Assessing and Remediation of Moisture and Mold in Residential Housing July 19,2003 The Building Performance Center.
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Transcript Assessing and Remediation of Moisture and Mold in Residential Housing July 19,2003 The Building Performance Center.
Assessing and Remediation of
Moisture and Mold in
Residential Housing
July 19,2003
The Building Performance Center
What is mold?
Biological Pollutant
A living organism
Can grow on almost
anywhere and on any
surface
Needs food,
temperature and
moisture to grow
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Mold or Fungi
Multi-cellular
and unicellular
Multi-cellular formed of microscopic
filaments called HYPHAE
A colony looks velvety, granular or leathery
May appear black, red, green, yellow or
brown
Most common aspergillus, pennicilium,
and stachybotrys.
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Mold and Fungi
Outdoors
mushrooms, puffballs, truffles
During lifecycles spores are formed
Spores small, light, travel by air
Need food from external sources
Water is critical to digestive process
Volatile compounds can be released called
mycotoxins
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Mold and Fungi
Grows on organic
materials
Wood
Paper
Foods
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Health Effects of Mold
Allergenic
Pathogenic
Toxigenic
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Allergenic Molds
Allergic reactions to mold are common
Inhaling or touching may cause allergic
reactions to sensitive individuals
Mold can be dead or alive
Repeated exposure may cause sensitivity
Symptoms include Hay fever reaction, sneezing,
runny nose, red eyes, skin rash
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Pathogenic Molds
Cause
infections
Only small group of molds associated with
infections
Most dangerous for immune compromised
individuals
Some infections include Hypersensitivity
Pneumonitis, Histoplasmosis
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Toxiogenic Molds
Cause
disease
Exposure thru inhalation, ingestion and
skin contact
Mycotoxins
Some molds have been proven to cause
liver damage, central nervous system
damage
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Building Science Basics
Moisture
Flow Concepts
Air Flow Concepts
Indoor Air Quality Concepts
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Liquid Flow
Driven by gravity or
air pressure
Examples: roof Leaks
and plumbing leaks
The most serious
threat for a home
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Capillary Flow
Liquid water creates a suction of its own as it moves
through tiny spaces within and between building
materials
Examples: Capillary action can also move liquid water
into a home through damp soil and a porous concrete
slab or stem concrete wall
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Air Movement
Air movement carries water vapor into and out of
the building and it’s cavities
Example: Hot air rises through the cracks and
crevices in the top of the building shell taking
water vapor with it.
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Vapor Diffusion
Water
vapor will move through solid
objects depending on their permeance and
vapor pressure
Is the the slowest form of moisture
movement
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Moisture Rules
Moisture
moves from warm to cold
Moisture
flows from more to less
Moisture
hitchhikes with air:
high pressure to low pressure
Gravity pulls water down
Water wicks up
l
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Air Flow Basics
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Air Flow
1 Cfm out = 1 Cfm
in
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Air Flow
High pressure flows to
low pressure
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Air Flow
A hole + a driving force
=Airflow
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Driving Forces
Natural
Mechanical
Wind
Stack Effect
Bath Fans
Kitchen Fans
Dryers
Forced air heating
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IAQ Basics
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Most vulnerable to the effects
of indoor air pollution
Elderly
Children
Disabled
Immune deficient or
chronically ill
Pregnant
woman/unborn child
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Children the most vulnerable
Their bodies are still developing.
Their immune systems are still developing and may be less
protective
They take in more food, water and air per pound of body weight than
adults
They are smaller and therefore closer to pollutants on or near the
ground.
They put their hands in their mouth more than adults
Early environmental insults may have a lifelong consequences
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Indoor Air Pollutants
Moisture
Pressed wood furniture
Moth repellents
Dry cleaned goods
Dust mites
Personal care products
Car exhaust
Paint supplies
Paneling
Radon
Tobacco smoke
Carpets
Insects
Household chemicals
Pesticides
Lead based paint
Woodstove
Pets
Cleaners
Products of combustion
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Seven Steps to a Healthy
Home
Dry and Clean
Water, clutter and dust permit or encourage the growth of mold, insects rodents and
mites. Keeping a home dry and clean controls mold and pests.
Well ventilated
Ventilation provides a mechanism to remove contaminants.
Combustion Product Free
Combustion products like carbon monoxide should not be present in a healthy home
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Seven Steps Cont.
Toxic Chemicals Free
Toxic cleaning compounds, pesticides, oil based paints and solvents can lead to poor indoor air
quality.
Pest Free
Pests lead to allergic reactions and pests lead to pesticides. Food and water
lead to pests.
Comfortable
Uncomfortable homes can make people take action that makes a home unhealthy. If
people can’t afford to heat their home they won’t ventilate their home.
