mold basics

Mold in the Workplace Basic Information

&What to Do About It

Shawn HolleSafety AnalystDPH/OSH

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Agenda

What is Mold? What Does Mold Need to Grow? Examples of Mold in Buildings Cleanup Approaches Personal Protective Equipment (PPE) Potential Health Issues?

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What is Mold?

Mold is a variety of fungus (a plant): Range From Single Cells to Mass Growth

Examples: Mushrooms, Shower Mold

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What Does Mold Need to Grow?

Constant Temperature: Between 60°F to 105 °F Oxygen Food Sources:

Carbohydrates, Starch (Think Wall Board)

Organic Debris Constant Moisture (Liquid Water)

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Examples of Mold Growth in Buildings

Water + Food = Mold Growth. Most Building Materials are Potentially a Food

Source

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1. Gravity: Rain

2. Air Movement: Heated air rises to

the attic. Heated air carries moisture vapor with it. Vapor condenses when in contact with unheated.

Water Movement

roof leak

water wicking up end grain

low pressure

high pressure

water molecule

air molecule

flow of air and water

bulk moisture capillary action

vapor diffusion air-transported moisture

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Basic Moisture Terms

Relative Humidity: Ratio of water vapor in air to total amount of water vapor air can hold (Warm air holds more water vapor than cold air does).

Saturated Air: 100% humidity. Air cannot hold any more water vapor.

Condensation: When water vapor turns into liquid Dew Point: Temperature at which water vapor

condenses from gas to liquid.

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Inside Moisture

Additional Sources:

Pets, aquarium, houseplants, humidifiers, exposed soil in crawl space, malfunctioning gas or oil appliances, construction moisture, unvented space heaters.

Breathing:

2.88 lb/day per person

Laundry:

Drying clothes (if not vented to the outside) 1lb/each lb of clothes.

Bath:

.12 lb/each per bath

.5 lb/each per shower

Kitchen:

Mopping floor (10’ x 10’ room) 3 lb… Cooking (gas) 4.7 lb/day… Cooking (electric) 2 lb/day…Dishwashing 1 lb

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Carpeting / Flooring

Mold Growth Beneath Wood Floor

Carpet Infested With Stachybotrys chartarum

Concrete Moisture Trapped

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Flooring

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Flooring

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Outdoor Moisture: Precipitation & Soil Contact

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Roof

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Roof

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Roof:Penetrations

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Windows & Door Openings

Air leaks in where window

sash slides past frame: weather-

strip here

Air leaks in where window casing meets

wall: caulk here

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Plumbing

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PlumbingUnder the Toilet

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Plumbing

Floor Framing

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HVAC Systems

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Lath & Plaster (Stucco)/CladdingBehind the Drywall

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Lath and Plaster (Stucco)/Cladding

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Personal Protective Equipment (PPE)

Choose PPE on Case by Case Basis

Call DPH OSH for Guidance (415)554-2736

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Cleanup Approaches

Identify Water Source Repair Area and Prevent Water Intrusion Clean Surfaces (3 applications minimum) Dry Surfaces Thoroughly Repeat as Necessary

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Potential Health Effects?

Some Varieties Can Cause Allergic Reactions in Sensitive Individuals

May Provoke Asthma Attack in Allergic Individuals

Irritate Eyes, Nose, Throat, & Lungs Potentially Toxic Effects Rare

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Toxic Mold:Potential Health Effects?Recent Study Conclusions

Population Prevalence of Mold Related Allergic Respiratory Symptoms ==5%

Other Serious Allergic Conditions Rare Outdoor Molds Generally More Important Than

Indoor Molds Indoor Molds Should Be Remediated After

Addressing Moisture Sources Stachybotrys Chartarum Has Not Been

Demonstrated to Be a Particularly Harmful Mold

mold basics

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