by sadia_badhon | February 14, 2019 3:49 pm
by Tiffany Coppock, AIA, NCARB, CDT, ASTM, RCI, EDAC, LEED AP, and Angela Ogino
When specifying insulation systems for healthcare facilities, architects and contractors can borrow wisdom from the world of real estate: it is all about location, location, location. Specifying the right type of insulation to address the performance challenges in various locations within the healthcare facility enclosure can not only support the building’s performance objectives, but also help meet life-safety, comfort, and sustainability goals.
It is important to look beyond the frequently discussed thermal properties of insulation to consider how it addresses life-safety, moisture management, privacy, and sustainability challenges in healthcare enclosures. Before addressing the use of insulation in specific areas of the healthcare enclosure, it is helpful to take a broader look at construction and healthcare trends.
Connecting evidence-based design to patient outcomes
The United States still continues to see high rates of new construction and remodeling in the healthcare environment. According to Joint Commission International’s 2017 report, “Planning, Design, and Construction of Healthcare Facilities,” increases in healthcare facility spending are driven in part by an aging population that is living longer (see “Planning, Design, and Construction of Healthcare Facilities,” from Joint Commission Resources). The growing need for safe, efficient care environments is spurring both new construction and medical facility remodeling in the country.
As healthcare construction activity increases, evidence-based design is influencing decisions throughout the architecture, engineering, and construction (AEC) community. As the name implies, this process involves making decisions about the built environment based on credible research to achieve the best possible results. According to the Joint Commission, it may lead to positive patient outcomes such as shorter hospital stays and improved morale due to environmental design factors (e.g. more natural light in patient rooms) or result in fewer medication errors because well-lit and isolated medication prep rooms encourage focus.
These findings are supported by a breadth of other research reports. In fact, more than 600 studies have linked the built environment to factors such as patient satisfaction, stress, health outcomes, and overall quality of care (for more information, consult “Healing environment: A review of the impact of physical environmental factors on users,” published in Building and Environment in December 2012). Conversations with directors overseeing these facilities provide further anecdotal evidence the healthcare environment affects patients’ satisfaction.
Different areas of the healthcare facility present distinct challenges when it comes to the insulation material specified. Whether insulation is used in a vegetated roof assembly atop a hospital to provide a positive view of nature while managing moisture, in walls and ceilings to improve acoustic performance, or to support passive life-safety systems, this element is integral to achieving performance goals.
Start with size, function, and occupants
Whether a research and teaching hospital or a rehabilitation center, specifying insulation in the healthcare facility begins with a thorough understanding of the building’s size and function, as well as the occupants it serves. A building’s occupancy classification, along with the number of floors and square footage, will determine the building code requirements and subsequently influence the materials specified for the enclosure.
The International Building Code (IBC) includes dozens of different occupational classifications covering everything from assisted living facilities and medical spas to drug rehab centers, ambulatory surgery facilities, and research hospitals. Hospitals are classified as Institutional Group 1 or 2 occupancy, while ambulatory clinics (facilities with less than a 24-hour patient stay) are often classified as Business Group occupancy. Institutional Group 1 occupancy includes those capable of slow evacuation, while Institutional Group 2 includes those incapable of self-preservation.
Occupancy classifications such as institutional and business identify the capability of occupants of self-preservation in relation to risks. In turn, specific construction types and height and area requirements are imposed based on different occupancy types. For example, Institutional I-2 category buildings have special requirements listed in Section 407, “Group I-2,” of IBC, including those related to corridor construction, exit distances, limits to sleeping areas, and essential electrical supply.
Many facilities will include both institutional and business occupancies—for example, administrative and outpatient offices located in a building that houses surgical suites.
When more than one occupancy is permitted, compartmentation may be allowed by demising walls of specific fire and smoke resistance. Various standards present additional requirements for hospitals, such as fire and smoke protection, egress, and isolation. Some of these standards include those set by the Joint Commission, College of American Pathologists (CAP), Facility Guidelines Institute (FGI), Medicaid, and Medicare, as well as the Occupational Safety and Health Administration (OSHA), along with Hospital Consumer Assessment of Healthcare Providers and Systems (HCAPS) scores. While codes set the baseline standard for compliance, achieving performance objectives requires consideration of each area within the enclosure.
The nature of the occupants served also drives decisions regarding safety systems in the healthcare facility. Are the occupants very old, very young, sedated, or connected to equipment? Are oxygen and other flammable materials in proximity to the patients? As life safety is such an integral issue, it is best to start by examining the perimeter of the healthcare enclosure and the special considerations that come into play when specifying insulation for the perimeter fire containment system.
