Microbial growth in homes

Microbial Growth in

HomesPresented by: Bernard L. Fontaine, Jr., CIH, CSP The Windsor Consulting Group, Inc.14 Sheinfine Avenue,South River, NJ 08882Email: [email protected] TEL: (732) 221-5687

mailto:[email protected]

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Microbial Growth in Homes

● Over a million species of fungi and bacteria

● Less than 10% microorganisms identified

● Fungi are multi-cellular – bacteria single cell

● Hyphae from fungi grow to form mycelium

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● Hyphae are vegetative or reproductive

● Vegetative hyphae get nutrients for fungus

● Reproduction may produce aerial hyphae and spores

● Spores released from colony to disperse fungus

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● Fungal growth depends on ambient temperature, free water, nutrients, and time

● Fungi lack chlorophyll – get energy from organic compounds

● Fungi excrete enzymes into food and digest substrate and absorb water-soluble compounds

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● Temperature: Range 0oC (cryophile) to 50oC (thermophile) Most growth between 20-30 oC

● Water: Most fungi require free water but Asp. species extract moisture from the air

● Nutrients: Minimal – organics with carbon

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● Time: Adequate moisture and nutrients at suitable temperature

First few days: Produce vegetative hyphaeOnce hyphae base established over 5-7 days then start spore production for fungus flourish and spread

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● Fungi and/or bacteria comes from:

◘ Plants◘ Food◘ Soil◘ Air◘ Contaminated indoor/outdoor materials

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● Environmental Health Hazards:

◘ Irritation of eyes, nose, throat, and skin

◘ Infections – local or superficial (athlete’s feet); local and deep (lung); or invasive

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◘ Infections – brain abscesses, corneal ulcers, endocarditis, necrotizing

esophagitis, cysts, liver disease, meningitis, peritonitis, pneumonia, sinusitis, and fatal systemic diseases

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◘ Allergies up to 20% of the US population◘ Most serious allergic problem is asthma

◘ UK study showed wheezing in children as a predictor for fungal growth in the home

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◘ Mycotoxins: Metabolites of fungi that can have detrimental effects in humans

Often produced when nutrients limited

Affect immune system, blood, nervous system, genetics, and some are human carcinogens

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◘ Endotoxins: Metabolites of bacteria causing detrimental effects in humans

Fever, malaise, elevated white blood cell count, respiratory distress, shock, and possible death

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● Indoor Indicating Fungal Species

Alternaria sps. Aspergillus sps.Aureobasidium sps. Chaetomium sps.Cladosporium sps. Penicillium sps.Trichoderma sps. Fusarium sps.

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● Common Outdoor Fungal Species

Ascospores BasidiosporesBotrytis sps. Epicoccum sps.Pithomyces sps. Ulocladium sps.Myxomycetes sps. Periconia sps.

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● Moisture Control Key to Prevent Microbial Growth

◘ Check moisture content of lumber – Wood is considered dry (<19% moisture)◘ Cover building materials delivered onsite◘ Seal framed house with plastic sheeting◘ Insert driers to reduce moisture content

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◘ Store building materials on pallets◘ Cover dirt with plastic sheeting◘ Cover exposed building materials◘ Schedule construction on drier days

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◘ Fix leaks and seepage along foundation◘ Remove water from basement or slab◘ Keep windows and doors closed◘ Avoid condensation in HVAC ducts◘ Install dehumidifiers inside residence

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● Inspection Key to Prevent Microbial Growth

◘ Suppliers to inspect all building materials◘ Cover loads delivered to construction site◘ Framers and site construction managers check lumber for visible fungal growth◘ Report unsatisfactory building materials

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● Inspection Key to Prevent Microbial Growth

◘ Check flashing around windows and doors, roof vents, and chimney◘ Gutters drain water away from house◘ Adequate ventilation in attic space◘ Report water leaks immediately

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● Testing for Microbial Growth

◘ Inspect all building surfaces◘ Air samples for fungal or bacterialcounts◘ Surface samples for fungal spores mycelial fragments, and mycotoxins

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● Testing for Microbial Growth

◘ Surface samples for bacteria and endotoxins◘ Air temperature and relative humidity◘ Moisture measurements of affected

building substrates

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● Remediation for Microbial Growth

◘ Define work area and Level I-V◘ Set up containment barriers, air locks,

and decontamination chambers◘ Post warning signs for other trades and

emergency response personnel

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◘ Install air filtration devices and air movers◘ Inspect containment for leaks◘ Test airflow and static pressure inside the containment barrier

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◘ Remove damaged building materials◘ HEPA vacuum all affected building substrates◘ Damp wipe affected surfaces with a

biocide

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◘ Dry building substrates with dehumidifier◘ Apply antl-microbial coating ◘ Inspect work for quality of workmanship◘ Clean work area, tools, and equipment

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● Post-Remediation for Microbial Growth

◘ Visually inspect all building surfaces for visible microbial growth, dampness, and containment of work area◘ If acceptable, conduct air and surface sampling inside/outside work area

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