Concern about indoor exposure to mold has been increasing as the public becomes aware that exposure to mold can cause a variety of health effects and symptoms, including allergic reactions. This article presents guidelines for the remediation/ cleanup of mold and moisture problems in schools and commercial buildings; these guidelines include measures designed to protect the health of building occupants and remediators. It has been designed primarily for building managers, custodians, and others who are responsible for commercial building and school maintenance. It should serve as a reference for potential mold and moisture remediators. Using this document, individuals with little or no experience with mold remediation should be able to make a reasonable judgment as to whether the situation can be handled in-house. It will help those in charge of maintenance to evaluate an in-house remediation plan or a remediation plan submitted by an outside contractor.1 Contractors and other professionals who respond to mold and moisture situations in commercial buildings and schools may also want to refer to these guidelines.
Molds gradually destroy the things they grow on. Prevent damage to building materials and furnishings, save money, and avoid potential health risks by controlling moisture and eliminating mold growth.
Molds can be found almost anywhere; they can grow on virtually any organic substance, as long as moisture and oxygen are present. There are molds that can grow on wood, paper, carpet, foods, and insulation. When excessive moisture accumulates in buildings or on building materials, mold growth will often occur, particularly if the moisture problem remains undiscovered or unaddressed. It is impossible to eliminate all mold and mold spores in the indoor environment. However, mold growth can be controlled indoors by controlling moisture indoors.
Molds reproduce by making spores that usually cannot be seen without magnification. Mold spores waft through the indoor and outdoor air continually. When mold spores land on a damp spot indoors, they may begin growing and digesting whatever they are growing on in order to survive. Molds gradually destroy the things they grow on.
Many types of molds exist. All molds have the potential to cause health effects. Molds can produce allergens that can trigger allergic reactions or even asthma attacks in people allergic to mold. Others are known to produce potent toxins and/ or irritants. Potential health concerns are an important reason to prevent mold growth and to remediate or clean up any existing indoor mold growth.
Since mold requires water to grow, it is important to prevent moisture problems in buildings. Moisture problems can have many causes, including uncontrolled humidity. Some moisture problems in buildings have been linked to changes in building construction practices during the 1970s, 80s, and 90s. Some of these changes have resulted in buildings that are tightly sealed, but may lack adequate ventilation, potentially leading to moisture buildup. Building materials, such as drywall, may not allow moisture to escape easily. Moisture problems may include roof leaks, landscaping or gutters that direct water into or under the building, and unvented combustion appliances. Delayed maintenance or insufficient maintenance are also associated with moisture problems in schools and large buildings. Moisture problems in portable classrooms and other temporary structures have frequently been associated with mold problems.
When mold growth occurs in buildings, adverse health problems may be reported by some building occupants, particularly those with allergies or respiratory problems. Remediators should avoid exposing themselves and others to mold-laden dusts as they conduct their cleanup activities. Caution should be used to prevent mold and mold spores from being dispersed throughout the air where they can be inhaled by building occupants.
Prevention
The key to mold control is moisture control. Solve moisture problems before they become mold problems!
Mold Prevention Tips
- Fix leaky plumbing and leaks in the building envelope as soon as possible.
- Watch for condensation and wet spots. Fix source(s) of moisture problem(s) as soon as possible.
- Prevent moisture due to condensation by increasing surface temperature or reducing the moisture level in air (humidity). To increase surface temperature, insulate or increase air circulation. To reduce the moisture level in air, repair leaks, increase ventilation (if outside air is cold and dry), or dehumidify (if outdoor air is warm and humid).
- Keep heating, ventilation, and air conditioning (HVAC) drip pans clean, flowing properly, and unobstructed.
- Vent moisture-generating appliances, such as dryers, to the outside where possible.
- Maintain low indoor humidity, below 60% relative humidity (RH), ideally 30-50%, if possible.
- Perform regular building/HVAC inspections and maintenance as scheduled.
- Clean and dry wet or damp spots within 48 hours.
- Don’t let foundations stay wet. Provide drainage and slope the ground away from the foundation.
Excerpted from Mold Remediation in Schools and Commercial Buildings by EPA.
Footnotes
1 If you choose to use outside contractors or professionals, make sure they have experience cleaning up mold. Check their references, and have them follow the recommendations presented in this document, the guidelines of the American Conference of Government Industrial Hygienists (ACGIH), and/or guidelines from other professional organizations.
References
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American Conference of Governmental Industrial Hygienists. Bioaerosols: Assessment and Control. Macher, J., editor. ACGIH. Cinncinati, OH. ISBN 1-882417-29-1. 1999.
American Conference of Governmental Industrial Hygienists. Guidelines for the Assessment of Bioaerosols in the Indoor Environment. ISBN 0-936712-83-X. 1989.
American Industrial Hygiene Association. Field Guide for the Determination of Biological Contaminants in Environmental Samples. Dillon, H. K., Heinsohn, P. A., and Miller, J. D., editors. Fairfax, VA. 1996.
American Society of Heating, Refrigerating, and Air Conditioning Engineers. Method of Testing General Ventilation Air-Cleaning Devices for Removal Efficiency by Particle Size. ASHRAE Standard 52.2. 2000.
American Society for Microbiology. Manual of Environmental Microbiology. Hurst, C., Editor in Chief. ASM Press. Washington, DC. 1997.
Canada Mortgage and Housing Corporation. Clean-up Procedures for Mold in Houses. ISBN 0-662-21133-2. 1993.
The Clean Trust, The Clean Trust S500, Standard and Reference Guide for Professional Water Damage Restoration, 2nd Edition. 1999.
Eastern New York Occupational and Environmental Health Center. Proceedings of the International Conference, Saratoga Springs, NY. October 6-7, 1994. Fungi and Bacteria in Indoor Air Environments - Health Effects, Detection, and Remediation. Johanning, E., and Yang, C., editors. Eastern New York Occupational Health Program. Latham, NY. 1995.
Eastern New York Occupational and Environmental Health Center. Bioaerosols, Fungi and Mycotoxins: Health Effects, Assessment, Prevention and Control. Johanning, E., editor. Albany, NY. 1999. (Proceedings of the Third International Conference on Fungi, Mycotoxins and Bioaerosols: Health Effects, Assessment, Prevention and Control. September 23-25, 1998.)
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Lstiburek, J. Building Science Corporation Builder’s Guide, Mixed-Humid Climates. Building Science Corporation and the Energy Efficient Building Association. 1999.
National Academy of Sciences, Committee on the Assessment of Asthma and Indoor Air. Clearing the Air: Asthma and Indoor Air Exposures. National Academy Press. 2000.
National Academy of Sciences. Indoor Allergens: Assessing and Controlling Adverse Health Effects. National Academy Press. 1993.
National Institute for Occupational Safety and Health. Guide to the Selection and Use of Particulate Respirators Certified under 42 CFR 84. DHHS (NIOSH) Publication No. 96-101. January 1996.
New York City Department of Health, Bureau of Environmental & Occupational Disease Epidemiology. Guidelines on Assessment and Remediation of Fungi in Indoor Environments. 2000.
Occupational Safety & Health Administration. Respiratory Protection Standard, 29 CFR 1910.134. 63 FR 1152. January 8, 1998.
U.S. Environmental Protection Agency. Should You Have the Air Ducts In Your Home Cleaned? EPA-402-K-97-002. October 1997.
