very busy road and roundabout in central London, so the glazing and ventilation strategy had to be robust to meet indoor ambient noise level criteria.
The hotel’s opposite façade is situated next to a data centre which emitted constant plant noise. Many rooms in the hotel are looking out directly onto the tops of plant such as ASHPs, so this had to be considered in the design of the glazing and ventilation strategy as well.
Existing acoustic test data for the proposed bedroom doors looked a bit too good to be true. This would have to be something to investigate.
There is a lot of plant situated on the roof of the building. We had to accurately model all plant to demonstrate that the plant noise did not exceed the criteria of 45dBA outside any hotel windows.Solution
SRL worked closely with the design team to develop a cost-effective acoustic design strategy for the new building which met the client design criteria. This included:
the building envelope and ventilation strategy to meet the indoor ambient noise level criteria (including testing to satisfy BREEAM credit Hea 05 for indoor ambient noise levels);
internal elements, e.g. partitions, floors, doors and glazed screens to meet the sound insulation criteria;
room finishes to meet the reverberation time criteria; and
noise propagation modelling to demonstrate the impact of noise from rooftop plant on the hotel bedroomsIn addition:
We managed to value engineer the glazing specification from the original acoustician’s recommendations.
We had acoustic tests done in our own lab which proved the performance of the doors to be overstated.
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Westfield, White City
Acoustics case study
Westfield, White City
Background
As our shopping habits have changed over time so have the locations where we shop. The growth of the Mega-store and the development of US style shopping complexes have given architects the scope to design some fantastic spaces. Building Regulations still apply to these new spaces and mean that innovative solutions have to be found.
Challenge
With the continued growth of large commercial and retail developments it has become increasingly important to create the right ambiance for the complex.
Solution
For the Westfield shopping complex at White City SRL provided acoustic design advice so that all Building Regulations around noise were met. With the design of the complex including many levels and large atrium spaces it was essential to design the acoustics so that the PA system was intelligible in case emergency announcements had to be made. Within the complex certain areas were designed to be quieter to encourage a calmer ambiance such as within the Designer Village. With such a large number of outlets all under one roof the issue of plant noise could have been a problem, but by being involved from an early stage we were able to include noise reduction measures into the design. A multi screen cinema was also included in the development and we were able to advise on the shell design to make sure that breakout noise did not affect the surrounding development.
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PAVA Design at Crossrail’s Bond Street Station
Acoustics case study
PAVA Design at Crossrail’s Bond Street Station
Background
SRL Technical Services Limited were commissioned by Costain Skanska JV to assess the acoustic performance of the ‘Public Address / Voice Alarm’ (PAVA) system in the Bond Street Station for the new Crossrail line.
Challenge
The critical feature of the PAVA system is that the message being delivered must be intelligible (i.e. the public can clearly hear what is being said). For this reason the Crossrail contract requires a minimum Speech Transmission Index (STI) of 0.5 to be achieved in all public areas.
Solution
We developed detailed computer models of all public areas of the station to calculate the STI in accordance with BS EN 60268-16:2011 ‘Sound system equipment Part 16: Objective rating of speech intelligibility by speech transmission index’. The areas assessed included the Platforms and Tunnels, Eastern Ticket Hall, Western Ticket Hall and Link Tunnels. We used our models to map the STI and SPL coverage throughout these areas and identify non-compliance with Crossrail’s PAVA performance criteria.
In areas where the PAVA performance criteria were not achieved, we worked closely with the design team to improve the performance of the PAVA design. This included modifications to the speaker specifications and locations, and also changes to the architectural design, e.g. incorporating additional acoustic absorption to shorten the reverberation time.
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Ditton Park Academy, Slough
Acoustics case study
Ditton Park Academy, Slough
Background
Ditton Park Academy in Slough is a 1,100 student capacity new build secondary school and sixth form. Although predominantly a mainstream education school, it also included a SEN department to cater for students with special hearing and communication needs.
Challenge
The site is situated under the Heathrow flight path, and is consequently exposed to high levels of aircraft noise throughout the day. The challenge was to meet the BB93 internal ambient noise level criteria (for both the mainstream and SEN areas within the building, whilst providing sufficient ventilation and cooling to meet the “Normal” and “Summertime” ventilation conditions.
Solution
We worked closely with the design team to develop suitable ventilation strategies which allowed the BB93 indoor ambient noise level criteria to be achieved in all areas of the building.
A hybrid ventilation strategy was used for the mainstream areas which utilised façade mounted heat recovery units and a single louvre with a volume control damper to provide fresh air. This strategy allowed the required ventilation rates to be provided using relatively small openings within the façade. The relatively small openings within the façade meant that a reasonable level of sound insulation could still be provided by the building enevlope.
