All images courtesy of K.R. Moeller Associates, Ltd.

Over the past several years, researchers have highlighted the importance of acoustic control in healthcare settings. Topics include patients' right to speech privacy, as well as the physical and psychological effects of noise on patients and caregivers. Studies have shown that noise disrupts sleep, affects health and mood, decreases productivity, and increases error rates.

These studies frequently identify facility design as a key factor in addressing such issues. One design component, a sound-masking system, can help solve noise and speech- privacy problems, thereby providing an environment that promotes healing, provides auditory confidentiality, and supports proficient healthcare delivery.

Noise Affects Health

Conversations, footfall, medical equipment and procedures, televisions, telephones, carts, and mechanical and paging systems—among many other sources—ensure that noise is ever-present in most healthcare facilities. These noises contribute significantly to patients’, visitors’, and staff's stress levels. In fact, several studies identify noise as a health hazard. Documented effects include elevated blood pressure, quickened heart rate, increased metabolism, and sleep disruption.

Because noise is disruptive, it can also affect mood. Individuals report feeling irritable, anxious, or agitated in noisy environments. Furthermore, the noises, discussions, and sounds of distress patients overhear can become the context for their healthcare experience. Because illness can cause increased sensitivity to environmental stressors, such sounds can create anxiety and increased nursing calls, as well as more pain and sleep medication requests.

Noise Disrupts Sleep

Sleep is an important part of the healing process but, obviously, noise often prevents patients from getting the rest they need. Hospitals conducting patient satisfaction surveys often find that noise and the resulting lack of sleep top their list of complaints. Sleep disruption types include delayed sleep onset, shifts to lighter sleep stages, motility (tossing and turning), awakenings, and cardiovascular changes.

Sleep deprivation appears to weaken the immune system, impede the body's ability to generate new cells, and decrease pain tolerance—all of which can lengthen hospital stays. Some studies indicate that at least one-third of sleep-deprived patients exhibit nighttime disorientation symptoms or “ICU psychosis.”

Researchers have found that the sick and the elderly are the people most likely to have their sleep disturbed by noise, and that people never completely habituate themselves to nighttime noise.

Noise Affects Productivity

Because noise disruptions affect concentration, cause fatigue, and reduce efficiency, acoustics are an essential consideration in providing an environment conducive to optimal work performance. In fact, a survey of 400 business managers conducted by the Buildings Owners and Managers Association and the University of Maryland indicated that noise control, over all other things, could boost productivity more than any other measure—by 26%, they said. The findings of another survey, commissioned by the American Society of Interior Designers, are similar in that more than 70% of respondents said they would be more productive if their workplace were quieter.

In healthcare settings, it is wise to select acoustic materials and methods that limit noise disruptions and increase speech privacy but simultaneously allow staff to easily access patients and interact with each other. These competing requirements can present a challenge to healthcare facility designers.

Noise Increases Error Rates

Noise has also been shown to disrupt cognitive and problem- solving capabilities in healthy adults. Staff members can have difficulty concentrating on their work in a noisy environment, and they indicate that it is easier to make errors in their daily tasks. This, of course, can have a direct effect on patient outcomes.

The American Hospital Association and the Institute for Safe Medication Practices recommend that programs to prevent medical errors consider environmental stress factors such as poor lighting, heat, noise, and frequent interruptions, all of which can diminish job performance.

These considerations are particularly important when transcribing or filling drug orders. In “Create a Hospitable Indoor Climate” (Pharmacy Post, September 2000), Wayne Morgan Caverly shows that noise distractions substantially increase dispensing errors and that as noise levels increase, so do error rates.
Most sound-masking systems are installed above the suspended ceiling. However, if you are planning to install the system in an open ceiling, select a design that features attractive speakers and tidy cabling to ensure that the system does not detract from your facility's look

Speech Privacy Is Key

Most of us have been in the following situation: You visit your doctor and sit in the waiting room, listening to the “people” sounds, including the receptionist/patient discussions. You are shown into an examining room and hear a doctor/patient conversation coming from the next room. You would prefer not to eavesdrop because you know that in a few minutes, your conversation with your doctor will likewise be overheard.

Speech privacy is critical in any healthcare setting—from doctors' offices to hospitals, insurance interview rooms to pharmacies. Conversations occur between caregivers and between patients and visitors at central administrative stations, in the hallways, and in semiprivate rooms and clinics. Often, areas used for the input and retrieval of medical and financial information, and areas where face-to-face and telephone communications take place, are located in or near patient waiting and care areas.

This diagram shows a sound-masking system installed above the suspended ceiling. Workstation and underfloor systems are also available but typically do not provide facility-wide coverage or paging distribution, a key secondary benefit of in-ceiling systems
Patients know that if they can overhear conversations occurring in adjacent areas, others can hear them, as well. This makes them uncomfortable and less likely to discuss private matters with their caregiver. Patients have a right to a level of auditory privacy, which has been officially recognized in a set of federal regulations developed by the U.S. Department of Health and Human Services.

