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By Mara Baum, Adeleh Nejati, and Fumi Docker
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In the late 1800s, Florence Nightingale wrote her thoughts on the design of hospitals, citing the importance of access to daylight, windows with views, and natural ventilation. Over a century later, the principles she laid out are backed by recent research that measures improved health outcomes when the outdoors are welcomed in. These old roots are springing forth in modern versions of healing architecture and interior environments, reinvigorated by evidence-based practices and building science that demonstrate the importance of a connection to nature in healing.
Evidence-based design loosely addresses broader issues that impact staff health and well-being, including daylight, contact with nature, and acoustics. In addition, newer health-focused green building rating systems such as LEED, WELL, Fitwel, and the Living Building Challenge help to translate the wellness goals pioneered by Nightingale into focused design strategies.
Fundamentally, the research and concepts that went into the creation of these tools, along with other healthcare-focused evidence-based design research, can help design teams create environments that better promote health and healing as well as staff well-being.
In particular, four specific areas of design, backed by research, have been shown to have an impact on well-being and health and should be considered for all new healthcare projects and renovations.
1. Biophilic design
Naturalist and author Edward O. Wilson coined the term “biophilia” when describing the “missing link in sustainable design” that bonds people to the natural world. Developed over millennia — when our ancestors were more connected to nature than we are — biophilia explains why our bodies respond in specific and positive ways to conditions found in nature. In recent decades healthcare designers have begun exploring how biophilia can positively impact patient outcomes as well as staff satisfaction, wellness, and productivity.
For example, in comparing patients recovering from gall bladder surgery, environmental psychologist Roger Ulrich found that patients who had views of trees required less pain medication and recovered faster than those whose view was limited to a brick wall. Numerous follow-up studies have further quantified the positive impact that contact with nature can have on our health and well-being, addressing issues such as stress reduction, improved sleep, reduced blood pressure, and more.
Direct contact with nature — through sight, touch, smell, and sound — is not the only biophilic design strategy. Metaphoric connections to nature leverage its patterns, textures, and cycles. Our bodies have a physiological response to natural elements like stochastic patterns (like cloud formations), the diurnal cycle, and familiar natural materials that mitigate stress reactions and support health and well-being. Metaphoric connections to nature also have a positive impact on stress reduction and are correlated with improved health outcomes, including shorter lengths of stay for a wide range of conditions.
An example of metaphoric biophilia can be found at Eskenazi Health Main Campus in Indianapolis. The LEED Gold hospital includes water features that mimic a natural spring, artwork inspired by the stochastic patterns found in nature, and a rooftop farm. Meanwhile, Ng Teng Fong General Hospital in Singapore features more direct connections to nature with natural ventilation, a saw-tooth floorplan that provides each patient direct access to an operable window, and garden balconies that provide nature views even from the 18th story. Although very different, both Eskenazi and Ng Teng Fong demonstrate an integrated approach to biophilic design.
(Vegetated balconies provide patients with a view of nature even on the highest floors of the Ng Teng Fong General Hospital in Singapore. Image copyright Rory Daniel/ courtesy of HOK)
2. Daylight exposure
The benefit of daylighting to health is a another well-researched topic. Over the past 25 years, numerous studies have documented the diverse effects of daylight on physiological and psychological patient health and well-being. For example, multiple studies (from 2012, 2013, and 2016) show that patients with more access to natural light heal more quickly and return home sooner than patients with limited exposure to daylighting.
The presence of daylight has a significant impact on our bodies, particularly the systems that are impacted by our circadian rhythms — our 24 hour day/night cycle. A broad range of research over the past few years supports the importance of lighting with “circadian stimulus,” or lighting that stimulates the part of the eye that triggers melatonin and seratonin production, thereby regulating our circadian rhythm. A minimum 40 percent window-wall ratio is necessary to provide sufficient circadian stimulus for a patient lying down, while a minimum 30 percent ratio is required for a patient sitting up. Bigger is not always better – a window-wall ratio of more than 60 percent has been found to provide little if any added benefit for circadian stimulus.
