Managing Crossover Noise in Healthcare Begins with Design

By Tiffany Coppock

History shows that managing hospital noise is an enduring challenge. In her 1859 book, “Notes on Nursing,” Florence Nightingale described the significance of the problem, writing, “Unnecessary noise is the most cruel abuse of care which can be inflicted on either the sick or the well.” More than 160 years later, hospital noise remains a top complaint among patients, staff and visitors – and for the world at large.

Today’s environment brings a conflux of acoustic challenges unheard of in Nightingale’s day – especially crossover noise. This term relates to noise traveling from room to room in a healthcare setting and it can be a significant pain point for both patients and caregivers. Mechanical systems, HVAC equipment, monitors, alarms, and construction related to expansion present just a sampling of challenges for healthcare facility designers seeking to manage crossover noise.

Patient satisfaction, wellness and emerging trends

As various audio sources cross paths in the 24/7 hospital environment, crossover noise can be more than a nuisance. Sound quality can potentially impact patient evaluations, patient safety, privacy and hospital compensation. Standardized Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) scores routinely reveal that noise receives the poorest response among questions asked of patients. This is concerning from an economic perspective considering that HCAHPS scores are related to federal reimbursements made to hospitals.

Then there is the objective of the hospital itself – to foster wellness. High noise levels in hospital settings can impede healing in patients and have negative effects on caregivers. A University of Michigan Occupational Nursing Program found that chronic noise in the workplace caused an increase in blood pressure and heart rate.

Finally, emerging trends present new challenges when designing for acoustics in a healthcare setting. For example, the growth in “telemedicine” demands appropriate acoustics to optimize clear communication between patient and provider, reduce risk of distortion and assure confidentiality and privacy.

Guidelines inform acoustic approaches

To help manage these considerations, the Facility Guidelines Institute (FGI) maintains and works to elevate acoustic and other recommendations for healthcare facilities in the U.S. FGI guidelines were updated in 2018 and include site exterior noise, acoustic surfaces, room noise levels, interior wall and floor/ceiling construction, speech privacy and building vibration. The LEED for Healthcare rating system also includes provisions for noise pollution interventions that “minimize the effect on building occupants of site exterior noise produced by road traffic, aircraft flyovers, outdoor facility mechanical equipment, and plumbing, and building services equipment.”

Design considerations for sound management

Good design is the first strategy designers should turn to when seeking to reduce crossover and all types of noise. And thinking about design at the outset of a project (i.e. insulating walls) is more cost-effective than post-construction remediation. Following are some tips for supporting sound performance in the healthcare environment.

Space function: Both the function of a space and its traffic levels should be considered during planning. For example, areas with heavier traffic and activity, such as nurse stations, should be isolated away from consult areas. The nature of certain areas of a hospital make them inherently noisy. MRI, X-ray suites and neonatal intensive care units are a few examples. As such, conversation has turned toward establishing a baseline level of “normal noise” to create a more consistent level of noise and remove the stress of widely fluctuating sound levels.

Prioritize privacy: In hospitals or ambulatory settings, doorways or entrances to patient rooms and other privacy-sensitive spaces should be positioned so they are not directly across from each other to help protect both speech privacy and visual privacy.

As hospitals are home to some of life’s most critical conversations, speech privacy is critical. Design strategies such as placing waiting areas away from consultation rooms should be programmed into the design. Providing constant background sound levels through active equipment such as sound masking should not be viewed as a panacea for managing acoustics although it may resolve some design challenges particularly in retrofit designs.

Look for low-cost retrofits: As the cost of retrofitting areas inside the enclosure can be cost-prohibitive, retrofit efforts should target interventions that are easy to introduce – for example adding drop down door seals addresses one major leak point without incurring major costs. Adding acoustic absorbers, replacing ceiling tiles, and installing insulation batts above the ceiling for walls that do not extend to deck, may improve privacy at a lower price point compared to replacing/retrofitting ducts or walls. These “small fixes” are generally not as effective as lined ducts and insulated walls at reducing noise. Therefore, initial design should focus on lining ducts and insulating walls first. Introducing additional sound reducing enhancements may be added as budget allows.

