working in a biological safety cabinet
Post on 03-Feb-2016
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WORKING IN A BIOLOGICAL SAFETY CABINET
BTO
Biological Services Ltd.
Risk Group Definitions• Risk Group 1
Low 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
Biological Agent
• Biological agents include but are not limited to:Bacteria ParasitesFungi Viral vectorsViruses Recombinant productsRickettsiae Prions
Cultured human or animal cellsand the potentially infectious agents they might contain
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
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 aerosols
inhalable 0.01-100 micronsnasopharyngeal deposition 25-100 micronstracheobronchial deposition 5-25 micronsalveolar deposition 0.01-5 microns
Route of Transmission & Entry
• Inhalation
• Ingestion
• Inoculation
• Direct or indirect contact
Biological Safety Cabinets
• Bad terminologyLaminar flow cabinetsTissue culture cabinetsSterile benches
• Good terminologyBiological Safety cabinetsBiosafety cabinets
• In general, BSC’s are classified according to the method by which air volumes are recirculated or exhausted.
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
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%
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
Types of BSC’s
• Class IProtects the environment and the user – does not protect the product
It 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
Types of BSC’s• Class II
The 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.
Subtypes of Class II BSC’s
• Class IIA1predominant cabinet protects the product user and environment
• Class IIA2protects the product user and environment
• Class IIB1protects the product, user and environment can be used with small amounts of volatiles and gases
• Class IIB2protects the product, user and environment
Class IIA BSC’s
Class IIA BSC’s
Class IIA BSC’s
• Air curtain between sash and work surface is critical to containment
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 --------
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
• Don’t pass dirty items over clean ones
• Do not block the front intake grille
• Work on plastic backed absorbent material – for quick clean ups
Fire in BSC
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
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
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