OM0228
Page
57
of
99
February/2014
NOTE:
If
the
upstream
challenge
port
is
deemed
contaminated
and
not
accessible,
use
both
downflow
and
exhaust
volume
for
determining
challenge
concentrations.
Use
following
area
information
below
with
average
downflow
velocity
and
spot
‐
check
exhaust
velocities
as
measured
to
determine
volume
(CFM)
(CMH).
Use
exhaust
volume
as
given.
Model
Size
*Supply
Area
(ft
2
)(m
2
)
Exhaust
Volume
CFM
(CMH)
400
7.57
(.214)
754
(1281)
600
11.48
(.325)
1100
(1869)
*
Measured
4
inches
(102mm)
above
the
bottom
edge
of
the
window.
Laskin
Nozzle
Concentration
Formula
#
Nozzles
x
135
CFM
x
100
ug/L
Challenge
Downflow
(CFM)
+
Exhaust
(CFM)
Concentration
(ug/L)
#
Nozzles
x
229
CMH
x
100
ug/L
Challenge
Downflow
(CMH)
+
Exhaust
(CFM)
Concentration
(ug/L)
7.7
Airflow
Smoke
Pattern
Test
The
airflow
smoke
pattern
test
is
performed
using
a
smoke
source
(i.e.
smoke
tubes)
in
and
around
the
cabinet
workzone
and
access
opening
to
determine
a
visual
representation
of
the
cabinet’s
containment
performance.
To
perform
the
test,
the
smoke
source
should
be
passed
through
the
following
areas:
1.
A
smoke
source
shall
be
passed
from
one
end
of
the
cabinet
to
the
other,
along
the
center
line
of
the
work
surface,
at
a
height
of
4
inches
(102mm)
above
the
top
of
the
access
opening.
2.
A
smoke
source
shall
be
passed
from
one
end
of
the
cabinet
to
the
other,
1
inch
(25mm)
just
inside
the
view
screen,
at
a
height
6
inches
(152mm)
above
the
top
of
the
access
opening.
3.
Pass
a
smoke
source
along
the
edges
of
the
entire
perimeter
of
the
work
opening
approximately
1.5
inches
(38mm)
outside
the
cabinet,
with
particular
attention
paid
to
corners
and
vertical
edges.
4.
Pass
a
smoke
source
2
inches
(51mm)
from
the
sides
up
inside
of
the
window
at
the
side
channel
seals,
and
along
inside
of
the
cabinet
along
the
top
of
the
work
area
or
immediately
below
the
wiper
gasket.
The
criteria
used
to
evaluate
the
smoke
patterns
is
the
following:
1.
The
smoke
inside
the
cabinet
shall
show
smooth
downward
flow
with
no
dead
spots
or
reflux.
2.
No
smoke
shall
escape
from
inside
the
cabinet.
3.
No
smoke
refluxes
out
of
the
cabinet
once
drawn
in,
nor
does
smoke
billow
over
the
worksurface
or
penetrate
onto
it.
4.
No
smoke
shall
escape
from
the
cabinet.
7.8
Site
Installation
Assessment
Tests
These
tests
are
performed
to
verify
the
sash
position,
airflow
or
pressure
setpoint
where
an
audible
and/or
visual
alarm
will
activate
to
signify
unfavorable
operating
conditions
within
the
biological
safety
cabinet
and/or
the
remote
exhaust
blower.
7.8.1
Sash
Alarm
Step
1:
With
sash
alarm
switch
enabled,
raise
the
sliding
sash
1inch
(2.5cm)
above
the
manufacturer’s
designated
sash
height
for
normal
operation.
Verify
that
the
audible/visual
alarm
activates/sounds.
Step
2:
Return
the
sash
to
its
normal
operating
height.
7.8.2
Airflow
or
Pressure
Alarm
(Verified
During
Exhaust
Airflow
Calibration)
Step
1:
Using
the
primary
or
secondary
inflow
test
method,
lower
the
exhaust
airflow
to
reduce
the
total
flow
by
20%
from
the
certified
testing
value.
Step
2:
Verify
that
the
alarm
activates
when
the
total
flow
has
dropped
to
this
point.
Step
3:
Adjust
alarm
setpoint
as
necessary.
=
=
Summary of Contents for Labgard NU-430-400
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