Labconco Biological Safety Cabinets 34609 Series - Manual (Page 29)

Chapter 4: Performance Features and Safety Precautions
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Cabinet Air Intakes (Grilles), Ductwork and Air
Balance Controls
The location, size, and pattern of the grilles at the front and rear of the work
area affect cabinet containment and performance.
Note: Never block or obstruct the grilles of the Biosafety Cabinet.
The internal ductwork of the Biosafety Cabinet conveys the air from the work
area to the blower, and then from the blower to the filters. The positive
pressure rigid plenum of the Biosafety Cabinet is designed to deliver a more
uniform airflow to both HEPA filters, optimizing filter loading and
operational life.
Ultraviolet (UV) Lamp
Note: The Ultraviolet (UV) lamp is not recommended or readily available for
Cell Logic Biosafety Cabinets with the Scope-Ready Package because the
sash cannot be safely closed with the microscope in place. Good surface
disinfection is the preferred method. Furthermore, the following factors
cause concern with UV and microscopes:
• The microscope creates a shadow where the UV light cannot reach.
• Removing the microscope is often undesirable.
• Running UV light with the microscope inside will degrade the
microscope.
The optional UV lamp generates a primary wavelength of light of 254nm. A
secondary emission is in the visible (blue) wavelength, resulting in the
characteristic blue color while operating. UV light with a wavelength of 254
nm is biocidal, primarily by creating thymine dimers in DNA. These dimers
prevent the correct transcription of the DNA into RNA, resulting in cellular
death or viral inactivation. In order to be effective, the UV light must directly
strike the nucleic acid, and its effectiveness can be diminished or negated by
dissolved proteins or metals, or by other UV-opaque substances protecting
the target nucleic acid.
Because of its limitations, UV light should be used as an adjunct to good
surface disinfection practices. In order to get optimum performance from the
UV light, it should be replaced after 6,000 hours of operation or less, and the
exterior surface of the lamp should be kept clean and free of dust.
Note: The Cell Logic Biosafety Cabinet records the number of hours of
operation of the UV light. You can program in the number of hours (in 100-
hour increments) it will operate before a replacement message is displayed.