Mold & Moisture

This page contains educational material about Chronic Inflammatory Response Syndrome due to a water damaged building (CIRS). This is a biotoxin illness that is caused by mold and the interaction between mold, bacteria and chemicals used in building materials. Other biotoxin illnesses have similar signs and symptoms. They are also treated similarly. Some of them are discussed on this site. This information is for educational purposes only. Nothing in this text is intended to serve as medical advice. All medical decisions should be made only with the guidance of your own personal medical authority. I am doing my best to get this data up quickly and correctly. If you find errors in this data, please let me know.

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Much of the data on this page comes from United States EPA and CDC reccomendations. If you want to review all their extensive data, go to this CDC link. I have attempted to take their recommendations as well as other data that I think is important to know and compile it here on this page. It is a work in progress.

Mold is everywhere. You can't eliminate it completely or permanently. Mold is also necessary as if we did not have mold, we would not have compost, nothing would ever decay and we'd all be so buried in junk and debris that nothing could grow on the earth. But we don't much like to see mold indoors and certainly not on our walls, ceilings, or furniture.

Causes of Moisture Issues

Moisture problems can have many causes. Some moisture problems have been linked to changes in building construction practices since the 1970s. These practices led to buildings that are tightly sealed but, in some cases, lack adequate ventilation. Without adequate ventilation, moisture from daily living may build up indoors and mold may grow.

A building must be properly designed for climate, site location, and use, and its design must be accurately followed during construction or the building may have moisture issues.

Mold/bacteria can grow due to undiscovered or ignored moisture problems. Delayed or insufficient maintenance can also lead to mold/bacterial growth. Moisture problems in temporary structures, or structures used infrequently are more likely associated with mold problems.

Where to look for common moisture problems

Leaking roofs.
Leaking or condensing water pipes, especially pipes inside wall cavities.
Leaking fire-protection sprinkler systems.
Landscaping, gutters, and down spouts that direct water into or under a building.
High humidity (> 60% relative humidity).
Unvented combustion appliances such as clothes dryers vented into a garage, an attic or a crawl space. (Clothes dryers and other combustion appliances should be vented to the outside.)
Some moisture problems are not easy to see. For example, the inside of walls where pipes and wires are run (pipe and utility tunnels) are common sites of mold growth. Mold is frequently found on outer walls in cold corners behind furniture where condensation forms. Other possible locations of hidden moisture, resulting in hidden mold growth are:
Poorly draining condensate drain pans inside air handling units.
Porous thermal or acoustic liners inside duct work.
Roof materials above ceiling tiles.
The back side of drywall (also known as gypsum board, wallboard, or sheet rock®), paneling, and wallpaper.
The underside of carpets and pads.
Around sinks and showers/tubs

You may suspect mold, even if you can't see it, if a building smells moldy. You may also suspect hidden mold if you know there has been a water problem in the building and its occupants are reporting health problems.

Many buildings incorporate vapor barriers in the design of their walls and floors. Vapor barriers must be located and installed properly or the building may have moisture problems. A vapor barrier is a layer of material that slows or prevents the absorption or release of moisture from or into a wall or floor. Vapor barriers can prevent damp or wet building materials from drying quickly enough to prevent mold growth. For more information on building design see the Resource List.

Investigating Hidden Mold

This can be difficult and may require a professional with experience investigating water and mold-damaged buildings. Specialized equipment such as bore scopes and moisture meters, and in some cases special sampling techniques, may be helpful in locating and identifying hidden mold areas. Investigating hidden mold requires caution since disturbing moldy areas may spread mold throughout the building. Personal protective equipment is sometimes needed when looking for mold. If mold might be released into the air, investigators should use protective equipment to reduce exposure. This can include masks or respirators, and full body suits.



Sometimes, humidity or dampness (water vapor) in the air can supply enough moisture for mold growth. Indoor relative humidity should be kept below 60 percent — ideally between 30 percent and 50 percent, if possible. Low humidity has also been shown to discourage pests (such as cockroaches) and dust mites.

Humidity levels can rise in a building as a result of the use of humidifiers, steam radiators, moisture-generating appliances such as dryers, and combustion appliances such as stoves. Cooking and showering also can add to indoor humidity. Even breathing and sweating adds to humidity, especially when there are many people in the building.

One function of the building heating, ventilation, and air conditioning (HVAC) system is to remove moisture from the air before the air is distributed throughout the building. If the HVAC system is turned off during or shortly after major cleaning efforts that involve a lot of water, such as mopping and carpet shampooing or cleaning, the humidity may rise greatly, and moisture or mold problems may develop.

Condensation can be a sign of high humidity. When warm, humid air contacts a cold surface, condensation may form. (To see this, remove a cold bottle of water from a refrigerator and take it outside on a hot day. Typically, condensation will form on the outside of the bottle.) Humidity can be measured with a humidity gauge or meter.

Hygrometer: Relative Humidity Gauge

Tells you how much moisture is in your house. You can find these in an electronic gadget store. This is one I have used and had good luck with.

Dehumidify the air if you have high humidity in your house. (Check with a hygrometer.)

Dehumidifiers by EdgeStar

30 pint, 50 pint and 70 pint are all linked here.

HVAC Systems

Mold growing near the intake to an HVAC system indicates potential ventilation humidity problems. An HVAC system that is part of an identified moisture problem may also be a site of mold growth. Experience and professional judgment should be used when working with the HVAC system; consult a professional if needed.

