Tag Archives: Healthcare

Designing Stone Wool Ceiling Assemblies

All images courtesy Rockfon

All images courtesy Rockfon

by Corey Nevins

Specifiers have an increasing number of choices for commercial ceiling systems. Among the performance considerations for selecting the most appropriate for a particular application are acoustics, fire performance, humidity resistance, hygienic properties, dimensional stability, indoor air quality (IAQ), and light reflection. Added to these are choices pertaining to design aesthetics, ease of installation, maintenance, durability, sustainability, and cost.

Stone wool ceiling panels and metal suspension systems meet these selection criteria for both new construction and renovation projects throughout North America. The material was discovered on the islands of Hawaii, where it occurs naturally as a by-product of volcanic activity. The primary rock involved is basalt, the earth’s most abundant bedrock. The igneous material forms by the rapid cooling of lava from eruptions on the sea floor. Seismic activity, including the earth’s volcanoes, produces 38,000 times more rock material than is used by the world’s largest producer of stone wool.

The typical production process for stone wool begins with the fusion of this volcanic rock at a temperature of 1500 C (2732 F). Emerging from the furnace, the melt runs out of the bottom and onto a spinning machine, where wool is whipped into thin strands, similar to making cotton candy. The strands form ‘wool,’ held together with minor amounts of organic binders.

Stone wool ceilings offer good sound absorption, high light refl ectance, fi re protection, and humidity resistance. These panels are well-suited to create modular ceiling designs, such as long corridors.

Stone wool ceilings offer good sound absorption, high light reflectance, fire protection, and humidity resistance. These panels are well-suited to create modular ceiling designs, such as long corridors.

Now a fleecy web, the material is gathered and formed; the number of layers varies depending on the final product’s desired structure and density. The layered fibers then move to a curing oven. Once cured, the wool emerges with non-directional fibers that contribute to its multiple performance characteristics of the stone wool products. In addition to ceiling panels, stone wool’s unique combination of thermal, fire, and acoustic properties make it suitable for:

  • blown insulation in cavity walls;
  • rolls of loft insulation;
  • pre-formed and faced pipe sections; and
  • wall slabs.

A mineral fleece and water-based paint are layered on top of the stone wool to produce the finished ceiling panels. The stone wool products proceed to cutting saws, finishing and packing equipment, or are led to off-line equipment for special treatment. The majority of the waste created during the production is fully recyclable.

Use of suspended ceilings
Since the 1950s, drop ceilings have been the preferred method for concealing HVAC vents, electrical wires, plumbing pipes, phone cables, and security lines in interior commercial buildings. These suspended, interconnected ceiling systems consist of a metal grid comprising cross-tees and main runners.

The main runners are suspended by hanger wires from the structure above, and wall channels or angles provide a clean look throughout the perimeter. Panels are used to conceal the plenum—hiding the visible structure, suspension system, HVAC, and other equipment, while providing simple access for future maintenance.

The suspension ceiling system is selected for aesthetics, maintenance, and specialized performance such as fire resistance, seismic mitigation, or limited accessibility in security applications. For all ceiling designs, specifiers should check the suspension systems are manufactured to ASTM International standards. On request, suspension manufacturers may provide reports from the International Code Council (ICC) and third-party seismic performance testing and certification reports.

Corrosion resistance is also a priority for metal suspension systems supporting stone wool and other ceiling panels. The industry standard is 23.8-mm (15/16-in.) galvanized steel for suspended metal ceiling grids; most may be specified with a minimum of 25 percent recycled content.

While the ceiling panel’s size, orientation, color, finish, and edge largely determine the overall aesthetic, changing the size of the grid’s face also changes the appearance. For example:

  • a 14.28-mm (9/16-in.) narrow face diminishes the distinction between grid and panel for a more monolithic look;
  • adding a 3.17-mm (1/8-in.) slender, center regress with a ‘bolt-slot’ design accentuates the shadow between panel and grid;
  • mitered intersections provide crisp, continuous lines for a uniform ceiling plane;
  • wide-face 34.92-mm (1 3/8-in.) ceiling suspension offers bolder expression of the ceiling grid modules, especially at high elevations; and
  • in curved drywall applications, radius systems create concave and convex shapes, including barrel-vaulted ceilings.
When a sound wave hits a surface, part of the energy is refl ected, part of it is absorbed by the material, and the rest is transmitted. Undesired sound from various potential sources can include noise transmitted into the building from the exterior, or coming in from other interior spaces.

When a sound wave hits a surface, part of the energy is reflected, part of it is absorbed by the material, and the rest is transmitted. Undesired sound from various potential sources can include noise transmitted into the building from the exterior, or coming in from other interior spaces.

The noise reduction coeffi cient (NRC) refers to a surface’s ability to reduce noise by absorbing sound. NRC is important in areas where high levels of noise (like a photocopier) are present.

The noise reduction coefficient (NRC) refers to a surface’s ability to reduce noise by absorbing sound. NRC is important in areas where high levels of noise (like a photocopier) are present.

 

 

 

 

 

 

 

 

 

 

 

Specifying acoustic comfort
According to the World Health Organization (WHO):

noise seriously harms human health by causing short- and long-term health problems. Noise interferes with people’s daily activities at school, at work, at home and during leisure time. It can disturb sleep, cause cardiovascular and psychophysiological effects, hinder work and school performance and provoke annoyance responses and changes in social behavior.1

Therefore, it could be argued design professionals have a duty to create acoustic comfort and well-being for the occupants of their buildings. Stone wool can help with two primary components of acoustic comfort: speech intelligibility and noise reduction.

The material’s airflow resistance and density contribute to its high noise absorption properties. The fibers’ size and non-directional orientation lead to stone wool’s inherent sound-absorbing qualities. The measures and concepts discussed in this article provide a foundation for understanding the relationship between stone wool’s characteristics as a material and achieving acoustic comfort.

Speech intelligibility
One important component of acoustic comfort and sustainability, speech intelligibility refers to a listener’s ability to hear and understand a speaker in a room or space. It is measured as a signal-to-noise ratio, expressed in decibels (dB). For this application, the signal typically is speech and the noise usually is everything else in the background.

