WORKING IN A BIOLOGICAL SAFETY CABINET

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WORKING IN A BIOLOGICAL SAFETY CABINET

• BTO
• Biological Services Ltd.

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Risk Group Definitions

• Risk Group 1Low individual and community
  riske.g., E.coli K12, Lactobacilli,
• Risk Group 2Moderate individual risk, low
  community riske.g., Staphylococcal species,
  enterotoxigenic Escherichia coli, Shigella
  species, Salmonella species
• Risk Group 3High individual risk, low community
  riskM. tuberculosis, C.burnetii,
• Risk Group 4High individual risk, high community
  riske.g., Ebola virus

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Biological Agent

• Biological agents include but are not limited
  toBacteria ParasitesFungi Viral
  vectorsViruses Recombinant productsRickettsiae
  PrionsCultured human or animal cellsand the
  potentially infectious agents they might contain

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Biohazard

• A biohazard is a biological agent or a biological
  material that is potentially hazardous to a life
  form
• The manipulation of a biological agent or
  biological material so that the capacity or
  potential to produce infection or disease in a
  living form is present

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Aerosols

• DefinitionAn aerosol is a liquid or particulate
  suspended in a gaseous medium
• Size range is from 0.01 microns 100 microns
• Health relevant fractions of aerosolsinhalable
  0.01-100 micronsnasopharyngeal
  deposition 25-100 micronstracheobronchial
  deposition 5-25 micronsalveolar
  deposition 0.01-5 microns

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Route of Transmission Entry

• Inhalation
• Ingestion
• Inoculation
• Direct or indirect contact

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Biological Safety Cabinets

• Bad terminology Laminar flow cabinets Tissue
  culture cabinets Sterile benches
• Good terminology Biological Safety
  cabinets Biosafety cabinets
• In general, BSCs are classified according to the
  method by which air volumes are recirculated or
  exhausted.

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Air Cleaning Device

• The primary air cleaning device in biological
  safety cabinets is a HEPA filter (High Efficiency
  Particulate in Air)
• HEPA filters do not provide protection against
  volatiles gases or vapours only particulates

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Filter Efficiency

• HEPAA minimum efficiency of capture is 99.97
  for 0.3 micronsAny particulate bigger or smaller
  than 0.3 microns is captured more efficiently
  than 99.97

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Biosafety cabinet review

• When do you work in a Class II BSC?
• When there is potential to create aerosols
• When you need to protect yourself, the product
  and the environment

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Types of BSCs

• Class IProtects the environment and the user
  does not protect the productIt is a partial
  containment device and is suitable for work
  involving low to moderate risk agents
  (containment levels 1, 2 and 3)
• User and environmental protection is made
  possible by constant unidirectional movement of
  air into the cabinet, away from the user through
  HEPA filtration before re-entry into the
  environment. The product is not protected

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Types of BSCs

• Class IIThe Class II biological safety cabinet
  has three key features(i) A front access
  opening with carefully maintained inward
  airflow. (ii) HEPA-filtered, vertical,
  unidirectional airflow within the work area.
  (iii) HEPA-filtered exhaust air to the room or
  exhaust to a facility exhaust system.

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Subtypes of Class II BSCs

• Class IIA1 predominant cabinet protects the
  product user and environment
• Class IIA2protects the product user and
  environment
• Class IIB1 protects the product, user and
  environment can be used with small amounts of
  volatiles and gases
• Class IIB2 protects the product, user and
  environment

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Class IIA BSCs
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Class IIA BSCs
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Class IIA BSCs

• Air curtain between sash and work surface is
  critical to containment

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Working in a Class IIA BSC

• Whenever there is potential for aerosol
  generation you must work in a BSCe.g.,
  manipulating human or animal tissues or fluids
  opening a closed centrifuge cupafter
  centrifugation, taking spent media off Tissue
  culture.
• You need to employ good techniquee.g., employ
  good start up procedures disinfect everything
  you need to work with into the BSC prior to
  commencing work do not block the grilles be
  seated at the right height ensure that nothing
  you need to use is outside the cabinet --------

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Working in a Class IIA1 BSC

• Place everything you need to work with inside the
  cabinet
• Purge to establish airflow
• Separate clean items from dirty items
• Dont pass dirty items over clean ones
• Do not block the front intake grille
• Work on plastic backed absorbent material for
  quick clean ups

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Fire in BSC
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UV Radiation

• UV germicidal lamps produce UV light at 253.7 nm
  wavelength (40 ?Wcm-2) - this has limited
  penetrating power
• The intensity or destructive capability of UV
  decreases by the square of the distance from the
  lamp
• Exposure time is always related to distance
• The intensity of the lamp also decreases with
  time

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UV Radiation

• The intensity of the lamp is drastically affected
  by the accumulation of dust and dirt on it
• UV lights should never be on while someone is
  working in the cabinet
• UV lights should not be left on while anyone is
  in the area and likely to be exposed to reflected
  UV radiation