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wiki: Mold growth, assessment, and remediation

(2013-07-03 20:31:38) 下一個

 


en.wikipedia.org/wiki/Mold_growth,_assessment,_and_remediation



Assessment[edit]


The first step in an assessment is to determine if mold is present. This is done by visually examining the premises. If mold is growing and visible this helps determine the level of remediation that is necessary. If mold is actively growing and is visibly confirmed, sampling for specific species of mold is unnecessary.[6]


These methods, considered non-intrusive, only detect visible and odor-causing molds. Sometimes more intrusive methods are needed to assess the level of mold contamination. This would include moving furniture, lifting and/or removing carpets, checking behind wallpaper or paneling, checking in ventilation duct work, opening and exposing wall cavities, etc.


Careful detailed visual inspection and recognition of moldy odors should be used to find problems needing correction. Efforts should focus on areas where there are signs of liquid moisture or water vapor (humidity) or where moisture problems are suspected. The investigation goals should be to locate indoor mold growth to determine how to correct the moisture problem and remove contamination safely and effectively.


Sampling[edit]


In general the EPA does not recommend sampling unless an occupant of the space is symptomatic. When sampling is necessary it should be performed by a trained professional who has specific experience in designing mold-sampling protocols, sampling methods, and the interpretation of findings. Sampling should only be conducted to answer a pertinent question: examples "what is the spore concentration in the air", or "is a particular species of fungi present in the building." The following additional question should be asked before sampling: "what action can or should a person take upon obtaining data."


The sampling and analysis should follow the recommendations of Occupational Safety and Health Administration (OSHA), National Institute for Occupational Safety and Health (NIOSH), Environmental Protection Agency (EPA), and the American Industrial Hygiene Association (AIHA). Most importantly, when a sample is taken the proper chain of custody should be adhered to. The AIHA offers lists of accredited laboratories that submit to required quarterly proficiency testing.


Three types of sampling include but are not limited to::



  • Air sampling: the most common form of sampling to assess the level of mold. Sampling of the inside and outdoor air is conducted and the results to the level of mold spores inside the premises and outside are compared. Often, air sampling will provide positive identification of the existence of non-visible mold.

  • Surface samples: sampling the amount of mold spores deposited on indoor surfaces (tape, and dust samples)

  • Bulk samples: the removal of materials from the contaminated area to identify and determine the concentration of mold in the sample.


When sampling is conducted, all three types are recommended by the AIHA, as each sample method alone has specific limitations. For example, air samples will not provide proof of a hidden source of mold. Nor would a tape sample provide the level of contamination in the air.[7]


Though it may not be recommended, air sampling following mold remediation is usually the best way to ascertain efficacy of remediation, when conducted by a qualified third party.[8]


Remediation[edit]


The first step in solving an indoor mold problem is stopping the source of moisture. Next is to remove the mold growth. Common remedies for small occurrences of mold include:



  • Sunlight

  • Ventilation

  • Wall insulation/Dry Wall

  • Non-porous building materials

  • Household cleansers

  • Dehumidifiers


There are many ways to prevent mold growth; see heating, ventilating, improved insulation and air conditioning, and dry fog. New technology allows some mold remediation companies to fill a room with a dry fog that kills mold and stops its growth. This fog uses a chemical that is EPA approved and does not harm or damage the physical well being of persons or animals. There are also cleaning companies that specialize in fabric restoration - a process by which mold and mold spores are removed from clothing to eliminate odor and prevent further mold growth and damage to the garments.


Improper methods for cleaning mold include exposure to high heat, dry air, sunlight (particularly UV light), ozone, and application of fungicides. These methods may render the mold non-viable, however, the mold and its by-products can still elicit negative health effects. As noted in following sections, the only proper way to clean mold is to use detergent solutions that physically remove mold. Many commercially available detergents marketed for mold clean-up also include an anti-fungal agent.


Significant mold growth may require professional mold remediation to remove the affected building materials and eradicate the source of excess moisture. In extreme cases of mold growth in buildings, it may be more cost-effective to condemn the building rather than clean the mold to safe levels.


The goal of remediation is to remove or clean contaminated materials in a way that prevents the emission of fungi and dust contaminated with fungi from leaving a work area and entering an occupied or non-abatement area, while protecting the health of workers performing the abatement.[9]


Cleanup and removal methods[edit]


The purpose of the clean-up process is to eliminate the mold and fungal growth and to remove contaminated materials. As a general rule, simply killing the mold with a biocide is not enough. The mold must be removed since the chemicals and proteins, which cause a reaction in humans, are still present even in dead mold.


Evaluating mold exposures[edit]


Before beginning mold remediation you should make sure you assess the area infected with mold to ensure safety, you clean up the entire moldy area, and properly approach the mold.[6]



  • Assess the area infected with mold, checking for any hidden mold

  • Fix moisture problems before you remove and clean up the moldy area to prevent future mold growth issues

  • If the area of mold is large you should get a remediation manager to properly dispose of the mold

  • Be sure to identify the source of water or moisture that caused the mold growth to begin with

  • Check all air ducts, ventilation systems and air handling units so that the mold problems do not persist in the indoor environment

  • Consult a qualified professional if you have any problems or if you are not confident that you can properly remove all mold or sources of mold growth


Cleaning recommendations[edit]


These steps should always be done by a trained professional.[10]



  • First, make sure to remove any object near the insulation system that may have been contaminated from floodwater. Properly dispose of the contaminated materials according to your local, State, and Federal regulations. (The insulation you might removed may be contaminated with asbestos. Always make sure to call a trained professional to avoid serious injury or death)

  • Make sure to remove the contaminated HVAC filter media to ensure your HVAC system is not bringing in contaminated air. Make sure to dispose of it reading the same regulations listed above.

  • Remove any debris and insulation; clean all components of the HVAC system to ensure nothing becomes contaminated and/or more contaminated from floodwater. Use a HEPA-filtered vacuum, cleaner to make sure you get rid of all the debris, dirt, and microorganisms. Pay special attention to the drain pans, filter areas, curves, and air ducts since debris often collects in these places.

  • Disinfect all components of the HVAC system after turning off the HVAC system. To clean use 1 cup of normal household chlorine bleach mixed with a gallon of water, do not mix this with cleaning products containing ammonia.

  • Be sure to use fans to create filtration by blowing the contaminated air outdoors, to protect the health of the workers.

  • After cleaning all components with bleach rinse with clean water to eliminate the potent bleach smells.

    • Important: You must remove and properly discard the HVAC components that are contaminated with floodwater to prevent the growth of mold if it cannot be cleaned, and replace them with new components.



  • After the HVAC has been properly cleaned and disinfected, replace the insulation in the HVAC system with an external, smooth-surfaced insulation to prevent future floodwater contamination.

  • To ensure safety have you HVAC system tested by a qualified professional before you begin using your HVAC system again.

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