Presentation on theme: "Airflow and BSC Biosafety and Biosecurity Awareness Training"— Presentation transcript:
1 Airflow and BSC Biosafety and Biosecurity Awareness Training For Afghan and Pakistani BioscientistsJanuary 12-14, 2010SAND No PSandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.11
2 Biological Safety Cabinets (BSCs) Primary means of containmentThree design typesClass I, Class II, and Class IIIDesigned to provide protection forPersonnelDirectional flow of air into cabinetEnvironmentHEPA filtered exhaustProduct (except Class I)Laminar flow of HEPA filtered airBut, how?
3 Primary Barriers – Ventilation Equipment PersonnelProductEnvironmentChemical Fume HoodsxLaminar Flow Clean BenchesClass I Biological Safety CabinetClass II Biological Safety CabinetClass III Biological Safety CabinetIsolators
4 How do HEPA Filters Work? HEPA = High Efficiency Particulate AirMinimum efficiency of 99.97% removal of 0.3 micron particlesHEPA filters do not filter out gases, vapors or volatile chemicals, they only filter out particulates (bacteria and viruses)
5 Class I Biosafety Cabinet Provides personnel and environmental protection, but no product protectionTypical applications include: Housing centrifuges, fermenters, cage dumping in an animal labLABCONCOA. Front opening B. Sash C. Exhaust HEPA D. Exhaust plenumNUAIRE
6 Class II Biosafety Cabinet Provides personnel, environmental, and product protectionType A2Exhaust to room or outside through thimble connection30% recirculated, 70% exhaustedType B2Must be hard ducted to outsideTotal exhaust (100%)Pro: may be used with volatile chemicalsCon: more expensive to operate, harder to balance airflows in lab
9 Primary Barriers: Working in Biosafety Cabinets Proper technique is critical to maintaining personnel and product protection!ElementsDecontaminationSetupWork flowLocations of supplies and waste containersMovement in and outOthersWorkflow from clean to contaminated (“dirty”)
10 Recognizing the Limitations of BSCs Personnel protection depends on inward airflow through the work openingRequires proper techniques by userOnly small quantities of volatile chemicals in any type of BSCMotors on standard BSCs are not sparkproofShould not use bunsen burners or alcohol lamps in BSCsOver time, heat can damage the HEPA filterHeat can create turbulent airflow, compromising protectionAnd, potential for fire to destroy BSCBuildup of flammable vapors with 70% recirculationBSCs need to be tested and certified regularly to have assurance getting expected protectionPrior to serviceAfter repairs or relocationAnnually
11 Secondary BarriersContain the agent within the room or facility in case an agent escapes from the primary barriersBuilding & Room ConstructionSeparated from public areasEasily cleanedFor containment laboratories:Room penetrations sealedDouble-door entryHVAC Issues:Directional airflowExhaust filtrationOther Engineering Controls:Solid waste treatmentWastewater treatmentBuildingRoomBSCTube
12 How do You Establish Directional Airflow? Airflow Offset ControlRelies on airflow through doors at all times“Leaky Box” conceptProvides “Zone Control” of hazards and odorsLabZone 1LabZone 2LabZone 3Directional inward airflow provided such that air will always flow towards areas of higher containmentAirflow
13 Airflow Offset Control 900 cfm Supply1000 cfm ExhaustHow much should the offset be? – IT DEPENDS!(USDA ARS 242.1: 15%, min 50 cfm cfm more appropriate)Modified by P.Jennette100 cfm“Leaky” Level 3
15 Heating Ventilation and Air Conditioning (HVAC) Issues Pressure monitoring devices at entrySmoke testHVAC controlled to prevent sustained positive pressurizationInterlock exhaust/supplyAlarms for HVAC failure (inside and outside the facility)Exhaust air HEPA filtered (sometimes necessary)Sealed ductworkBackflow prevention on supply air (Damper, HEPA)1978 Smallpox lab infection in Porton Down England - Exhaust failure combined with poor practices led to the escape of virus from the BL4 lab (when the lab became + pressurized without an alarm and workers were discarding waste outside of the biosafety cabinet) -- the virus was carried out of the lab through a penetration around a pipe into a research darkroom on the floor above the containment laboratory. The infected researcher died, her mother was infected and survived, and the PI took his own life after the autopsy proved his lab was responsible for the researcher's demise.