Reverberation time
An important factor for creating speech intelligibility, it is defined as the time it takes for the sound pressure level to decrease 60 dB below its original level. In most situations (excluding unamplified music performance), a lower reverberation time improves speech intelligibility and acoustic comfort. For most rooms requiring speech intelligibility, mid-frequency reverberation time should be between 0.50 and 1.00 seconds when the room is unoccupied.

Noise reduction coefficient
The noise reduction coefficient (NRC) indicates a surface’s ability to reduce noise by absorbing sound. It is calculated by averaging the absorption coefficients from the 250-Hz, 500-Hz, 1-kHz, and 2-kHz octave bands. It varies between 0.0 (i.e. absorbs very little sound) and 1.0 (i.e. absorbs a lot of sound). NRC is one of two important variables in determining reverberation time (the other being room volume). A higher NRC indicates more noise reduction (or sound absorption) and leads to lower reverberation times and greater speech intelligibility. Stone wool ceiling products typically have an NRC of 0.85 or higher.

Background noise
Undesired sound from various potential sources can include noise transmitted into the building from the exterior, or coming in from other interior spaces. It can also include sounds generated by the building’s systems or even those reverberating too long inside the room.

Speech intelligibility
Factors influencing speech intelligibility include:

  • speech signal’s strength and clarity;
  • sound source’s direction;
  • level of background noise;
  • room’s reverberation time and shape; and
  • listeners’ hearing acuity and attention span.

Reverberation time depends on two main variables: the volume of the room and the amount of sound-absorbing materials. As volume decreases or as the amount of sound-absorbing materials increases, reverberation time decreases and speech intelligibility generally increases. Since the volume of the room often depends on functional and aesthetic criteria, reverberation time is often solely dependent on the amount and efficacy of sound-absorbing materials.

In many cases, placing sound-absorbing materials on the walls is not desirable due to its tendency to get damaged, dirty, or worn because of occupant contact. As a result, whether speech intelligibility is poor, fair, or good can highly depend on the ceiling specified. This is why acoustic standards and guidelines for schools, hospitals, offices, and other types of facilities have minimum NRCs of 0.70 and up to 0.90. Stone wool ceiling panels, more than other panels made of less-absorbing materials, help ensure projects comply with acoustic performance requirements in these standards and guidelines.

Even if reverberation time is appropriate, speech intelligibility can be low if the background noise in the room is too loud. Speech intelligibility equates to a high signal to noise ratio. Consequently, it is also important to ensure noise from the exterior, other interior spaces, and from the building’s systems is controlled.

Noise reduction
In other rooms or spaces like open offices, cafeterias, libraries, and gymnasia, speech intelligibility is not the primary acoustic goal; rather, the push is for overall noise reduction for stress relief and concentration. Noise reduction equates to an overall decrease in sound pressure level from loud continuous noise (e.g. traffic noise transmitting into the building), as well as event-specific noise (e.g. a crying baby). The sound pressure level in a room depends on the strength of the sound source, the room’s size, and the quantity and quality of sound-absorbing surfaces.

Just 30 decibels of periodic noise can be disturbing to sleep or concentration. Conversational speech is generally between 50 to 70 dB. Noise with sound levels of 35 decibels or more can interfere with speech intelligibility in smaller rooms. This is demonstrated by a phenomena known as the ‘cocktail party effect,’ whereby as noise levels get louder and louder, people try to talk louder and louder to be understood. Despite their efforts, speech intelligibility decreases and acoustic stress increases. It is not until someone leaves the ‘party’ that they realize just how agitated they were as their muscles begin to relax, heart rate slows, and respiration deepens. Stone wool, because of its high noise-absorbing characteristics, also helps achieve the overall noise reduction goals.

Whether sound reduction is needed for speech intelligibility or overall acoustic comfort, blocking noise that could be in the plenum above the ceiling can also be important in some instances. As more acoustics standards and guidelines place minimum noise control criteria on wall constructions (i.e. sound transmission class [STC]), the need for ceilings to block noise from adjacent spaces traveling via the overhead plenum is becoming less frequent. This is because achieving the minimum STC wall requirements necessitates the walls be extended up to, and sealed against, the underside of the deck above them. However, in the cases where the walls do not extend full height, or where there may be noisy mechanical equipment in the plenum, the ceiling also may need to block noise from transmitting into the space below them.

Ceiling attenuation class (CAC) indicates the ceiling’s ability to prevent airborne sound from traveling between adjacent rooms when the demising walls do not intersect with the structural deck above. CAC is also a good measure to judge how much protection is offered against noisy mechanical equipment in the plenum. The higher the CAC value, the greater the ceiling’s blocking capacity. A CAC value of 35 dB is considered to be moderately high and may be specified for stone wool ceiling panels. When even higher sound-blocking capacity is required, stone wool ceiling panels can be specified with a CAC value up to 43 dB in combination with a high NRC of 0.85.

Insulation infl uences the sound level in the receiving space, helping provide more privacy between rooms and better concentration in the adjacent room.

Insulation influences the sound level in the receiving space, helping provide more privacy between rooms and better  concentration in the adjacent room.

In practice, there is a strong link between sound absorption and room-to-room sound insulation. This link may not be accurately refl ected in laboratory testing. In practice, two ceilings with the same ceiling attenuation class (CAC), but different NRCs, produce different levels of perceived sound insulation. The ceiling with the highest NRC will do a better job of lowering the sound pressure in both the sending and the receiving room.

In practice, there is a strong link between sound absorption and
room-to-room sound insulation. This link may not be accurately
refl ected in laboratory testing. In practice, two ceilings with the same ceiling attenuation class (CAC), but different NRCs, produce different levels of perceived sound insulation. The ceiling with the highest NRC will do a better job of lowering the sound pressure in both the sending and the receiving room.

Total sound insulation is the ability of a total construction (e.g. partitions, ceiling, fl oor and all connections) to prevent sound from traveling through the ceiling void and through building elements. Sound insulation of ceilings is measured using CAC, while walls are measured using the sound transmission class value (STC).

