Issue link: https://hi.iaq.net/i/248503
www.epa.gov/iaq/moisture Chapter 1: Moisture Control in Buildings Introduction To be successful, moisture control does not require everything be kept completely dry. Moisture control is adequate as long as vulnerable materials are kept dry enough to avoid problems. That means the building must be designed, constructed and operated so that vulnerable materials do not get wet. It also means that when materials do get wet, the building needs to be managed in such a way that the damp materials dry out quickly. Moisture control is fundamental to the proper functioning of any building. Controlling moisture is important to protect occupants from adverse health effects and to protect the building, its mechanical systems and its contents from physical or chemical damage. Yet, moisture problems are so common in buildings, many people consider them inevitable. Excessive moisture accumulation plagues buildings throughout the United States, from tropical Hawaii to arctic Alaska and from the hot, humid Gulf Coast to the hot, dry Sonoran Desert. Between 1994 and 1998, the U.S. Environmental Protection Agency (EPA) Building Assessment Survey and Evaluation (BASE) study collected information about the indoor air quality of 100 randomly selected public and private office buildings in the 10 U.S. climatic regions. The BASE study found that 85 percent of the buildings had been damaged by water at some time and 45 percent had leaks at the time the data were collected.2 Health Implications of Dampness in Buildings At the request of the U.S. Centers for Disease Control and Prevention (CDC), the Institute of Medicine (IOM) of the National Academy of Sciences convened a committee of experts to conduct a comprehensive review of the scientific literature concerning the relationship between damp or moldy indoor environments and the appearance of adverse health effects in exposed populations. Based on their review, the members of the Committee on Damp Indoor Spaces and Health concluded that the epidemiologic evidence shows an association between exposure to damp indoor environments and adverse health effects, including: Moisture causes problems for building owners, maintenance personnel and occupants. Many common moisture problems can be traced to poor decisions in design, construction or maintenance. The American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) notes that, more often than not, the more serious problems are caused by decisions made by members of any of a number of different professions.3 However, such problems can be avoided with techniques that are based on a solid understanding of how water behaves in buildings. • Upper respiratory (nasal and throat) symptoms. • Cough. • Wheeze. • Asthma symptoms in sensitized persons with asthma. The committee also determined that there is limited or suggestive evidence of an association between exposure to damp indoor environments and: Moisture control consists of: • Dyspnea (shortness of breath). • Preventing water intrusion and condensation in areas of a building that must remain dry. • Lower respiratory illness in otherwise healthy children. • Limiting the areas of a building that are routinely wet because of their use (e.g., bathrooms, spas, kitchens and janitorial closets) and drying them out when they do get wet. • Asthma development. 2 http://www.epa.gov/iaq/base/. Accessed November 6, 2013. 3 Limiting Indoor Mold and Dampness in Buildings. 2013 (PDF) at https://www.ashrae.org/about-ashrae/position-documents. Accessed November 6, 2013. 1