Since its inception in 2000, the Pebble Project has cultivated a community of researchers and practitioners committed to sharing knowledge to further research, advocacy, and education in the healthcare design field. Without proper research, evidence will not exist to help advance our healthcare facilities and create better patient outcomes. A major benefit to becoming a Pebble Partner is gaining access to many different resources including a community of peers, experts, and staff, as well as cutting edge knowledge in the field. As new hospitals join the Pebble Project, they are not only partnering with The Center for Health Design (CHD), but also with other Pebble Partners, corporate affiliates, students, and volunteers.

The Pebble Partners are at the forefront in adopting new innovation, as well as testing the impact of these findings on patient, staff, and organizational outcomes. They often address current key issues through their design and research projects. For example, an issue that most hospitals around the country (and the world) are struggling with is that of poor acoustic environments. The high ambient noise levels and peak noise levels in hospitals have a serious impact on patient and staff outcomes ranging from sleep loss and elevated blood pressure among patients to emotional exhaustion and burnout among staff. Poorly designed acoustical environments can pose a serious threat to patient confidentiality and patient safety and can impede effective communication between patients and staff and between staff members by rendering speech and auditory signals less intelligible or detectable. A well-designed acoustical environment is critical to addressing problems related to noise and communication of information. Our Pebble Partners decided that this issue merited further discussion and focus.

The Center for Health Design research team recently brought together several interested members of the Pebble community, acoustics experts, CHD volunteers, and CHD board members to lead a discussion around:

  • Noise control best practices in hospitals;

  • Standard methodologies to measure different aspects of the acoustics environments; and

  • Developing a research agenda around acoustic issues in healthcare settings.


In discussing these topics, several issues and challenges surfaced around sound control in healthcare environments including balancing acoustics with infection control, the need to determine an appropriate benchmark for sound levels, equipment and material choices, and privacy and work performance issues.

Acoustics versus infection control

Being mindful of infection control practices while balancing a good acoustical environment can be a challenge. Sound absorbing acoustical materials tend to be porous. The fact that such materials tend to accumulate dust and become difficult to clean is the challenge that needs to be addressed. Further, there is a lack of standard guidelines for using different materials and the associated set of infection control and cleanability requirements for different areas of the hospital.

Acoustic privacy in healthcare settings

The use of acoustical modifications such as sound masking techniques can ensure privacy and support compliance with HIPAA guidelines. Sound masking techniques—methods used to balance sound reduction—may add slightly to the overall background noise level, but they decrease the transient noise instances (e.g., an ice machine or hallway carts) that tend to be more disruptive to patients. Human behavior is an important factor in noise control and promoting patient privacy. Design strategies that can foster behavioral change (e.g., quiet nooks near the patient rooms for clinicians to talk) are needed.

Noise threshold levels

The noise threshold levels according to the EPA guidelines for a hospital environment are 45 decibels for daytime and 35 decibels for nighttime. Consistently, hospitals exceed these levels. There is a need for research to determine the threshold decibel levels for creating an optimal healing environment as well as to determine thresholds at which sleep disruption occurs. Research also needs to address how noise from medical equipment can be reduced (IV pumps, alarms required to function at a certain level, etc.).

Equipment and material choices

A few environmental modifications can be made quickly and at minimal cost to improve the acoustical environment such as higher-grade acoustical ceiling tiles, different wheels on equipment, foam in retractable door handles, and quieter flooring. Materials such as carpet may reduce noise but can add physical stress on staff because of cleaning issues and the difficulty pushing carts and wheelchairs on the surface. While equipment alarms contribute to noise levels, they often provide essential cues to nursing staff for monitoring patients.

Further discussion

The goal of this discussion was to develop a community of experts and practitioners around these issues; the following Pebble work groups have been formed to continue the discussion:

Impacting equipment manufacturers. This Pebble group will focus on developing a list of equipment in the healthcare environment that could potentially be made quieter, and then develop strategies for reaching out to these groups.

Guidelines and standards. This Pebble group will understand the intersection between infection control and acoustics guidelines, and work with committees within the Facilities Guidelines Institute to address these issues.

Standard methodology. The focus of this Pebble group will be on developing standard protocols for measuring different aspects of the acoustic environment—decibel levels, noise perception, conducting a noise audit, sound intelligibility, etc. The group will identify standard techniques in the literature and ongoing efforts as basis for work.

Research agenda. This Pebble group will develop a research agenda around acoustic issues in healthcare, identifying research gaps and developing research questions that can be addressed through future research.

Acoustics are already an integral area of focus in furthering evidence-based design. Among the Pebble Partners that have initiated research are: The Children's Hospital in Denver, Colorado, in partnership with Johns Manville with acoustic comfort as a topic of study; Jersey Shore University Medical Center along with Armstrong Ceiling Systems are studying the impact of carpeting and acoustical tiles on noise levels and staff perceptions in a renovated unit; Palomar Pomerado Health and Paoli Heath Care are also in their beginning stages of identifying their acoustic studies. HD

The Center for Health Design is a nonprofit research and advocacy organization of forward-thinking healthcare, elder care, design, and construction professionals and product manufacturers who are leading the quest to improve the quality of healthcare facilities and create new environments for healthy aging.
Healthcare Design 2008 August;8(8):12-14