Labconco Biological Safety Cabinets 34269 Series - Manual (Page 28)

Chapter 4: Performance Features and Safety Precautions
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Original instructions
ULPA Filters
Optional ULPA filters may be used to replace the standard HEPA filters in
the Purifier Logic+ biosafety cabinets. ULPA filters have the same properties
as described above except they are rated at least 99.999% efficient in
removing particles 0.1-0.2 or 0.2-0.3 micron.
Laminar Airflow
Laminar airflow is defined as the movement of a body of air in a single
direction, with a uniform velocity. In practice, the laminar downflow of air in
the cabinet captures any aerosol generated in the work area of the cabinet,
and directs it to the HEPA filters. In order to be true laminar downflow, a
number of individual downflow velocity test points (The Downflow Velocity
Profile) must be +/- 16 feet per minute (0.08 m/s) of the average of all the test
points. This is illustrated in Figure 4-2.
Figure 4-2