Mold Elimination

Defining the Problem.

The presence of mold in the indoor environment along with the potential for health problems that may be aggravated due to mold presence is increasingly considered as one of the most serious threats to indoor air quality. Moreover, the presence of mold and related biological forms, whether as a failure of the construction process, the inappropriate selection of materials, or inadequate ventilation, continues to represent a growing percentage of construction-related litigation. Hospitals and other health care facilities should be especially sensitive to the potential for mold in the interior environment. Understanding and applying appropriate construction methods as well as selecting materials and systems that promote a healthy indoor environment is a collaborative effort that demands the attention of designers, contractors, and owners.

• A food source, such as wood, paper facing on gypsum wallboard, ceiling tiles with cellulosic content, or carpeting with jute backing
• Temperatures between 40° and 100° Fahrenheit
• Relative humidity of at least 75% on the surface of the food source

The Nature of Mold
Molds are the most typical form of fungus found on earth, comprising approximately 25% of the earth’s biomass. Molds gain the nutrients they need through the decomposition of organic matter. Most molds found in indoor air are saprotropic, meaning that they gather their food from dead moist organic matter such as wood, paper, paint, fabric, plant soil, dust, and cooked or raw foods. However, molds can also grow on the surface of damp inorganic matter such as glass and bare concrete covered by an invisible biofilm (an extremely thin layer of organic matter). In short, all that molds need to germinate and grow is a readily available food source, undisturbed water, and time. Molds and other fungi may start to grow within 24 to 48 hours after water enters a building or its systems.

Mold will most likely be a serious issue at one of two times in a building’s lifecycle:

• Improper materials management during the construction process, which includes storage, phasing, and installation deficiencies, will most certainly lead to the compromising of materials that are, by nature, susceptible to mold growth.

• Inappropriate detailing; heating, ventilation, and air conditioning (HVAC) design; piping installation; and indoor chemical and pollutant source control will be factors in promoting mold growth in occupied facilities.

Most molds are capable of producing mycotoxins, natural organic compounds that are capable of initiating a toxic response in vertebrates. The most common molds known to potentially produce mycotoxins and that have been isolated in infestations causing adverse health effects due to their presence on building materials include certain species of Aspergillus, Penicillium, and Stachybotrys. There are 200 different species of both Aspergillus and Penicillium, some of which are toxic and may be found in the interior environment on such products as gypsum wallboard, carpet, wallpaper, and fiberglass insulation facing. Stachybotrys may be the most widely recognized mycotoxin and is commonly present on water-damaged ceiling tiles, cellulose insulation, and gypsum wallboard. Each of these mycotoxins can potentially be the cause of minor medical problems such as dermatitis, coughs, and headaches (typically associated with sick building syndrome) or may represent more serious life-threatening illnesses by exacerbating asthma or pulmonary hemosiderosis. Molds also produce a variety of volatile organic compounds (VOCs). Exposure to high levels of VOCs, from either organic or inorganic sources, irritates the mucous membranes and affects the central nervous system, producing such symptoms as headaches, attention deficit, inability to concentrate, and dizziness.

Minimizing the Risk

The 2006 Facility Guidelines Institute (FGI) and American Institute of Architects (AIA) Guidelines for Design and Construction of Health Care Facilities recommends an Infection Control Risk Assessment (ICRA) for all projects. In addition, the Joint Commission on Accreditation of Healthcare Organizations (JCAHO) Standard EC.3.2.1 requires that when planning demolition, construction, or renovation work, the organization conducts a proactive construction risk assessment using risk criteria to identify hazards that could potentially compromise patient care in occupied areas of the organization’s buildings. The potential for mold infestation should always be an element of any ICRA plan. Control of mold or the control of situations that can lead to formation and exposure of mold begins during design and continues into construction activities.