Total sound insulation is the ability of a total construction (e.g. partitions, ceiling, floor and all connections) to prevent sound from traveling through the ceiling void and through building elements. Sound insulation of ceilings is measured using CAC, while walls are measured using the sound transmission class  value (STC).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Fire performance
Every second counts once a fire has started. Specifiers know choosing the right building materials can delay the spread of fire and provide the vital extra minutes needed to save the occupants and limit the damage.

Given its volcanic origins, stone wool can withstand temperatures up to 1177 C (2150 F). It is non-combustible, will not develop toxic smoke, and does not contribute to the development and spread of fire even when directly exposed to fire.

Ceiling panel products are required to be tested for surface burning characteristics to Underwriters Laboratories (UL) 723/ASTM E84, Standard Test Method for Surface Burning Characteristics of Building Materials. Testing requires 7.31 m (24 ft) of material to be exposed to a flame ignition source in a Steiner Tunnel Test to determine how far the fire will spread during 10 minutes, and how much smoke is developed during this period.

The test was developed by Al Steiner of UL and has been incorporated as a reference into North American standards for materials testing. The progress of the flame front across the test material is measured by visual observation, while the smoke emitted from the end of the test assembly is measured as a factor of optical density. A Flame Spread Index and a Smoke Developed Index are calculated from these results. Both indices use an arbitrary scale in which asbestos-cement board has a value of 0, and red oak wood has a value of 100.

Many commercial applications require a Flame Spread Index of 25 or less and a Smoke Developed Index of 50 or less. Products labeled “FHC 25/50” (Fire Hazard Classification 25/50) or “Class A” (ASTM E1264, Standard Classification for Acoustical Ceiling Products) fulfill these requirements. Stone wool ceiling panels may be specified to meet the most stringent requirements with a maximum Flame Spread Index of 0 and a maximum Smoke Developed Index of 5.

Humidity and hygienic attributes
Humidity can weaken the structure of certain ceiling materials, causing them to sag and, in extreme cases, even fall out of the suspension system. This often happens in buildings under construction where the building is not yet temperature- and humidity-controlled, or materials have not yet dried. Additionally, humidity levels are naturally high in wet rooms like kitchens and sanitary areas, and moisture problems may occur.

The stone-wool core in acoustic ceiling panels can be specified as hydrophobic, which means it neither absorbs water nor holds moisture. This makes the ceiling panels ‘sag-resistant,’ even up to 100 percent relative humidity (RH) and in temperatures ranging from 0 to 40 C (32 to 104 F). The material is dimensionally stable and does not warp, curl, or cup. It also neither rots nor corrodes. Further, its characteristics remain unaltered over time, maintaining its dimensions and physical characteristics throughout a building’s lifecycle.

Since stone wool is inorganic, it also does not promote the growth of mold or bacteria. North American studies show a relationship between mold and damp conditions, and an increase in allergic reactions, along with eye, nose, and throat irritation.2 They have also been associated with litigious concerns that some commercial building owners have termed ‘sick building syndrome.’

Twenty-three percent of office workers experience frequent symptoms of respiratory ailments, allergies, and asthma. The impact has been an increased number of sick days, lower productivity, and increased medical costs. The economic impact is enormous, with an estimated decrease in productivity around two percent nationwide, at a cost of $60 billion annually.3

Helping maintain cleanliness, stone wool ceiling panels may be specified with a smooth, non-textured finish that can be vacuumed with a soft brush attachment. Specially treated hygienic and medical surface finishes allow cleaning with water and some diluted disinfectants, such as chlorine, ammonia, and quaternary ammonium. In some cases, specially treated surface finishes on stone wool ceiling panels allow for more intensive cleaning, such as steam cleaning twice a year following a defined protocol.

Sustainability
In addition to being composed from the earth’s most abundant bedrock, stone wool ceiling panels can contain up to 42 percent recycled content. When removed, undamaged stone wool products may be reused or recycled for other projects. However, if recycling, one should be observant of recycling plant locations.

Stone wool is an excellent thermal insulator and contributes to energy-efficient buildings. Stone wool ceilings’ reflective, smooth surface also can play a significant role in enhancing energy efficiency through better light distribution. The health benefits of natural light include a more positive mood, improved productivity, and lower absenteeism.4 Maximizing use of natural daylight may allow a reduction in the number of lighting fixtures. The subsequent lowering of electric loads may reduce cooling costs.

Further contributing to sustainable goals, stone wool ceiling panels may be specified with UL Environment’s Greenguard Gold Certification for low-emitting products. Certification is only given to products compliant with the associated requirements, which among others include stringent limits on emissions of more than 360 volatile organic compounds (VOCs).

UL Environment states indoor air can be two to five times more polluted than outdoor air. Greenguard Gold criteria incorporate health-based emissions requirements as denoted by the U.S. Environmental Protection Agency (EPA), the State of California Department of Public Health’s Section 01350, and others.

More than 400 green building codes, standards, guidelines, procurements policies, and rating systems give credit for Greenguard products. Certification also fulfills the low emission requirements of the U.S. Green Building Council’s (USGBC’s) Leadership in Energy and Environmental Design (LEED) v4 program, and the Collaborative for High Performance Schools’ Criteria (CHPS) for low-emitting materials.

Stone wool, the core material of stone wool ceiling products, can withstand temperatures up to 1177 C (2150 F). It is made from basalt rock and is non-combustible; it will not contribute to the development and spread of fi re.

Stone wool, the core material of stone wool ceiling products, can withstand temperatures up to 1177 C (2150 F). It is made from basalt rock and is non-combustible; it will not contribute to the development and spread of fire.

Stone wool acoustic ceiling products that have been certifi ed to GreenGuard Gold certifi cation standards for low chemical emissions into indoor air during product usage are suitable for environments such as schools and healthcare facilities.

Stone wool acoustic ceiling products that have been certified to GreenGuard Gold certification standards for low chemical emissions into indoor air during product usage are suitable for environments such as schools and healthcare facilities.

Aesthetic design
Beyond sustainability and performance, there are numerous aesthetic considerations in selecting the best stone wool ceiling panels to achieve the desired architectural expression.