Our analysis of the external noise levels showed that a hybrid strategy wasn’t capable of meeting the more onerous internal ambient noise level criterion for SEN rooms. Therefore we advised the design team to mechanically ventilate the SEN spaces using centrally located air handling units using a system which didn’t rely on open windows or other façade openings. We also provided the optimum acoustic specifications for the sound insulation performance of the external wall and glazing.
Our commissioning measurements of the completed building demonstrated that the BB93 internal ambient noise level criteria were achieved in all spaces including the SEN areas. All other acoustic criteria were also achieved in the new building.
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Downtown, Woden Street, Salford
Acoustics case study
Downtown, Woden Street, Salford
Background
New-build mixed use development of over 350 apartments with associated gym, cinema room and business centre on the banks of the River Irwell in Salford. Downtown is a collection of 6 interlinked blocks completed over two phases of construction, varying in height from 4 storeys up to 14. The development will provide a mixture of one, two and three-bedroom apartments close to Manchester city centre.
Challenge
SRL were initially commissioned in 2014 to provide a noise impact assessment for the proposed development. We have since provided detailed design up to RIBA Stage 4, construction stage support, site inspections and a full schedule of commissioning testing to demonstrate compliance with Approved Document E. Phase 1 was successfully completed in 2019 and the second phase is on schedule for handover in the first quarter of 2020.
As with most other schemes, we identified areas of the design which could be value engineered which saved our client a significant sum of money. The two areas our client wanted us to focus on value engineering were:
- Reducing the specification of the high performance glazing and mechanical ventilation across all facades due to the proximity Metrolink trams and heavy rail trains to the south
- Avoiding the need for a resilient layer above the separating floor slab between apartments to comply with Approved Document E impact sound insulation criteria
Solution
Salford City Council’s planning authority set strict internal and external noise limits due to the proximity of a rail viaduct to the south of the development. SRL measured noise levels at key positions on the site and used detailed acoustic modelling techniques to show that only the most exposed facades at the south of the building required high performance glazing and mechanical ventilation to meet the internal noise limits. Facades below viaduct level, and those more sheltered from noise could meet internal noise limits using lower performance glazing and natural ventilation.
The locations of each glazing and ventilation was presented using colour coded facades, making our advice easier for other members of our design team to understand and saved our client a significant sum of money.
Our client also wanted to avoid using a resilient layer throughout the development, but needed to understand the risks involved and develop a solution to comply with the impact sound insulation requirements of Approved Document E.
Our proposed solution was to use a latex screed above the slab, which would be both cheaper and easier to install than a resilient layer. SRL provided impact sound insulation testing between two trial apartments which showed that the latex screed could sufficiently control impact noise above the slab. This also saved our client a significant sum of money and time.
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Royal Liverpool University Hospital
Acoustics case study
Royal Liverpool University Hospital
Background
The new Royal Liverpool University Hospital is being built at a cost of about £335m, next to the current hospital and will open in 2017. Once completed the existing facility will be demolished to make way for building of the Liverpool BioCampus. The new hospital has been designed with patients in mind and will be the largest hospital in the country to provide all single en-suite bedrooms creating improving patient privacy and further improving infection control.
The new hospital will have 18 operating theatres, 23 wards as well as a 40 bed Critical Care Unit. The Emergency Department will include a CT scanner and lifts for major trauma patients that go straight to theatres.
Challenge
SRL’s brief was to provide a full acoustic design, site support and commissioning testing for the new hospital. The design of the building includes an interstitial plant deck on the third floor where all the major plant is housed with rooms above and below.There was also the challenge of designing a building that met the acoustic requirements of the guidance in HTM08-01, which SRL helped to write. The hospital needed to be delivered with good levels of acoustic privacy between all of the rooms whilst still meeting the clinical and operational requirements.
Solution
Working with the M&E consultants we reviewed the design to help find the quietest plant. We also looked a louvre design to provide a solution that met both the airflow and acoustic requirements. Glazing design was also reviewed as there was the potential for noise break-in into the rooms above the plant deck louvres.
Internal partition construction has been optimised to achieve the required privacy whilst minimising cost and maximising area. Hybrid constructions were developed for some key walls to allow modular installation of M&E services.
Testimonial
I just wanted to thank Richard Budd for his great counsel over the years we have been working together, particularly on this difficult project. Richard has helped us with some really complex issues on Royal Liverpool University Hospital, which arose as a result of Carillion’s liquidation back in 2018. There were a number of complex acoustic performance issues arising from the structural remediation/impact to the atrium smoke extract system. Richard was great at helping achieve a compromise solution between the local authority and the Trust/project team. We could not have got through the completion works without him.