The following strategies should be enforced:

• Tightly control, sequence, and coordinate phased work where interior finishes are installed prior to the building being made weather-tight.
• Provide moisture intrusion protection for work areas and materials susceptible to water damage before the building is made weather-tight.
• Provide and follow specific instructions on storage of materials susceptible to water damage.
• Maintain a clean site, free of uncontrolled running water.
• Identify any other contractor responsible for care, custody, and control of specific work areas.
• Provide for and immediately respond (within 24 to 48 hours) to any discovery of water intrusion or mold with appropriate action.

Mold-Resistant Products

A growing number of products are being marketed as being “mold-resistant.” Paints, adhesives, carpets, upholstery, floor waxes, air filters, wall coverings, duct coatings, and a myriad other building products are manufactured with biocides to protect against microbial growth. Such sanitizers, biocides, and antimicrobials are no more than pesticides. The U.S. Environmental Protection Agency (EPA) controls these under the Federal Insecticide, Fungicide, and Rodenticide Act. Substances are registered as either public health or non public health antimicrobial agents. Public health agents are intended to control infectious micro-organisms that may be a hazard to human health. To obtain the designation of “public health” antimicrobial, a manufacturer must present data to EPA demonstrating that the agent is effective against specific infectious micro-organisms and meets safety and toxicity standards. An agent is considered effective if it controls the specified micro-organisms, not necessarily the diseases caused by the micro-organisms. The manufacturer cannot claim that the agent prevents diseases.

The Centers for Disease Control’s (CDC’s) June 2000 draft of Public Health Action Plan to Combat Antimicrobial Resistance called for an evaluation of “the benefits and risks of incorporating antimicrobial disinfectants or antiseptic chemicals into consumer products (e.g., soap, toys, kitchen utensils, clothes, paints, plastics and film preservatives).” The National Institute for Occupational Safety and Health (NIOSH)/EPA document entitled Building Air Quality: A Guide for Building Owners and Facility Managers recommended that biocides, disinfectants, and sanitizers “be used with caution to ensure that occupant exposure is minimized.” In the CDC’s 2003 Guidelines for Environmental Infection Control in Health-Care Facilities, the Construction Design and Function Considerations for Environmental Infection Control stress proactive design measures such as adequate ventilation, humidity management, and pressurization to achieve infection control in lieu of recommending products with pesticides to achieve those same results.

Although biocides may definitely be effective in killing bacteria, there is considerable controversy surrounding their health benefits. Some scientists believe this is a potential danger because laboratory conditions used in the research studies do not represent the “real world.” Others believe the use of these agents creates a false sense of security that may cause architects and engineers to become lax in designing an appropriate building envelope or mechanical system, or facilities managers to become indifferent to practicing fundamental maintenance or infection control. Hospitals may wish to consider enacting policies that, at a minimum, require architects or product suppliers to identify those products that have been bio-engineered with pesticides and determine their long-range impact on the environment at large.

Key Resources:

“Whole Building Design Guide: Indoor Air Quality and Mold Prevention of the Building Envelope”: Roger Morse, AIA and Don Acker, PE (Morse Zehnter Associates). March 1, 2006. Describes how microbiological organisms, such as fungi and bacteria, can proliferate in buildings and adversely impact indoor air quality, create hazardous health conditions for the occupants, and contribute to the deterioration of building components.

“Guidelines on Assessment and Remediation of Fungi in Indoor Environments”: New York City Department of Health and Mental Hygiene, Bureau of Environmental and Occupational Disease Epidemiology. Presents policies for medical and environmental evaluation and intervention to address all fungi (mold) and is based both on a review of the literature regarding fungi and on comments obtained by a review panel consisting of experts in the fields of microbiology and health sciences; it is intended for use by building engineers and management but is available for general distribution to anyone concerned about fungal contamination, such as environmental consultants, health professionals, or the general public.

“Mold in Homes”: Minnesota Department of Health. Presents the health concerns associated with mold exposure and advice on finding and removing mold contamination.

“Mold Remediation in Schools and Commercial Buildings”: U.S. Environmental Protection Agency. Provides 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.