Labconco Type C1 Biosafety Cabinet Models 30468 - Manual (Page 82)

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Downflow Velocities
All Axiom models, are classified as having uniform downflow, and the average downflow
velocity for all 4-foot models is 65+/-5 FPM, and all 6-foot models is 55+/-5 FPM, tested
as per ANSI/NSF Standard 49:2012.
All readings should be in a plane 4 inches above the bottom edge of the sash, and the
UV Lamp, IV bar and all other accessories must be removed before performing
downflow test. The test grid dimensions are outlined in Table 5-3. When taking readings
in the back two rows, the anemometer probe should be pointing toward the nearest side
wall, as shown in figure 5-8. When reading the front row, the probe should point
outward, toward the front of the cabinet, as shown in Figure 5-9. The thermal
anemometer’s time constant should be set at 10-15 seconds for greater readout
stability.
Table 5-3
Downflow Test Specifications
Cabinet Width (Feet) 4 4 6 6
Sash Height (inches) 8 10 8 10
Nominal Avg. Downflow
(FPM)
65+/-5 65+/-5 55+/-5 55+/-5
Downflow test grid # of
points
24 24 36 36
Test Grid (# rows x #
columns)
3 x 8 3 x 8 3 x 12 3 x 12
Test Grid Data (in
inches)
Grid distance from back & sides 6.0 6.0 6.0 6.0
Distance between rows 5.75 5.55 5.75 5.55
Distance between columns 5.21 5.21 5.50 5.50