Mold
is a health Concern
Concern about indoor exposure to mold
has been increasing as the public becomes aware
that exposure to mold can cause a variety of health
effects and symptoms, including allergic reactions.
This document presents guidelines for the remediation/cleanup
of mold and moisture problems, including measures
designed to protect the health of building occupants
and remediators.
Where Mold Grows
Mold can be found almost anywhere; it can grow
on virtually any organic substance, as long as
moisture and oxygen are present. There is mold
that can grow on wood, paper, carpet, foods, and
insulation. When excessive moisture accumulates
in buildings or on building materials, mold growth
will often occur, particularly if the moisture
problem remains undiscovered or unaddressed. It
is impossible to eliminate all molds and mold
spores in the indoor environment. However, mold
growth can be controlled indoors by controlling
moisture indoors.
Moisture Leads to Mold
Since mold requires water to grow, it is important
to prevent moisture problems in buildings. Moisture
problems can have many causes, including uncontrolled
humidity. Some moisture problems in buildings
have been linked to changes in building construction
practices during the 1970s, 80s, and 90s. Some
of these changes have resulted in buildings that
are tightly sealed, but may lack adequate ventilation,
potentially leading to moisture buildup. Building
materials, such as drywall, may not allow moisture
to escape easily. Moisture problems may include
roof leaks, landscaping or gutters that direct
water into or under the building, and un-vented
combustion appliances. Delayed maintenance or
insufficient maintenance is also associated with
moisture problems in schools and large buildings.
Moisture problems in portable classrooms and other
temporary structures have frequently been associated
with mold problems.
Prevention 
Fix leaky plumbing and leaks in the building envelope
as soon as possible.
Watch for condensation and wet spots. Fix source(s)
of moisture problem(s) as soon as possible.
Prevent moisture due to condensation by increasing
surface temperature or reducing the moisture level
in air (humidity). To increase surface temperature,
insulate or increase air circulation. To reduce
the moisture level in air, repair leaks, increase
ventilation (if outside air is cold and dry),
or dehumidify (if outdoor air is warm and humid).
Keep heating, ventilation, and air conditioning
(HVAC) drip pans clean, flowing properly, and
unobstructed.
Vent moisture-generating appliances, such as dryers,
to the outside where possible.
Maintain low indoor humidity, below 60% relative
humidity (RH), ideally 30-50%, if possible.
Perform regular building/HVAC inspections and
maintenance as scheduled.
Clean and dry wet or damp spots within 48 hours.
Don't let foundations stay wet. Provide drainage
and slope the ground away from the foundation.
Hidden Mold
In some cases, indoor mold growth may not be obvious.
It is possible that mold may be growing on hidden
surfaces, such as the backside of dry wall, wallpaper,
or paneling, the top of ceiling tiles, the underside
of carpets and pads, etc. Possible locations of
hidden mold can include pipe chases and utility
tunnels (with leaking or condensing pipes), walls
behind furniture (where condensation forms), condensate
drain pans inside air handling units, porous thermal
or acoustic liners inside ductwork, or roof materials
above ceiling tiles (due to roof leaks or insufficient
insulation).
Some building materials, such as dry wall with
vinyl wallpaper over it or wood paneling, may
act as vapor barriers, trapping moisture underneath
their surfaces and thereby providing a moist environment
where mold can grow. You may suspect hidden mold
if a building smells moldy, but you cannot see
the source, or if you know there has been water
damage and building occupants are reporting health
problems. Investigating hidden mold problems may
be difficult and will require caution when the
investigation involves disturbing potential sites
of mold growth—make sure to use PPE.
For example, removal of wallpaper can lead to
a massive release of spores from mold growing
on the underside of the paper. If you discover
hidden mold, you should revise your remediation
plan to account for the total area affected by
mold growth.
Remediation Plan
Assess the size of the mold or moisture problem
and the type of damaged materials before planning
the remediation work.
The decision to relocate occupants should consider
the size and type of the area affected by mold
growth, the type and extent of health effects
reported by the occupants, the potential health
risks that could be associated with debris, and
the amount of disruption likely to be caused by
remediation activities. If possible, remediation
activities should be scheduled during off-hours
when building occupants are less likely to be
affected.
Remediation
Fix the water or humidity problem. Complete and
carry out repair plan if appropriate. Revise and
carry out maintenance plan if necessary. Revise
remediation plan as necessary, if more damage
is discovered during remediation.
Continue to communicate with building occupants,
as appropriate to the situation. Be sure to address
all concerns.
