Copyright 2002 Dri-Eaz Products, Inc.
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Use the DefendAir as a negative air machine for remedia-
tion. A negative air machine vacuums air from a containment
area to create a negative air pressure on the inside. See
"Negative Air Pressure" below for more details.
Run the DefendAir without interruption for the duration of
every remediation job. The DefendAir filters 99.5% of parti-
cles 0.3 microns and larger, such as mold spores and fungi
from the air passing through the filter.
If either Filter Change Light illuminates during the reme-
diation process, immediately change the appropriate filter.
See "Changing Filters" for more information. Upon comple-
tion of remediation, replace all filters and clean the unit thor-
oughly to avoid cross-contamination of other spaces. Always
wear an appropriate NIOSH-approved respirator and, if
needed, other appropriate personal protective equipment
when removing or replacing filters or pre-filters, or when
cleaning the DefendAir. See "Cleaning the Unit" for more
information.
Containment During Remediation
Containment is a critical part of remediation. When damaged
materials are disturbed during the remediation process, par-
ticles are released into the air. These particles could include
mold spores, bacteria and other hazardous particles. A con-
tainment barrier prevents particles from spreading into
nearby unaffected areas while the DefendAir filters the air.
Use the DefendAir EX to maintain a negative air pressure
inside the containment area. At no time should the DefendAir
EX be used to supply air to the containment area. See
"Negative Air Pressure" for more information.
To set up a containment barrier, use 6-mil fire-retardant
polyethylene or a comparable material. For smaller areas,
poly sheeting can be affixed to walls and ceilings with duct
tape. Larger areas may require the construction of a steel or
wood stud frame to support the poly sheeting. All supply and
air vents, doors, chases, and risers within the containment
area must be sealed with poly sheeting to minimize the mi-
gration of contaminants. Cover any and all materials within
the work area that are not being remediated. Access to the
containment area should be by slit entry with a covering flap
on the outside.
Always wear an appropriate NIOSH-approved respirator,
and, if needed, other personal protective equipment when
working either inside or outside the containment area. The
foregoing procedures are not a substitute for compliance with
applicable U.S. Environmental Protection Agency (EPA)
guidelines for mold remediation or any applicable Occupa-
tional Health and Safety Administration (OSHA) standards
for containment and remediation. Consult the EPA guide-
lines at www.epa.gov for more information on appropriate
health and safety precautions for mold remediation activity
and the OSHA guidelines at www.osha.gov for more informa-
tion on appropriate containment and remediation procedures.
Negative Air Pressure
An area has negative air pressure when the air pressure in-
side is lower than the air pressure outside. Since uneven
pressures seek equilibrium, high-pressure air from outside
will move toward the low-pressure air through any opening,
regardless of size. This is advantageous for remediation. Re-
moving filtered air from a contained area by ducting creates
a negative pressure inside the affected area. High-pressure
air from the rest of the structure will flow toward the low-
pressure area. Since the airflow is always toward the af-
fected area, the contamination has less chance of spreading.
To create a negative pressure, install the DefendAir out-
side the containment area and vacuum air out of the affected
area with ducting. Use proper instrumentation to monitor air
pressures. See "Balancing CFM for Containment" for more
information. A tightly sealed containment area will aid in cre-
ating an effective negative pressure. If the containment area
is well sealed, the poly sheeting should billow in toward the
room at all points.
Balancing CFM for Containment
Use a manometer to balance the DefendAir's cubic feet per
minute (CFM) with the size and style of containment. Too
little CFM will not create sufficient negative air pressure in
the containment area. Too much CFM might collapse the
containment barrier. As a general rule, the larger the con-
tained area, the greater the CFM requirement. A manometer
will show the pressure differential between your contained
and unaffected area. Adjust the variable speed switch on the
DefendAir to maintain the desired pressure differential.
Beware of Backdrafting
Use extreme caution when creating negative air pressures in
structures with open combustion appliances such as fire-
places, boilers, furnaces, water heaters and HVAC systems.
It is possible to overpower the exhaust ventilation of these
units with negative air pressure inside the structure. Too
much negative air pressure will backdraft deadly carbon
monoxide fumes. Inspect the structure thoroughly for the
possibility of backdrafting. It may be necessary to turn off gas
appliances as well as the gas supply for safety during reme-
diation.
Recommended Installations
STANDARD REMEDIATION: For the majority of remedia-
tions, install the unit outside the containment area. Use inlet
ducting to pull air out of the containment area and create a
negative air pressure. Use a manometer to measure air
pressures and determine the proper CFM setting on the De-
fendAir.
LIGHT REMEDIATION: For light remedial work, the Defen-
dAir may be installed inside the containment area and used
solely as a highly efficient filter to recirculate scrubbed air to
the work area.
CATEGORY 1 (CLEAN) WATER LOSS: Place the DefendAir
near the center of the affected area. No ducting is required.
