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Containment Equipment and NSF 49. Containment – BMBL . Primary containment is the protection of personnel and the immediate lab environment from exposure to infectious agents, and is provided by good microbiological technique and the use of appropriate safety equipment.
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Containment – BMBL • Primary containment is the protection of personnel and the immediate lab environment from exposure to infectious agents, and is provided by good microbiological technique and the use of appropriate safety equipment. • Safety equipment (primary barriers) includes biological safety cabinets, enclosed containers, and other engineering controls (i.e. safety centrifuge cups) designed to remove or minimize exposure hazards to biological materials.
Containment – BMBL • Note: If a containment device such as a biological safety cabinet is impractical then personal protective equipment may form the primary barrier between personnel and the infectious materials. Ex. Certain animal studies, agent production activities, and activities related to the maintenance, service or support of the lab facility.
Biological Safety Cabinets (BSCs) • Primary means of containment for infectious splashes or aerosols • Can provide personnel, product, and environmental protection provided appropriate use and cabinet maintenance • Not to be confused with horizontal laminar flow (clean benches) or vertical laminar flow hoods • BSCs described in Appendix A of the BMBL
BSCs – Recommendations and Guidance • NSF/ANSI 49 – Class II (laminar flow) Biosafety Cabinetry (2002) • CDC/NIH Primary Containment for Biohazards – Selection, Installation and Use of Biological Safety Cabinets (2000) • BMBL 5th Edition (2007), Appendix A • Institutional Biological Safety Cabinet Guidance Documents
Class II A2 • Has HEPA filtered downflow air that is a portion of the mixed downflow and inflow air • May exhaust HEPA filtered air back into the laboratory or to the exterior of building through an exhaust canopy
Class II B2 • Has HEPA filtered downflow air drawn from the laboratory or the outside air (i.e., no recirculation) • Class II B2 cabinets are always hard ducted for exhaust to outside of building
Safe Use of BSCs • BSC must be turned on at least 5 minutes prior to starting work • Personnel working within BSCs should wear lab coats, as well as appropriate gloves and safety glasses • BSC work surfaces must be decontaminated with an appropriate disinfectant at the end of each work operation
Safe Use of BSCs • Avoid excess motion and be aware of drafts in room that may interfere with normal air flow • All cabinets must be certified for use on annual basis when first installed, moved, or repaired
TYPE FACE VELOCITY (LFPM) AIRFLOW PATTERN RAM or CHEMS? BSL’s PRODUCT PROTEC-TION CLASS I 75 In at front; rear & top through HEPA NO 2,3 NO CLASS II TYPE A1 75 70% recirculated through HEPA; exhaust through HEPA NO 2,3 YES CLASS II TYPE A2 100 Same as IIA1; but plena under neg. pressure; exhaust through HEPA or ducted LOW LEVELS 2,3 YES CLASS II TYPE B1 100 30% recirculated through HEPA; exhaust via HEPA & ducted LOW LEVELS 2,3 YES CLASS II TYPE B2 100 No recirculation; total exhaust via HEPA & ducted YES 2,3 YES CLASS III N/A Supply air inlets and exhaust through double HEPA or HEPA/incineration combo YES 3,4 YES BSC Types and Operation
HEPA Filters • Removes particles > 0.3µm (includes all bacteria, spores, and viruses) to 99.97% efficiency - inertia, interception, diffusion, and electrostatic attachment • The filter medium is borosilicate fibers treated with water-repellant binder • Pleated to provide more surface area of filter, with separators to prevent collapse from air flow
BSCs – General Use • Provide personnel, product and environmental protection for the use infectious biological agents in appropriate BSCs; can also be used to provide sterile environment. • Leave unit on 24/7 or let run for 5 minutes prior to work. • Do not block baffle openings or place bulky items in the cabinet that will prevent air from entering the baffle opening. • Conduct work at least six inches from the edge of the hood at appropriate sash height. • Keep cabinet clean and uncluttered. Wipe up spills immediately w/ 70% ETOH or other disinfectant. • UV lights can be used but not generally recommended. Chemical disinfection is preferred. • Be aware that drafts from open windows, open doors, fans, air conditioners, or high traffic walkways may interfere with normal cabinet air flow. • Decontaminate all materials prior to exit from unit; including waste. • No open flames in cabinet!
