Mold in the Schoolhouse By: Robert H. Weidner, P.E., Brinjac Engineering, Inc., Harrisburg, PA According to the U.S. Environmental Protection Agency, indoor air pollutant levels can be two to five times higher--occasionally even 100 times higher--than outdoor levels. Nearly 55 million Americans--20% of the population--spend their days inside elementary and secondary schools. A 1995 federal government report estimated that 50% of U.S. schools have problems linked to poor indoor-air quality (IAQ). Students are at the greatest risk: children have less developed immune systems. Indoor air pollutants can cause physical discomfort, not to mention reduced school attendance and productivity. Pollutants can cause or contribute to short- and long-term health problems, including asthma, respiratory tract infection and disease, allergic reactions, headaches, nasal congestion, eye and skin irritations, coughing, sneezing, fatigue, dizziness and nausea. Furthermore, poor IAQ can contribute to closing of schools, create liability problems, and strain relationships among parents, teachers and the school administration. How mold grows and thrives Mold is found almost everywhere--outdoors and indoors--and can be a significant contributor to poor IAQ and sick-building syndrome (SBS). Mold spores enter buildings through doors, windows and wall penetrations, or by attaching to people, pets or objects that are brought into buildings. Like all buildings, schools have viable mold spores and the desirable thermal environments and abundant food source--wood, paper, carpet, wall board, ceiling tiles, cafeteria foods--for them to thrive. But mold spores remain dormant until adequate moisture becomes available. The common mold Molds are fungi, which serve as breakdown agents of organic matter. Without molds and other fungi, we would be soon overrun with thick layers of dead trees, leaves and other expired organic materials. Found growing on soil, foods, plant matter and various other materials, there are over 645,000 known species of fungus and more than 100,000 mold species. At least 1,000 species of mold are common in the United States, but only a few dozen are thought to be common in buildings. According to the Center for Disease Control and Prevention (CDC), the most commonly found species of mold are Cladosporium, Penicillium, Aspergillus and Alternaria. Aspergillus and Penicillium are considered toxin producers and have been implicated in some health problems. Stachybotrys chartarum, less common indoors than the others mentioned, is a more notorious toxin producer and is considered by some mycologists to be a cause of SBS. Most routinely-encountered molds are not considered hazardous for healthy individuals. However, too much exposure to mold may cause or worsen health conditions. Depending on the amount of exposure and individual vulnerability, more serious health effects, such as fevers and breathing problems, can occur but are unusual. Mycologists, physicians, public health officials and attorneys are regularly in conflict about the health effects of mold in buildings because conclusive evidence is hard to find. In fact, the EPA has yet to establish any regulations or guidelines for evaluating the potential health risks associated with molds. However, mold growth in buildings is certainly undesirable and potentially destructive to the facility's structure. While there is no practical way to eliminate mold spores from a building's indoor environment, the best way to stop mold from growing and becoming a potential health problem is to take away the moisture source. When excessive humidity, moisture or water accumulates indoors and goes unnoticed or unaddressed, mold growth will occur. The following steps should be considered to minimize water or moisture accumulation and thus minimize mold growth in schools: Humidity control: Provide proper air-conditioning and ventilation systems to maintain indoor humidity levels between 30% and 60%. Humid spaces such as restrooms, locker rooms, kitchens and janitor closets and associated fixtures or equipment should be ventilated directly to the outside. Building inspections: Look for visible signs of mold growth, or investigate areas with noticeable musty odors, discoloration, or fuzzy growths on the surface of building materials. Visible signs of water damage (ceiling tiles, basement walls, etc.) standing water (toilet rooms, mechanical rooms, etc.) or condensation (windows, exterior walls, roofs, floors or piping) should also be investigated for mold growth. Search behind and underneath building materials. Destructive testing may even be necessary if mold growth is suspected but not visible. Leaks, spills or flooding: Clean and dry surfaces damaged by water within 24 to 48 hours of occurrence. Fix or repair the moisture problem source or leak. Clean and disinfect mold on hard surfaces with water, detergent or bleach and replace materials heavily damaged by water. Condensation control: Minimize the potential for condensation on windows, exterior walls, roofs, floors or air-conditioning piping by providing additional insulation or a vapor barrier. For equipment drain pans and piping, ensure that proper drainage is provided and the correct type of insulation is utilized on cold surfaces. Close-celled insulation is preferred over fiberglass insulation on cold pipes and equipment. Floor and carpet cleaning: Clean up spots and stains as soon as they occur and prevent excess moisture accumulation during cleaning operations. Avoid the use of carpet where moisture problems are regularly anticipated such as for basement floors and beneath drinking fountains and sinks. Minimize health effects: Once viable mold growth has been determined or suspected, immediate steps should be taken to minimize the potential health effects and the continued damage caused by the mold. The first priority is to identify and correct the moisture source if possible. In some cases, this may require the help of a professional. Laboratory testing, including air, wipe and bulk samples, may be necessary to help determine the types of molds present to establish the potential health risks to the building occupants and to respond to concerns by concerned parties. Implement a remediation plan: Once the moisture sources have been identified and testing has been completed, a remediation plan should be developed and put into action. This may include cleaning and disinfecting of the contaminated area and partial or total removal of the contaminated materials, depending on how extensive the damage. Most large-scale mold remediation work--including cleaning, disinfecting and removal should be performed by experienced professionals.

Back