Shape
The shape of a stone wool panel’s edge significantly contributes to the ceiling’s overall appearance. Demountable options include:

  • square lay-in—cost-effective, provides easy access to the plenum, and mounts in standard suspension systems;
  • tegular—square or angled, hangs on a visible and recessed suspension system that creates a shadow between the tiles, and mounts in standard suspension systems;
  • semi-concealed—appears to float under the suspension system, the profiled edge and deeply recessed grid profiles presents an elegant shadow (an effect emphasized by specifying the suspension system in black); and
  • concealed—hides the suspension system to create a monolithic appearance, but only some concealed panels are demountable.

Another option is the direct-mount assembly, where ceiling panels are directly bonded to the structural soffit or an existing ceiling surface. These systems are for areas where ceiling heights do not permit the use of the suspension setup.

Panels are not limited to two dimensions of squares and rectangles; they may be formed into three-dimensional cubes. Baffles and clouds provide an alternative solution for rooms where contiguous ceilings are unsuitable. They are suited to thermal mass applications where the soffit needs to be left exposed. They can be used as part of a retrofit or to create a design feature.

A wide range of sizes contributes to the design freedom and flexibility offered with stone wool ceiling panels. By combining different module sizes, even small rooms may seem larger and long corridors can seem less distant. The line of a ceiling impacts the perception of a space and creates focal points that may show direction, outline an object, or divide a large space into more comfortable zones.

Horizontal lines convey stability, grounding, and direction. Vertical lines, on the other hand, also communicate stability, as well as pillar-like attributes of strength and balance. Diagonal lines are perceived as dynamic and transformational with overtones of freedom, while curves are considered playful, organic, and soothing.

Texture and color
Based on today’s design styles, stone wool ceiling panels are preferred in smooth and lightly textured surface finishes. This gives the impression the ceiling is lighter in texture, weight, and color. White and neutral tones are the most popular color choices for interior ceilings. For more vibrant spaces, stone wool ceiling panels can be specified in a breadth of other hues.

A viewer’s perception and relation to a color changes depending on whether it stands alone, is dominating a space, or if it is in play with other colors. It also is influenced by the quality and quantity of light hitting it.

Colors evoke physical and psychological reactions, and the brightness or color temperature creates different moods and ambiance: Warm colors—such as red, orange, and yellow—are considered stimulating. Cool colors—like blue, purple, and light green—generally have a calming effect.

Spatial perception is also affected by color. Lighter hues tend to make spaces seem bigger, while darker ones can make spaces feel more intimate. A dark ceiling will seem lower than it really is, or—when installed high enough above—simply disappears.

Color schemes also can indicate the purpose and usage of a space with boundaries and transitions. Consideration should be given to how the visual stimulation in a space will be perceived by the brain to evoke a desired response. This is of utmost importance in environments where varied spaces have different tasks and functions, to avoid any confusion that can cause stress in the occupants.

Segment-specific demands
Color certainly has a place in educational settings, but aesthetics may need to be secondary to performance requirements. Fire performance and indoor air quality are top-of-mind, and acoustics also need to be of primary importance. Classrooms in the U.S. typically have speech intelligibility ratings of 75 percent or less, meaning every fourth spoken word is not understood.5 Loud or reverberant classrooms may cause teachers to raise their voices, leading to increased teacher stress and fatigue.6

In school activity areas, stone wool ceiling panels may be specified with both a high acoustic performance and impact-resistance. The panel’s reinforced surface withstands tougher-than-average wear and tear, as well as frequent mounting and demounting.

Along with durability and flexibility for future redesign, health care facilities seek products with easy-to-clean surfaces to support infection control. Most Methicillin-resistant Staphylococcus Aureus (MRSA) infections occur in people who have been in hospitals or other health care settings and are resistant to the antibiotics commonly used to treat ordinary staph infections.7

Stone wool ceiling panels designed for medical use have been classified Class 5, or better, in accordance with International Organization for Standardization (ISO) 14644-1, Cleanrooms and Associated Controlled Environments−Part 1: Classification of Air Cleanliness. Those that have specially treated medical and hygienic surface finishes also help mitigate:

  • MRSA bacteria resistant to antibiotics and responsible for post-surgery infections and septicaemias;
  • Candida Albicans, which is yeast responsible for skin infections and pneumonias; and
  • Aspergillus Niger, which is mold responsible for pneumonias.

Noise also contributes to patients’ slower recovery times. Studies show high levels of sound have negative physical and psychological effects on patients by disrupting sleep and increasing stress.8

With respect to auditory privacy, acoustic performance not only is relevant to patient decency and respect, but also to the protection of corporate intellectual property, and to increased concentration levels in working environments. After surveying 65,000 people over the past decade in North America, Europe, Africa, and Australia, researchers at the University of California-Berkeley reported more than half of office workers are dissatisfied with the level of speech privacy, making it the leading complaint in offices everywhere.9

Conclusion
From acoustics to fire performance and aesthetics to sustainability, stone wool ceiling systems provide the versatility and attributes to meet the varied requirements of commercial and institutional buildings’ new construction and renovation projects.

Notes
1 Visit www.euro.who.int/en/health-topics/environment-and-health/noise. (back to top)
2 Visit www.hc-sc.gc.ca/ewh-semt/air/in/poll/mould-moisissure/effects-effets-eng.php(back to top)
3 See William J. Fisk’s “Health and Productivity Gains from Better Indoor Environments,” from the 2000 edition of Annual Review of Energy and the Environment. Visit www2.bren.ucsb.edu/~modular/private/Articles/Fisk%20HealthandProductivity%202000.pdf(back to top)
4 For more, see Vanessa Loder’s article, “Maybe Money Really Does Grow on Trees,” in the May 4, 2014 edition of Forbes. Visit www.forbes.com/sites/vanessaloder/2014/05/04/maybe-money-really-does-grow-on-trees/2(back to top)
5 See Classroom Acoustics, by Seep et al, published in 2000 by the Acoustical Society of America (ASA).(back to top
6 See Tiesler & Oberdörster’s 2008 article, “Noise: A Stressor? Acoustic Ergonomics of Schools,” in Building Acoustics (15 [3]). (back to top)
7 Visit www.mayoclinic.org/mrsa(back to top)
8 See “Sound Practices: Noise Control in the Healthcare Environment?” published by HermanMiller Healthcare in 2009, and “Sound Control for Improved Outcomes in Healthcare Settings,” by Joseph Ulrich, published in 2004 by the Center for Health Design. (back to top)
9 See John Tierney’s article, “From Cubicles, Cry for Quiet Pierces Office Buzz,” in the May 19, 2012 edition of the New York Times. Visit www.nytimes.com/2012/05/20/science/when-buzz-at-your-cubicle-is-too-loud-for-work.html. Also, visit www.cbe.berkeley.edu/research/index.htm(back to top)

