TRG ENVIRONMENTAL SERVICES

"An Authorized Service Provider of The Home Depot"

ESTABLISHED NOVEMBER 11, 1996

 

 

Moisture Control is the Key to Mold Control

INVESTIGATING, EVALUATING, AND REMEDIATING MOISTURE AND MOLD PROBLEMS

Sampling

Is sampling for mold needed? In most cases, if visible mold growth is present, sampling is unnecessary. In specific instances, such as cases where litigation is involved, the source(s) of the mold contamination is unclear, or health concerns are a problem, you may consider sampling as part of your site evaluation. Surface sampling may also be useful in order to determine if an area has been adequately cleaned or remediated. Sampling should be done only after developing a sampling plan that includes a confirmable theory regarding suspected mold sources and routes of exposure. Figure out what you think is happening and how to prove or disprove it before you sample!

If you do not have extensive experience and/or are in doubt about sampling, consult an experienced professional. This individual can help you decide if sampling for mold is useful and/or needed, and will be able to carry out any necessary sampling. It is important to remember that the results of sampling may have limited use or application. Sampling may help locate the source of mold contamination, identify some of the mold species present, and differentiate between mold and soot or dirt. Pre- and post-remediation sampling may also be useful in determining whether remediation efforts have been effective. After remediation, the types and concentrations of mold in indoor air samples should be similar to what is found in the local outdoor air. Since no EPA or other Federal threshold limits have been set for mold or mold spores, sampling cannot be used to check a building's compliance with Federal mold standards.

Sampling for mold should be conducted by professionals with specific experience in designing mold sampling protocols, sampling methods, and interpretation of results. Sample analysis should follow analytical methods recommended by the American Industrial Hygiene Association (AIHA), the American Conference of Governmental Industrial Hygienists (ACGIH), or other professional guidelines (see Resources List). Types of samples include air samples, surface samples, bulk samples (chunks of carpet, insulation, wall board, etc.), and water samples from condensate drain pans or cooling towers.

A number of pitfalls may be encountered when inexperienced personnel conduct sampling. They may take an inadequate number of samples, there may be inconsistency in sampling protocols, the samples may become contaminated, outdoor control samples may be omitted, and you may incur costs for unneeded or inappropriate samples. Budget constraints will often be a consideration when sampling; professional advice may be necessary to determine if it is possible to take sufficient samples to characterize a problem on a given budget. If it is not possible to sample properly, with a sufficient number of samples to answer the question(s) posed, it would be preferable not to sample. Inadequate sample plans may generate misleading, confusing, and useless results.

Keep in mind that air sampling for mold provides information only for the moment in time in which the sampling occurred, much like a snapshot. Air sampling will reveal, when properly done, what was in the air at the moment when the sample was taken. For someone without experience, sampling results will be difficult to interpret. Experience in interpretation of results is essential.

 
Moisture Control is the Key to Mold Control

INVESTIGATING, EVALUATING, AND REMEDIATING MOISTURE AND MOLD PROBLEMS

How Do You Know When You Have 
Finished Remediation/Cleanup?

  1. You must have completely fixed the water or moisture problem.
  2. You should complete mold removal. Use professional judgment to determine if the cleanup is sufficient. Visible mold, mold-damaged materials, and moldy odors should not be present.
  3. If you have sampled, the kinds and concentrations of mold and mold spores in the building should be similar to those found outside, once cleanup activities have been completed.
  4. You should revisit the site(s) shortly after remediation, and it should show no signs of water damage or mold growth.
  5. People should be able to occupy or re-occupy the space without health complaints or physical symptoms.
  6. Ultimately, this is a judgment call; there is no easy answer.

Moisture Control is the Key to Mold Control

CHECKLIST FOR MOLD REMEDIATION

Investigate and evaluate moisture and mold problems
bulletAssess size of moldy area (square feet)
bulletConsider the possibility of hidden mold
bulletClean up small mold problems and fix moisture problems before they become large problems
bulletSelect remediation manager for medium or large size mold problem
bulletInvestigate areas associated with occupant complaints
bulletIdentify source(s) or cause of water or moisture problem(s)
bulletNote type of water-damaged materials (wallboard, carpet, etc.)
bulletCheck inside air ducts and air handling unit
bulletThroughout process, consult qualified professional if necessary or desired

Communicate with building occupants at all stages of process,
as appropriate

bulletDesignate contact person for questions and comments about medium or large scale remediation as needed