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People
Pollutants
Pathways Pressures
July 7, 2003
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Review
Mold spores are everywhere
Mold needs a temperature range from 40’F to
100’F to grow
Mold needs food to grow
Mold needs moisture to grow
Mold can cause moderate to severe reactions
Mold is a symptom of a moisture problem
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Assessing for Mold and
Moisture Problems
Procedures
for assessments
Guidelines for assessments
Tools for assessments
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Procedure for Assessing
Mold and Moisture
Client
interview
Pollution Source Survey
Physical survey of the building
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Client Interview
Very valuable in
assessing a IAQ problem
May have a complaint
that should be recognized
Often know a lot about
their home
A chance for further IAQ
education
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Pollution Source Survey
Documents
existing conditions
Can indicate possible problems
Identifies risks
May help in designing solutions
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Pollution
source
survey
Pollution
source
survey
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Physical Survey
Survey
possible moistures sources from
outside and document
Examples
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Physical Survey
Survey
possible sources from inside and
document
Examples
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Assessment Tools and
Measurements
Eyes,
ears, nose
Measure relative humidity
Measure building materials moisture
content
Measure surface temperatures
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Measuring Relative Humidity
Thermo-Hygrometer
homeowner model
Digital
$19
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Measuring Relative Humidity
Sling Psychrometer
For measuring RH
takes 2 minutes
$35
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Detecting Moisture
Pin tester
The process requires
making holes in the
material to tested
Works on wood,sheetrock
,plaster, concrete
$350
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Detecting Moisture
Non destructive tester
Slides across material
to be tested without
damaging it
$200 to $400
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Measuring Temperature
Infrared Pointer
Measures common
surface temperatures
$350
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Guidelines for Evaluating
Mold Contamination
New
York City Guidelines
CMHC Homeowners Guide
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Small Areas
NYC
defines as 10 sq ft or less designated
LEVEL 1
CMHC defines a “small area” no larger
than one sq meter and no more than three
of those areas
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Small Areas
NYC
remediation conducted by trained
maintenance staff
Training includes clean up methods,
personal protection and potential health
hazards
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Small Areas
CMHC
say homeowners can clean up with
detergent and gloves and dust mask and
guidance from Homeowners’ Guide
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Mid-Sized Areas
NYC
defines as 10-30 sq ft. designated as
LEVEL 2
CMHCC considers mid sized to be more
than three patches, each smaller than a sq
meter or there is one or more isolated
patches larger than a square meter but
smaller that three sq meters
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Mid-Sized Areas
NYC
remediation conducted by trained
maintenance staff
Training includes clean up methods,
personal protection and potential health
hazards
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Mid-Sized Areas
CMHC
recommends assessment by a
professional but if proper procedures are
followed can be cleaned up by the
homeowner
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Large Areas
NYC
defines as 30-100 sq ft
CMHC considers an single patch greater
than sheet of plywood “extensive
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Solving Problems
Mold
is the outcome of another problem
MOISTURE
Solve the moisture problem and you solve
the Mold problem
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Moisture Sources
Interior
Exterior
Quantifying
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Moisture contributions from
inside
Respiration, perspiration
4pints / person / day
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Moisture contributions from
inside
Unvented dryers
5.0 pints / load
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Moisture contributions from
inside
Plants
.96 pints / day / 7
plants
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Moisture contributions from
inside
Crawlspaces
0 to 105 pints / day
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Moisture contributions from
inside
Firewood
0-5 pints / day
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Moisture contributions from
inside
Dishwashing
.044 / pints / day / 4
people
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Moisture contributions from
inside
Showering,bathing
.52 pints / 5 minutes
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Moisture contributions from
inside
Floor mopping
.03 pints / sqft
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Moisture contributions from
inside
Cooking
.088 pints / day / 4
people
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Moisture contributions from
inside
Plumbing Leaks
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Moisture contributions from
inside
Drying laundry inside
4-6 pints per load
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Standing water in crawl space
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Moisture from outside
This
can be the largest source of moisture
in a house
Roof leaks
Broken or disconnected gutters and
downspouts
Improper site drainage
Broken footing drains
Improperly functioning landscape irrigation
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Roof Leaks
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Improper flashing details
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Site Drainage
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Disconnected Downspout
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Broken Footing Drains
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Moisture Problems are either
A surface
temperature problem or
A vapor pressure problem
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Common Surface
Temperature Problems
1.
2.
Poor air circulation
Closets
Exterior corners
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Common Surface
Temperature Problems
1.
2.
Wind washing and Low insulation levels
Exterior wall line at ceiling
Near leaky windows or doors
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Solving problems
1.
2.
Reduce vapor pressure
Source control
Dehumidification
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Psychrometric Basics
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Dry Bulb Temperature
The
air mixture temperature as measured
by an ordinary thermometer
It is plotted as a family of lines along the
x-axis
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Absolute Humidity
The
ratio of actual amount of moisture in
grains of water per pound of dry air
Absolute humidity ratio is plotted on the yaxis of the chart
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Relative Humidity
Relative humidity is the ratio of the amount of moisture in
the air compared to the maximum amount of moisture
the air could contain at the same temperature and
pressure.
It is a family of curved lines that slope upward from left to
right
100 % relative humidity line is called the saturation curve
and it forms the boundary on the left side of the chart
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Wet Bulb Temperature
Wet bulb temperature is another measurement of the
amount of moisture in the air.
Measured with a wetted cotton wick placed over the bulb
of a thermometer.
As the wick evaporates it lowers the reading on the
thermometer due to evaporative cooling.
The lower the amount of moisture in the air, the lower will
be the wet bulb temperature because a higher rate of
evaporation will occur in dyer air.
These values are shown along the saturation curve.
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Dew Point Temperature
It
is the dry bulb temperature at which
condensation first occurs as heat is
removed from the air.
The dew point is found by moving
horizontally along the chart from the given
point to the saturation curve.
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Enthalpy
It
is the total amount of heat contained in
the air mixture
Enthalpy is plotted as a family of diagonal
lines on the chart that slope upward from
right to left.
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Specific Volume
Is a measurement of the volume occupied by the
air based on it’s weight.
It’s measured in terms of cubic feet per one
pound of dry air.
Specific volume is is plotted as a family of
diagonal lines that slope sharply upward right to
left.
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Psychrometrics Exercise #1
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Psychrometrics Exercise #2
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Psychrometrics Exercise #3
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Mold and Rot
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MOLD
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Mold
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More Mold
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Mold
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