Long hospital bright corridor with rooms and blue seats 3D rendering

We Can’t Afford Not To Consider Acoustics When Designing Healthcare Facilities

It is easy to think of “design” first and foremost as the things we can see – the glossy atrium and shiny curtain walling. In the current climate, there is of course no money and little appetite for such things – we all want the NHS to put its staff and patients first and foremost – but this does not mean that there is no role for good design in healthcare buildings.

Acoustics is often the poor cousin at the design team table, sometimes seen as an item which can be value engineered out altogether.  This could be a false economy for a number of reasons which we will discuss below.  The topics we will cover here are equally applicable to new build and refurbishment, to large hospitals and smaller community or specialist facilities, private and public sector.

Of course, the inclusion of acoustic provision within a design has an up front cost impact, but this can be mitigated by allowing the acoustic design to be fully integrated with the overall proposals rather than seen as a “bolt on” late in the design phase.  The salient point to remember can be summed up in a cliché – “spend a little to save a lot”.

Current Practice

Health Technical Memorandum (HTM) 08-01: Acoustics provides design criteria for noise intrusion from external sources, internal noise due to mechanical and electrical services, privacy between different spaces, and reverberation control (how ‘lively’ a room sounds).  Key considerations in acoustic design of healthcare facilities are generally patient privacy and confidentiality, and reasonable conditions for rest.

The guidance within HTM 08-01 provides an appropriate acoustic standard and is well considered – however the experience of many acoustic consultants will be that, wherever possible, design teams will attempt to derogate away from this standard in order to save costs.  In particular, reverberation control is often omitted or value engineered due to a sentence which says that it should be allowed for “where cleaning, infection-control, patient safety, clinical and maintenance requirements allow”.  This get out of jail free card is often abused in order to reduce costs with little thought to the long term impact on patients and staff.

To compound the potential acoustic problems which arise, there are also several sources of noise where it is not possible for HTM 08-01 to be prescriptive.  This includes items such as the selection of quiet medical equipment, the use of audible nurse call systems, and noise from pneumatic tube systems.  Recommendations are given within the HTM that quiet systems should be selected, the routing of services should be considered etc, but as these are not mandated and in some cases beyond the control of the design team, they are generally overlooked.

The effect of poor acoustics

Both researchers and patients have understood for years that high noise levels (over 80 dBA) can occur in intensive care facilities, and that shift changeovers and staff activity are generally perceived as disturbing.  Sleep disturbance and stress result (1).  Half of all sleep in hospital occurs during the daytime (2) and as such, any measures implemented cannot be restricted only to the night time period. To compound the issue, noise tolerance is lower in those who are unwell (3).

As far back as 2004, researchers in Sweden (4) examined sleep disturbance factors before and after the implementation of a behavioural modification programme.  This programme involved changing nursing and medical routines and the introduction of afternoon and night non disturbance periods.  These changed were found to reduce sleep disturbance both objectively and subjectively as well as supporting the findings of earlier researchers (5) that general nursing activities disturbed patients most.

The effect of noise on patients is not solely related to sleep disturbance, and are both physiological and psychological (3). Physiologically, high noise levels increase adrenaline secretion, blood pressure, and peripheral vasoconstriction.  Psychologically, the associated stress can trigger abnormal behaviours in patients and, presumably, also in staff. One paper has even posited a link between high noise levels and wound healing! (6)

Spend a little….

The implication here is that the responsibility lies with staff, who should be encouraged to understand and consider sleep hygiene; this is certainly an important factor and all health providers should consider their practices and aim to increase staff self awareness.

This isn’t enough on its own to solve the problems.  There are clear steps which can be taken in the acoustic design of any healthcare facility which can significantly benefit both the patient and staff experience and (as we will discuss in the next section), ultimately save money. The concept of “supportive design” (7) puts forward the theory that environmental characteristics “support or facilitate coping and restoration with respect to the stress that accompanies illness and hospitalisation…fostering gains in numerous other patient health outcomes”. The role of the design team as a whole must be to provide facilities in which these factors are considered and implemented.

As a starting position in acoustic design, the requirements of HTM 08-01 with regard to privacy, reverberation control and noise levels must be adhered to; in particular a move away from the “common” derogation with regard to reverberation control is imperative.  Appropriate control of reverberation provides a subjectively more comfortable environment but also helps to control the build up and transmission of noise, and improves privacy in open wards and other open plan environments.

There is potential for designers to change the “traditional” hospital setting, too, replacing the curtained cubicle with part- or full- height partitions between beds with a curtain to the circulation space only. This could save costs in terms of the maintenance, cleaning and replacement of curtains, as well as providing a greater level of acoustic separation between adjacent beds.

The location of nurse stations is clearly driven by the need to supervise and attend to bays and must be central; again, though, careful positioning, screening (glazed if necessary) and design could be used to mitigate noise transfer from conversations at this location to bed areas.

Simple consideration in the selection of equipment and fittings can have a significant effect too; visual rather than audible call bells, a bin which closes quietly rather than slamming shut, rubberised trolley wheels to reduce rattling and squeaking.

There are complexities in incorporating good acoustic design.  We must of course consider cost, infection control and patient supervision.  None of these is insurmountable with careful thought from the designers.

…save a lot?

The earliest paper cited here is dated 1971 and yet, as any of us who have had the misfortune to find ourselves as inpatients can testify, these problems have not been resolved. Perhaps with a proven financial benefit, now is the time to change this.