Plan remediation

bulletAdapt or modify remediation guidelines to fit your situation; use professional judgment
bulletPlan to dry wet, non-moldy materials within 48 hours to prevent mold growth (see Table 1 and text)
bulletSelect cleanup methods for moldy items (see Table 2 and text)
bulletSelect Personal Protection Equipment - protect remediators (see Table 2 and text)
bulletSelect containment equipment - protect building occupants (see Table 2 and text)
bulletSelect remediation personnel who have the experience and training needed to implement the remediation plan and use Personal Protection Equipment and containment as appropriate

Remediate moisture and mold problems

bulletFix moisture problem, implement repair plan and/or maintenance plan
bulletDry wet, non-moldy materials within 48 hours to prevent mold growth
bulletClean and dry moldy materials (see Table 2 and text)
bulletDiscard moldy porous items that can't be cleaned (see Table 2 and text)

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* For details, see main text of this publication. Please note that this checklist was designed to highlight key parts of a school or commercial building remediation and does not list all potential steps or problems.

* The printed version of this document has an additional copy of this checklist in a pocket in the back.

 
Moisture Control is the Key to Mold Control

TABLE 1

INVESTIGATING, EVALUATING, AND REMEDIATING MOISTURE AND MOLD PROBLEMS

Equipment

Moisture Meters: Measure/Monitor Moisture Levels in Building Materials

Moisture meters may be helpful for measuring the moisture content in a variety of building materials  following water damage. They can also be used to monitor the process of drying damaged materials. These direct reading devices have a thin probe which can be inserted into the material to be tested or can be pressed directly against the surface of the material. Moisture meters can be used on materials such as carpet, wallboard, wood, brick, and concrete.

Moisture Meter

photo9_1.jpg

[Click on image for larger picture]
Photo 9: Moisture meter measuring moisture content of plywood subfloor

 

Humidity Gauges or Meters:  Monitor Moisture Levels in the Air

Humidity meters can be used to monitor humidity indoors. Inexpensive (<$50) models are available that monitor both temperature and humidity.

Humidistat: Turns on HVAC System at Specific Relative Humidity (RH)

A humidistat is a control device that can be connected to the HVAC system and adjusted so that, if the humidity level rises above a set point, the HVAC system will automatically come on.

HVAC System Filter: Filters Outdoor Air

Use high-quality filters in your HVAC system during remediation. Consult an engineer for the appropriate efficiency for your specific HVAC system and consider upgrading your filters if appropriate. Conventional HVAC filters are typically not effective in filtering particles the size of mold spores. Consider upgrading to a filter with a minimum efficiency of 50 to 60% or a rating of MERV 8, as determined by Test Standard 52.2 of the American Society of Heating, Refrigerating, and Air Conditioning Engineers. Remember to change filters regularly and change them following any remediation activities.

Moisture Control is the Key to Mold Control

INVESTIGATING, EVALUATING, AND REMEDIATING MOISTURE AND MOLD PROBLEMS

Table 2: Mold Remediation Guidelines (7)

Table 2 presents remediation guidelines for building materials that have or are likely to have mold growth. The guidelines in Table 2 are designed to protect the health of occupants and cleanup personnel during remediation. These guidelines are based on the area and type of material affected by water damage and/or mold growth.  Please note that these are guidelines; some professionals may prefer other cleaning methods.

Mold and Indoor Air Regulations and Standards
Standards or Threshold Limit Values (TLVs) for airborne concentrations of mold, or mold spores, have not been set. As of December 2000, there are no EPA regulations or standards for airborne mold contaminants.
If you are considering cleaning your ducts as part of your remediation plan, you should consult EPA's publication entitled, Should You Have the Air Ducts In Your Home Cleaned?(8) (see Resources List). If possible, remediation activities should be scheduled during off-hours when building occupants are less likely to be affected.

Although the level of personal protection suggested in these guidelines is based on the total surface area contaminated and the potential for remediator and/or occupant exposure, professional judgment should always play a part in remediation decisions. These remediation guidelines are based on the size of the affected area to make it easier for remediators to select appropriate techniques, not on the basis of health effects or research showing there is a specific method appropriate at a certain number of square feet. The guidelines have been designed to help construct a remediation plan. The remediation manager will then use professional judgment and experience to adapt the guidelines to particular situations. When in doubt, caution is advised. Consult an experienced mold remediator for more information.

In cases in which a particularly toxic mold species has been identified or is suspected, when extensive hidden mold is expected (such as behind vinyl wallpaper or in the HVAC system), when the chances of the mold becoming airborne are estimated to be high,

Health Concerns
If building occupants are reporting serious health concerns, you should consult a health professional.
or sensitive individuals (e.g., those with severe allergies or asthma) are present, a more cautious or conservative approach to remediation is indicated. Always make sure to protect remediators and building occupants from exposure to mold.