The HVAC system has the potential to spread mold throughout a building. Known or suspected mold growth in HVAC ducts or other system components should be investigated and resolved promptly. If mold can be seen growing on the inside of hard surface ducts (e.g., ducts made of sheet metal), consider cleaning the ducts. There is an EPA guide Should You Have the Air Ducts in Your Home Cleaned?

If the HVAC system has insulation on the inside of the air ducts, and the insulation gets wet or moldy, it should be removed and replaced because the material cannot be cleaned effectively. (Personally, insulation inside an air duct that can get moist just seems silly. I would not buy such ductwork.) Please note that there are no antimicrobial products or biocides approved by EPA for use on lined ductwork.

Control Moisture- A Key Issue

Controlling moisture is the most effective way of keeping mold from growing in air ducts.

Steps to control moisture in ductwork include:
Promptly and properly repair any leaks or water damage.
Remove standing water under the cooling coils of air handlers by making sure the drain pans slope toward the drain and the drain is flowing freely.
Making sure ducts are properly sealed and insulated in all non-air-conditioned spaces so moisture due to condensation does not enter the system and the system works as intended. To prevent condensation, the heating and cooling system must be properly insulated.
Operating and maintaining any in-duct humidification equipment strictly according to the manufacturer's recommendations. (These systems worry me. I would not use them in my house.)
Make sure that carpets, drapes, furniture, and other furnishings are dried promptly after they have been cleaned.

Crawl Spaces
Crawl spaces where relative humidity is high are common sites of hidden mold growth, particularly if the crawl space has a bare earth floor. The soil will wick moisture, through capillary action, from moist to dry areas. The relative warmth of the crawl space will dry the soil by evaporation, adding this moisture to the air in the crawl space where it can cause mold to grow. Also, in areas where the water table is high and weather conditions are suitable, ground water may enter a crawl space.

The moisture that accumulates in a crawl space may also enter another part of the building and contribute to mold growth there. Moisture can pass from a crawl space into a building through cracks in walls, floors, and ceilings.

Crawl spaces should be designed specifically to avoid moisture problems. Most crawl spaces are vented. However, the new thought is that conditioned crawl spaces are a better way to go.

Crawl spaces should be designed and constructed to be dry. Crawl spaces should control rainwater, groundwater and provide drainage for potential plumbing leaks or flooding incidents. There should be a drying mechanism. One of the most effective ways to provide a drying mechanism to a crawl space is to condition a crawl space by heating and cooling the crawl space as if the crawl space is included as part of the home. Air must be supplied to the crawl space from the home in order to provide this conditioning. Although some contractors suggest returning this air back to the home, I would have it exhausted to the outside unless I was assured by the encapsulation system in the crawlspace that there was no way there would be any type of mold laden air in the crawl space returning to the inside of my home. Most homes do better with actively conditioned air to the crawl space from a heating system in the house. This becomes unnecessary if the house is in a dry climate or if the crawl space has free air flow with a conditioned basement space.

Crawl spaces must have a ground cover that prevents evaporation of ground moisture into the crawl space. One of the most common is 6 mil sheet polyethylene that has taped/sealed joints and that is attached to the crawl space perimeter walls. This ground cover must be continuous through piers and supports.

Crawl space perimeter walls, steps, rim joist areas and any other concrete or exposed masonry should be insulated with an insulation that prevents moisture in the air from accessing these surfaces and creating condensation.

For more details on conditioned crawl spaces check out this link. Also see the vapor barrier section below.

Drying Buildings, Building Materials, and Furnishings
Buildings and building furnishings will often get wet. They must be dried or "allowed to dry" quickly (within 24-48 hours) in order to avoid mold growth. In general, increasing air circulation and temperature will increase the speed of drying.

Commercial firms that do mold remediation work or work on water- and fire-damaged buildings often use large fans, dehumidifiers, and other equipment to dry wet buildings and items quickly before mold has a chance to grow. This action can save money in the long run, because if the building or furnishings are dried completely and quickly, mold will not grow, and a mold remediation will not be needed.

During a flood cleanup, the indoor air quality in your home or office may appear to be the least of your problems. However, failure to remove contaminated materials and to reduce moisture and humidity can present serious long-term health risks. Standing water and wet materials are a breeding ground for microorganisms, such as viruses, bacteria, and mold. They can cause disease, trigger allergic reactions, and continue to damage materials long after the flood.
Buildings that have been heavily damaged by flood waters should be assessed for structural integrity and remediated by experienced professionals.


Equipment to locate hidden moisture

Sometimes your eyes and nose are not enough to find hidden moisture.

Moisture Meters: Many investigators use moisture meters to find wet areas where mold may be growing. These meters measure the moisture in many types of building materials. They also can monitor the process of drying these materials. A moisture meter typically has a thin probe that can be inserted into the material to be tested or pressed directly against its surface. Moisture meters can be used on carpet, wallboard, wood, brick, and concrete. Because mold often grows where moisture is high, a moisture meter can help an investigator locate hidden areas of mold growth.

Borescopes: Some investigators use borescopes to look for mold growth behind walls without significantly damaging the drywall. (A borescope is an optical probe, inserted through a small hole drilled into a wall, that lets an investigator inspect a small portion of the wall without causing extensive damage.) High humidity in a building can lead to mold growth, so humidity gauges may be useful for checking or monitoring humidity throughout the building.



