Acoustical design in healthcare: An issue that needs to be heard
Noise in healthcare is an important concern. Achieving high-performance acoustical design in healthcare facilities is a challenge that often requires decisions balancing competing interests such as visibility versus enclosure, surface maintenance versus sound absorption, and initial construction budget versus long-term value. Nevertheless, effective acoustical performance is a critical need for all types of healthcare facilities.
A growing awareness of the problem of noise in healthcare environments has become most evident in recent years. A widely-reported 2005 study at Johns Hopkins Hospital (Busch-Vishniac, West, et. al. ) determined that hospital noise has been rising to levels well beyond the World Health Organization’s recommended guidelines since the 1960s to the detriment of patients and caregivers. In “A Review of the Research Literature on Evidence-based Healthcare Design” (Ulrich, Zimring, et al., Health Environments Research and Design 2008), this and other examples illustrate the negative effects of noise on caregivers and patients. These negative impacts include elevated psychological and physiological stress levels that can worsen other outcomes, create difficulty in staff communications, and contribute to poor sleep quality, which is detrimental to healing. In some cases, noise distractions can be linked to medical error.
Standards have recently been introduced to help address this problem. The 2010 edition of the Guidelines for Design and Construction of Health Care Facilities from the Facilities Guidelines Institute includes a new detailed section on acoustical performance. The authors of the Green Guide for Heath Care (GGHC) and LEED for Healthcare worked together to include a two-point credit holistically addressing acoustics—exterior noise, acoustical finishes, room noise levels, sound isolation, paging, and call systems—and building vibration.
Consider the measureable benefits of high acoustical performance: it helps to facilitate speech communications, supports a more focused work environment to reduce medical error, lessens stress for staff and patients, promotes healing, enhances patient privacy, and supports HIPPA compliance. GGHC highlights improved health, economic, and even ecological benefits. Also consider how a noisy environment and lack of sleep may influence a patient’s perception of the healthcare facility and quality of care as measured through the widely-used Press Ganey patient satisfaction survey.
Many factors contribute to the successful acoustical performance of space—the physical configuration, engineering systems, equipment features, and facility operations greatly contribute to acoustical performance, and many factors such as noise generated by equipment and staff are out of the designer’s hands. A team consisting of the client, architect, interior designer, acoustician, and engineer can work together to achieve the greatest possible improvement to the acoustical environment.
A positive example is the Mayo Clinic, which has been building quality healthcare environments for many years, evolving the designs through lessons learned, and striving for the most supportive spaces for all occupants. In 2004, the Mayo Clinic implemented procedures to reduce noise at their Rochester, Minnesota, facility and recognized the importance of high acoustical performance in the operations and design for the new Mayo Hospital in Jacksonville, Florida, which opened in 2008. Perkins+Will configured the space to support patient care, but also to reduce sound transmission to the patient bedside, integrating an acoustical expert’s recommendations in order to reduce noise. The following guiding principles were recommended by Mark Penz, an acoustical engineering consultant with Kirkegaard Associates:
- Wherever possible, absorbent material should be located as close as possible to noise sources.
- Absorptive materials should be integrated into large open areas to curtail any excessive reverberation that might develop.
- Sound-critical walls should be carefully detailed to ensure airtight, resiliently sealed penetrations around conduit, ductwork, etc.; any open-air pathways will dramatically reduce the effectiveness of sound-rated partitions.
- Background noise levels should be well calibrated to their respective spaces-high enough to mask distant speech, but not so loud as to prove offensive.
The design team carefully adhered to these principles. High-performance acoustical tile ceilings (.95 NRC) were specified above corridors and over staff work areas in order to absorb sound before it ricocheted through corridors. Soffits were designed to surround work areas and interrupt corridor ceiling surfaces over which sound can travel. Lower nighttime lighting levels were designed to promote sleep and quiet activity, also having the effect of reducing ambient noise at night.
Functional planning of the Patient Care Units at Mayo also provides acoustical benefits. All patient rooms are single rooms, with adjacent satellite charting stations that allow direct patient observation through view windows, with integral blinds that are controllable from both sides. This, along with privacy curtains at bedside, allows layers of privacy and control that support both the patient and caregiver. Dedicated teaching areas at the center of each unit contain conference rooms with digital workstations utilized for physician rounding. This avoids noisy group meetings in corridors. Staff utility and supply rooms are located on conveniently-accessed cross corridors, perpendicular to patient room corridors. Because sound travels in a straight line, support rooms were located so as to not be opposite patient bedroom, thereby helping to prevent sound from noisy areas travelling directly to the bedside.
The staff work zone within the patient room is located near the door and is equipped with nighttime task lighting, to allow less-disruptive evening access. In order to reduce sound transmission between patient rooms, the patient headwall construction was designed with two separated stud systems with acoustical batt insulation between. Acoustical sealant was also specified to wrap around staggered utility backboxes, also helping to reduce direct sound transmission between rooms. Door frames were specified with rubber silencer pads attached to the door stops to soften noise from the closing doors. Windows for patient observation are located in satellite nursing stations, which are designed to allow visual control of all rooms, allowing patient doors to be closed to corridor noise.
The acoustical benefits resulting from these features are significant. During a recent follow-up visit to the Mayo Hospital, Mayo’s operational approach to creating a quiet environment was evident. Of particular note, we visited the Cardiology Care Unit at 10:00 p.m. in order to observe nighttime lighting levels and were delightfully surprised to enter a softly-lit, serene unit. Nursing staff greeted us with whispers, and as we walked the floor, we observed that the majority of patient room doors were closed, with caregiver view-windows in use. Although we were unable to assess the quality of sleep, by appearances, the environment of the patient unit was peaceful and very quiet.
The results at Mayo demonstrate that positive outcomes can be achieved if the project design team follows a comprehensive and thoughtful approach to acoustical performance, lead by a focused and enlightened client. The advantages outweigh the challenges and underscore the critical importance of effective acoustical design in the healthcare environment.