Damp Indoor Spaces and Health (2004) / Chapter Skim
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6 Prevention and Remediation of Damp Indoor Environments
6 Prevention and Remediation of Damp Indoor Environments
Pages 270-310
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From page 270... ...
Every organism has strategies for locating a hospitable environment, obtaining water and nutrients, and reproducing. Intervention in one or more of those strategies can improve the resistance of the environment against microbial contamination.
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From page 271... ...
. For example, moving people during intense remediation activities is an intervention that involves occupants, removing fungal growth and remediating the moisture problem are interventions that involve the source, depressurizing a moldy crawl space with fan-powered exhaust intervenes in the transport mecha
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From page 272... ...
For containment, the guidelines recommended that air-handling equipment be turned off during remediation. The 1992 booklet Repairing Your Flooded Home published by the American Red Cross and the Federal Emergency Management Agency provided guidance for drying, cleaning, and rebuilding a flood-damaged home but did not specifically address mold growth or exposure to dampnessrelated contaminants (ARC and FEMA, 1992)
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From page 273... ...
The second half of the document provided guidance for containment, worker protection, and training requirements for abatement personnel. Four levels of contamination were described, and identifying and eliminating the moisture source supporting mold growth was required for all four levels.
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From page 274... ...
• The underlying moisture condition supporting mold growth should be identified and eliminated. Only the International Society of Indoor Air Quality and Climate (ISIAQ)
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From page 275... ...
The original NYCDOH guidance requires the use of biocides, whereas ISIAQ suggests it for hard surfaces. Only two of the documents -- those of ISIAQ and ACGIH -- discuss the prevention of mold growth in buildings to any substantial degree.
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From page 276... ...
276 DAMP INDOOR SPACES AND HEALTH TABLE 6-1 Comparison of Seven Mold-Remediation Guidance Documents Flannigan and NYCDOH, Health Canada, Morey, 1996 1993 1995 (ISIAQ) General Guidance specific Fairly In addition to to Stachybotrys comprehensive remediation atra; earliest best- discussions with guidance, problem practice cohesive logic tree moisture sources remediation for assessment and and indoor fungal document to give remediation of ecology receive guidance on indoor microbial substantial selecting contamination treatment containment and worker protection Process Summary of Sections written by Written by recommendations members of members of Task from expert panel federal-provincial Group 1, working group after International literature review Society of Indoor Air Quality and Climate ASSESSMENT Triggering events Visible mold, Not specifically Not specifically water damage, identified but by identified, but by symptoms implication visible implication consistent with mold growth, observation of exposure accumulations of sampling that bird droppings, or confirms evidence of fungal colonization by growth from mold, mites, or sampling bacteria Health assessment Conditional; brief Conditional/ No specific discussion extensive coverage discussion of assessment included Visual inspection Required; identify Required; extensive and building extent of mold coverage history growth and water damage Intrusive Not discussed Conditional; inspection cautions on disturbance Fungal Bulk sampling to Conditional; sampling document S
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From page 277... ...
PREVENTION AND REMEDIATION 277 ACGIH, 1999 NYCDOH, 2000 U.S. EPA, 2001 AIHA, 2001 Most extensive Expands original Primarily schools and Reviews existing discussions of scope from single commercial buildings; guidance, basis for health effects, species to molds in has specific section on recommendations, sampling strategies, general; provides planning remediation information gaps, and data analysis detailed guidance and specific remediation and recommenda on assessments, methods for different tions for 11 key containment, and materials issues worker protection Written by Based on literature Prepared by Indoor Review of existing members of review and Environments Division guidance by Bioaerosols comments from of EPA; internal and Microbial Growth Committee of expert review panel external review process Task Force of ACGIH AIHA; minority report included Visible fungal Presence of mold, Not specifically Consensus of growth identified water damage, or identified, but by published guidance: in remediation musty odors implication visible visible mold growth section; other identified in mold growth and moisture sections give assessment section damage; hidden insight into medical growth may be and environmental important but may sampling not be immediately obvious Conditional; Conditional; brief Conditional; brief Not covered extensive coverage discussion reference Required; extensive Required; brief Assumed; brief Not specifically coverage discussion reference covered but implicit in many sections Brief discussion; Brief reference Discussion of hidden Includes appendix cautions on mold; caution on on making holes; disturbance disturbance cautions on spore release Conditional; Conditional; part of Conditional; part of Discusses dust extensive coverage medical evaluation, medical evaluation, sampling and cavity for many methods suspect HVAC suspect hidden mold, sampling; other contamination, litigation methods extensively suspect hidden mold discussed in AIHA, 1996 (continued on next page)
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From page 278... ...