Dry items before mold grows, if possible. In most cases, mold will not grow if wet or damp items are dried within 24-48 hours.

To dry carpet and backing within 48 hours, remove water with a wet vacuum, pull the carpet and pad off the floor, and dry them using a fan to blow air over them. A dehumidifier can be used to reduce the humidity in the room where the carpet and backing are drying, while fans can be used to accelerate the drying process.

Water can be removed from concrete or cinder block surfaces with a water-extraction vacuum. The drying also can be accelerated by using dehumidifiers, fans, and heaters.

Hard surface flooring (such as linoleum, ceramic tile, and vinyl) should be vacuumed or damp wiped with a mild detergent and allowed to dry. They should be scrubbed clean, if necessary. If the under-flooring is wet, it should be dried using a vacuum or by exposing it to the air.

Non-porous, hard surfaces such as plastics and metals should be vacuumed or damp wiped with water and mild detergent, then allowed to dry. Scrubbing may be necessary to thoroughly clean the surfaces.

Water should be removed from upholstered furniture with a water-extraction vacuum. Fans, dehumidifiers, and heaters may be used to accelerate the drying process. Completely drying upholstered furniture within 48 hours may be difficult, so if the piece is valuable, you may consider consulting a restoration or water-damage professional who specializes in furniture.

Drywall, also known as gypsum board or gypsum wallboard, may be dried in place if there is no obvious swelling and the seams are intact. Otherwise, removal is necessary. The wall cavity is the most difficult area to dry, and it should be ventilated if drywall is left to dry in place. (Drywall is not made out of boards of wood; traditionally, drywall is made of the mineral gypsum with a layer of heavy paper on the outside and inside. Commercial gypsum boards and drywall are also available with a variety of outside layers and coatings. According to the U.S. Geological Survey, a typical new home contains more than 7 metric tons of gypsum.)

To clean water-damaged window drapes, follow the manufacturer's laundering or cleaning instructions.

To clean wooden surfaces, remove moisture immediately and use dehumidifiers, fans, and gentle heat to dry them. (Be very careful when applying heat to hardwood floors.) Treated or finished wood surfaces can be cleaned with mild detergent and clean water, then allowed to dry. Wet paneling should be pried from the wall for drying.
Some water-damaged items, including ceiling tiles, cellulose and fiberglass insulation, drywall and gypsum board, and books and papers, may have to be discarded. If valuable or important books, documents, or other items are moldy or water damaged, you may wish to consult a restoration, water damage, or remediation expert. (See Table 1 for more details. )
These guidelines are for damage caused by clean water. If you know or suspect that the water is contaminated with sewage, or with chemical or biological pollutants, then PPE and containment are required by OSHA. An experienced professional should be consulted if you or your remediators do not have expertise remediating in contaminated water situations. Do not use fans until you have determined that the water is clean or sanitary.


Avoid Mold Exposure
Do not touch mold or moldy items with your bare hands.
Do not get mold or mold spores in your eyes.
Avoid breathing in mold or mold spores.
Consider using PPE if disturbing mold during a building inspection, assessment, or walk through, for example. The minimum PPE is an N-95 respirator (available at most hardware stores), gloves, and goggles.
The highest priority in a remediation is to protect the health and safety of the building occupants and the remediation workers. Remediation plans vary according to the size and complexity of the job. They may require updating if circumstances change or more extensive contamination is discovered.
The remediation plan should include:
Whether containment will be required.
What level of PPE will be used.
How the water or moisture problem will be fixed so the mold problem does not recur. How the moldy building materials will be removed to avoid spreading mold.

Mold Remediation Procedures
A variety of methods are available to remediate damage to buildings and furnishings caused by moisture- control problems and mold. The procedures selected depend on the size of the moldy area and the type of contaminated materials. Budget may also be a concern. The methods presented in this section outline approaches that some professionals are using; other professionals may prefer to use different methods. Be aware that mechanical disturbance such as the agitation of moldy materials during demolition or cleaning can cause an extreme increase in the level of airborne spores and other fungal materials. If possible, remediation activities should be scheduled during off-hours, when building occupants are less likely to be affected.

General Cleanup methods may include:

Wet Vacuum

Wet vacuum (in the case of porous materials, some mold spores/fragments will remain in the material but will not grow if the material is completely dried). Steam cleaning may be an alternative for carpets and some upholstered furniture.

Wet, or water-extraction, vacuums
are designed to collect water. They can be used to remove water that has accumulated on floors, carpets, and hard surfaces. Wet vacuums should be used only when materials are still wet, otherwise they may spread mold spores. Wet vacuums alone will not dry carpets. Wet carpets must be pulled up and dried, then reinstalled. The carpet padding also must be dried. The tanks, hoses, and attachments of wet vacuums should be thoroughly cleaned and dried after use because mold and mold
spores may stick to their surfaces.

Damp Wipe

Damp-wipe surfaces with plain water or with water and detergent solution (except wood -use wood floor cleaner); scrub as needed.

Mold can generally be removed from hard surfaces by wiping or scrubbing with water and detergent. Always follow the cleaning instructions on product labels. Surfaces cleaned by damp wiping should be dried quickly and thoroughly to discourage further mold growth. Porous materials that are wet and have mold growing on them may have to be discarded. Because mold will infiltrate porous substances and grow on or fill in empty spaces or crevices, completely removing mold can be difficult, if not impossible. Mold can also cause staining and other cosmetic damage.

