Factor Acoustics Into Your Healthcare Designs

Healthcare-facility types are changing rapidly, requiring architects to properly assess spaces to achieve optimum sound management.

Accurate communication, auditory privacy, background sound, and auditory distractions determine are just some of the factors that affect the acoustic design of today’s healthcare facilities.

By Gary Madaras, Rockfon North America

Today’s shift in healthcare away from hospitals and toward local ambulatory care facilities, neighborhood clinics, retail stores, and even telemedicine in homes is driven not only by advances in medical technology, but more so by patient-centered factors such as convenience, lower costs, and better recovery. The issue of current concern is that most of the limited research in healthcare acoustics that bolsters evidence-based design and industry standards, guidelines, and building-rating systems focuses on patients in acute-care hospitals. New acoustics research that focuses on understanding the impact of quietness, auditory privacy, designed background sound, and music in different types of healthcare settings such as assisted-living homes, chemotherapy clinics, and dialysis-treatment centers is practically non-existent. Yet more and more healthcare is being provided in these types of facilities.

Two other factors affected by acoustics are hearing loss and individuals who use English as a second language. The role these two factors play are the subject of a podcast editorial director Gary L. Parr recorded with Gary Madaras, author of this article and acoustics specialist at Rockfon North America, Chicago. Listen to the podcast above.

Even if newer and more-relevant acoustics-research findings for these alternative healthcare facilities existed today, there will remain, for some time, a widening gap between research findings and inclusion in an industry standard or design guideline. The way that designers and specifiers can move forward is to avoid defaulting to some table that has a limited list of generic room types and minimum sound-transmission-class (STC) ratings for the walls and maximum background noise levels (dBA) for the mechanical system. Instead, patients will benefit more from a fundamental, humane, and empathetic approach to the acoustic design.

The first step is to completely understand what the patient will be enduring in that particular room and for how long. The objective is to gain a greater appreciation for the range of their potential feelings of fear, discomfort, pain, anxiety, confusion, and even boredom. As the length of time or criticalness of a procedure increases, so does the importance of optimizing the acoustics.

The second step is to assess the main acoustics goals from the perspectives of the patient, family members, and caregivers. This should be done on an individual-room basis. It cannot be done on a whole-building basis because most buildings, especially healthcare buildings, have a wide range of functions and acoustic needs. Rate each room or space type according to the following six acoustics goals. Use a scale from 1 to 5; 1 being low importance and 5 being high importance.

Accurate communication

It is typically very important for patients and caregivers to understand each other when they are speaking about healthcare. Miscommunication can lead to injury, complications, or even death. Fortunately, the speaker and listener are generally no more than an arm’s length away from each other in a relatively small room. This makes high speech intelligibility easy to achieve. When assessing this acoustic goal, there is no need to assess how important speech intelligibility is. In healthcare, it is always very important. Instead, assess how likely the particular setting is to interfere with speech intelligibility. The higher the score, the more crucial the acoustic design of the room.

A doctor standing next to a patient in a private exam room of a medical-office building will naturally involve high speech intelligibility due to the proximity of the individuals, the limited reverberation in the small room, and the limited exposure to occupant noise from outside the room. Simply specifying a moderately sound-absorptive, acoustic-panel ceiling with a noise-reduction coefficient (NRC) of 0.70 will ensure that accurate communication is achieved (a score of 1 on the scale).

Conversely, for a physical therapist conducting small-group exercise sessions in a large, open, double-story rehabilitation center amongst other therapists and their patients (a score of 4 on the scale), the acoustic design of the room will play a much larger role in whether or not accurate communication can be achieved. Higher performing sound absorption of NRC 0.90+ will be required overhead and possibly additional absorption on the walls and floor.

Key conditions that could increase the score:

• Loud background noise, such as that in an operating room or MRI suite
• A room or space that is unnecessarily large or high; as room volume increases, reverberation increases, resulting in decreased speech intelligibility
• The speaker is more distant from the listener, perhaps being amplified over an audio system or because they are addressing a medium- to large-sized group from a lectern or in an operating theater.

Auditory privacy

Confidential health and financial information are discussed in healthcare environments. Speech privacy is not only important, but also required by federal law. Privacy goes beyond speech confidentiality. When someone is injured or ill, their need for privacy increases. When someone weeps or yells out in pain, it is a personal matter, not meant to be heard by strangers.

Unlike speech intelligibility, auditory privacy in healthcare settings usually requires more effort and investment due to the close proximity of many people. When assessing this acoustic goal, remember to evaluate how sensitive the situation could be and how often these private matters occur.

