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Noise annoys! Acoustic optimisation of rooms in hospitals

Everyone benefits from lower sound levels in healthcare premises

Mark Janssen, Marketing Development Manager, Ecophon Group, Saint-Gobain Ecophon AB, Sweden
E: [email protected]
Facilities managemen t F13
For information on products and services see  HHE 2009

Nowadays, healthcare facilities have to contend with unprecedented competition. Hospitals are transforming themselves into health centres courting not just patients but doctors and nursing staff as well. In this context, an environment that promotes and conserves health is assuming increasing importance in purely economic terms. In the process, room acoustics are attracting increasing scrutiny from forward-looking clients.

In the past the combination of good room acoustics and the smooth, hard surfaces that predominate in clinics for reasons of hygiene was an apparently insoluble problem. But because the noise level in hospitals caused by modern communication technologies, the increased use of medical equipment and other factors has far exceeded threshold values, recent years have seen a number of attempted “do-it-yourself” solutions to get a grip on this stress factor that is fraught with dire consequences.

But nowadays innovative system solutions for providing effective sound proofing are available “off the peg” and can be used without a second thought in healthcare facilities for all types of room. These sound absorbers satisfy the requirements for frequent cleaning and maintenance, as they do the need for chemical disinfection, and also comply with all other criteria of relevance to hospital areas.

Convincing evidence of the need to cut the average noise level in hospitals that has grown to as much as 68 dB comes not just from the third place in the league table of patients’ complaints demonstrably occupied by noise pollution. Science has long since confirmed this perceived discomfort with objective measurements that go so far as to demonstrate a correlation with slower convalescent processes, sleep disorders and increased medication intake. More than that, research has investigated the devastating effects on clinical personnel that manifest themselves in numerous adverse effects and stress reactions up to and including clinical errors.

Tractor noise in the operating theatre
The World Health Organization WHO has defined a level of 35 dB as the benchmark for the average constant background noise level in hospital wards. Nighttime peak values should not exceed 40 dB. However, numerous studies attest to typical peak values of 45 to 60 dB, and occasionally even higher than 80–90 dB, caused by the sound of alarm systems and numerous technical appliances. At 100 to 110 dB, the noise level in the operating theatre is proving to be particularly dangerous for clinical personnel where drills, saws and other items of equipment create a significant risk of noise-related hearing loss. The most common occupational ailment in Germany is deafness caused by excessive stress on the hair cells of the inner ear.

But how do you get a grip on this deplorable state of affairs? It would be presumptuous to claim that one could turn modern hospitals into oases of calm. But based on an evaluation of the acoustic environment one can at least use highly effective sound absorbers to achieve a considerable reduction in the sound level, to eliminate the sources of danger and demonstrably contribute to higher levels of patient and personnel wellbeing.

Noise-reducing initiatives more effective than preventive behaviour
The key factor in good room acoustics is the correct quantity and siting of sound-absorbing materials. That is why it helps to have a building profile in which the various acoustic and functional zones are catalogued having regard to their peak times in terms of activity and noise. A further important aspect in regulating the acoustic environment is to identify the sound sources themselves. Admittedly, these cannot simply be eliminated. But it is at least possible to reduce sound levels, for example by using a silent paging system. There are also attempts to improve the acoustic environment by means of organisational initiatives such as personnel training courses or by introducing so-called quiet times. Studies on the effectiveness of sound-reducing measures suggest, however, that tackling environmental and building aspects is more successful than activities to prevent individual behaviour. Referring to various studies, Roger S Ulrich, one of the most prominent advocates of evidence-based, convalescence-friendly hospital design, said on the topic of hospital noise: “There appears to be sufficient evidence on negative effects of noise to justify the recommendation that noise reduction should be a major consideration in the design of new healthcare buildings.” Roger S Ulrich PhD is director and professor of the Center for Health Systems and Design at Texas A&M University, USA.

Acoustic absorbers have to satisfy the most widely different requirements
When selecting appropriate acoustic elements one needs to ensure that they fully comply with hospitals’ specific requirements. We distinguish here between public, functional and clinical areas as well as care units. In public areas, where we are mainly talking about large, open spaces with their traditional sound propagation problems, the challenge is to create an acoustic environment that supports communication and orientation within the building. Reception areas must take equal account of the ability to understand what people are saying and personal acoustic space. High-performance acoustic ceilings make it possible to pull off this balancing act.

In patient areas the particular challenge is to offer the patient somewhere to rest and sleep, thus assisting convalescence. However, in clinics where the acoustic environment is left to chance, sleep disorders are the order of the day. As a Finnish study shows, 80% of the patients questioned in a central hospital of the Finnish town of Karelia viewed the environmental conditions caused by other patients, equipment and personnel going about their work as a significant source of disturbance. Only 50% referred in this context to pain.

The functional areas include laboratories, which make the very highest demands, in particular as regards their hygiene characteristics. They demand absorbers that can be regularly washed without any difficulty and also decontaminated by treating them with strong disinfecting chemicals. In clinical areas, such as operating theatres, this is compounded by the need for flexibility as these areas are often expanded to accommodate an increased use of technology. The acoustic ceiling then has to grow with it.

Farewell improvisation – long live the professional solution!
Nowadays there are highly and ultra-effective acoustic systems for all these different requirements that call time on improvised soundproofing measures. Only two years ago, James West, an acoustic engineer at Johns Hopkins University in Baltimore, complained that while there are numerous measurements of hospital noise, suggestions for reducing it were in short supply.

“You can’t carpet the floors and you also can’t cover the ceiling with porous material because they could be colonised by bacteria and you would then have a major hygiene problem,” said the US researcher. He therefore developed his own solution for one of the wards in Johns Hopkins, which certainly has the desired effect.

“As sound installation we chose a glass reinforced plastic which is typically used for thermal insulation. Obviously you can’t wash it, but we wrapped it in a sort of bin liner. We found a special material for the purpose that lends itself to a germ-free environment. You can take it down and clean it. Also, this skin has only a very small adverse effect on the sound insulation properties. All in all it works very well.”

The homemade sound absorbers fell down the walls, however, and have since been replaced by professional Ecophon solutions because the acoustic hygiene systems from Sweden combine outstanding cleaning characteristics with all the other performance features relevant to good hospital room acoustics. To say nothing of superior design and greater ease of handling.