Cory Nevins is Rockfon’s director of marketing, leading the company’s continuing education and training programs to keep commercial building team members updated on acoustic stone wool ceiling panels, specialty metal ceiling panels, and ceiling suspension systems. He has nearly 20 years of experience in the building products industry, the majority of which has focused on ceiling systems, and a bachelor’s degree in marketing from Miami University in Oxford, Ohio. Nevins can be contacted at cory.nevins@rockfon.com.

Designing to Prevent Infection

Photo © BigStockPhoto/Frank Boston

Photo © BigStockPhoto/Frank Boston

by Scott Blevins

U.S. healthcare organizations increasingly face the most daunting medical challenge since the pre-antibiotic age. While pharmaceutical manufacturers hope for a new era of treatment that is still years from the market, the challenge—and preventative solution—is found in the built environment itself.

Healthcare’s perfect storm is not an industry secret. The Centers for Disease Control (CDC), the media, and industry experts often focus on the ever-increasing number of multi-drug resistant and environmentally adaptive pathogens. These microorganisms commonly overwhelm limited Environmental Service Department resources and navigate air-handling systems with ease, leaving healthcare providers to battle increasing numbers of infections with ineffective environmental tools. Some of these pathogens are so environmentally adaptive they may rebound to a majority percentage of their pre-disinfection levels within a few hours of surface disinfection.1

However, as Healthcare Infection Control Practices Advisory Committee (HICPAC) states, the problem is multi-faceted. The challenge is not solely an increase in more dangerous pathogens—advances in medicine and an aging population have provided an increasing amount of immune-compromised patients highly susceptible to infection, which may become an environment’s host population.

Providers work on patients, not buildings. Across the nation, Environmental Service Departments are losing staff, unable to keep up with surface transfer potentials throughout an active hospital. Architects and designers now have their most important role to date in providing successful patient care. They may design an environment that inadvertently accumulates, propagates, and circulates pathogens—or one which is the best ally in continually mitigating surface and airborne microbial health safety concerns.

If advances in medicine and microbial-adaptive abilities are the ‘anvil,’ then the lesser-discussed factors of finance, regulation, and litigation are the ‘hammer’ confronting healthcare clients. In 2009, Medicare and private insurance ceased payment for hospital-acquired infection (HAI) incident expenses, putting the brunt of this burden on individual facilities. Subsequently, federal International Statistical Classification of Diseases and Related Health Problems 10th Revision (ICD10) regulations continue to tighten the paperwork, documenting an increasing number of HAI incidents—meaning an ever increasing number of non-paying patients under federal reporting.

Public awareness has grown thanks to mandatory public reporting, millions of additional patients battling multi-drug resistant organisms (MDROs) joining the community, high-profile patients raising awareness, and CDC issuing press releases on the “superbug of superbugs.” This is now the age of HAI litigation, resulting in numerous eight-figure lawsuits.

How can architects and designers help?
Healthcare workers (HCWs), infection preventionists, and environmental service staff work harder than ever to achieve positive patient outcomes, but they have little control over the actual physical environment provided to them which supports their success. It is critical to address transmission and environmental pollution from C. Difficile spores, methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci (VRE) microbes, Norovirus, and ribonucleic acid (RNA) influenza via unprotected vectors such as toilet aerosolization, surface transfer, humidity levels, and HVAC travel.

Photo © BigStockPhoto/Tyler Olson

Healthcare staff work harder than ever to achieve positive patient outcomes, but they have little control over the actual physical environment provided to them. This is where the design professional comes in. Photo © BigStockPhoto/Tyler Olson

Healthcare-worker hand hygiene continues to be the best-known and recognized means of infection transmission. Numerous studies have been completed, documenting up to 40 percent of HCW hand contamination occurs from contact with the environment. Additionally, certain MDROs achieve 100 percent surface transfer success to multiple surfaces from origination, enabling exponential migration to what is quickly Sick Building Syndrome (SBS)—and once a facility is overwhelmed by microbial contamination, it can be hard to eradicate.

Patients may shed and exhale millions of pathogen particles daily, which may have weeks’ worth of environmental viability, putting a significant challenge on Environmental Services staff that may only have time to clean a surface once daily. Additionally, studies on microbial rebound have shown despite perfect cleaning and disinfection, surface porosity successfully harbors pathogen deposits such as MRSA and VRE that rebound up to 40 percent of their pre-cleaned level within a few hours, without recontamination.2

In most U.S. facilities, the existing minimum efficiency reporting value (MERV) filters do an excellent job of capturing 1-µm (0.04-mil) particles. Unfortunately, 0.3-µm (0.012-mil) particles—the same size HICPAC identifies as “potentially viable microorganisms, capable of indefinite suspension”—are often in the hundreds of thousands of particles per cubic foot. Particles are able to float from the lobby to the operating room, even picking up additional organic materials electrostatically from surfaces en route. Other environmental vectors—such as air dissemination to patient surfaces and the constant electrostatic particle interchange that occurs between surfaces and air—are well understood, but rarely addressed outside the highest level manufacturing facility clean rooms.

Specifying air-handling and surface products from a microbial perspective provides a direct and lasting impact on variables as diverse as:

  • patient care quality;
  • patient outcomes;
  • HCW hand hygiene;
  • surface hygiene;
  • indoor air quality (IAQ);
  • surface cleanability;
  • ongoing bioburden levels (or quantity of microbial material) of an occupied space;
  • transmission incidents; and
  • the facility’s financial viability.