Bronwyn Paterson NBBJ
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Olympia, London
Acoustics case study
Olympia, London
Background
The work to create the new Olympia includes creating a new 4,400-seat live music venue, a 1,500-seat theatre, two hotels, offices, retail outlet, public realm space and affordable commercial units for a wide range of potential tenants. All this whilst retaining listed exhibition halls and other buildings; Grand Hall, National Hall, Pillar Hall and West Hall, and what’s more, allowing exhibitions in these spaces to continue whilst the construction happens.
Challenge
It’s a highly complex project in all aspects; acoustics is one of those and by the project’s nature it’s a key consideration. All uses of the site compete with each other for acoustic requirements and many need acoustic protection from other activities. And on a site sitting amongst existing residential and commercial properties, alongside a railway and a busy road, the acoustic challenges are complicated, continuous and enormous. We joined the project in 2020 after reviewing designs for the building envelope of the high-performance music venue and found that some changes were needed for the project to meet the acoustic requirements. From then on, we have been Laing O’Rourke’s acoustic consultant across the entire project, to help them successfully deliver the project. We are heavily involved with all disciplines to find solutions to meet all the technical and contractual requirements amongst the constraints. Additional challenges have been created with the need for contractual lines between shell & core and fit-out contracts, varying stakeholder input and requirements and site constraints for what can be achieved.
Solution
For the site to function successfully once complete and operational, we have created acoustic designs to control loud music to the neighbours and to other on-site uses. And to prevent road and rail noise affecting quiet hotel bedrooms and offices. The very high-performance envelope for the music venue is unique to the project and has been carefully designed to get the best from the available space. High-performance glazing to hotels, structure-borne noise and vibration control, isolated floor slabs, isolated columns and suitably attenuated ventilation systems are just some of the acoustic design solutions incorporated across the project.
As the existing exhibition areas are remaining open during the redevelopment, a proportion of the works has to be done outside of normal construction hours. Coupled with the close proximity of residential receptors around, we have developed a close collaborative relationship with the site teams, to make sure the correct mitigation measures can be incorporated to the works to minimise potential disturbance, and attain the necessary CoPA section 61 consents.
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Noise at Work
Acoustics case study
Noise at Work
Background
It is an established fact that excessive noise causes damage to hearing. If the exposure is brief, the damage may be temporary. However in the workplace exposure can be repetitive and long term which can result in permanent hearing damage and deafness. In 1989 the Noise at Work Regulations were introduced. These regulations are now superseded by The Control of Noise at Work Regulations 2005. The new regulations impose tighter limits on noise exposure to reduce the risk of noise induced deafness of employees, and place more emphasis on the need to take action to reduce exposure levels.
There are new “Action Levels” defined in the Regulations. These are:- Lower Action Value A daily/weekly noise exposure of 80 dB LEp,d
- Upper Action Value A daily/weekly noise exposure of 85 dB LEp,d
- Exposure Limit Value A maximum exposure of 87 dB LEp,d
Challenge
There is a duty on employers to reduce the risk of excessive exposure to noise for their employees. The risk must be assessed and employees informed of it. Where action is shown to be needed, a noise control action plan must be implemented.
There are various processes that can be used to assess noise:
- Noise at Work risk assessment
- Noise dosimetry
- Advice on hearing protection
- Design of noise control measures
- Design of buildings to contain/reduce noise
- Vibration monitoring
- Action plans for noise control
Solution
The assessment involved a survey, which was conducted over one day, can be described in two main parts:
The first part involved a noise survey at locations across the site with the aim of generating a ‘noise map’ of the facility. This enabled quick identification of the noise ‘hotspots’ and demonstrates the overall noise climate in different areas.Secondly, we assessed the noise exposure of individual employees during a typical working shift by attaching noise doseBadges to the shoulders of employees for the minimum of an hour while they carried out typical work tasks.
Operational noise levels were monitored at various positions around the site and shown on a Noise Map. Noise doseBadges were fitted to the shoulders of employees for periods ranging from 3hrs to 3.5hrs. The doseBadges were set to measure while the wearer was going about their normal work tasks. Post processing enabled the calculation of the personal noise dose of each employee over their working shift. From the noise map we were able to provide demarcation lines within the workplace and advice on the signage required to show what protective equipment was required in each area. The map and doseBadge information was used to produce rota patterns that avoided employees exceeding legal maximum exposure times.
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New Cross, Manchester (Broadside)
Acoustics case study
New Cross, Manchester (Broadside)
Background
274-unit mixed residential scheme at New Cross, Manchester. The £65m scheme opened in Summer 2020, comprising a mixture of one-to-three bedroom apartments, rooftop pavilions, basement car park, courtyard concierge and ground floor commercial units.
