Why are hospitals noisy?
There are two main reasons why hospitals are noisy. First, there are many noise sources present, and, second, environmental surfaces in hospitals—walls, floor, and ceiling—tend to be sound-reflecting rather than sound-absorbing (Ulrich et al. 2004; Ulrich 2003). Sounds contributing to the loud noise levels in hospitals come from mechanical equipment in use—alarms, paging systems, telephones, computer printers, ice machines, staff conversations, and noises generated by roommates and visitors. Many studies have found that staff conversation in particular is a major source of loud noises on the hospital unit
(Allaouchiche et al. 2002; Bentley, Murphy, and Dudley 1977; Bayo, Garcia, and Garcia 1995).
The presence of hard sound-reflecting surfaces in the hospital tends to aggravate the noise problem in hospitals.
Sound-reflecting surfaces cause noise to propagate considerable distances, traveling down corridors and into patient rooms, and adversely affecting patients and staff over larger areas (Ulrich 2003). Sound-reflecting surfaces typical of hospitals cause sounds to echo, overlap, and linger or have long reverberation times (Cole, Blomkvist, and Ulrich 2005; Blomkvist et al. 2005).
Reverberation is the persistence of sound in an enclosed space, resulting from multiple reflections after a sound source has stopped. The reverberation time of a room is the time it takes for sound to decay by 60 dB(A) once the source of sound has stopped and is largely determined by the presence of sound-absorbing materials in the room (Joint Subcommittee on Speech Privacy of the Acoustical Society of America, Technical Committees for Architectural Acoustics and Noise; Institute of Noise Control Engineering; and National Council of Acoustical Consultants 2006). Extensive use of sound-absorbing material will mean that the sound is absorbed and, thus, prevented from “building up” (Cole, Blomkvist, and Ulrich 2005). When acoustic conditions are characterized by long reverberation times, echoes will cause blending and overlapping of sounds, resulting in reduced speech intelligibility. To make themselves heard, staff members then need to raise their voices, thereby compounding the noise problem even further.
(Sound Control for Improved Outcomes in Healthcare Settings January 2007)
Acoustics in WORK HEALTH AND SAFETY
AUSTRALIAN WORK HEALTH AND SAFETY STRATEGY 2012–2022 is set to promoting worker health, wellbeing in health care and social assistance industry.
Acoustics are a key element of the modernised healthcare system. There is a whole bank of clinical research out there that proves that better acoustics led to improved healthcare outcomes. It has been shown that well-designed, high-quality spaces promote a decrease in the use of analgesics, improves patient recovery times and increases staff efficiency.
Hospitals are noisy and they are getting noisier. Several studies performed by the WHO (World Health Organization) reveals that hospital noise levels have been increasing consistently since 1960 (Ryherd, Waye & Ljunkvist, 2008).
Researchers have concluded that all hospitals, regardless of their size, type of patients they care for, at all times of day, every day of the week, exceed recommended noise levels put forth by EPA and WHO (Choiniere, 2010). We can assume that, with the constant evolution of technology, the number of sources of noise will also increase because some patients´ lives are depending on it.
Good acoustic conditions are fundamental to the quality of healthcare facilities. Excess noise hasthe potential to in-crease blood pressure, heart and respiration rates, and con-tribute to cognitive impairment and sleep disturbance (Ampt, Harris, & Maxwell. 2008).
Guidance (Ampt, Harris, & Maxwell. 2008) indicates that good acoustic design can:
• Improve patient comfort, privacy and dignity
• Assist in providing essential sleep patterns to aid the healing process
• Improve staff comfort, privacy, efficiency and accuracy
In short, control of unwanted noise is of critical importance. Design of efficient, effective hospitals must incorporate noise control as a primary consideration.
(Samuel Clarke Proceedings of ACOUSTICS 2011)
The World Health Organization (WHO) Loudness Guidelines
The World Health Organization (WHO) has developed guidelines for noise in healthcare facilities where nighttime noise should not exceed 40 dB (LAmax). For inpatient wards, the recommended interior noise level is 30 dB LAeq during daytime and 35 dB LAeq at night. (Taskforce, April 1999). In 1997, the American Academy of Pediatrics established that noise levels higher than 45 dB should not be admitted in a NICU setting. (American Academy of Pediatrics, 1997)
Contemporary acoustic standards are essential to ensure standardization across government, private, and public sectors.
Between 28–32% of the Australian workforce is likely to work in an environment where they are exposed to loud noise at work.
In the model WHS Regulations the exposure standard for noise :
LAeq,8h of 85 dB(A)
LAeq,8h of 85 dB(A) means that over an eight-hour shift a worker can’t be exposed to more than 85 decibels. Whether this is exceeded depends on the level of noise involved and how long a worker is exposed to it.
These limits should protect most but not all people. The risks from workplace noise must be eliminated or minimised so far as is reasonably practicable.
Ideally, you should keep noise levels below:
50 decibels if your work requires high concentration or effortless conversation
70 decibels if your work is routine, fast-paced and demands attentiveness or if it is important to carry on conversations.
Noise at levels that do not damage hearing can have other adverse health effects. This can arise when noise chronically interferes with concentration and communication. Persistent noise stress can increase the risk of fatigue and cardiovascular disorders including high blood pressure and heart disease.
Acoustic treatments in Healthcare & Well-beings facilities
Sound-absorbing ceiling tiles
To absorb or block noise pollution acoustic paneling, door seals, low-reverb flooring and wall coverings all aid this process. Eliminating or at the very least minimizing reflective surfaces assist by making sure that reverberation is decreased when noise does occur. Controlling reverberation is particularly important for speech intelligibility, the control of noise and for desirable subjective qualities. There have been many studies conducted which concluded that where high-performance sound-absorbing ceiling tiles were used, patients slept better, were less stressed and reported greater satisfaction. It is highly stressed though the importance that bacteria-resistant materials are used, as traditional sound absorption materials often fail to meet hospital requirements in the ways of the ease of cleaning, bacteria resistance and flammability.
Research suggests that environmental interventions may be effective in reducing the noise levels in hospitals and improving the acoustical environment. Key interventions include installing high performance sound-absorbing ceiling tiles.
At least three studies have shown that installing high-performance sound-absorbing ceiling tiles and panels results in reduced noise levels and perceptions of noise and impacts other outcomes such as improved speech intelligibility and reduced perceived work pressure among staff (Berens and Weigle 1996; Blomkvist et al. 2005; MacLeod et al. 2006; Hagerman et al. 2005). Though decibel levels were not greatly reduced as a result of the ceiling-tile intervention in these studies (reduction of 3 to 6 dB(A)), reverberation times and sound propagation were significantly reduced. This impacted the perception of the unit being less noisy and also improved speech intelligibility, which has implications for staff communication (Blomkvist et al. 2005; MacLeod et al. 2006).
Noise pollution can have significant negative effects on healthcare staff and patient recovery, and can also even have an impact on the legal obligations of healthcare facilities. In saying this, utilizing acoustic treatments can eliminate or alleviate these issues in a more sustainable and cost-effective way.