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." Chris Schaffner, CEO of the Green Engineer, describes operable windows as the "HVAC engineer's ultimate safety factor." 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. 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.
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