Healthy building refers to an emerging area of interest that supports the physical, psychological, and social health and well-being of people in buildings and the built environment. Buildings can be key promoters of health and well-being since most people spend a majority of their time indoors. According to the National Human Activity Pattern Survey, Americans spend "an average of 87% of their time in enclosed buildings and about 6% of their time in enclosed vehicles."
Healthy building can be seen as the next generation of green building that not only includes environmentally responsible and resource-efficient building concepts, but also integrates human well-being and performance. These benefits can include "reducing absenteeism and presenteeism, lowering health care costs, and improving individual and organizational performance."
Integrated design Healthy building involves many different concepts, fields of interest, and disciplines. 9 Foundations describes healthy building as an approach built on building science, health science, and building science. An integrated design team can consist of stakeholders and specialists such as facility managers, architects, building engineers, health and wellness experts, and public health partners. Conducting charrettes with an integrated design team can foster collaboration and help the team develop goals, plans, and solutions.
Buildings and health components There are many different components that can support health and well-being in buildings.
Indoor air quality Spengler considers indoor air quality as an important determinant of healthy design. Buildings with poor indoor air quality can contribute to chronic lung diseases such as asthma, asbestosis and lung cancer. Chemical emissions can be outgassed by building materials, furnishings, and supplies. Air fresheners, cleaning products, paints, printing, flooring, and wax and polish products can also be a source of volatile organic compounds (VOCs) and semi-volatile compound (SVOCs). The LEED v4 Handbook posits that indoor air quality is "one of the most pivotal factors in maintaining building occupants' safety, productivity, and well-being."
Ventilation Higher rates of ventilation affect indoor pollutants, odors, and the perceived freshness of air by diluting contaminants in the air. ASHRAE's Standard 55-2017 has minimum standards of 8.3 L/s/person. In one study, raising the rate to 15 L/s/person increased performance by 1.1% and decreased sick building symptoms by 18.8%. Whole Building Design Guide recommends separating ventilation from thermal conditioning so as to increase comfort.
Natural ventilation is discouraged in buildings that have strict filtration requirements, contaminant dilution concerns, special pressure relationships, speech privacy concerns, and internal heat load demands. The San Joaquin ASHRAE chapter recommends assessing the outside air quality and configuration of the facade and building before demonstrating compliance and control of natural ventilation. ASHRAE Standard 55-2017 section 6.4 requires the natural ventilation be "manually controlled or controlled through the use of electrical or mechanical actuators under direct occupant control."McConahey, E. (2019). The Feasibility of Natural Ventilation [PowerPoint]. Retrieved from https://sjvashrae.starchapter.com/images/downloads/Natural_Ventilation.pdf Chris Schaffner, CEO of the Green Engineer, describes operable windows as the "HVAC engineer's ultimate safety factor."Schaffner, C., (2020) Pandemic Resilience in Buildings: Proposed LEED Pilot Credit [PowerPoint presentation]. USGBC Healthy Economy Forum, Online Spengler and Chen recommend natural ventilation being used wherever possible.
Dust and pests Dust and dirt can be a source of exposure to VOC and lead as well as pesticides and allergens. High efficiency filter vacuums can remove particles such as dander and allergens that otherwise result in breathing issues. A study of asthmatic children in inner city urban communities suggests they became sensitive to the presence of cockroaches, mice, or rats due to their presence in their homes.
The use of disposable material
The US culture relies heavily on disposable products, especially within healthcare, to minimize on cost and time. In hospitals, for example, healthcare providers cut on costs associated with sterilizing equipment between patient cares by using ready-to-use disposable trays. However, this may at a cost to the environment; in one study, disposable cotton towels were suspected to have an adverse environmental impact. It is estimated that cotton production requires 6.6 kg of carbon dioxide equivalents and 0.024 kg of nitrogen emissions, in addition to a substantial amount of water, fertilizer and work. Healthcare managers are urged to request transparency of medical product production (and waste management) lines to provide assurance that products used have zero or minimal impacts on human health and our environment.