Don’t overlook insulation’s passive performance: New hospital construction should always include insulation in the walls to help mitigate noise carrying over from one room to another. Regrettably, insulation has become so well known for its thermal performance and energy conserving properties, that its role in managing sound, moisture and other concerns in the healthcare enclosure has often been overlooked.

Wall design and the materials inside the assembly have a big impact on how sound is transmitted through a space. Designers have various insulation options when it comes to insulation materials used in the assembly to support acoustic performance. While fiberglass batt insulation has traditionally been widely used for this purpose, research has shown mineral wool insulation also offers similar sound transmission class performance depending upon the wall assembly. For example, some studies have shown that a wall with lightweight drywall insulated with mineral wool can provide comparable acoustic performance to an assembly with standard weight drywall and fiber glass insulation.

Spec full-height walls: A full height partition’s ability to limit flanking sound should also be considered to protect against noise crossing over above the ceiling to other patient rooms. Full-height wall partitions that extend up to the ceiling deck are the best defense against noise traveling from room to room through space above the ceiling. When a full-height wall partition is not practical, adding a row of insulation 6 inches thick and 24 inches wide along the perimeter of each wall above the ceiling can help mitigate sound transmission and achieve STC goals. Installing crown molding at the intersection of wall and ceiling is another tactic to help reduce cross-over noise.

Don’t neglect mechanical and HVAC equipment: The phrase “the pipes are coming up” is often referred to among those working in and near mechanical areas of a hospital. As the boiler and network of pipes power various systems, noise is a natural by-product. While pipe insulation provides good thermal and moisture protection and also defends against corrosion under insulation, only fibrous pipe insulation provides protection against noise radiating through the pipe. When insulating with non-fibrous pipe insulation, insulating in the wall assembly of the mechanical room and surrounding area can help keep pipe noise from infiltrating other areas of the hospital.

HVAC systems are often located on the rooftop and mounted to curbs to limit transfer of noise into the building. When properly mounted on the curb and supported with appropriate flex duct and duct liner, noise from hospitals’ HVAC systems can be effectively minimized. The selection of proper grills and diffusers can help mitigate HVAC air flow noise into rooms, however, air flow can also be used to mask some background noise.

Line Ducts. In addition to being increasingly modular, hospitals continue to look for opportunities to introduce nature into the environment. Environmental design principles like daylighting have created more “glass box” designs. The increased use of glass means designers should consider how insulation throughout the enclosure and lining in ducts can help manage sound transmission in spaces with plenty of hard surfaces. Infection control measures seem to be influencing a decrease in soft surfaces – upholstery, drapes, etc. – in the healthcare space, providing yet more reason to consider passive approaches including wall and above ceiling insulation and duct lining products.

Technology demands acoustic quality: Finally, telemedicine presents its own set of challenges. Conventional approaches to masking sound, such as white noise, can disrupt audio quality. Early design consideration and the inclusion of passive acoustic elements such as fibrous acoustic panels and other sound absorbing materials can support audio quality in telemedicine spaces.

Building science drives sound innovation

Owens Corning continues to invest in research to improve the acoustic performance of walls assemblies via new innovations. For example, researchers recently evaluated 296 walls to identify key variables that influence sound performance. Team members studied the impact of new lightweight drywall options, stud types, varied insulation options and configurations on sound performance. Another study tested 18 pipe insulation combinations including various jacketing materials, the combination of FOAMGLAS® cellular glass insulation with mineral wool and layering of mass loaded vinyl materials

As noted earlier, sound management has long been on the minds of those working in the health care environment. Acoustics is also a global challenge, the International Commission for Acoustics has decided to declare 2020 as the International Year of Sound and each year, the last Wednesday in April is observed as International Noise Awareness Day to raise awareness of the impact of noise on the health and welfare of people. For designers in the healthcare space, this observance provides an opportunity to pause and consider how this enduring challenge can be managed.

Tiffany Coppock, AIA, NCARB, CSI, CDT, RCI, LEED serves as commercial building systems specialist for Owens Corning.