advisable
to
seal
the
contaminated
side of the
filter
by
taping
a plastic
sheet
or
cardboard
over
the
face
before
removal. This
should
minimize
the
number
of
particles
shaken
loose from the
filter.
Once
removed,
the filter
should
immediately
be
sealed
in a chemical
hazard
bag
and
then
disposed
of safely
in
accordance
with
environmental
regulations.
After
filter
replacement
has
been
camp
leted,
the
cabinet
and
the
room
should
be cleaned
and
decontaminated
in
a
manner
consistent
with
the
nature
of
the
hazardous
material. The cleaning
materials,
along
with
the
protective
gear
and
clothing,
should
be
properly
disposed
of.
HEP
A filters
are
very
easily
damaged,
and
you
will
want
to
use
great
care
in
handling
so
as to
avoid
injury to the filter mectia
and
gasket
surfaces.
When
installing
the
new
filters, it is a
good
idea
to
tape
a p ieee
of
cardboard over
the
filter
media
to
give
protection against
dropped
wrenches
or
misdirected
fingers.
Of
course, you'll
need
to
make
sure
that
the
cardboard
is
removed
before
the access
panels
are
re-insta.lled. Inspect
the
filters carefully before
and
after installation. A
broken
or
damaged
filter is worthless.
Changing
the
Exhaust
Filter
Move
the
viewscreen
to its fully-closed position.
Remove
the
canopy
retaining
wing
nuts
and
swing
the
canopy
down
to its
open
restraint
position.
Loosen
the
retaining
hardware
(cap
nuts)
at
top
backside
of
each
upper
track. Pull
the
upper
tracks
out
to the
side
at
the top to clear
the
slots
and
pull
them
up
and
out
of
the
lower tracks
to
ren
tove
the11
t.
Remove
the
front
access
panel
on
the top section
of
the
unit,
as
well
as
the
smaller inner
exhaust
access panel. Loosen
and
remove
the
exhaust
filter
damps
and
remove
the filter thrmJgh the
front
opening
into
a heat-sealable polyethylene
bag
for disposal. If the
unit
is
not
connected to
an
exhaust
system,
the
exhaust
filter
nl_ay
be
rerno\'ed
from
the
top
of
the
w1it
Prepr:re
the
new
fHter
by
puttirtg a Light coat of
silicone
grease
on
the
face
of
the gasket.
Clean
the
sealing
flange
thoroughly.
Then
carefully slide
the
new
filter
into
place
and
make
sure
that
it
is
22
properly
seated
on
the
flange. Replace
the
filter
clamp assemblies
and
screw the
stainless
steel
studs
finger-tight. Tighten the
studs
unifom1ly
and
moderately,
a few
threads
at
a time,
until
the
filter
gasket
has
been
compressed
about
20
percent. Do
not
overtighten.
Then
replace
the
exhaust
filter access
panel
securely
and
make
the
leak
test described earlier
in
this
chapter.
Changing
the
Supply
Filter
Move
the
viewscreen to its fully-closed
position.
Remove
the
canopy
retaining
wing
nuts
and
swing
the
canopy
down
to its
open
restraint
position. Loosen
the
retaining
hardware
(cap
nuts) at top backside of each
upper
track.
Pull
the
upper
tracks
out
to the
side
at
the top to
clear
the
slots
and
pull
them
up
and
out
of
the
lower
tracks
to remove them.
Remove the front access
panel
on
the
top
section
of the cabinet, as well
as
the
inner
supply
filter
access panel. Loosen
and
remove
the
supply
filter
clamps
and
carefully lift the dirty filter
into
a
heat-
sealable
polyethylene
bag
for disposaL
Use a replacement filter
of
the correct type.
Put
a light
coat
of
silicone grease
on
the
face of
the
replacement filter gasket. Clean
the
sealing
flange
thoroughly. Then slide
the
new
filter
into
place
and
make
sure
that
its correctly
seated
on
the
flange.
Replace the filter clamp assemblies
and
screw
the
stainless sh1ds finger-tight.
The
filter
gasket
should
be
compressed
about
20
percent.
Finally,
replace both the access
panels
securely
and
then
the
viewscreen
frame/light
canopy
assembly.
vVhen filters are replaced, the
airflow
must
be
balanced.
Thorough
filter
and
cabinet
leak
tests
must
be
made
by
qualified
personnel.
Adjustment
of
the
Balancing
Damper
Filters for the cabinet
should
be
selected
as a
pair
so that their resistance
~Nill
be
as
close as
reasonably possible. Resistance of
HEPA
filters
may
vary considerabl.Y from one to
another,
so
a
damper
has
been
installed
on
vour
cabinet's
exhaust
to
maintain
the
proper
balance
between
To Next Page
Loading...