IV- ON-SITE CHECKS
AND
MAINTENANCE PROCEDURES
We
recommend
that
the following checks be
performed before initial use, after
reloca~i
on,
and
after each filter change. They
should
also
be
carried
out
at regular intervals, usually six
months
or
one
year, as specified by an i.rldustrial
hygienist, safety officer or other qualified person.
The
tests described below
meet
recommended
minimum requirement
s.
They
must
be
performed
by an experienced technic.km using
pr
oper
procedures
and
instruments.
Our
representatives can tell
you
about
other tests
which
you
may
consider desirable.
As
reported earlier in this manual, each individ-
ual cabinet
made
by The Baker Company
is
care-
fully t
es
ted before it leaves the factory. Your copy
of
the
test report, which you will find
a!'
the
back
of
this manual, gives the factory test results for
your
own
SteriiGARD
~'
II
cabinet. Use
it
as
your
record of the original
testing,
and
as your guide to
testing in
the
future. To
gain
many
years
of
satis-
factory service, please be
sure
that
your
mainte-
.)
nance
personnel come
as
close
as
possible to
du-
plicating these original test figures.
2.
Usc
one
of
the following
methods:
I) Primary method using a Direct
In
st
rument
Measurem
ent
Device (
DE'vl)
sea
led
lo
the
fronl
acce
ss opening. Tak
in
g
th
e
av-
erage of
five
reading, divided by the front access opening
square
footage lo calculate inflow
ve
locity. Sash areas arc noted
be
low. The
ca
l
cu
lated
infl
ow veloc
it
y required is I 00 to 1
10
FPM.
2)
Secondary method using a
thermal
anemometer mounted
on a
ring
stand S inches above
the
exhaust
filler,
lake reading on
a grid
as
shown
on
the
cabinet air
fl
ow
data plat
e.
Average
these
reading and
multip
ly
lhc
average by the open area of the
exhaust collar installed over
the
exhaust
filter.
SG400
1.72
square
fee
l
and
SG600 2.37 square
feel.
Divide
thi
s
va
lue
(CFM) by the sash open area lo determine the
infl
ow
ve
locity.
The calculated
inflow velocities required are, SG400
125
to
135
FPM
and SG 600
liS
to
125
FPM
Sash areas
SG 400
SG600
8
In
ch
sash
2.56
ft
2
3.89
ft
2
10
loch sash
3.19
ft
2
4.
86 ft
2
3. Using the sa
me
instrument
mounted on a ring stand
within
the
work area,
take
readings
with
the
anemometer probe set
in
pl
ane
of
the
bouom
of
the
sash
wit
h
the
sup
pl
y air diffuser
in
-
sta
ll
ed.
TI
1e
lo
cat
io
n and average of
th
ese
readings sh
ou
ld
be
the
same
as
shown
in
the factory
test
report and
the
table
below.
U
niform
Downflow
Zo
ne
Downfl
ow
Sin Sash
lOin
Sash
SG400 60 to 70
FPM
Zone I 62-
72
FJ>M
60-70
FP
.\1
Zo
ne
2
110-120
FPM
110-120
FPM
Your test procedures
should
be identical to
ours
so
that
comparing
test results will have meaning.
Please correspond directly
with
us
to
request
detailed procedures for
your
particular cabinet
model. Alt
erna
te testing procedures
can
be found
in
the
NSF
International Standard No.
49.
SG600
60
to
70
FPM*Zone I 60-
70
FPM
62
-
72
FP
i
'vl
The
Airflow
Bala
n
ce
Warning! This procedure should
be
performed
by
4.
qualified
te
chnicians only.
The
airflow balance which
is
set
at
the
factory provides 5.
your
unit
with air
volume
and
vc
locit
y contr
ol
to
minimize
leakage of airborne contamination either
in
or out of
the
work
area.
In
order lo duplicate as closely
as
possible the aiflow char-
acteristics described
in
lhe
original factory
le
st report. please
follow
th
ese s
teps:
I.
Adju
st
the
viewscrecn to
its
connerct 8-inch operating
bcigbl. If
the
viewscre
en
is
scllo any other
bcighl
an
alarm
will
so
un
d.
19
Zone 2
10
5-11
5
FPM
100-110
FPM
*SG600 10" sash
is
only zo
ne
downflow.
Alter
you
have
compared
your
figures
with
tho
se
origin.aUy recorded
at
the
factory,
make
whatever adjttstments
may
be necessary.
As the
HEP
A (High Efficiency
Particulate
Air) filters
load
up
with particulates, airflow
wiJI
be maintained automatically,
at
l
east
until the filter resistance i:rtcreases 50
percent
or
more.
When
airflow
eventually
diminishes,
an
alarm
wi.ll
sound.
fiNe explained
the
alarm
function
at
the beginning of Section 3.) You
will
have
to
increase
the
blower
speed
in
or-
der
to
maintain
the
original
volume
of
recir-
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