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Primary engineering control

Primary engineering control
Type B1 cabinets must be hard-ducted preferably to their own dedicated exhaust system or to a properly designed laboratory building exhaust As indicated earlier blowers on laboratory exhaust systems should be located at the terminal end of the ductwork A failure in the building exhaust system may not be apparent to the user as the supply blowers in the cabinet will continue to operate A pressure-independent monitor should be installed to sound an alarm and shut off the Biological safety cabinets supply fan should failure in exhaust airflow occur Since this feature is not supplied by all cabinet manufacturers it is prudent to install a sensor in the exhaust system as necessary To maintain critical operations laboratories using Type B Biological safety cabinets should connect the exhaust blower to the emergency power supply
This type II B2 Biological safety cabinets is a total-exhaust cabinet no air is re-circulated within it This cabinet provides simultaneous primary biological and chemical containment The supply blower draws in room air or outside air at the top of the cabinet passes it through a HEPA filter and down into the work area of the cabinet The building or cabinet exhaust system draws the air through both the rear and front grilles capturing the supply air plus the additional amount of room air needed to produce a minimum calculated or measured inflow face velocity of 100 lfpm All air entering this cabinet is exhausted and passes through a HEPA filter and perhaps some other air-cleaning devices such as a carbon filter prior to discharge to the outside Exhausting as much as 1200 cubic feet per minute of conditioned room air makes this cabinet expensive to operate Class II Type B3 Biological safety cabinets This biological safety cabinet is a ducted Type A cabinet having a minimum inward airflow of 100 lfpm All positive pressure contaminated plenums within the cabinet are surrounded by a negative pressure plenum Thus leakage in a contaminated plenum will be into the cabinet and not into the environment
The Class III biological safety cabinet was designed to work with biosafety level 4 microbiological agents and provide maximum protection to the environment and the worker It is a gas-tight enclosure with a non-opening view window Access for passage of material into the cabinet is through a dunk tank that is accessible through the cabinet floor or double-door pass-through box such as an autoclave that can be decontaminated between uses Both supply and exhaust air are HEPA filtered Exhaust air must pass through two HEPA filters or HEPA filter and an air incinerator before discharge to the outsiders Long heavy-duty rubber gloves are attached in a gas-tight manner to ports in the cabinet and allow for manipulation of the materials isolated inside Although these gloves restrict movement they prevent the user’s direct contact with the hazardous materials The trade-off is clearly on the side of maximizing personal safety Depending on the design of the cabinet the supply HEPA filter provides particle-free though somewhat turbulent airflow within the work environment
The biological safety blower must be turned on at least five minutes before starting work in order to purge the air and remove any particulates in the cabinet Prior to performing work be sure the biological safety cabinet is exhausting properly If cabinet is not working properly then notify laboratory supervisor or the educating professor The laboratory supervisor or educating professor shall contact the Department Chemical Hygiene Officer and the Department of Environmental Health and Safety Laboratory personnel shall wear a closed-front laboratory coats
and gloves The gloves should overlap the cuffs All materials needed for the manipulations shall be placed in the cabinet before the work is initiated to minimize in-and-out motions The rapid movement of a worker’s arm in a sweeping motion and out of the cabinet will disrupt the air curtain and may compromise the partial barrier containment provided by the BSC Moving arms in and out slowly perpendicular to the face opening of the cabinet will reduce the turbulence Do not cover air intake grill Laboratory personnel shall not rest arms on the air intake grill All operations shall be performed at least four inches from the front grill on the work surface Biohazard collection bags should not be taped or placed on the outside of the cabinet The frequent inward outward movement needed to place objects in these bags is disruptive to the integrity of the cabinet air barrier and can compromise both personnel and product protection Potentially contaminated materials for example containers equipment etc should not be brought out of the cabinet until they have been surface decontaminated

Biological safety cabinets is the most important equipments for environmental control.

In this video, Deputy Chiang will explain in detail the categories of these biological safety cabinets. By knowing these, you may get the idea about how to choose or how to evaluate a qualified equipments for your hospitals.

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