While insulation is commonly thought of in terms of its thermal performance, its function in the healthcare facility extends far beyond energy efficiency. From facilitating privacy to managing moisture and complementing environmental design initiatives, the right type of insulation installed with precision can play an integral role in contributing to a healthcare building’s performance. Objectives related to acoustic performance, moisture management and safety should be considered when specifying the type of insulation used in a healthcare facility.
It all starts with building size and function
A precursor to specifying insulation in a healthcare environment is a thorough understanding of the size and purpose of the facility. The “Institutional” occupancy classification, coupled with the height and area (number of floors and square footage) will determine the building code requirements and subsequently influence the materials used. Understanding the functions that will be carried out in the building as well as the nature of the building’s occupants (i.e. elderly, very young, sedated, connected to equipment, etc.) are critical to determining required safety designs.
More than 25 different occupancy classifications are covered by the building code, including “Institutional” governing healthcare buildings ranging from assisted living facilities and medical spas, to drug rehab centers, surgery centers and research hospitals. While hospitals are classified as Institutional 1 or 2 occupancy, ambulatory clinics (less than a 24-hour patient stay) are classified as businesses occupancy. Some facilities will include both areas classified as institutional and business occupancy. These classifications will heavily influence the safety components of the facility. Various standards present additional requirements for hospitals and standards such as JCAHO guidelines, CAP guidelines, FGI Guidelines, Medicaid, Medicare, OSHA, and HCAPS Scores all impact design and accreditation of facilities. While an extensive review of building code requirements is beyond the scope of this article, the key takeaway is that the building size and its purpose will determine building code requirements including the construction type and ultimately the insulation specified.
A “sound” approach to insulating the enclosure
Monitoring systems, alarms, respirators/ventilators, and the building’s mechanical systems are just a few contributors to noise within the healthcare facility. Noise is a special concern when one considers that high noise levels in hospitals have been shown to adversely affect both patient and staff physiological conditions, including heart rate, blood pressure, respiration rate, and muscle tension.1
Privacy is another concern to consider when selecting insulation. The Health Insurance Portability and Accessibility Act of 1996 (HIPPA) emphasizes both acoustic and visual privacy. Although HIPPA does not regulate the design of a health care facility, its implications may influence where processes and procedure areas are located within a building. The building materials specified for those areas can support privacy initiatives, including sound isolation.
When it comes to reducing sound transmission, wall design as well as the type of insulation used in the wall should be considered. Studies have shown that a lighter gauge steel stud can provide better acoustical performance than a heavier gauge. Depending on construction details, the acoustic performance of mineral wool compared to fiber glass insulation in a wall construction can vary. Another important consideration is sound transmission classification (STC) of an assembly.
STC is a composite rating derived from wall system sound attenuation performance at a variety of sound frequencies. In some instances, specific frequencies characteristic of the environment should be considered. For example, conversation and general activity in a public space such as a cafeteria will have different frequencies compared to heart rate monitors and IV pumps in a patient’s room or NICU suite.
STC is a composite rating on general performance across multiple frequencies of how well a building partition attenuates airborne sound and is widely used to rate interior partitions, ceilings/floors, and wall configurations. However, for a specific frequency of sound the composite STC may not be the best comparison of one assembly to another. Considering individual frequencies can help improve a wall’s acoustic performance and inform the type of insulation used within the wall.
Note that insulation by itself does not have a sound transmission class (STC) number. Rather STC ratings reflect acoustical performance for an entire wall system. Some specific areas within a healthcare facility that are especially important when it comes to isolating noise include consultation rooms, speech pathology and audiology areas, neonatal intensive care areas, and medication prep rooms.
Design and specification assistance
To assist architects in comparing wall systems, insulating materials and many other considerations, Owens Corning recently launched the Building Science Solutions Center, a free-of-charge service provided through the architectural specification team that draws on the company’s extensive building science resources. Sound Transmission Class (STC) consulting is among the dozen services offered by the Building Science Solutions Center.
Beyond addressing noise frequencies, moisture management is also an issue for emerging trends in healthcare design. The placement of insulation within the enclosure should be part of a healthcare facility’s efforts to address moisture/humidity challenges. For example, in the MRI suite, equipment operates utilizing strong electromagnetic forces, necessitating careful attention to humidity levels. If the humidity in a given area gets too low, the machine may even shut off. The placement of both the vapor barriers/retarders and insulation in the wall play an integral role in controlling humidity, helping the building envelope support a highly functioning HVAC system.
Green roofs bring nature into healthcare
Green roofs are becoming increasingly popular as healthcare facilities strive to deliver experiences with nature. Vegetative and green roofs are essentially protected roof membrane assemblies where insulation is installed over the waterproofing membrane with vegetation and various accessories installed atop the assembly to support plant life and paved walkways. This application demands a high performing, water-resistant insulation. The compressive strength, closed cell structure and hydrophobic molecular behavior of extruded polystyrene (XPS) make it the ideal water-resistant insulation for application in green roofs atop hospitals and covering below grade entryways. In fact, the National Roofing Contractors Association (NRCA) recommends only XPS for these rooftop applications because of the demanding environment. The unique properties of highly water-resistant XPS insulation delivers the compressive strength required to support rooftop placement of an ambulance, helicopter or heavy equipment.
A number of combustible and flammable materials are used in the healthcare environment, ranging from oxygen administered to patients to xylene, ethyl methyl alcohol, and even higher-level preservatives used in the pathology lab. Due to the nature of stored materials, coupled with the unique and often limiting occupant characteristics in medical facilities, their design relies on a combination of materials to compartmentalize and resist the spread of fire. Naturally non-combustible mineral wool insulation in properly designed assemblies can contain the interior spread of fire, and when used with a fire-rated assembly can keep it from spreading upward at the perimeter floor/wall joints. A fire-rated assembly paired with the proper smoke/air sealant supports the compartmentalized design approach and can keep smoke and heat from spreading.
Again, design trends influence approaches to perimeter fire safety. As more healthcare facilities are constructed as “glass boxes” to integrate nature into the patient experience, slab edges meeting the face of the curtain wall glass must be properly sealed to guard against fire spreading up the exterior wall from floor to floor. A fire resistance-rated perimeter fire barrier is an essential part of the passive life safety system considerations.
Professionals who work in healthcare facilities understand that positive patient outcomes are the result of many often unseen participants working together. In the built environment, insulation can be an integral component not just for delivering superior thermal performance, but supporting acoustic objectives, managing moisture and contributing to safety.
1 “Noise Pollution in Hospitals: Impact on Patients,” by Timothy Hsu, PhD, et al. Visit www.turner-white.com/pdf/jcom_jul12_noise.pdf.