Specifying for improved surface hygiene
Designers benefit from working with epidemiology, infection-prevention, and environmental hygiene client resources, along with expert consultant resources whenever available. The locations of highest touch deposits and most frequent interchanges—such as nurse stations or push plates—must be identified. Locations and equipment interacting with critical or multiple areas of a facility or its staff must also be noted, along with the potential traffic patterns of surface-borne microbes.

When selecting materials for high-contact surfaces, one must pay special attention to microscopic surface porosity and texture relative to cleanability, microbial rebound, pathogen reservoir development, and surface transfer potentials.

Self-disinfecting surfaces, or continually active antimicrobial materials and surface modifiers, should be specified to improve surface hygiene and cleanability. This also reduces the ‘anytime levels’ of colony-forming units (CFUs) of bacteria and resultant transmission potentials at high contact surfaces. Available materials include titanium dioxide (TiO2) and silicon (Si14) coatings, antimicrobial copper, and antimicrobial linen treatments.

Modifiers, such as Si14, virtually eliminate porosity, making surfaces inhospitable to deposits, and enabling them to be cleaned more efficiently. Being highly hydrophobic, this also prevents staining and improves the shine appearance of common materials. Active antimicrobials, such as TiO2, actually trap and destroy microbes and spores through a naturally occurring electrostatic property that incorporates continuous photo-catalytic oxidation. These coatings may be specified like any other coating, and then incorporated seamlessly by Environmental Services maintenance for periodic reapplication. The result is a space that cleans easier, has a lower microbial content, and diminishes health concerns rather than harboring and circulating them.

Engineered ultraviolet (UV) surface disinfection may be additionally employed at critical spaces, such as operating rooms, to guarantee surface sterility. Surface UV disinfection success is a function of output, distance, and exposure time, so these installations are typically best custom-designed for the specific space by a UV engineer.

Airborne prevention
In terms of preventing the spread of airborne infections, it becomes critical to work with mechanical engineers, infection prevention specialists, and epidemiologists to better understand the specific demands of a project. Employing independent IAQ resources adept in infection prevention can also assist in documenting bacterial loads and air dissemination potentials.

It is important to consider:

  • particulate air travel potentials (remembering ‘indefinite suspension’);
  • positive and negative pressurization relative to a true ‘air lock’ performance;
  • placement of patient bath exhausts;
  • air dissemination potentials; and
  • continual bioburden contribution of occupants.

Similarly, the design professional should consider the electrostatic particulate dissemination and detachment continually occurring between air and surfaces—and how this relates to IAQ, surface hygiene, HCW hands, and transmission potentials.

Depending on a hospital’s mechanical system, problematic particles can float from the lobby to the operating room, picking up additional organic materials electrostatically en route.

Depending on a hospital’s mechanical system, problematic particles can float from the lobby to the operating room, picking up additional organic materials electrostatically en route. Photo © BigStockPhoto/Vadim Kozlovsky

Existing MERV filtration systems should be replaced with low-pressure-drop high-efficiency-particulate-air (HEPA) performance wherever possible, and not just in surgical areas. Ultraviolet germicidal irradiation (UVGI) systems should be specified at 800 to 25,000 microwatts per centimeter squared to dramatically improve IAQ—this also eliminates coil cleaning and the resultant respiratory irritant exposure to compromised patients of coil-cleaning chemicals. Even the best chemical coil cleaning does not completely remove biological material, and allows cleaning agents to travel downstream into occupied areas.

Critical or high-risk areas may greatly benefit from ‘first pass kill’ air disinfection specifications (up to 25,000 microwatts per cm2), which, per federal or military specifications will prevent the airborne transmission of any known microbe, and may affect majority reductions of C. Difficile spores. Bi-polar cold plasma systems are specified more commonly to address pollution challenges, such as helicopter or ambulance exhaust, but also provide a potent microbial reducing performance for occupied areas, after an air-handler.

Attention to detail can have substantial impact in infection prevention. The cardboard housing on common AHU pre-filters, for example, may sag in the presence of moisture as well as feed mold and microbes; similarly, a plastic laundry cart may travel from the soiled utility room to the ER to the neonatal intensive care unit (NICU) twice daily, contacting numerous surfaces and staff en route, while an elevator button may be touched by 600 people—including MRSA or VRE-positive patients—in one 24-hour period between cleanings.

The good news
Most of these specifications provide significant returns on investment (ROIs) completely unrelated to their environmental health safety benefits. Si14 surface treatment, for example, has a remarkable electrostatic repellency, which improves appearance, stain-resistance, and cleaning at critical surfaces. It also extends exterior window cleaning cycles by up to 75 percent.

UVGI systems may be used to reduce fresh air intake in administrative or other areas not subject to American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) 170, Ventilation of Health Care Facilities, often resulting in up to 25 percent fresh air reduction and significant energy savings. Coil cleaning elimination alone can provide a quick return on investment and credits under the U.S. Green Building Council (USGBC) Leadership in Energy and Environmental Design (LEED) rating program. By recycling UV-sterilized cooling tower water, some facilities have saved tonnes in consumption annually.

Conclusion
Architects and designers now have many tools to create a safer environment, providing facilities ultimately with improved patient care and a much healthier bottom line. Surfaces and building equipment such as laundry carts and over-bed tables may be empowered to continually disinfect themselves. Further, air filtration can be improved to capture a larger number of microbial particles, and to sterilize the air at critical areas. Air movement and staff traffic may be anticipated to limit the potential of microbial migration from one patient to another.

Singular applications of these solutions have greatly lowered infection incidents. Many of these systems provide significant ROIs for owners, outside the targeted HAI reduction. Excellent resources exist from domestic manufacturers, as well from focused consultant and distribution organizations specializing in the wide range of healthcare environmental tools.

Notes
1 For more information, see the article, “Intrinsic Bacterial Burden Associated with Intensive Care Unit Hospital Beds: Effects of Disinfection on Population Recovery and Mitigation of Potential Infection Risk,” by Attaway et al. It appeared in the December 2012 edition of American Journal of Infection Control. (back to top)
2 See note 1. (back to top)

Scott Blevins is a managing partner at Portland, Maine-based I.C. Solutions. He has worked in healthcare construction management as a senior project manager and estimator since 2001, serving as a regular expert speaker to CSI, and engineering and environmental plant managers associations, on surface hygiene, antimicrobial systems, and air filtration. Blevins can be contacted via e-mail at sblevins@icscertified.com.