Life safety and perimeter fire containment
Passive fire containment—also referred to as compartmentation—complements and enhances a building’s active and detective life-safety systems. Unlike active systems (e.g. sprinklers) and detection systems (e.g. smoke and heat detectors), passive systems operate without external activation once correctly installed. As such, they are an integral part of a comprehensive approach to fire containment.
Passive systems help contain a fire to its room of origin, delaying its spread and providing time for firefighters to access the building and occupants to egress. As medical facilities commonly store oxygen and other highly flammable materials—and because occupants may be sedated, connected to equipment, or otherwise unable to vacate on their own—fire containment is especially critical in these environments.
Section 715.4, “Exterior Curtain Wall/Floor Intersection,” of IBC requires a barrier to prevent the spread of fire and hot gases from the interior joint, where a void exists between the fire-rated slab perimeter joint and the exterior nonrated curtain wall. Various local codes require the same. As tested and proven per ASTM E2307, Standard Test Method for Determining Fire Resistance of Perimeter Fire Barriers Using Intermediate-scale, Multistory Test Apparatus, noncombustible mineral wool could contain the interior spread of fire. Some varieties have been shown to withstand temperatures above 1093 C (2000 F), meaning they are a natural insulating material for the perimeter space.
Managing moisture from foundation to roof
Throughout the enclosure, moisture—whether vapor, liquid, or solid—is a pervasive threat, and insulation plays a key role in controlling it from the rooftop to the foundation. In both these locations, extruded polystyrene (XPS) rigid insulation supports moisture management, sustainability, and energy efficiency. Naturally resistant to water, XPS will not mold or support mildew growth, an important consideration in the healthcare environment.
The moisture performance of XPS is demonstrated in its industry-standard testing under ASTM C272, Standard Test Method for Water Absorption of Core Materials for Sandwich Constructions. The test requires insulation samples be submerged in water for 24 hours, then weighed for moisture absorption. In ASTM C272 laboratory tests, XPS has proven to be highly effective at resisting moisture absorption.
Due to its moisture resistance and ability to retain thermal performance, XPS can be used in harsh environments such as below grade and placed over the roof membrane in protected roof membrane assemblies. A range of densities/thicknesses and compressive strengths allow it to be tailored to individual applications.
In healthcare settings, the facility is often located in a densely populated area where stormwater management is required by stringent guidelines. Vegetated ‘green’ roofs and paver roofs are a type of protected membrane assembly (PRMA) with insulation installed over the waterproofing membrane as part of a configuration that can support plants and vegetation. When the insulation is placed above the membrane, water may be diverted from the storm sewer system, the waterproofing membrane is protected and therefore lasts longer, and the view of the roof from the patient area can be much more favorable.
The National Roofing Contractors Association (NRCA) recommends XPS products for rooftop vegetation installations because of their ability to resist absorption in a high-moisture location where water is being collected above the waterproofing membrane.
Additionally, tapered units can be used in roofing assemblies to create slope for positive drainage. While tapered units are common under the roof membrane in single-ply assemblies, tapered XPS may also be installed above the membrane due to its moisture resistance. This creates a range of design possibilities, including allowing for sloped drainage to manage stormwater on the deck while installing reverse tapered pieces to create a flat surface for vegetation or pavers.
Another trend in healthcare construction is sprawl. Helipads on roofs, parking structures, below-ground expansions, and underground tunnels to connect parts of a medical campus are a few construction examples vulnerable to moisture. Anything built below ground is more susceptible to this threat, as well as to hydrostatic pressure. Additionally, below-grade construction must be able to withstand traffic loads from above. Again, the natural properties of XPS support moisture control while also providing the necessary compressive strength for these critical areas.
Finally, the placement of insulation within the enclosure can support a healthcare facility’s efforts to address moisture/humidity issues. For example, in a magnetic resonance imaging (MRI) suite, the equipment operates utilizing strong electromagnetic forces. If the humidity in a given area falls too low, a machine may shut off—an incident that would directly affect patient care quality and negatively impact stress levels for both patients and staff. Careful placement of both the vapor barriers/retarders and the insulation in the wall support the HVAC system in controlling humidity within the building enclosure.
Acoustic privacy and performance
Privacy is another design factor that can have a direct impact on the patient experience and satisfaction. Insulating interior walls can improve overall noise reduction and increase patients’ privacy by decreasing the likelihood sensitive medical conversations will be overheard. The 1996 Health Insurance Portability and Accountability Act (HIPAA) sets guidelines for both visual and acoustic privacy. Although HIPAA does not regulate how a healthcare facility is designed specifically, its implications influence all aspects, such as the location of procedure areas and even the construction materials used. Insulation can support privacy initiatives by isolating sound.
