The following information was in a handout distributed
by Mr. Offermann:
Excessive moisture in buildings leads to:
The critical factor governing fungal growth in building is moisture.
For fungal growth to develop in buildings, surfaces of materials must become wet and stay wet for prolonged periods of time (i.e. days, weeks).
Building materials can become wet if the building envelope does not preclude liquid or capillary flow of water (rain or landscape irrigation), or if the surface temperature of the building materials falls below the dew point and condensation occurs.
With respect to condensation of water vapor, the relationship between air temperature, relative humidity, absolute humidity (humidity ratio), and dew point are summarized in the ASHRAE psychometric chart.
If a surface temperature falls below the dew point temperature then condensation of moisture will occur on that surface (e.g. surface temperatures lower than 51 OF in air that is 50% relative humidity @70 OF).
What are fungi and molds? Fungi are a class of organisms that are not plants (because they lack chlorophyll) and not animals (because they have no organs for food uptake).
Fungi may be divided into three groups:
The filamentous fungi, or molds, are of particular concern in buildings with chronic moisture problems since they produce spores which readily become airborne and can be inhaled.
Many types of fungal spores contain toxic and allergenic compounds which can cause irritation or disease to those exposed. Exposure to the toxic compounds produced by fungi may be by skin contact (rash and lesions) or by inhaling the airborne spores (allergies, asthma, respiratory disease). Breathing air contaminated with fungal spores can lead to significant health problems for some individuals. Health effects range from aggravated allergy symptoms and asthma attacks to respiratory infection and systemic toxicoses. Some people are more susceptible to developing serous health effects from exposure to fungal contamination such as infants and elderly people and those individuals undergoing chemotherapy, organ and bone marrow transplantation, or those with HIV/AIDS.
Moisture problems and resulting fungal growth can occur:
Assessment of the fungal contamination in a building
generally involves a visual survey of the extent of the contamination
on visible indoor surfaces as well as on concealed surfaces.
Air samples can provide the forensic evidence upon which opinions regarding the personal injury aspects of a fungal contamination case may be based. Air samples can also be used to forensically prove that there is a source of fungus in the building. Samples are collected form indoor and out door locations and the concentrations compared. In buildings without indoor sources of fungal contamination the concentrations of airborne fungal contamination, on a general basis, are less indoors than outdoors. Conversely, buildings with elevated indoor concentrations represent those with an indoor source of fungal contamination.
Mitigation of extensive fungal contamination in buildings (i.e. more than a few small spots, square feet of contamination) requires the following to safely remove the contamination:
Isolation of the contaminated area (negative
With respect to workers in fungal contaminated buildings, the OSHA General Duty Clause, Section 5, Subsection A, and the Hazard Communication Standard require that employees be notified by employers of potentially hazardous work conditions.
Application of biocides (e.g. bleach) are not recommended
as they do not remove the fungal contamination but rather kill the
spores and dead fungal spores still contain all the toxins that live
fungal spores have plus those associated with the biocide. Nor are
biocides effective in preventing re-growth of the fungal contamination.
If moisture intrusion re-occurs then re-growth will occur as a result
of the deposition of new viable fungal spores following the biocide
treatment. The only way to insure no further re-growth is to insure
that the moisture intrusion problems have been solved.
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