(0.2–3.0 m 2) Containment Bag refuse; cover Clean before Bag refuse; local adjoining surfaces removal containment; with poly HEPA-filtered exhaust air Worker Full respiratory Half-face Proper respiratory protection protection; respirators and protection 29 CFR 191O.134 gloves Training Building Trained personnel Building maintenance with maintenance some mold- personnel cleanup training
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From page 279... ...
; 29 CFR 1910.134 judgment worker protection Building Not covered based on ACGIH maintenance with recommendations; some mold-cleanup health evaluation of training workers advised by NYCDOH (2000) recommended Moderate 10–30 ft2 10–100 ft 2 Local; HEPA- Vacate and cover Poly sheeting around filtered exhaust work area with poly; area; HEPA-filtered air dust suppression; exhaust air; block bag refuse; HEPA- HVAC vacuum and damp wipe area N95 mask, full- N95 mask, gloves, N95 mask or half-face body covering and eye; HEPA coverall, eye and eye 29 CFR 1910.134 Building Not covered maintenance with some mold-cleanup training (continued on next page)
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From page 280... ...
280 DAMP INDOOR SPACES AND HEALTH TABLE 6-1 continued Flannigan and NYCDOH, Health Canada, Morey, 1996 1993 1995 (ISIAQ) Area 3 >30 ft2 >108 ft 2; area >32 ft2 between 32 and 108 ft2 does not seem to be directly addressed Containment Full; HEPA- Full; HEPA-filtered Full; HEPA filtered exhaust exhaust air; critical filtered exhaust air; critical barriers; airlocks; air; critical barriers, airlocks; HVAC barriers; air locks; HVAC HVAC Worker Full-face HEPA, Full-face HEPA, Full-face HEPA, protection coverall, and eye coverall, and eye coverall, and eye implied but not specified Training Hazardous waste Trained personnel Hazardous waste Area 4 NA NA NA Containment Worker protection Training HVAC Containment Full; HEPA- Unclear Depends on area filtered exhaust as above air; critical barriers; airlocks; HVAC
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From page 281... ...
PREVENTION AND REMEDIATION 281 ACGIH, 1999 NYCDOH, 2000 U.S. EPA, 2001 AIHA, 2001 Extensive; 30–100 ft 2 >100 ft2 references NYCDOH, 1993 and Flannigan and Morey, 1996; does not define areas Full; HEPA- Vacate work and Full; HEPA-filtered filtered exhaust adjacent areas; cover exhaust air; critical air; critical work area and barriers; air locks; barriers; HVAC directly adjacent HVAC areas with poly; seal HVAC openings; bag refuse; dust suppression; HEPA vacuum and damp wipe area; upgrade to next level of protection if dust will be raised N95 mask, N95 mask, gloves, Full-face HEPA, coverall, and eye; coverall, and eye and eye 29 CFR 1910.134 Hazardous waste Hazardous waste NA >100 ft2 NA Oversight by health and safety professional; vacate work area; full containment; HEPA filtered exhaust air; critical barriers; airlocks; HVAC Full-face HEPA, coverall, and eye Hazardous waste Depends on area <10 ft same as Area Refers to EPA as above; specific 2; >10 ft2 same as document Should You guidance for Area 4 Have the Air Ducts in cooling towers Your Home Cleaned?
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From page 282... ...
282 DAMP INDOOR SPACES AND HEALTH TABLE 6-1 continued Flannigan and NYCDOH, Health Canada, Morey, 1996 1993 1995 (ISIAQ) Worker Full-face HEPA, Unclear Depends on area protection coverall, and eye as above Training Hazardous waste Unclear Depends on area as above Remediating Not directly HEPA-vacuum; HEPA-vacuum; hard surfaces discussed damp-wipe damp-wipe; and semiporous disinfect Remediating Discard Discard Discard porous contaminated materials absorbent materials Biocide use Required use of Discouraged or Suggested for bleach to clean conditional; use hard surfaces areas adjacent to charcoal filters in contaminated respirators areas; cautions on use of chlorine dioxide or ozone in HVAC systems Clearance Air monitoring Not specifically Surfaces cleaned for >30 ft2 and covered; everything until only HVAC must be cleaned background fungi and bacteria remain; materials dry
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From page 283... ...