 

Specifying Doors for a Healthier Environment

All photos courtesy Assa Abloy

All photos courtesy Assa Abloy

by Marilyn A. Collins, EDAC

In an effort to create a more restorative environment for behavioral health facilities, both design and healthcare professionals are looking to door openings. The shape of hardware, locking devices, and integrated trims can include aesthetic design elements while remaining safe and secure.

There are almost 6000 hospitals in the United States. Of those, approximately 30 percent house an in-patient psychiatric or behavioral health unit—with almost eight percent dedicated to behavioral health. Additionally, there are many specialized clinics and out-patient treatment offices. A project’s specific needs may vary widely, from children’s units to adult therapeutic environments, but many requirements are common to all types of facilities, including code compliance.

Behavioral health is concerned with the prevention, diagnosis, treatment, and rehabilitation of those exhibiting aggressive or self-destructive behaviors. One of the main goals of behavioral health is to keep patients safe during recovery or rehabilitation. Security and safety are critical challenges as facilities accommodate other occupants—whether family, clinical and professional staff, or environmental services personnel who have access to virtually every area of the facility, and use potentially harmful cleaning agents and/or chemicals.

Built environment and healthcare
The built environment can make a difference in behavioral health facilities. Doorways, doors, hardware, and accessories can be integrated in such a way as to reduce noise levels, increase security, facilitate sight lines, and improve patient safety. Options for sustainable features such as recycled content, health declarations, and certifications ensuring the elimination of volatile organic compounds (VOCs) in doors are becoming standard in the specifications for most healthcare spaces.

Writing a Division 08 specification for a behavioral health unit demands expert product knowledge to capitalize on the opportunities they present to create a restorative environment as well as to avoid the threat they can pose to patients’ wellbeing. Questions to consider during specifications include:

  • Should the door be specified as a single leaf to avoid flush bolts that could represent a ligature point?
  • Would the use of a continuous hinge be preferred to swing clear hinges?

In addition to protecting against security risks from the outside, behavioral health openings are also designed to lessen the potential of patients using some portion of the opening to inflict self-harm. This is readily apparent in the shape and form of these products—many hardware items, and some specialized doors, look different from those used in standard openings. Such products address potential threats to patients, and are designed to mitigate these risks.

Thermal fused doors withstand abusive conditions and the harsh cleaning compounds used in sanitary environment.

Thermal fused doors withstand abusive conditions and the harsh cleaning compounds used in sanitary environment.

In North America, there are no design standards for door and hardware products used in a behavioral health environment. Product manufacturers often research overseas standards, consult with behavioral health facility staff, or conduct observational research to determine door and hardware designs. However, once a product is created it can be sent for review to agencies such as the New York State Office of Mental Health (OMH) or the National Association of Psychiatric Health Systems (NAPHS). These agencies carefully scrutinize the product, and then issue guidance recommending whether a product is suited for use in high-, medium-, or low-risk areas.

Healthcare organizations and specifiers can consult these reviews to determine if the products they have in place or plan to use have earned a seal of approval to match the risk level of each opening. Without such reviews, specifiers may select products not optimal for the facility’s function. In some cases, facility staff must make aftermarket product choices to provide a safe opening addressing a specific level of risk.

Alternatives
Patients placed in a high-risk area are at an elevated danger of inducing self-harm; they might look at an opening for potential ligature points. The products used on the opening should therefore minimize these points. A standard door lever should not be specified for these locations.

Alternative hardware trim has been designed to perform the same function of a lever without the catch points, sharp edge, and large protruding profile. Openings that overcome attempts at barricading may also be required in this environment.

Various alternatives to openings in healthcare facilities are available for high-, medium-, and low-risk openings.

High-risk
There are door and hardware alternatives for high-risk openings accepted by New York’s OMH, which is the standard followed by most of the United States.

Heavy-duty door stops reduce damage from doors hitting walls.

Heavy-duty door stops reduce damage from doors hitting walls.

An emergency door stop thwarts barricade efforts by allowing the door to swing open in the opposite direction.

An emergency door stop thwarts barricade efforts by allowing the door to swing open in the opposite direction.

Detention knobs are used with mortise locks and feature a sloped surface throughout it.

Detention knobs are used with mortise locks and feature a sloped surface throughout it.

 

 

 

 

 

 

 

 

 

 

 

Integrated trim
This type of device integrates the door lever with the escutcheon to create a safe, low-profile mechanism for opening the door that is also Americans with Disabilities Act (ADA)-compliant. The tapered surface is free of catch points, and works with mortise locks so it can withstand abusive conditions.

Recessed flush pull
A flush pull recessed into the door with concealed fasteners will prevent patient tampering. Also, the smooth flush design is free of catch- and pinch-points.

Hinges with hospital tips
A hinge’s knuckle or cap can be tapered with smooth-angled surfaces, called ‘hospital tips.’ This tapering eliminates catch-points found on traditional hinges.

Emergency door stops
An emergency latch release allows doors to swing open in the opposite direction, thwarting barricade efforts. The latch releases with a touch of the finger. A second touch of the lever returns the latch to its original position. This device allows center-hung or 3.2-mm (1/8-in.) inset doors to be opened in both directions without damaging the frame; it can be used to convert double-acting doors hung on center pivots to single-acting doors.

Heavy-duty door stops and wall stops
Molded rubber bumpers mounted into the floor or wall without exposed fasteners reduces costly wall and door damage caused by doors slammed open. Wall stops with concealed mounting resists patient tampering.

The paddle shape of push/pull trim creates a target for door activation.

The paddle shape of push/pull trim creates a target for door activation.

Recessed flush pulls are flush-mounted and designed without pinch points.

Recessed flush pulls are flush-mounted and designed without pinch points.

Wrought wall stops are free of catch points and reduce damage from a door slamming into a wall.