BSCs – Installation Considerations • Ducting - If necessary depending on type (i.e. B1, B2) • Plumbing - No combustible gas! Vacuum only. • Electrical • Outlet above or below unit for access purposes during field certification process • Location • BSCs should be located in lab where airflow patterns are not disrupted (i.e. away from doors, drafts, etc.)
BSCs – Design, Operation, and Certification NSF 49 – Basic requirements for design, construction, and performance of BSCs; standards for performance testing and field certification testing • Installation recommendations • Reliable operation • Durability and structural stability • Cleanability • Limitations on noise and vibration • Motor/blower performance • Illumination
NSF 49, Annex F – Field Tests Certification performed at time of installation, removal of any panels, or after relocation; annually thereafter recommended REQUIRED: • Downflow velocity profile test • Inflow velocity test • Airflow smoke patterns test • HEPA filter leak test • Cabinet integrity tests (Type A1 only) • Site installation assessment tests OPTIONAL: • Lighting intensity • Vibration and noise level • Electrical leakage, ground circuit resistance, polarity tests
Downflow Velocity Profile Test Purpose: measure velocity of air moving through workspace at 4 inches above bottom edge of window sash Measuring apparatus: thermal anemometer Acceptance: avg downflow velocity within +/- 5 ft/min of manufacturers specifications; within +/-16 ft/min for any individual point
Inflow Velocity Test Purpose: measure velocity of air moving through unit opening (face velocity) Measuring apparatus: thermal anemometer; direct inflow measurement instrument Acceptance: avg velocity within +/- 5 ft/min of normal flow for cabinet type
Air Smoke Patterns Test Purpose: measure airflow along the entire perimeter of the work access opening is inward, airflow within the work area is downward with no dead spots or refluxing, ambient air does not pass on or over the work surface, and there is no escape to the outside of the cabinet at the sides and top of the window Measuring apparatus: visible cold smoke such as titanium tetrachloride Acceptance: visual evidence verifying above purpose
HEPA Filter Leak Test Purpose: ensure integrity of downflow and exhaust HEPA’s, filter housing, and filter mounting frame Measuring apparatus: aerosol photometer capable of measuring 10 µg/L of polydisperse dioctylphthalate (DOP)particles; other aerosol generator w/ pressure gauge Acceptance: sustained aerosol penetration shall not exceed 0.01% of the upstream concentration at any point
Cabinet Integrity Tests Pressure Decay/Soap bubble: performed to determine if exterior surfaces of all plenums, welds, gaskets, and plenum penetrations or seals are free of leaks • Pressurize cabinet to 2” wg for 30 minutes with no soap bubbles or leakage of <0.2”wg
Site Installation Assessment Tests • Airflow alarm • Sash alarm • Interlocks • Exhaust system performance / canopy connection
Understanding & Using Protective Hoods During Animal Husbandry Activities
Types of Hoods at UTHSC-H • Biosafety cabinets (BSC) • Chemical fume hoods • Animal cage changing stations • Laminar flow hoods
What is a Chemical Fume Hood? • Protective barrier for working with hazardous chemicals • Has no HEPA filtration- exhausted directly out of building • Chemical fume hoods are not BSCs!!! • Protects worker, but not work environment • Protection from animal dander • Ideal for those with allergies
Safe Use of Chem Fume Hood • Conduct work at least six inches from the edge of the hood • Lower the sash to a reasonable height to protect yourself • Keep hood clean and uncluttered • Have a general awareness of the operation of hood and • Be aware of any visual or audible differences that may indicate a change in function
Cage Changing Station Features • The downdraft airflow pattern provides personnel allergen protection from animal hair, dander, and bedding materials • HEPA filtered • Protection provided to animals, cages and bedding
Safe Use of a Animal Changing Station • Personnel working with station should wear personal protective equipment • Any required vivarium clothing • Lab coat/wrap around gown • Gloves • Safety glasses • Decontaminate surface with an appropriate disinfectant at the end of each work operation
Laminar Air Hood Features • Provides the ideal particle free, bacteria free, clean air environment • HEPA filtered • Positive Air Flow-outflow towards worker • Creates airflow throughout the entire work zone • Protects animals, not personnel • Not for use with biohazardous animals!!!!
Safe Use of Laminar Flow Hood • Personnel working with station should wear personal protective equipment • Any required vivarium clothing • Lab coat/wrap around gown • Gloves • Safety glasses • Decontaminate with an appropriate disinfectant at the end of each work operation • Not for use with biohazardous animals!!