PREVENTION AND REMEDIATION 283 ACGIH, 1999 NYCDOH, 2000 U.S. EPA, 2001 AIHA, 2001 Depends on area <10 ft2 same as Area as above 2; >10 ft2 same as Area 4 Depends on area <10 ft2 same as Area as above; refers 2; >10 ft2 same as to NADCA and Area 4 EPA;cautions against biocide use Clean; discard if Damp-wipe with Specific guidance for HEPA-vacuum, physically detergent solution different materials: damp-wipe, or damaged wet-vacuuming, scrub as needed; damp-wiping, discard damaged HEPA-vacuuming materials or discarding Discard Discard with See above Discard contaminated exceptions material; wash or HEPA-vacuum materials that may harbor spores Comprehensive Refers to ACGIH, Discussion; discouraged Discouraged or use discussion; 1999; recommends or use with caution with caution discouraged or detergent solutions; use with caution prohibits gaseous ozone and chlorine dioxide Visual; possible All areas left dry Judgment call; water Recommends sampling and visibly free of source fixed; dry and documenting contamination and free of visible mold; successful debris; air monitor- reoccupying produces intervention in ing for areas no complaints; if air moisture source, >100 ft2 samples have been containment, taken, differential cleaning, removal, interpretation completeness, final surface dusting, and use of HEPA vacuum (continued on next page)
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From page 284... ...
respiratory protection standard. A minority report in the AIHA document raises concerns about treating all molds as hazardous substances and the consequent recommendations for decontamination, worker protection, containment, and disposal.
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From page 285... ...
-- Establish appropriate containment and worker and occupant protection. -- Eliminate or limit moisture sources and dry the materials.
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From page 286... ...
A remediation-assessment consultant may determine whether fungal growth has occurred and what actions are required. Remediation contractors may set up the appropriate containment, remove some contaminated materials, and clean up materials that can be salvaged.
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From page 287... ...
. Some of the guidance documents recommend removing people who are more sensitive to fungal contaminants from buildings during remediation activities.
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From page 288... ...
Because mold problems are also moisture problems, understanding how water behaves in buildings is a valuable component of the inspection. Some remediation-guidance documents base worker protection and containment recommendations on the area of visible mold growth (Flannigan and Morey, 1996; Health Canada, 1995; NYCDOH, 1993, 2000)
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From page 289... ...
. A number of methods can be used to augment the ability to find hidden mold, for example, moisture meters, bulk or surface samples to identify organisms that are contaminating materials, and air samples of rooms, cavities, and outdoor air to identify fungal spores.
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From page 290... ...
To reduce the necessity for large openings and to limit the release of fungal spores, inspectors have developed several methods to detect fungal growth and to predict where it is most likely to occur. As already noted, wall or ceiling cavities that have visible signs of moisture damage, produce increased moisture-meter readings, or yield positive moisture-assessment test results are areas where inspectors will concentrate their efforts.
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From page 291... ...
Culturable samples can be used to identify to the species level, but species that compete poorly may be missed. A number of studies have compared indoor spore concentrations in buildings or rooms that have visible mold growth with those in buildings or rooms that do not have visible growth.
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From page 292... ...
(2000) conducted a series of experiments to assess the extent of fungal colonization of wall cavities in 58 apartments that had suffered some water damage but had little visible mold on interior surfaces (some apartments were reported to have light mold growth in bathrooms and behind refrigerators)
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From page 293... ...
This dynamic can result in extensive fungal contamination without revealing a drop of moisture on the interior or exterior finish of the wall. Identifying and solving moisture problems parallel identifying the extent and location of fungal problems.
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From page 294... ...
and 99% RH in a closet on an exterior wall, the closet will be a hospitable niche for fungal growth. Temperature and RH can be used to calculate the amount of water vapor in each pound of air, and inferences can be drawn about moisture sources.