The Health Insurance Portability and Accountability Act (HIPAA) includes consideration of the oral communication of protected health information and of any individually identifiable health information. Oral communication includes a variety of spoken communications, such as in-person and telephone conversations with patients and between employees. HIPAA requires that healthcare entities take “reasonable safeguards” to ensure speech privacy, including administrative, technical, and physical measures.
The four methods of noise control are: reduce noise at the source by selecting quiet equipment and enforcing appropriate office etiquette; absorb noise using absorptive ceiling tiles, wall materials, and flooring, and by limiting the number of reflective surfaces used in the space; block noise using an appropriate layout and partition height (pictured), “A” being the noise source and “B” being the listener; and cover noise using a sound-masking system

The “Quest for Silence”

When attempting to resolve acoustic problems, noise-control strategies are often pursued in the “quest for silence”—the notion that good acoustics are achieved when the sound levels in a space are as low as possible, with zero being the best. However, just as with ergonomic factors such as light, temperature, and humidity, the comfort zone for the level of sound is not zero.

The noise floor is the level of continuous sound that characterizes a space at any given time. If this floor is too high, the environment will be irritating and tiring. If this floor is too low, conversations and noises can easily be overheard, compromising both confidentiality and concentration. Noticeable rises and falls in sound over time and across facilities make it even more difficult for patients and caregivers to block out noise.

Sound masking is part of a proactive approach to providing patients with speech privacy and comfort, and providing caregivers with the productive “space” they need to excel. It is the only acoustic treatment that can be used to properly control the noise floor, which should generally range between 42 and 48 dBA.

What Is Sound Masking?

Sound masking has been used for several decades and in hundreds of thousands of facilities worldwide, including commercial, financial, government, medical, institutional, educational, hospitality, and judicial environments. Health-related applications include clinics, hospitals, pharmacies, medical labs, government and healthcare organizations, doctors' offices, and insurance interview rooms.
By raising the noise floor in a controlled fashion, sound masking reduces the distance over which speech and noise can be heard or understood

Despite sound masking's extensive history, many people don't know much about it. A sound-masking system consists of a series of speakers that distribute an electronically generated background sound within a facility. Many people refer to such systems as “white noise systems,” but that term is actually a misnomer. White noise actually describes a specific type of sound used in early masking systems developed in the 1970s. These systems were largely unsuccessful because of their inflexibility and the irritating, hissing quality of the sound they produced, but the name became widely used. Newer sound-masking products do not use a white noise signal; rather, they offer an engineered sound that is much more comfortable, unobtrusive, and effective.

What Are the Benefits?

Sound masking is easily installed in both new and existing facilities and provides an effective way of treating acoustic problems without large-scale remodeling. Because it is not a physical barrier, sound masking can satisfy competing requirements for auditory privacy, reduced noise disruptions, and caregiver access and interaction.

Sound masking makes noises and conversations more difficult—or impossible—to hear or comprehend. Because it reduces speech intelligibility, patients' fear of being overheard is reduced. And the resulting auditory privacy helps fulfill HIPAA-related requirements. Sound masking also reduces the dynamic range, or sound variation over time, making the space seem quieter. It minimizes the differences in the sound level and quality across the space, making movements from one area to another less disruptive. Studies have found that this sound type also shortens the time it takes to fall asleep, does not disrupt sleep itself, and helps to reduce sleep disruption from noises.

Sound masking can also reduce construction costs and the need to pursue other acoustic treatments, although maximum performance is achieved with a combination of masking, physical barriers, and absorptive materials.

How to Select a System

When selecting a sound-masking system, it is important to consider the following key features, which can significantly influence its effectiveness and long-term benefits, as well as the comfort of the workplace occupants:

  • method of control

  • size of adjustment zones

  • frequency and volume adjustment capabilities

  • masking sound generation

  • zoning technology

  • timer functions

  • masking uniformity

  • installation versatility

  • scalability

  • appearance (in situations where the masking system is visible)

A number of sound-masking systems are available today, and it is important to understand that their performance varies dramatically in each of the above areas. Investing in a fully functional system will allow you to design the masking sound to meet local acoustic conditions and occupant needs, increasing speech privacy, productivity, and comfort. Carefully selecting a system based on its performance capabilities will also ensure that your needs are met for years to come, no matter how your functional requirements change.

Because success depends on more than just the right product, it is also important to select a sound-masking system supported by professionals who can properly design and implement the system and provide you with ongoing support as your organization grows and changes. HD

Niklas Moeller is Vice-President of K.R. Moeller Associates, Ltd. He has been involved in many aspects of the sound-masking industry, including manufacturing, research, product development, installation, sales and marketing, and international market development.