 

Table 2: Guidelines for Remediating Building Materials 
with Mold Growth Caused by Clean Water*
Material or Furnishing Affected  Cleanup Methods† Personal Protective Equipment Containment

SMALL - Total Surface Area Affected Less Than 10 square feet (ft2)
Books and papers   3 Minimum

N-95 respirator, gloves, and goggles

 None required
Carpet and backing  1, 3 
Concrete or cinder block  1, 3 
Hard surface, porous flooring (linoleum, ceramic tile, vinyl)  1, 2, 3
Non-porous, hard surfaces (plastics, metals)  1, 2, 3 
Upholstered furniture & drapes  1, 3 
Wallboard (drywall and gypsum board)  3 
Wood surfaces  1, 2, 3

MEDIUM - Total Surface Area Affected Between 10 and 100 (ft2)
Books and papers   3 Limited or Full

Use professional judgment, consider potential for remediator exposure and size of contaminated area

 

 Limited

Use professional judgment, consider potential for remediator/occupant exposure and size of contaminated area

 
Carpet and backing  1,3,4
Concrete or cinder block 1,3
Hard surface, porous flooring (linoleum, ceramic tile, vinyl)  1,2,3
Non-porous, hard surfaces (plastics, metals)  1,2,3
Upholstered furniture & drapes  1,3,4
Wallboard (drywall and gypsum board)  3,4
Wood surfaces  1,2,3

LARGE - Total Surface Area Affected Greater Than 100 (ft2) or Potential for 
Increased Occupant or Remediator Exposure During Remediation  Estimated to be Significant
Books and papers   3 Full

Use professional judgment, consider potential for remediator/occupant exposure and size of contaminated area

 

 Full

Use professional judgment, consider potential for remediator exposure and size of contaminated area

 
Carpet and backing  1,3,4
Concrete or cinder block 1,3
Hard surface, porous flooring (linoleum, ceramic tile, vinyl)  1,2,3,4
Non-porous, hard surfaces (plastics, metals)  1,2,3
Upholstered furniture & drapes  1,2,4
Wallboard (drywall and gypsum board)  3,4
Wood surfaces  1,2,3,4

Table 2 continued
*Use professional judgment to determine prudent levels of Personal Protective Equipment and containment for each situation, particularly as the remediation site size increases and the potential for exposure and health effects rises. Assess the need for increased Personal Protective Equipment, if, during the remediation, more extensive contamination is encountered than was expected. Consult Table 1 if materials have been wet for less than 48 hours, and mold growth is not apparent. These guidelines are for damage caused by clean water. If you know or suspect that the water source is contaminated with sewage, or chemical or biological pollutants, then the Occupational Safety and Health Administration (OSHA) requires PPE and containment. An experienced professional should be consulted if you and/or your remediators do not have expertise in remediating contaminated water situations.

†Select method most appropriate to situation. Since molds gradually destroy the things they grow on, if mold growth is not addressed promptly, some items may be damaged such that cleaning will not restore their original appearance. If mold growth is heavy and items are valuable or important, you may wish to consult a restoration/water damage/remediation expert. Please note that these are guidelines; other cleaning methods may be preferred by some professionals.

Cleanup Methods

bullet Method 1: 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.
bullet Method 2: Damp-wipe surfaces with plain water or with water and detergent solution (except wood —use wood floor cleaner); scrub as needed.
bullet Method 3: 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.
bullet Method 4: Discard _ remove water-damaged materials and seal in plastic bags while inside of containment, if present. Dispose of as normal waste. HEPA vacuum area after it is dried.

Personal Protective Equipment (PPE)

bulletMinimum: Gloves, N-95 respirator, goggles/eye protection
bulletLimited: Gloves, N-95 respirator or half-face respirator with HEPA filter, disposable overalls, goggles/eye protection
bulletFull: Gloves, disposable full body clothing, head gear, foot coverings, full-face respirator with HEPA filter

Containment

bulletLimited: 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.
bulletFull: 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.

Table developed from literature and remediation documents including Bioaerosols: Assessment and Control (American Conference of Governmental Industrial Hygienists, 1999) and IICRC S500, Standard and Reference Guide for Professional Water Damage Restoration, (Institute of Inspection, Cleaning and Restoration, 1999); see Resources List for more information

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7 Please note that Tables 1 and 2 contain general guidelines. Their purpose is to provide basic information for remediation managers to first assess the extent of the damage and then to determine whether the remediation should be managed by in-house personnel or outside professionals. The remediation manager can then use the guidelines to help design a remediation plan or to assess a plan submitted by outside professionals.

8 Although this document has a residential focus, it is applicable to other building types.