Completely clean up mold and dry water-damaged
areas. Select appropriate cleaning and drying
methods for damaged/ contaminated materials. Carefully
contain and remove moldy building materials. Use
appropriate Personal Protective Equipment (PPE).
Arrange for outside professional support if necessary.
The Key to Mold Control
If you are unsure what to do, or if the item is
expensive or of sentimental value, you may wish
to consult a specialist. Specialists in furniture
repair/restoration, painting, art restoration
and conservation, carpet and rug cleaning, water
damage, and fire/water restoration are commonly
listed in phone books. Be sure to ask for and
check references; look for affiliation with professional
organizations. Molds Can Damage Building Materials
and Furnishings
Cleanup Methods
A variety of mold cleanup methods are available
for remediating damage to building materials and
furnishings caused by moisture control problems
and mold growth. The specific method or group
of methods used will depend on the type of material
affected. Please note that professional remediators
may use some methods not covered in these guidelines;
absence of a method in the guidelines does not
necessarily mean that it is not useful.
Method 1: Wet Vacuum
Wet vacuums are vacuum cleaners designed to collect
water. They can be used to remove water from floors,
carpets, and hard surfaces where water has accumulated.
They should not be used to vacuum porous materials,
such as gypsum board. They should be used only
when materials are still wet—wet vacuums
may spread spores if sufficient liquid is not
present. The tanks, hoses, and attachments of
these vacuums should be thoroughly cleaned and
dried after use since mold and mold spores may
stick to the surfaces.
Method 2: Damp Wipe
Whether dead or alive, mold is allergenic, and
some molds may be toxic. Mold can generally be
removed from nonporous (hard) surfaces by wiping
or scrubbing with water, or water and detergent.
It is important to dry these surfaces quickly
and thoroughly to discourage further mold growth.
Instructions for cleaning surfaces, as listed
on product labels, should always be read and followed.
Porous materials that are wet and have mold growing
on them may have to be discarded. Since molds
will infiltrate porous substances and grow on
or fill in empty spaces or crevices, the mold
can be difficult or impossible to remove completely.
Method 3: HEPA Vacuum
HEPA (High-Efficiency Particulate Air) vacuums
are recommended for final cleanup of remediation
areas after materials have been thoroughly dried
and contaminated materials removed. HEPA vacuums
are also recommended for cleanup of dust that
may have settled on surfaces outside the remediation
area. Care must be taken to assure that the filter
is properly seated in the vacuum so that all the
air must pass through the filter. When changing
the vacuum filter, remediators should wear PPE
to prevent exposure to the mold that has been
captured. The filter and contents of the HEPA
vacuum must be disposed of in well-sealed plastic
bags.
Method 4: Discard
Remove Damaged Materials and Seal in Plastic Bags
Building materials and furnishings that are contaminated
with mold growth and are not salvageable should
be double-bagged using 6-mil polyethylene sheeting.
These materials can then usually be discarded
as ordinary construction waste. It is important
to package mold contaminated materials in sealed
bags before removal from the containment area
to minimize the dispersion of mold spores throughout
the building. Large items that have heavy mold
growth should be covered with polyethylene sheeting
and sealed with duct tape before they are removed
from the containment area.
Always use gloves and eye protection when cleaning
up mold!
Personal Protective Equipment (PPE)
If the remediation job disturbs mold
and mold spores become airborne, then the risk
of respiratory exposure goes up. Actions that
are likely to stir up mold include: breakup of
moldy porous materials such as wallboard; invasive
procedures used to examine or remediate mold growth
in a wall cavity; actively stripping or peeling
wallpaper to remove it; and using fans to dry
items.
The primary function of Personal Protective Equipment
(PPE) is to avoid inhaling mold and mold spores
and to avoid mold contact with the skin or eyes.
Skin and Eye Protection
Gloves are required to protect the skin from contact
with mold allergens (and in some cases mold toxins)
and from potentially irritating cleaning solutions.
Long gloves that extend to the middle of the forearm
are recommended. The glove material should be
selected based on the type of materials being
handled. If you are using a biocide (such as chlorine
bleach) or a strong cleaning solution, you should
select gloves made from natural rubber, neoprene,
nitrile, polyurethane, or PVC. If you are using
a mild detergent or plain water, ordinary household
rubber gloves may be used. To protect your eyes,
use properly fitted goggles or a full-face respirator
with HEPA filter. Goggles must be designed to
prevent the entry of dust and small particles.
Safety glasses or goggles with open vent holes
are not acceptable.
Respiratory Protection
Respirators protect cleanup workers from inhaling
airborne mold, mold spores, and dust.