In recent years there has been a growing research interest in the long term cost benefits of good acoustic design.  Whilst this is ongoing, recent studies in coronary care settings (8) have demonstrated that…

  • Reducing noise levels and enhancing sleep quality has been found to significantly reduce re-admission rates (from 48% to 21% at three months).
  • Patient recovery times can be shortened by up to 30%, reducing the length of stay in hospital.
  • Less sedative medication and fewer beta blockers are prescribed in settings with good acoustic conditions.
  • By improving the speed of recovery, patients can be moved sooner from intensive or acute care to less costly care

Benefits of reducing the stress associated with high noise levels and poor acoustic conditions are not restricted to patients. Studies carried out in the United States (8) have demonstrated a likelihood that staff errors and conflicts between staff are reduced when acoustic conditions are improved.  This is thought to be due both to improved conditions for communication between staff and reduced stress due to lower noise levels.  The same study found that due the increased comfort and reduced stress of patients, staff reported lower work demands and decreased pressure and strain.  The implication of this is that savings can be made both in terms of staff sickness (and associated use of agency staff) and turnover.

Conclusion

When faced with a building or refurbishment project, it is easy to be led by cost constraints and see acoustics as a “nice to have” item rather than a necessity.  Acoustic treatment it not free, and the temptation will be to value engineer or altogether omit the recommendations of the acoustic consultant wherever possible.

When the whole life cost of the building is considered, however, this can be seen to be a false economy.  The benefits of good acoustic design in promoting speedier recovery, improving patient outcomes, reducing readmission rates, reducing the prescription of various medications, and in reducing staff turnover and errors, must not be overlooked. If we are to produce truly cost effective, “supportive” and sustainable design, acoustics should be at the forefront of the design agenda.

References

1. BM Dlin, H Rosen, K Dickstein, JW Lyone, HK Fischer. The problems of sleep and rest in the intensive care unit. Psychosomatics. 1971, Vol. 3, 12.

2. Gabor JY, Cooper AB, Crombach SA, Lee B, Kadikar N, Betteger HE, Hanly PJ. Contribution of the intensive care unit environment to sleep disruption in mechanically ventilated patients and healthy subjects. American Journal of Respiratory Care Medicine. 167, 2003, Vol. 5.

3. BA, Hilton. Noise in acute patient care areas. Research in Nursing Health. 1985, Vol. 8, 3.

4. Maria G. Monsen, Ulla M. Edell-Gustafsson. Noise and sleep disturbance factors before and after implementation of a behavioural modificiation programme. 2004.

5. Khan DM, Cook TE, Carlisle CC, Nelson DL, Kramer NR, Millman RP. Identification and modification of environmental noise in an ICU setting. Chest. 1988, Vol. 114, 2.


dBx Case Studies - Education

There is a proven link between acoustic conditions in schools and educational outcomes. Building Bulletin 93 (BB93) mandates minimum standards in primary and secondary schools for noise levels and room acoustics, as well as acoustic separation between teaching spaces.

The dBx Acoustics team can help you comply with BB93, but our expertise goes even further. We have extensive experience designing environments for pupils with additional needs, including autism and hearing loss, as well as higher education and noisier, practical workshop spaces.

New and refurbished school buildings must comply with Building Regulation E4 and the acoustic performance standards of Building Bulletin 93 (BB93) ‘Acoustic Design of Schools’. Whilst BB93 is not mandatory for higher education establishments, it typically forms the basis of the initial design for such establishments, with modifications as appropriate to allow for specific HE uses. Where projects are being designed with BREEAM in mind, credits HEA05 and POL05 are also relevant.

There are a number of different acoustic aspects which come together to ensure that acoustic conditions in schools are appropriate to support learning, and it’s so important to get it right – studies have shown that educational attainment can be directly correlated to acoustic conditions.

Our involvement often begins at the planning stage with an environmental noise survey, which allows us to advise on ventilation and glazing requirements to control noise ingress to the building. If mechanical ventilation is proposed, if there is an external MUGA, or if community use is proposed, the noise survey also allows noise emission limits to be set to ensure that existing neighbours are not adversely affected by noise.

Internal ambient noise levels in teaching spaces are also affected by mechanical ventilation, and we work with the M&E consultant to specify appropriate noise control measures, such as silencers.
When it comes to the design of the building itself, BB93 requires us to specify partitions and floors to control airborne and impact sound transmission between teaching spaces, based on their relative sensitivity and noise generation characteristics. The detailing of junctions and sealing of any services penetrations is critical in maintaining acoustic separation between adjacent rooms.

Having provided a suitably quiet teaching environment which won’t be adversely affected by activity in other classrooms, our focus moves to room acoustics and control of reverberation. Often this is as simple as specifying the acoustic performance of a suspended ceiling, but for large spaces such as Assembly Halls and Sports Halls, we undertake acoustic modelling to optimise the specification and placement of acoustic finishes. Where an exposed soffit is preferred, we calculate the specification and quantity of finishes, such as acoustic rafts and wall panels to control room acoustic conditions.

Finally, we carry out pre-completion acoustic testing on-site to ensure that all of the acoustic criteria for the project have been complied with on-site.

The dBx Acoustics team also have a particular interest in acoustic design for SEN schools, particularly schools catering to neurodiverse pupils. BB93 specifies design criteria for “children with special hearing and communication needs”, which is intended to include autism, ADHD and auditory processing difficulties, and assists in providing an environment in which speech transmission is clear and effective. The standard does not, however, consider the other acoustic aspects of school life which affect such pupils, including auditory sensitivities and the need to provide spaces to allow a retreat from the noise and bustle of daily school life. Our team’s direct and personal experiences of neurodiversity, both as parents and as individuals, helps us to understand the requirements of individual educational clients, and help guide the design of educational buildings to provide an acoustically diverse and appropriate environment.

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