Challenge
One of the challenges surrounding the ground floor commercial units was to reduce risk to the client and provide assurance to building control that noise from the commercial units would not adversely affect residents in the apartments above. Given that the operators of the commercial units were unknown, we based our assessment on typical restaurant noise levels.
Solution
We set noise limits in the commercial units to maintain acceptable levels in the apartments above and placed responsibility to the operators to provide upgraded sound insulation if these noise limits were to be exceeded. This reduced the risk to the client of future noise complaints.
We allowed for a programme of four site inspections, arranged in close collaboration with the site team to observe a range of site-specific issues over a period of 9 months. On a scheme of this size, comprising two blocks and a construction duration of around 2 years, this allowed us to monitor workmanship through contractor changes and identify potential acoustic related issues at a stage of the build where they could be rectified.
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Manchester Engineering Campus Development
Acoustics case study
Manchester Engineering Campus Development
Background
The £400m Manchester Engineering Campus Development (MECD) is the largest, most ambitious single construction project completed by any UK higher education institute. The specialist engineering buildings enable a co-located community of 8000 academics to work alongside each other in a world leading research and education facility. It is not, however, the impressive scale of MECD which makes it deserving of an ANC Award. The functionality of MECD is dependent on its exemplar acoustic performance. The seven faculties must operate alongside each other without impacting on each other’s work, much of which is exceptionally noise and/or vibration sensitive ground-breaking research.
Challenge
The brief from the University was to deliver a fully integrated engineering campus to house seven co-located engineering faculties and institutes. Each faculty has its own specific laboratory, teaching and research requirements, and these would need to function alongside each other. Facilities would be bespoke and spread over 80,000m2 of floor space, eight stories, four separate buildings and with a building footprint equivalent to 11 football pitches.
The basement of the development is home to highly sensitive electron microscope suites. These spaces have onerous octave band IANL criteria below the threshold of hearing, low vibration criteria, onerous reverberation time criteria and high-performance walls and floors surrounding them. There were significant engineering conflicts to overcome, and much effort and design focus was made to ensure that these criteria were all collectively met.
Above the basement are a mixture of flexible teaching, heavy engineering, lecture, research and laboratory spaces. Many of the faculties teach in laboratories and each contain purpose selected equipment with bespoke reverberation and IANL criteria to match.
A huge interconnecting atrium named “the street” runs the 200m length of the MECHall building.
Solution
Many of the laboratories were so heavily serviced that the implementation of acoustic treatment meant innovative solutions backed up by extensive acoustic modelling.
Acoustic modelling of the interconnecting atrium ensured that reverberant sound build up didn’t impact on adjacent academic spaces, and that the spaces were also suitable for use as break-out working zones.
The approach to reverberation control in the street allows all users (including catering units), to share the space successfully.
The acoustic engineering approach throughout the project was to design to “just meet”. Risk and reward were shared with the client on big ticket items such as overall levels of acoustic treatment. Requirements and levels of treatment evolved through the design informed by early on-site testing. Final testing has demonstrated very little overdesign occurred and we have succeeded in delivering a lean sustainable project.
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Sir William Henry Bragg Building (Leeds University)
Acoustics case study
Sir William Henry Bragg Building (Leeds University)
Background
The building was designed explicitly in terms of its acoustic performance, to create a world class facility housing some of the most advanced electroscope technology in the UK. SRL won the Association of Noise Consultants’ Building Acoustics Award for our work on this project. The new facility enables researchers to see and video the motion of individual molecules. Expert and detailed acoustic design advice provided has enabled the client’s requirements to be realised in full and help researchers continue their ground-breaking work.
Challenge
The Bragg Building is located close to noise sensitive receptors including existing university buildings and residential buildings. A planning condition was attached to the development which required noise from mechanical plant to be limited to 5dBA below background noise levels at the nearest noise sensitive receptors with the measurements and assessment made in accordance with BS4142.
The Bragg Building is a working University building so the control of noise and vibration had to be achieved without limiting the functionality for users in the other more traditional teaching areas and laboratory spaces.
Solution
We calculated the cumulative environmental noise emissions from all building services plant associated with the new building. Using manufacturer’s data for plant noise levels, attenuation performance data and plant layout drawings we created a 3D noise propagation model to predict noise levels from the proposed plant at the various noise sensitive receptors.
The smallest movements in the structure have the potential to affect the equipment within the building and so every single source of noise and vibration had to be considered in detail. This included isolation of all mechanical services plant and reduced airborne noise from mechanical services (to avoid erroneous air movement affecting test samples).