HEPA Vacuum

High-efficiency particulate air (HEPA) vacuum after the material has been thoroughly dried. Dispose of the contents of the HEPA vacuum in well-sealed plastic bags.

High-Efficiency Particulate Air (HEPA) vacuums
are recommended for the final clean up of remediation areas after materials have been thoroughly dried and contaminated materials have been removed. HEPA vacuums are also recommended for cleaning up dust that has settled outside the remediation area. When changing the vacuum filter, workers should wear PPE to prevent exposure to mold that has been captured in the vacuum. (See Lesson 4 in Chapter 6 of this course.) The filter and contents of the HEPA vacuum must be disposed of in well-sealed plastic bags. Care must be taken to ensure that the new filter is properly seated on the vacuum so there are no leaks.

Throw Away Damaged Materials

Discard and remove water-damaged materials. Seal them in plastic bags while inside of containment, if present. Dispose of as normal waste. HEPA vacuum area after it is dried.

Mold-contaminated building materials that cannot be salvaged should be double-bagged in 6-mil or thicker polyethylene bags. The bagged materials usually can be discarded as ordinary construction waste. Packaging mold-contaminated materials in sealed bags before removing them from the containment area is important to minimize the spread of mold spores throughout the building. Large items that have heavy mold growth should be covered with polyethylene sheeting and sealed with duct tape before being removed from the containment area.

Specific Types of Water Damaged Materials & Ideas on how to Dry them.

Books/Papers: The best thing to do is toss them. However, you can photocopy them or in some cases people have free-dried papers/books

Carpet and pad
: I suggest throwing them all away generally as they are so hard to clean and dry properly. However some people use water extraction vacuum and reduce the humidity created with a dehumidifier. Fans and heat can also be used to speed the process up.

Ceiling Tiles
: Discard and replace.

Cellulose Insulation: Discard and replace.

Concrete or Cinder Blocks: Remove water with water extraction vacuum. Dehumidifiers, heaters and fans can speed up the process.

Fiberglass insulation: Discard and replace

Hard surface porous flooring ( linoleum, ceramic tile, vinyl): Check to make sure the underflooring is dry. If not, it has to be dried also. If unable to dry quick enough, it will all have to be discarded. Vacuum or wipe up water as needed, use cleaner and scrub as necessary.

Nonporous, hard surfaces (plastics, metals): Vacuum or damp wipe with water and mild cleaner and scrub if necessary. Allow to dry.

Upholstered furniture: Remove water with water extraction vacuum. Dehumidifiers, heaters and fans can speed up the process. These may be hard to dry in the necessary 48 hours and in this case it should be discarded or you could consult a restoration/water damage professional who specializes in furniture.

Wallboard (drywall & Gypsum board): This is a touchy area. It depends on if just the outside of it is a bit moist or if there is water inside the wall. If water is in the wall, the wall cavity will need to be opened, and dried. If the wall cavity is dry and you can dry the entire wallboard all the way through in 48 hours, they go for it by using dehumidifiers, heaters and fans.

Window Drapes: Clean and launder as recommended by manufacturer.

Wood Surfaces: Remove all moisture quickly with fans, carefully applied heat (use caution when applying heat to a wood floor) and dehumidifiers. Make sure the subfloor is not wet. If it is, it will need to be dried within that 48 hour window. You (or a professional) may need to go under the floor to work on it.  If you have wet wood paneling, it should be pulled away from the wall to dry and make sure the material underneath is not wet also. If, so it too will need to be dealt with as well as the inside of the wall cavity if it too is wet.
If mold growth has occurred or materials have been wet for more than 48 hours, consult Table 2 guidelines. Even if materials are dried within 48 hours, mold growth may have occurred. Items may be tested by professionals if there is doubt. Note that mold growth will not always occur after 48 hours; this is only a guideline.


Personal Protective Equipment (PPE)

Limited: Gloves, N-95 respirator or half-face respirator with HEPA filter, disposable overalls, goggles/eye protection

Full: Gloves, disposable full body clothing, head gear, foot coverings, full-face respirator with HEPA filter


Limited: Use polyethylene sheeting ceiling to floor around affected area with a slit entry and covering flap; maintain area under negative pressure with HEPA filtered fan unit. Block supply and return air vents within containment area.

Full: Use two layers of fire-retardant polyethylene sheeting with one airlock chamber. Maintain area under negative pressure with HEPA filtered fan exhausted outside of building. Block supply and return air vents within containment area.

     Personal Protective Equipment (PPE)
The primary function of personal protective equipment (PPE) is to limit mold exposure.
If a remediation job disturbs mold, and mold spores then become airborne, the risk of respiratory exposure increases. Actions likely to stir up mold include breaking moldy porous materials such as wallboard, using invasive procedures to examine or remediate mold growth in wall cavities, stripping or peeling wallpaper to remove it, and using fans to dry items.

Gloves protect the skin from contact with mold. They also protect the skin from potentially irritating cleaning solutions. Long gloves that extend to the middle of the forearm are best.