Thermal comfort
Thermal comfort is influenced by factors like air temperature, mean radiant temperature, relative humidity, air speed, metabolic rate, and clothing.Kubba, Sam. (2016). LEED v4 Practices, Certification, and Accreditation Handbook (2nd Edition) - 7.1 General Overview. Elsevier. Retrieved from https://app.knovel.com/hotlink/pdf/id:kt010SFR91/leed-v4-practices-certification/leed-v4-pr-general-overview Thermal conditions can affect learning, cognitive performance, task completion, disease transmission, and sleep. ASHRAE defines an acceptable thermal environment as one that 80% of occupants find acceptable, though individual occupant thermal control results in higher satisfaction of occupants. Indoor spaces that are not air conditioned can create indoor heat waves if the outside air cools but the thermal mass of the building traps the hotter air inside. Cedeño-Laurent et al. believe these may become worse as climate change increases the "frequency, duration, and intensity of heat waves" and will be harder to adjust to in areas that are designed for colder climates.
Moisture and humidity
The Whole Building Design Guide recommends the indoor relative humidity to be between 30 and 50% to prevent unwanted moisture and to design for proper drainage and ventilation. Moisture is introduced into the building either by rainwater intrusion, outside humid air infiltration, internally generated moisture, and vapor diffusion through the building envelope. High temperatures, precipitation, and building age enable mold. It contributes to mold and poor indoor air quality. Vapor retarders have traditionally been used to prevent moisture in walls and roofs.
Noise
While noise is not always controllable, it has a high correlation and causation relationship with mental health, stress, and blood pressure. One study suggests that there is a higher correlation of noise irritation and bodily pain or discomfort in women. Effects of excessive noise pollution include hearing impairment, speech intelligibility, sleep disturbance, physiological functions, mental illness, and performance. The World Health Organization recommends creating a "National Plan for a Sustainable Noise Indoor Environment" specific to each country.Berglund, Birgitta; Lindvall, Thomas; Schwela, Dietrich H. World Health Organization Occupational and Environmental Health (1999). "Guidelines for community noise".
Water quality Water quality can be contaminated by inorganic chemicals, organic chemicals, and microorganisms. The World Health Organization considers waterborne diseases to be one of the world's major health concerns, especially for developing countries and children. WHO recommends following water safety plans that include management, maintenance, good design, cleaning, temperature management, and preventing stagnation. Stagnant water is found to deteriorate the microbiological quality of water, and increase corrosion, odors, and taste issues. The bacterial pathogen Legionella may have a higher potential for growth in large buildings due to long water distribution systems and not enough maintenance.
Awareness of these issues is recommended by the WHO in order to maintain water quality: Backflow Cross connections External quality management Independent water supply Material use Minimization of dead ends and stagnation Seasonal use areas Storage tank integrity Water pressure Water temperature
Safety and security Concerns of safety affect the mental and possibly physical health of residents by reducing the amount of physical activity. Fear of crime can result in less physical activity as well as increased social isolation. Atkinson posits that crime is based on motivated offenders, targets, and the absence of guardians. Adjusting these in buildings may increase presumed safety.
Lighting and view The type and timing of light throughout the day affects circadian rhythms and human physiology. In a study done by Shamsul et al., cool white light and artificial daylight (approximately 450-480 nanometers) was associated with higher levels of alertness. Blue light positively affects mood, performance, fatigue, concentration, and eye comfort and enabled better sleep at night. Bright light during winter has also been shown to improve self-reported health and reduce distress.
Daylighting refers to providing access to natural daylight, which can be aesthetically pleasing and improve sleep duration and quality. The LEED handbook writes that daylighting can save energy while "increasing the quality of the visual environment" and occupant satisfaction.
Views to green landscapes can significantly increase attention and stress recovery. They can also have a positive influence on emotional states. Ko et al. consider views to be "important for the comfort, emotion, and working memory and concentration of occupants." Providing a view to nature through a glass window may benefit occupants' well-being and increase employee's effectiveness.
Site selection Creating a walkable environment that connects people to workplaces, green spaces, public transportation, fitness centers, and other basic needs and services can influence daily physical activity as well as diet and type of commute. In particular, proximity to green spaces (e.g., parks, walking trails, gardens) or therapeutic landscapes can reduce absenteeism and improve well-being.
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