A family activity room in an assisted-living facility for elders would have a low need for auditory privacy (score of 1 on the scale). The function is social in nature and sound privacy is not expected. In fact, the conversations and laughter could actually benefit other residents in need of socialization.

Conversely, a family consolation room in an end-of-life hospice would have a very high need for auditory privacy (score of 5 on the scale) due to the extremely sensitive and sometimes spiritual function of the room.

Key conditions that could increase the score:

• The information is highly confidential, being medical, financial, or spiritual.
• The function is being conducted in an open area with other people close by instead of in an enclosed, private room.
• The background sound level has not been properly designed and is too low.

Noise control

There is already enough stress on patients and their caregivers. Noise should not add to it. When assessing this acoustic goal, remember to evaluate the sensitivity of the healthcare activity to building occupant and equipment noise. While environmental noises transmitting through the building shell and mechanical-system noise are also important, they are beyond the scope of this particular design guide.

A pharmacy counter at a large retail store is already inside a rather noisy environment. While the customer needs to communicate with the pharmacist, they are generally very close to each other, making speech highly intelligible. Additionally, the duration of the transaction is generally very short, 10 minutes or less. Noise-control measures beyond those for the general store are not necessary (a score of 2 on the scale) and could actually decrease auditory privacy.

After surgery in an outpatient surgery center, patients recover in a postoperative-care unit. As they wake from anesthesia, they can be confused and emotional. An environment with startling sounds and high noise levels can make recovery worse (a score of 4 on the scale).

Key conditions that could increase the score:

• High speech intelligibility is needed, especially in larger rooms.
• Patients are confused or mentally impaired.
• Patients or residents are experiencing significant hearing loss.

Designed background sound

While the noise-control acoustic goal is important, achieving silence is not the goal. Silence can lead to the feeling of isolation and increase fear. Over long durations, it can create confusion and contribute to worsening dementia. It can make painful procedures seem endless. Silence also makes it very hard to achieve the auditory privacy goal.

Instead, background sound should be purposefully designed. What will patients hear subconsciously, and how will it make them feel? Will the background sound improve or worsen their medical outcome or quality of life? Design options include music, nature sounds, and electronic sound masking.

An aquatic-therapy pool room in a rehabilitation center would not require designed background sounds (score of 1 on the scale). There are a lot of water sounds and instructions from therapists. The natural sounds of the water are already providing a soothing background sound. No further design is required.

A respite garden in a cancer-treatment center is a space where cancer patients can choose to sit alone or with family members before or after their chemotherapy. It is a designated quiet area, meaning limited talking and no electronic devices. Yet, silence is the wrong approach and would be very uncomfortable. Instead, designed background sounds, such as flowing water and tall grasses that rustle in the breezes, should be included.

Key conditions that could increase the score:

• Long procedures or waiting for an hour or more
• The need to relax and de-stress
• Lack of physical separation or acoustic barriers and where high occupant density limits auditory privacy.

Positive auditory distraction

Positive auditory distraction is the intentional inclusion of favorable foreground sounds for the purpose of holding a person’s attention and distracting them from pain, worry, boredom, or other negative feelings. Positive auditory distractions are best when the patient or family members have complete control over content and volume. This control can be exercised by physically entering or leaving the room where the auditory distraction is occurring, for example an entry atrium in a medical center where choristers are singing from a small stage or electronically changing the content playing through a headset or loudspeaker with a remote control.

A cafeteria in a medical-office complex may or may not be a good place for positive auditory distraction. If it is the only place to eat and drink in the facility, then people who want to use it may feel trapped and annoyed by the content or volume while they eat. If however, there are options such as different places to eat or more remote seating areas, it may work fine.

A surgery suite in a dentist’s office where painful procedures, such as root canals, are performed is an excellent example of where positive auditory distractions are often necessary. An audio system and associated infrastructure for music players, in addition to internet access may be required. Smart terminals, wireless headsets, and remote controls should be provided to patients for use during painful procedures to drown out unpleasant sounds and distract their attention from the discomfort and length of the procedure.

Key conditions that could increase the score:

• Patient experience will be painful or uncomfortable; fear, worry or boredom is likely.
• Procedure or activity will last a long time—multiple hours.
• The conditions permit user control of content and volume. It is unlikely that anyone else will feel forced to listen.