When it comes to reducing sound transmission, wall design as well as the type of insulation used in the wall can affect noise levels. A lighter-gauge steel stud can provide better acoustical performance compared to a heavier one because the lower density reduces the transfer of acoustic energy. Depending on construction details and assemblies, the acoustic performance of mineral wool compared to fiberglass insulation in a wall construction can differ. Therefore, each wall design should be considered on a case-by-case basis when acoustic performance is required. It is recommended the actual insulation product be analyzed in the specific wall assembly to predict required performance.
Although sound transmission class (STC) will be similar, depending on the design of the wall or floor assembly and certain noise sources with low or high frequency, the performance of mineral wool versus fiberglass insulation may vary. It is important to reference specific acoustical testing results in order to determine which type of insulation is better suited for the application, since varying configurations can result in differences at certain frequencies.
The STC of an assembly can also affect noise levels and occupant comfort. STC is a composite rating that was derived from wall system sound attenuation performance across a range of frequencies. Within a healthcare facility, specific frequencies native to the environment should be evaluated. For example, conversation and general activity in a public space such as a lobby or cafeteria will generate different frequencies compared to a pediatric playroom or heart rate monitors in a critical care unit.
The STC composite rating reflects the general performance across multiple frequencies, indicating how well a building partition attenuates airborne sound overall. STC is widely used to rate interior partitions, ceilings/floors, and wall configurations. However, it may not be the best point of comparison when evaluating a specific frequency of sound. Taking into account individual frequencies, such as the beeping of intravenous (IV) pumps or the low-pitched voice of a male doctor or faculty member, can improve a wall’s acoustic performance and help an architect select the type of insulation best suited to a specific wall.
Insulation by itself does not have an STC rating. Instead, these metrics indicate acoustical performance for an entire wall system. Within a healthcare facility, some areas demanding special thought when it comes to isolating noise include consultation rooms, speech pathology and audiology areas, neonatal intensive care areas, and medication prep rooms. They may require a specific STC, but could be designed efficiently to meet the needs of specific noises.
The following are some practical examples of how architects and specifiers can mitigate specific sounds in areas demanding special thought when it comes to isolating noise.
From a comfort perspective, noise reduction is cited as a top concern when it comes to facility construction. Noise is also strongly linked to patient satisfaction. In addition to the increased isolation acoustically private spaces provide, quiet spaces lead to a better experience for patients. While much room noise—such as that generated by monitors, alarms, ventilators, and other systems—cannot be eliminated, reducing noise between rooms and from hallways can contribute to patients getting more rest, which can assist with recovery. High noise levels in hospitals have been shown to have a negative impact on heart rate, respiration, blood pressure, and muscle tension for both patients and medical staff. Improving insulation in new construction or during a renovation can cut down on disruptive noise.
By considering the location of insulation within the enclosure, incorporating evidence-based design, and applying WUFI analysis to healthcare building and renovation projects (see “Balancing Thermal, Moisture, and Airflow with WUFI,”), design profesionals can help achieve building safety, moisture control, and acoustic performance goals while improving both patient satisfaction and staff performance. The end result of all of these considerations may support improved patient outcomes.
Tiffany Coppock, AIA, NCARB, CDT, ASTM, RCI, EDAC, LEED AP, is Owens Corning’s commercial building systems specialist. She provides leadership and technical guidance in building science, testing, and documentation to design professionals and the Owens Corning team. Formerly, Coppock was a building science manager answering technical questions, reviewing drawings and specifications, and giving educational sessions on topics such as air barriers, waterproofing, vegetated roof assemblies, and insulation. She holds degrees from Texas A&M University and the University of Colorado, Coppock is a registered architect with specialization in healthcare design and historic preservation. Coppock can be reached via e-mail at email@example.com.
Angela Ogino is Thermafiber/Owens Corning’s technical services leader. She has more than 20 years of experience in the mineral wool and firestopping industry, where she provides engineering judgements and technical assistance on mineral wool product performance for architects, building officials, and contractors in the fire containment area. Ogino is the developer and coordinator of all perimeter fire containment testing for Thermafiber at Underwriters Laboratories (UL), Southwest Research, and Intertek/Omega Point Laboratories (OPL). She is a member of the Insulation Contractors Association of America (ICAA), the International Firestop Council (IFC), and Firestop Contractors International Association (FCIA). Ogino is active in code development for the International Building Code (IBC) Chapter 7, “Fire and Smoke Protection Features.” She can be reached via e-mail at firstname.lastname@example.org.
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