The material from which gloves are made should be suited to the type of materials being handled. If you choose to use a biocide, such as quaternary ammonium chloride, chlorine bleach, hydrogen peroxide, or other strong cleaning solution, gloves should be made from natural rubber, neoprene, nitrile, polyurethane, or polyvinylchloride (PVC). (I am not a fan of PVC for environmental toxic reasons, but include it here as they are used.) If a mild detergent is being used, ordinary household rubber gloves are suitable. The routine use of biocides is not recommended.

Properly fitted goggles or full-face respirators provide eye protection. Goggles must be designed to keep out dust and small particles. Safety glasses or goggles that have open vent holes are not acceptable.

Respirators protect remediation workers from inhaling airborne mold, mold spores, and dust. Three types of respiratory protection are described: minimum, limited, and full. Only respirators approved by the National Institute for Occupational Safety and Health (NIOSH) should be worn during mold remediation. These respirators must be used according to any applicable Occupational Safety and Health Administration (OSHA) regulations.

Use minimum PPE when cleaning up a small area affected by mold (less than 10 square feet total). Minimum PPE includes gloves, goggles/eye protection and an N-95 respirator. An N-95 respirator covers the nose and mouth, filters out 95 percent of airborne particulates, and is available in most hardware stores. It does not provide eye protection.

Limited PPE includes the use of half-face or full-face air purifying respirators (APRs) equipped with P100 filter cartridges. These respirators have inhalation and exhalation valves that filter the air and ensure it is free of mold particles. The P100 filters do not remove vapors or gases, and the half-face APRs do not protect the wearer's eyes. Limited PPE may be warranted when the total surface area affected by mold is between 10 and 100 square feet. Professional judgment should be used to make the final determination about whether to wear limited PPE.

Full PPE includes a full-face, powered air purifying respirator (PAPR). It is recommended when more than 100 square feet of mold is found, when high levels of airborne dust or mold spores are likely, or when intense or long-term exposures are expected. A powered air purifying respirator uses a blower to force air through a P100 filter. The filtered air is supplied to a mask that covers the wearer's face or a hood that covers the entire head. Positive pressure within the hood prevents unfiltered air from entering through penetrations or gaps. Individuals must be trained to use their respirators before they begin remediation.
Disposable clothing is recommended for medium and large remediation projects. It prevents the transfer and spread of mold to clothing and eliminates skin contact with mold. When limited protection is warranted, disposable paper coveralls can be used. When full protection is required, a body suit of breathable material such as TYVEK and mold impervious disposable head and foot coverings should be used. All gaps, such as those around ankles and wrists, should be sealed. (Many remediators use duct tape to seal clothing.)

Remediating Large Areas of Mold Contamination

For large or complex mold remediation jobs, you may consider hiring professionals who have experience working on large mold remediation projects, particularly since extensive containment and PPE may be needed. Be sure to check references and ensure that the professional has experience working in mold remediation situations.

Containment should be designed to prevent the movement of mold spores from one area of the building to another. This effort usually requires full containment using double layers of polyethylene sheeting and fans to create negative air pressure. A decontamination chamber or airlock should be used to separate the clean areas from the contaminated areas during entry into and exit from the remediation area. The entryways to the airlock from the outside and from the airlock to the main containment area should consist of a slit with covering flaps on the outside surface of each entry. Contaminated PPE, except respirators, should be sealed in bags while inside the containment exit chamber. Workers should wear respirators until they are in the uncontaminated area, where the respirators can be removed. Disposable respirators can be thrown away and re-usable respirators can be put into a bag for cleaning. Full PPE may also be necessary during these operations and may consist of protective clothing and full-face or powered air purifying respirators (PAPR) with HEPA filters. Protective clothing should include head and foot coverings with all gaps sealed with duct tape or the equivalent.