Wrought wall stops are free of catch points and reduce damage from a door slamming into a wall.

 

 

 

 

 

 

 

 

 

 

Patient room access door
Essentially a door within a door, the main unit of a patient room access door has the functionality of a standard in-swing patient room door. The inner door can open to the corridor giving authorized personnel quick access to the patient’s room. The ligature-resistant design is a key feature of the construction.

Roller latch with strike
For use only on non-fire-rated interior openings such as toilet rooms, bathrooms, shower rooms, and closets, roller latches with strikes are safe for en-suite bathroom doors and delivers patient privacy without locking the door.

Medium- and low-risk
A wider range of doors and hardware are available to meet the opening needs of medium- and low-risk environments. Similar to those used in high-risk areas, these devices often feature sleek curves that reduce catch points, but have protrusions or larger profiles making them less-than-ideal for at-risk patients. These types of products may be used with caution on medium- and low-risk openings.

Double-swing hinges enable doors to open wide in either direction.

Double-swing hinges enable doors to open wide in either direction.

Detention knobs
Detention knobs comprise overlapping knob and rose working with a mortise lock. The sloped surfaces throughout the knob minimize risks and can be used on many opening types.

Lever and push/pull trim
Lever trim devices function identically to normal levers, but they are designed with sloped surfaces and an overlapping rose. Similar in nature to a standard lever (including ADA-compliant), uses a standard mortise lock prep. This trim also retrofits easily on existing openings. Recent generations of push/pull trim products feature curves and slopes, compared with the earlier boxy and sharp-edged versions. Doors with this trim can be opened with a push or pull of a paddle that replaces a standard lever.

The paddle shape and location creates an easy target for door activation without the use of hands. This feature, along with multiple mounting orientations, makes push/pull devices popular on many openings, including patient room doors.

Double swing hinges
The need for wide opening doors make double-swing hinges ideal for many healthcare openings. A 100-degree swing design allows the door to swing wide in either direction to allow access for equipment and gurneys. An emergency release stop provides quick access in an urgent situation. These continuous geared hinges provide proper alignment and weight distribution that extend the door’s life. They are available with sloped hospital tips.

Thermal-fused doors
Behavioral health environments experience a lot of abuse from patients, facility personnel, and equipment. Rugged thermal fused doors are a natural fit in this environment. Edge banding on the tops and bottoms of the door seals out moisture, preventing damage from the rigorous cleaning in healthcare settings. This also adds protection against chipping.

Integrated trim is accepted by the New York State Office of Mental Health (OMH) for use in high-risk areas.

Integrated trim is accepted by the New York State Office of Mental Health (OMH) for use in high-risk areas.

Specifying integrated trim, push-pull trims, and other door hardware for high-, medium-, or low-risk areas directly aligns with patient safety and can eliminate or reduce potential ligature points. Products recommended by organizations such as the New York State OMH or NAPHS are good choices for this demanding environment. Various products designed for behavioral health applications, such as patient rooms, are also well suited for other areas in the healthcare environment such as for pharmacy, dock doors, kitchen entrances, and linen storage.

More options

Other options to consider for openings in a behavioral health setting include sustainability attributes and security of pharmaceutical storage areas. A facility looking to attain a green building certification can turn to Division 08 openings for assistance in categories such as building envelope thermal performance, material composition, and indoor environmental quality.

Specifying doors that are certified by the GreenGuard Environmental Institute ensures volatile organic compounds (VOC) are not present. For projects following the U.S. Green Building Council (USGBC) rating program, selecting doors with high recycled content, agrifiber cores, and Forest Stewardship Council (FSC)-certified products, can also contribute to Leadership in Energy and Environmental Design (LEED) credits.

Securing isolated doorways, such as those on pharmaceutical storage cabinets, carts, and closets can be accomplished with wireless electronic access control devices providing real-time notifications whenever a cabinet or closet door is opened.

Non-fire-rated interior openings can be equipped with roller latches to provide patient privacy without locking the door.

Non-fire-rated interior openings can be equipped with roller latches to provide patient privacy without locking the door.

Healing environments have made quite a transition, from custodial, long-term facilities to spaces that seek to restore clients and patients to community in the short to medium term. Therefore, specifying doors contributing to noise reduction, such as wood doors, is one way to shape the building with healing in mind. Reducing noise by incorporating wood creates a more home-like feel to a facility and allows treatment to be provided in surroundings mirroring the community patients return to. Door openings can be specified with sound transmission class (STC) ratings tested to the required ASTM standards, including:

  • ASTM E90, Standard Test Method for Laboratory Measurement of Airborne Sound Transmission Loss of Building Partitions and Elements;
  • ASTM E1332-90, Standard Classification for Determination of Outdoor-Indoor Transmission Class; and
  • ASTM E413, Classification for Rating Sound Insulation.

Conclusion

Since today’s healthcare facilities—including behavioral health units—have a décor suggesting hospitality rather than hospital, specifiers will want to choose doors and hardware adding to the building aesthetic without detracting from safety and security. Seasoned specifiers recognize there is beauty in the balance of form and function. A coordinated design, complementary finishes, and the right products in the right places can ensure compliance with National Fire Protection Association (NFPA) requirements and other building codes, and contribute to a healthier, more sustainable space—from the exterior to the interior of a facility.

Whether it is an outpatient or inpatient facility, a dementia unit, or a Department of Veterans Affairs (VA) medical center, the myriad choices for electronic locking, high-security cylinders, auto operators, integrated trims, wood and hollow metal or specialty door afford specifiers, architects, facility managers, and clinicians the range of options for an optimum healing place.

Marilyn A. Collins, EDAC, is director of business development for healthcare at Assa Abloy Door Security Solutions and has served healthcare and other end user markets for more than 20 years. She emphasizes evidence-based design in life safety, security, and access control solutions for the complete range of door openings. Collins is trained in evidence based design and is active in industry groups including Healthcare Executives, Buildings Vip, The Center for Health Design, FierceHealthcare, Society for the Advancement of Gerontological Environments (SAGE), and the Door and Hardware Institute (DHI). She can be contacted at marilyn.collins@assaabloy.com.