Minimum: When cleaning up a small area affected
by mold, you should use an N-95 respirator. This
device covers the nose and mouth, will filter
out 95% of the particulates in the air, and is
available in most hardware stores.
Limited: Limited PPE
includes use of a half-face or full-face air-purifying
respirator (APR) equipped with a HEPA filter cartridge.
These respirators contain both inhalation and
exhalation valves that filter the air and ensure
that it is free of mold particles. Note that half
face APRs do not provide eye protection. In addition,
the HEPA filters do not remove vapors or gases.
You should always use respirators approved by
the National Institute for Occupational Safety
and Health (see Resources List).
Full: In situations
in which high levels of airborne dust or mold
spores are likely or when intense or long-term
exposures are expected (e.g., the cleanup of large
areas of contamination), a full-face, powered
air-purifying respirator (PAPR) is recommended.
Full-face PAPRs use a blower to force air through
a HEPA filter. The HEPA-filtered air is supplied
to a mask that covers the entire face or a hood
that covers the entire head. The positive pressure
within the hood prevents unfiltered air from entering
through penetrations or gaps. Individuals must
be trained to use their respirators before they
begin remediation. The use of these respirators
must be in compliance with OSHA regulations.
Disposable Protective Clothing
Disposable clothing is recommended during a medium
or large remediation project to prevent the transfer
and spread of mold to clothing and to eliminate
skin contact with mold.
Limited: Disposable
paper overalls can be used.
Full: Mold-impervious
disposable head and foot coverings, and a body
suit made of a breathable material, such as TYVEK®,
should be used. All gaps, such as those around
ankles and wrists, should be sealed (many remediators
use duct tape to seal clothing).
Containment
 The
purpose of containment during remediation activities
is to limit release of mold into the air and surroundings,
in order to minimize the exposure of remediators
and building occupants to mold. Mold and moldy
debris should not be allowed to spread to areas
in the building beyond the contaminated site.
In general, the size of the area helps determine
the level of containment. However, a heavy growth
of mold in a relatively small area could release
more spores than a lighter growth of mold in a
relatively large area. Choice of containment should
be based on professional judgment. The primary
object of containment should be to prevent occupant
and remediator exposure to mold.
Limited Containment
Limited containment is generally recommended
for areas involving between 10 and 100 square
feet (ft 2) of mold contamination. The enclosure
around the moldy area should consist of a single
layer of 6- mil, fire-retardant polyethylene sheeting.
The containment should have a slit entry and covering
flap on the outside of the containment area.
For small areas, the polyethylene sheeting can
be affixed to floors and ceilings with duct tape.
For larger areas, a steel or wooden stud frame
can be erected and polyethylene sheeting attached
to it.
All supply and air vents, doors, chases, and risers
within the containment area must be sealed with
polyethylene sheeting to minimize the migration
of contaminants to other parts of the building.
Heavy mold growth on ceiling tiles may impact
HVAC systems if the space above the ceiling is
used as a return air plenum. In this case, containment
should be installed from the floor to the ceiling
deck, and the filters in the air-handling units
serving the affected area may have to be replaced
once remediation is finished.
The containment area must be maintained under
negative pressure relative to surrounding areas.
This will ensure that contaminated air does not
flow into adjacent areas. This can be done with
a HEPA-filtered fan unit exhausted outside of
the building. For small, easily contained areas,
an exhaust fan ducted to the outdoors can also
be used. The surfaces of all objects removed from
the containment area should be remediated/cleaned
prior to removal
Moisture Control is the Key to Mold Control
Full Containment
Full containment is recommended for the
cleanup of mold contaminated surface areas greater
than 100 ft 2 or in any situation in which it
appears likely that the occupant space would be
further contaminated without full containment.
Double layers of polyethylene should be used to
create a barrier between the moldy area and other
parts of the building. A decontamination chamber
or airlock should be constructed for entry into
and exit from the remediation area. The entryways
to the airlock from the outside and from the airlock
to the main containment area should consist of
a slit entry with covering flaps on the outside
surface of each slit entry. The chamber should
be large enough to hold a waste container and
allow a person to put on and remove PPE. All contaminated
PPE, except respirators, should be placed in a
sealed bag while in this chamber.
Respirators should be worn until remediators are
outside the decontamination chamber. PPE must
be worn throughout the final stages of HEPA vacuuming
and damp-wiping of the contained area. PPE must
also be worn during HEPA vacuum filter changes
or cleanup of the HEPA vacuum.
Information provided by http://www.ncsu.edu/
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