  • Mold Remediation in Heating, Ventilation, and Air Conditioning (HVAC) Systems
  • Mold remediation involving a heating, ventilation, and air conditioning (HVAC) system should be done only by professionals experienced in working with HVAC systems. Professionals may have several different methods and techniques for approaching HVAC remediation. As with the rest of a mold remediation project, professional judgment is required when working with HVAC systems, and professionals may use materials, methods, and techniques not mentioned in this course.
  • An HVAC system found to be contaminated with mold should be turned off and not used until the system has been remediated; using a mold-contaminated HVAC system may spread mold throughout the building and increase the exposure of building occupants. (There may be some exceptions or instances when all or part or the HVAC system can be run, based on professional judgment, if there is no risk of increasing occupant or worker exposure). If possible, the HVAC system should be remediated during off hours when the building is not in use.
  • Effective containment of the area served by the ventilation system is important to avoid the spread of mold and mold-contaminated materials. All intakes and supply vents should be sealed with plastic and tape, and negative air pressure should be maintained in work areas. (A fan can be used.) Contaminated porous materials in the HVAC system should be bagged and removed. Materials that can be cleaned should be vacuumed with a HEPA vacuum or cleaned with a moist cloth and detergent solution. All items should be dried promptly.
  • Confined Spaces
  • Confined spaces include pipe chases (areas within and under buildings where steam and utility pipes are run) and valve pits (areas below grade that contain utility shut-off valves). Working in confined areas presents numerous challenges. Movement and communication are difficult and, if a problem arises, immediate exit from the area may be impossible.
  • The air in some confined spaces may be contaminated or low in oxygen, posing significant health risks for workers. Efficient rescue of an injured worker may be difficult or impossible. Poor lighting may result in increased injuries. Because exposures may be greatly magnified in a confined space, workers must use a higher level of PPE than they would when working in a more accessible area.
  • Worker safety must be carefully considered when deciding whether to use disinfectants or biocides because confined spaces may increase the potential for exposure. In general, work in confined spaces should be conducted only by trained professionals who have the equipment required by OSHA to deal with the inherent dangers in this type of environment.
  • Before remediating mold in a confined space, the area should be evaluated for atmosphere and toxic substances. If there is any chance of low oxygen, the area should be tested using the appropriate equipment. The testing equipment should be kept on site and used periodically to ensure an adequate oxygen supply. If the area is sealed off from the rest of the building to prevent the spread of mold spores, oxygen testing should be conducted again after the area has been sealed. A frequent contaminant in crawlspaces and pipe chases of older buildings is asbestos; other chemicals such as natural gas and solvents can also be found in some of these spaces. These materials must be identified and dealt with properly to prevent worker exposure.
  • Once the hazards have been identified, procedures for working in the confined space should be included in the remediation plan. Special consideration should be given to who will be allowed into the area, how communications will be maintained, what materials can be taken into or used in the space, and what safety equipment is necessary. Only individuals trained in the hazards associated with that space should be allowed to enter. An attendant should be posted outside of the confined space area to summon help if necessary. The area should be well lit so that work can be conducted efficiently and injuries avoided.
  • In conducting the mold remediation, every effort should be made to keep dust and mold out of the air. This can be done by using moist techniques, such as a damp cloth or pad, for mold removal and by bagging the material in the confined space for later removal. Mold levels are likely to be high in a confined space, so PPE should be selected accordingly. Most cases will require full PPE, including skin and eye protection, and full respiratory protection using a full-face respirator or a powered air purifying respirator (PAPR) with a HEPA filter. The presence of asbestos may require other PPE for workers as well as monitoring and medical evaluation.
  • Overview of Containment
    The goal of containment is to limit the spread of mold throughout the building in order to minimize the
  • exposure of remediators and building occupants to mold.
  • The larger the contaminated area, and the greater the possibility that someone will be exposed to mold, the greater the need for containment. Although, in general, the size of the contaminated area indicates the level of containment required, the final choice of containment level should be based on professional judgment. Heavy mold growth in a small area, for example, could release more mold spores than lighter growth in a relatively large area. In this case, the smaller contaminated area may warrant a higher level of containment.
  • Two types of containment are described in EPA's mold remediation guidance: limited and full. Limited containment is generally used for areas involving between 10 and 100 square feet of mold contamination. Full containment is used when areas larger than 100 square feet are to be remediated or in cases where it is likely that mold could be spread throughout the building during remediation. (See Table 2. )
  • Maintaining the containment area under negative pressure will keep contaminated air from flowing into adjacent, uncontaminated areas and possibly spreading mold. A fan exhausted to the outside of the building can be used to maintain negative air pressure. If the containment is working, the polyethylene sheeting of the containment area should billow inward on all surfaces. If it flutters or billows outward, containment has been lost, and the problem should be found and corrected before remediation continues.
  • Depending on the situation, professional remediators may choose to use a variety of containment methods not described in detail here. For example, a remediator repairing a large building with extensive mold damage in the walls may choose to remove the outside layer of the wall and work inward, relying on appropriate containment to ensure mold is not spread throughout the building. Or, to limit the amount of mold that gets into the air, a remediator may apply sticky-backed paper or covering to a moldy wall component before removing it.
  • Limited Containment
  • Limited containment consists of a single layer of 6-mil fire-retardant polyethylene sheeting enclosing the moldy area. Access to the contained area is through a slit entry covered by a flap on the outside of the containment area. Limited containment is generally recommended for areas involving 10 to 100 square feet of mold contamination.
  • In small areas, the polyethylene sheeting can be secured to the floor and ceiling with duct tape. In larger areas, a frame of steel or wooden studs can be built to hold the polyethylene sheeting. Epoxy can also be used to fasten the sheeting to the floor or ceiling.
  • All supply and air vents, doors, and pipe chases in the containment area must be sealed with polyethylene sheeting to minimize the spread of mold and mold spores to other areas of the building. Stairs should also be sealed if a riser is missing or open. (A pipe chase is an enclosure through which pipes are run; a riser is the upright piece of a stair step, from tread to tread.)
  • Heavy mold growth on ceiling tiles may affect HVAC systems if the space above the ceiling is used as a return air plenum. In such cases, containment would be installed from floor to ceiling deck. The filters in the air-handling units serving the affected area may have to be replaced once the remediation is complete.
  • Full Containment
  • Full containment is recommended for the clean up of mold-contaminated surface areas of more than 100 square feet and when intense or long-term exposures are expected. It is also recommended if it appears likely that the occupant's space would be further contaminated if full containment were not used because high levels of airborne dust or mold spores are likely. Full containment requires double layers of polyethylene sheeting to create a barrier between the moldy area and other parts of the building. A decontamination chamber or airlock—an area with doors between the contaminated area and the clean area—should be built for entry into and exit out of the remediation area.
  • The entryways from the outside into the airlock and from the airlock into the containment area should be slits covered by flaps on the outside surface. The chamber should be large enough to hold a waste container and allow a worker to put on and remove Personal Protective Equipment (PPE). All contaminated PPE, except respirators, should be placed in a sealed bag while in this chamber.
  • Respirators should be worn until remediation workers are outside the decontamination chamber.