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From page 295... ...
The guidance documents listed in Table 6-1 all specify means for intervening in the moisture dynamic and removing problem fungal material. As was noted above, implementation of a remediation involves five essential steps • Establish appropriate containment and worker and occupant protection.
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From page 296... ...
Spots of mold growth on a refrigerator gasket do not require extensive containment or worker protection, but 1,000 ft2 of mold growth on the ceiling of a ground floor because of a flood on the second floor will require containment of the work area and respiratory, eye, and skin protection for workers. However, guidance documents are unclear on the subject of mold hidden in wall or ceiling cavities and growth that is not visible to the naked eye.
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From page 297... ...
Eliminate or Limit Moisture Sources and Dry the Materials The relevant moisture dynamic must be identified and stopped, at least in the short term, for remediation to proceed. In some cases, such as a leak in an exposed pipe, the identification of the moisture source may be rela
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From page 298... ...
Unless the contamination is minor or the value of the material great, the guidance documents recommend removing and disposing of soft porous materials that are difficult to clean or damaged by moisture.4 Paper, books, papercovered gypsum board, cellulose ceiling tile, and textiles are examples of these materials. Recommended cleaning methods include dry vacuuming with a HEPA vacuum cleaner, wet vacuuming, damp wiping with water or detergent mixtures, and bagging and removing.
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From page 299... ...
The guidance documents do not specifically consider responding to mold growth in spaces such as attics, crawl spaces, and garages. It is possible that intervening in the moisture dynamic and managing the direction of airflow with fan-induced pressure differentials can be used to prevent occupant exposure at a tiny fraction of the cost of removing all the fungi from the spaces.
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From page 300... ...
Regrowth often occurs because a faulty moisture dynamic was not mended or because a damaged area was reassembled before materials were completely dry; for example, the surface of porous materials, such as wood and concrete, may be dry while the interior remains damp. "Clean" in the context of a clearance inspection means that the remediated area is free of residual microbial contamination.
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From page 301... ...
• Removal of humidification equipment or controls of humidification or process-water systems. • Replacement of materials that offer superior nutrient and substrate for fungal growth with materials that are resistant to microbial growth (ceramics, concrete products, stainless steel, and the like)
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From page 302... ...
It seems likely, however, that normal variations in ventilation rates and filtration in buildings with closed windows will have a moderate effect on inhalation exposure to mold spores. Surface cleaning, such as vacuuming, can remove spores, potentially preventing their resuspension and inhalation and reducing the probability of exposure dermal contact and incidental ingestion.
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From page 303... ...
A few studies have also found that surface cleaning practices or frequency can influence airborne concentrations of particles or microorganisms. In a conference paper, Skyberg et al.
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From page 304... ...
Improved surface cleaning appears to have the largest and most practical potential for bringing about large reductions in exposure; however, further research is needed to characterize its effectiveness. FINDINGS, RECOMMENDATIONS, AND RESEARCH NEEDS On the basis of its review of the papers, reports, and other information presented in this chapter, the committee has reached the following findings and recommendations and has identified the following research needs regarding the prevention of moisture problems and the remediation of buildings that have water damage or microbial contamination.
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From page 305... ...
• Available literature addresses the management of microbial contamination when remediation is technically and economically feasible. There is no literature addressing situations where intervening in the moisture dynamic or cleaning or removing contaminated materials is not practicable.
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From page 306... ...
-- The risk of microbial contamination in the building but outside the general air circulation of the building -- in crawl spaces, attics, wall cavities, building sheathing, and the like. -- The effectiveness of managing contamination in place by using negative air pressure, encapsulation, and other means of isolation.
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From page 307... ...
1993. Monitoring Airborne Fungal Spores in an Experimental Indoor Environment to Evaluate Sampling Methods and the Effects of Human Activity on Air Sampling.
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From page 308... ...
2001. How Quickly Must Gypsum Board and Ceiling Tile Be Dried to Preclude Mold Growth After a Water Accident?
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From page 309... ...
1994. Suggested Guidance on Prevention of Microbial Contamination for the Next Revision of ASHRAE Standard 62.
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From page 310... ...
American Industrial Hygiene Association Journal 57:279–284. Rautiala S, Reponen T, Nevalainen A, Husman T, Kalliokoski P
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