Yet healthcare designers face a special challenge in implementing large areas of daylighting, given the relatively deep floor plates of most healthcare buildings — a significant number of spaces do not have access to windows. The Rhine Ordnance Barracks Medical Center Replacement (ROBMCR), currently in design, bucks this trend. As a U.S. military hospital located in Germany, it needs to meet requirements of both governments, including the German requirement that all regularly occupied spaces have access to daylight and views (either directly outside or into a large day-lit atrium). While the ROBMCR approach does not come without a cost — incorporating additional daylighting has increased the project budget — the added price is likely to be recuperated by the long-term healthcare savings of bringing daylight into all regularly occupied spaces, from offices to operating rooms.
Daylighting is only effective, however, when it functions as designers intended. Often daylighting is rendered useless when patients or staff adjust curtains and blinds to account for window glare. Once interior blinds are pulled, they are rarely lifted again — blocking the view even when there is no glare condition. A solution to this problem can be found in Humber River Hospital. This Toronto hospital incorporated electrochromic glazing into its patient rooms that automatically lightens or darkens the window glass based on the position of the sun and presence of clouds in the sky; it also allows for a manual override with control from the patient bed.
3. Acoustical and thermal comfort
Acoustics is another factor that has been shown to impact both the health and satisfaction of patients and staff. One study examining coronary patients showed that a fix as simple as changing ceiling tiles from sound-reflecting tiles to sound-absorbing tiles significantly improved patients’ perceived quality of care while reducing their overall incidents of re-hospitalization. Another study at the same location found that improved acoustic conditions resulted in the nursing staff experiencing reduced demands and pressure from patients. This pair of studies gives quantitative results to an issue that feels intuitive. Still, acoustical design considerations can be challenging when it comes to healthcare.
Thermal comfort, another important aspect of patient comfort, is affected by various environmental factors including air temperature, radiant temperature, relative humidity, and air velocity and turbulence. Physical activity, metabolic rate, and clothing also impact individual thermal comfort. With such a wide range of factors, it is no surprise that creating a single environment that is comfortable for all occupants can be a challenge. Thermal comfort is particularly important in patient rooms, where temperature impacts recovery conditions, as well as in operating rooms, where relatively low temperatures are required for infection control and indoor air quality of sterile environments.
Quality and quantity of patient sleep directly contributes to the healing process, although it is heavily impacted by thermal conditions within the patient room. Cold temperature not only can cause difficulty falling asleep and staying asleep, it also leads to shivering, inattentiveness, and muscular and joint tension. On the other hand, overly warm temperatures can lead to reduced total sleep time and also increased sleep disruption and wakefulness, indicating inefficient and fragmented sleep.
Perception of thermal comfort is typically impacted by individual and gender differences. In healthcare settings, it is also impacted by a patient’s physical and psychological conditions as well as their specific medication use. Given this, a comfortable patient requires a high degree of control over his or her environment, including bedding, according to studies from 2016 and 2008. There is very little research on patient thermal comfort in operating rooms, as the temperature and air velocity in ORs heavily depends on types of surgery, patient requirements, equipment, lighting conditions, etc. Some operating rooms require an indoor temperature of 18 C (64 F) or even lower. In addition to patient safety, memories of thermal comfort or discomfort during surgery have been shown to affect patients’ overall satisfaction with surgical care.
Both the LEED for Healthcare and the WELL Building Standard rating systems provide helpful guidance on acoustics and thermal comfort. The two systems also incorporate ASHRAE Standard 55 Thermal Environmental Conditions for Human Occupancy, although applying ASHRAE 55 to healthcare spaces requires interpretation as it was not originally designed for spaces for sleeping occupants with reduced metabolic rates.
The new replacement wing at Ventura County Medical Center took on the LEED for Healthcare criteria, implementing ASHRAE Standard 55 as well as a wide range of acoustical goals. Based on Facility Guidelines Institute (FGI) 2010 requirements, LEED for Healthcare addresses sound isolation, room noise from mechanical and other equipment, acoustical finishes, and noise coming in from the exterior. Strategies can include specially designed partitions to reduce sound transmission, interior finishes with high sound absorption properties, HVAC dampers, and a high-performance, insulated building façade. Achieving these goals requires special attention, as materials that absorb sounds don’t always align with a hospital’s requirements for sterile and easily cleanable environments.
Collectively these measures can help to improve acoustical comfort within patient spaces beyond conventional design practices, but they are not always easy to meet. In parts of the hospital, the strict FGI criteria can be difficult if not impossible to achieve. Nonetheless, any focus on acoustical design can positively impact patient health and well-being.