Completing Mold Remediation

Fix the water problem and clean up the mold. How do you know when you have finished remediation that it is truly clean? Ultimately, it is a judgment call unless you retest it. People should be able to occupy or work in the building without health complaints or physical symptoms. The most important action, if mold growth is to be controlled in a building, is to eliminate the source of moisture that caused the mold problem. No matter how good the mold cleanup is, if the water problem is not solved, mold will return. Therefore, determining whether moisture in the building is being controlled is key in assessing the effectiveness of the remediation effort. If moisture is not being controlled, even removing all the mold growing in the building will be only a temporary solution.
A visual inspection of the area that has been remediated should show no evidence of present or past mold growth. There should be no moldy or musty odors associated with the building, because these odors suggest that mold continues to grow. If mold or moldy odors are present in the building, the remediation has not been effective.
Keep in mind that remodeling, cleaning, and construction may have introduced new building materials or chemicals capable of causing upper respiratory irritation that, in some individuals, may mimic the symptoms caused by exposure to mold.

Check out this site for very good assistance:

Evaluating The Remediation Job: Go to this link for testing data.


Keeping It Clean

Once it is remediated, you want to keep the mold down. Here are some ideas.

Passive Filters

A passive filter does not involve ozone or ionization or any creation of electric fields and for this reason some people feel more comfortable with them. They also will only clean the particles out of the air that happen to float through them. They will not clean surfaces in the room. There needs to be air movement in the room to get all the air to move through the filter or you will need to move the filter around to get best use out of them. Smaller areas will be best cleaned by a passive filter usually because of this limitation.

Hepa Filters: HEPA filters remove at most 99.97% of 0.3-micrometer particles, and are usually more effective for particles which are larger. HEPA purifiers which filter all the air going into a clean room must be arranged so that no air bypasses the HEPA filter. They will catch mold spores and they will be on filter. The filter can grow mold spores on the actual filters if there is enough humidity in the air and they are not changed often. They work effectively to filter particles of 0.03 microns or larger such as allergens from pets, dust, and larger smoke particles. They only clean the air and only in the amount of space they are designed to serve. They are designed for a small space usually. They do not clean the surfaces in your home. They are not effective at removing odors, gases, and chemicals due to their small particle size.

Electrostatic filters: Precipitate out charged particles and don't expose very much air to the process. Like the hepa filter they do not clean surfaces, they clean air. They can trap very small particles (0.01 microns) using charged plates. They have trouble moving enough air for effective indoor coverage and pollutant absorption.

Activated Carbon: Activated carbon is a porous material that can adsorb volatile chemicals on a molecular basis, but does not remove larger particles. These are able to use a very large surface area to attract and neutralize odors and pollutants. Rarely used by itself and when the filter gets full, it stops absorbing and needs to be replaced. These can be very safe for sensitive individuals to use. This is one I purchased upon the recommendation of a very sensitive person who said this filter was fantastic. It cleaned up the air of a friends brand new apartment they moved into that had smelled like a cacophony of chemicals prior to his using this filter. The thing that my friend and I both like about this product is that it is easier to clean the machine if it gets contaminated with mold or some other material. My friend had just moved out of a mold contaminated house and she could not clean the brand new hepa filters she had purchased and was therefore unable to take them with her. So if this is an issue for you, you might examine using this as a possible air filtration unit. This is an air filter I like.

Aireox Air Filters

Active Air Filtration/Cleaning

Ozone generation: Uses proven element found in nature that effectively cleans outside air. Need to be able to control generation level to keep output within EPA guidelines.

Ozone or O3, or "trioxygen" is a molecule made of three oxygen atoms. In this form, and referred to as an "allotrope" of oxygen, ozone is an unstable gas - that means it breaks down into oxygen molecules. Lightening generates ozone. Whenever an electrical spark or corona occurs in air, some ozone is formed. This is the characteristic odor noted near an operating electric motor such as a printer. Most people can detect ozone at a concentration of from 0.02 to 0.05 ppm. (parts ozone per million parts air)

While ozone is helpful in the upper atmosphere (filtering out UV light rays), in lower atmosphere, or in buildings, it is an air pollutant that is harmful to humans and other animals, and a gas that can oxidize or burn plants or various materials found indoors. So although it can be helpful if used appropriately. If used without proper education, you can hurt yourself, your animals or your belongings. Do not expose yourself, others, or any living things to ozone. Ozone can cause a variety of respiratory problems if it is above 0.05ppm and it is suggested that people should not be exposed to more than 0.1 ppm over an 8-hr day.

Additionally, you need to be aware that although ozone can clear up a variety of odors in buildings, when used in excess it can create new ones. When high levels of ozone have been produced in an enclosed space, people have found that other materials in the space become partly oxidized. This can give off chemical-like odors. It appears that oxidation of furniture, curtains, paint, carpeting, carpet pad and other types of materials causes a new odor problem in this case. So, over use of ozone can create additionally air quality problems and can destroy your belongings. This odors seem to be especially problematic with synthetic objects. However, too much ozone can oxidize all objects, so just because your organic cotton drapes are not putting off bad odors into the air, it does not mean they can't get damaged. So, again you have to know what you are doing and be careful.