Collective goal consideration

After scoring a room or space on the six main acoustic goals, review the results collectively as the layout, size, shape, and appearance of the room begin to take form. Consider, as an example, a nurse station and connecting corridors in a specialty orthopedic-surgery center. Nurse stations are active places that can get quite noisy. A lot of private information is exchanged between patients, family members, nonclinical caregivers, and nurses.

The high-priority acoustic goals are noise control, accurate communication, and auditory privacy. Designed background sounds are important in relation to achieving auditory privacy. It is the wrong place for positive auditory distractions since nurses need to focus on their duties.

The primary design strategy when accurate communication, noise control, and auditory privacy are all needed in open or semi-open spaces, such as a nurse station, is to implement high-performing, sound-absorbing finishes. While carpet tiles on the floors have proven to be part of an overall, effective solution, the easiest way to add sound absorption is by using an acoustic ceiling with a high NRC rating of 0.90 or more. It absorbs troublesome sound reflections and reverberation, making it much easier to communicate. The same high-performing acoustic ceiling provides noise control as sound waves travel down the corridors toward patient rooms. Fewer patients are disturbed. When those waves are speech or other sounds that are meant to be kept private, the ceiling attenuates them so fewer people hear them.

Using electronic sound masking as designed background sound inside procedure and exam rooms to mask any noise not absorbed by the acoustic ceiling is the next most important design strategy. Using high NRC ceiling panels, carpet tiles, and sound masking, especially in a low-acuity orthopedic surgical center where it is more likely that the patient room doors can be closed at night, is the effective design strategy that considers all of the prioritized acoustic goals.

Communication is usually not a factor in a private exam room. An acoustic panel ceiling with an NRC of 0.70 will usually handle most sound-management needs.

Design strategies

As one progresses through the design of various room types in a healthcare facility, the following design recommendations should be given priority consideration. Note that some recommendations prove effective for achieving multiple acoustic goals.

Accurate communication:

• Use sound-absorbing surfaces such as an acoustic-panel ceiling with the optimal NRC rating (0.70 good, 0.80 better, 0.90 best) and carpet tiles to decrease reverberation. Under the most critical conditions, wall absorption may also be required.
• Lower the ceiling to decrease the room volume and reverberation. This also typically moves the sound absorption closer to sources of interfering noise.
• Use an audio system to amplify speech (limited application in healthcare settings).
• Ensure that noise from equipment is attenuated adequately by locating it remotely or enclosing it in sound-isolating construction.

Auditory privacy:

• Provide private enclosed rooms with full-height walls that extend from floor slab to floor slab. Use partition constructions with optimal STC ratings (40 good, 45 better, 50+ best).
• Use swinging doors that are solid-core wood or insulated metal and acoustic seals around the perimeters.
• When enclosed rooms are not possible and privacy is still needed, use sound-absorbing surfaces such as an acoustic-panel ceiling with a high NRC rating of 0.90, combined with designed background sounds to provide masking.

Noise control:

• Create acoustic zones. Keep noisy functions remote from quiet functions. Use “buffer zones” such as stairways and storage rooms between noisy and quiet zones.
• Provide sound-rated partitions and doors between noisy functions and quiet functions.
• Use sound-absorbing surfaces such as an acoustic-panel ceiling with a high NRC rating of 0.90 or higher to limit the amount of noise that transmits between acoustic zones.

Designed background sounds:

• Consider the purpose of the background sounds.
• Electronic sound masking is engineered for speech privacy.
• Music is uplifting and energizes.
• Nature sounds are comforting and soothing for relaxation and stress relief.

Positive auditory distractions:

• Consider whether they should be more communal or individual.
• Consider whether they are physical or electronic.
• Provide user control whenever possible.
• Provide infrastructure such as stage platform and nearby changing and storage rooms or, if electronic, appropriate playback or broadcast devices, internet access, wireless devices, and secure storage and charging locations.

The ways and locations in which healthcare is being provided are changing rapidly. Healthcare is moving away from acute-care hospitals and toward more local and convenient ambulatory services. To bridge the gap, first understand what the patient and caregiver will experience inside the space. Then assess and prioritize the six core acoustic goals. Then select the design strategies that work well for the project, based on the prioritized acoustic goals. Using this design approach will lead to optimal acoustic conditions in future, high-performing healthcare facilities.

Gary Madaras, PhD, Assoc. AIA, is an acoustics specialist at Rockfon, Chicago, where he helps designers and specifiers learn the Optimized Acoustics design approach. Madaras is a member of the Acoustical Society of America (ASA), the Canadian Acoustical Association (CAA), and the Institute of Noise Control Engineering (INCE). He can be reached at gary.madaras@rockfon.com.

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