4. IAQ and material toxicity
A myriad of chemicals — such as phthalates, Bisphenol A, halogenated flame retardants, and other substances emitted from building products — can pose serious health hazards, especially in medical environments with young children, the elderly, or immuno-compromised patients.
As the demand for healthier materials grows, so has the concern that some healthier product options may have an overall lower performance than their conventional alternatives; some of the most toxic additives also make materials more durable, flexible, adhesive, or damage-resistant.
The LEED and WELL rating systems have popularized IAQ product certifications, as well as product selection tools such as Cradle to Cradle, Green Screen, and Pharos. But the challenge remains that it can be difficult, if not impossible, to find products that don’t contain chemicals of concern for the healthcare environment. Additionally, regulatory requirements can at times be barriers to meeting health requirements. Halogenated flame retardants, for example, must be applied in rigid board building insulation — mandating exposure in spite of the risks.
Healthcare facility managers and designers currently face a chicken/egg problem. Design teams may not be able to pursue healthier or more sustainable products because they don’t exist in the market, while manufacturers are hesitant to develop healthier product lines or secure air quality testing until they have a confirmed market demand. The Healthier Hospitals Initiative, a consortium of healthcare organizations and their partners, is helping to change this with its Safer Chemicals Program. It aims to educate institutions on the benefits of reducing toxicity and builds coalitions between organizations that are committed to unified goals.
Several healthcare organizations have led the market towards transformation away from chemicals of concern. Kaiser Permanente, for example, is phasing out vinyl and halogenated flame retardants. Kaiser Redwood City Hospital, a LEED Silver facility, uses primarily rubber, terrazzo, and PVC-free broadloom carpet flooring in place of VCT and other vinyl products; reducing vinyl use helps to reduce the significant health impacts of the PVC manufacturing and disposal processes. This requirement extends beyond building products alone; Kaiser’s target for 2025 is for at least half of its durable goods to meet environmental standards.
Were Florence Nightingale alive today, she would no doubt marvel at the healthcare advances we’ve made over the past 100 years, particularly when it comes to surgery and medicine. Yet the founder of modern-day nursing would likely still see room for improvement when it comes to the hospital environments in which patients recover and her modern-day colleagues work. Answers to these challenges can be found in some of her own writings and the more recent research that points to how enhanced biophilia, daylighting, acoustics, thermal comfort, and air quality can improve hospital design for both patients and staff.
Mara Baum (email@example.com), Adeleh Nejati, and Fumi Docker are San Francisco-based architects who work in HOK’s healthcare practice. As WELL Accredited Professionals, they champion opportunities to support wellness in both patients and staff.
Email comments to firstname.lastname@example.org.
FOR FURTHER READING:
1. Acosta, I., Leslie, R. P., & Figueiro, M. G. (2017). Analysis of circadian stimulus allowed by daylighting in hospital rooms. Lighting Research & Technology, 49(1), 49-61. URL: http://journals.sagepub.com/doi/abs/10.1177/1477153515592948
2. Burpee, Heather. “History of Healthcare Architecture”. Integrated Design Lab Puget Sound, 2008. URL: https://www.scribd.com/document/339630095/historyofhealthcarearchburpee-pdf
3. Dunn, Rob. “In retrospect: Silent Spring” Nature 485, 578-579 (31 May 2012). URL: http://www.nature.com/nature/journal/v485/n7400/full/485578a.html?foxtrotcallback=true
4. Healthier Hospitals Initiative. (2015). Guidance to Achieve HH Safer Chemicals Challenge for Healthy Interiors. http://healthierhospitals.org/sites/default/files/IMCE/hhhealthyinteriorsguidance-version2.0updateddecember2015.pdf
5. Pelton, H. K., Ryherd, E., & Martin, M. (2009). Acoustical design of a burn acute care unit for enhanced patient comfort. Noise Control Engineering Journal, 57(1), 32-41. http://www.ingentaconnect.com/content/ince/ncej/2009/00000057/00000001/art00005
6. Torossian, A., Bräuer, A., Höcker, J., Bein, B., Wulf, H., & Horn, E. P. (2015). Preventing inadvertent perioperative hypothermia. Deutsches Ärzteblatt International, 112(10), 166. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4383851/