Ozone is really useful for cleaning up nasty smelling rooms, killing viruses, and bacteria, but not for killing mold. These can be useful after you have done all the cleaning and remediating of mold properly and you want to get the last little bit of residual mold spores etc that are still bothering you. It can be useful for sensitive individuals living in a home that has been properly remediated but still bothers them. They then use ozone and it can help immensely. They can also be used to clean smells out of your car and even possibly your HVAC system depending on how big it is. Do not think it will remove physical damage. You need to first do the physical remediation. However, this can be helpful after that has been done.

What is important with an ozone generator is to know how much space you need to ozonate and then to pick a generator that can put out enough ozone to get up to 10 parts per million of ozone as that is the amount necessary to kill off mold spores. You want to think about the amount of ozone that is being pumped out being adequate for the area as well as the fan being adequate to move the ozone around the area. If not you will need to add an outside fan to move the ozone around. It won't do you any good if it is not moved into the whole area. Also be aware that ozone is heavy and will fall towards the floor. Additionally be aware that the levels of ozone that are active to reduced smells are not safe for you to be around. However, you will need to start the machine and may need to move the device before it turns off. Protect yourself when you do this. If you are temporarily in a room with a machine running, be sure to wear an adequate mask as ozone is hazardous to your health. Wait for the ozone smell to leave a room before entering it. If you need to use a room quickly, open the windows to air the room out before use.

Be aware that some of the sellers are saying their machines cover larger areas than they really do.

How to use an ozone machine. Put it up high if possible as ozone is heavier than the air around it and will tend to go down. Some machines come with a hook to hang it. Sometimes people use furniture or a ladder to put it up high. What ever you do, make sure it is safe. There are some machines that come with attachments that allow you to use them directly into carpeting, upholstery or to put the arm attachment down your cool air return of the HVAC system. Bio3Blaster is set up this way. The one that I decided to go with is a small machine with a powerful capacity from New Age Living on Ebay.

Warning: The necessary concentrations to kill bacteria, viruses and mold are toxic enough to humans and animals that the FDA declared that ozone has no place in medical treatment and has taken action against businesses that violate this regulation by offering therapeutic ozone generators or ozone therapy. Ozone is a highly toxic and extremely reactive gas. A higher daily average than 0.1 ppm (0.2 mg/m³) is not recommended and can damage the lungs and olfactory bulb cells directly. This is why you should never be in an area with ozone being generated and must wait until the ozone is gone before entering such an area. There are masks that can be used to turn ozone machines on or if you are using them. Only use masks that are made specifically to protect you from ozone. My advise is simply to stay away from any and all ozone if you are using it to clean up a car, or indoor area.

Ionization: An air ionizer (or negative ion generator or "Chizhevsky's chandelier") is a device that uses high voltage to ionize (electrically charge) air molecules. Negative ions, or anions, are particles with one or more extra electrons, conferring a net negative charge to the particle. Ionization removes particles using negatively charged or both negatively and positively charged ions. Particles tend to fall out of the air and stick to walls and other items in a room. Particles are not always taken cleanly out of the air. Airborne particles are attracted to the electrode in an effect similar to static electricity. These ions are demonized by seeking earthed conductors, such as walls and ceilings. To increase the efficiency of this process, some commercial products provide such surfaces within the device. The frequency of nosocomial infections in British hospitals prompted the National Health Service (NHS) to research the effectiveness of anions for air purification, finding that repeated airborne acinetobacter infections in a ward were eliminated by the installation of a negative air ionizer—the infection rate fell to zero. There are no specific standards for these devices.

Ionizers should not be confused with ozone generators, even though both devices operate in a similar way. Ionizers use electrostatically charged plates to produce positively or negatively charged gas ions (for instance N2− or O2−) that particulate matter sticks to in an effect similar to static electricity. Sometimes ozone generators are optimized to attract an extra oxygen ion to an O2 molecule, using either a corona discharge tube or UV light. Even the best ionizers will produce a small amount of ozone. However, current belief is that it is a small enough amount that it is not harmful.

Polarized-Media Electronic Air Cleaners: These use an active electronically-enhanced media to combine elements of both electronic air cleaners and passive mechanical filters. Most Polarized-Media Electronic Air Cleaners convert 24 volt current to safe DC voltage to establish the polarized electric field. Airborne particles become polarized as they pass through the electric field and adhere to a disposable fiber media pad. Ultra-fine particles (UFPs) that are not collected on their initial pass through the media pad are polarized and agglomerate to other particles, odor and VOC molecules and are collected on subsequent passes. The efficiency of Polarized-Media Electronic Air Cleaners increases as they load, providing high efficiency filtration with air resistance typically equal to or less than passive filters. Polarized-media technology is non-ionizing which means no ozone is produced.

Photocatalytic oxidation systems (PCO): PCO's are able to completely oxidize and degrade organic contaminants. For example, Volatile Organic Compounds found low concentrations within a few hundred ppmv or less are the most likely to be completely oxidized. PCO uses short-wave ultraviolet light (UVC), commonly used for sterilization, to energize the catalyst (usually titanium dioxide (TiO2) and oxidize bacteria and viruses. Photo Catalytic Oxidation - uv light shines on a titanium oxide plate and that interaction with light and the plate produces hydroxyl radicals, hydroperoxide ions, and super oxide ions that interact with the environment to purify it similar to how nature does.

You might check out this link here about air purifiers that Dr. Mercola provides.

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