Building Design and Engineering Approaches to Airborne Infection Control

1. Building Design and Engineering Approaches to Airborne Infection Control This course has been supported by the President’s Emergency Plan for AIDS Relief (PEPFAR) through Centers for Disease Control &Prevention (CDC) under the terms of U2G/PS002710-02

2. Biohazard Safety Cabinets

3. Biohazard Safety Cabinets • The terms Biological Safety Cabinet and Bio-Safety Cabinet are used to describe a variety of containment devices equipped with HEPA filter(s) • The terms should only be applied to those devices that meet the requirements of Class I, II, or III specifications. • Provide personnel or both personnel and product protection from bio hazardous materials. • BSC Classes based on their construction, airflow velocities and patterns, and their exhaust systems This course has been supported by the President’s Emergency Plan for AIDS Relief (PEPFAR) through Centers for Disease Control &Prevention (CDC) under the terms of U2G/PS002710-02

4. Biohazard Safety Cabinets CLASS I – BSC • 100% Exhaust • Inflow Velocity Critical. • BSL 1 –3 Usage • Personnel protection only • CDC/NIH recommends a glove-port panel for use with small amounts of radionuclide’s when exhausted • Typical uses today: Toxic powder weighing, necropsy • Maybe thimble or direct connected to an exhaust system. This course has been supported by the President’s Emergency Plan for AIDS Relief (PEPFAR) through Centers for Disease Control &Prevention (CDC) under the terms of U2G/PS002710-02

5. Biohazard Safety Cabinets CLASS II A2– BSC • 30% Exhaust, 70% Re-circulate • Negative Pressure Plenum • Inflow Velocity and Downward velocities • BSL 1 –3 Usage. • Personnel, Environment and Product Protection. • Minute amounts of volatile toxic chemicals and radionuclide's if canopy/thimble exhausted. • Typical uses today: Bacterial, Viral, Fungal, Parasitic, Arbor-viruses. This course has been supported by the President’s Emergency Plan for AIDS Relief (PEPFAR) through Centers for Disease Control &Prevention (CDC) under the terms of U2G/PS002710-02

6. Biohazard Safety Cabinets CLASS II B2 – BSC • 100% Exhaust • Negative Pressure Plenum • Inflow Velocity 0.51m/sec minimum • BSL 1 –3 Usage. • Personnel Environment & Product protection. • Small amounts of volatile toxic chemicals and radionuclide’s • Must be directly connected to exhaust duct. • Must have interlocked internal blower with audible and visual alarm for exhaust failure. • Typical uses today: Bacterial, Viral, Fungal, Parasitic, Arbor-viruses, Prion, Cytotoxics This course has been supported by the President’s Emergency Plan for AIDS Relief (PEPFAR) through Centers for Disease Control &Prevention (CDC) under the terms of U2G/PS002710-02

7. Biohazard Safety Cabinets CLASS III – BSC • 100% Exhaust, Glove Box type design. • Negative Pressure at 125Pa Minimum • Double HEPA Filter Exhaust recommended. • BSL 1-4 • Personnel and Product Protection. • Small amounts of volatile toxic chemicals and radionuclides. • Must be direct connected with typical exhaust requirement being 23.7-70.8 L/s at 125 Pa. • Must have negative pressure alarm for cabinet or exhaust failure. • Typical uses today: Toxic Powders , BSL 4 Agents, BSL3 Agriculture. This course has been supported by the President’s Emergency Plan for AIDS Relief (PEPFAR) through Centers for Disease Control &Prevention (CDC) under the terms of U2G/PS002710-02

8. Biohazard Safety Cabinets CABINET SELECTION • Only the product protection required • Laminar Flow Bench • Only Personnel protection • Fume Hood • Only Personnel and environmental protection • BSC I • Personnel, product, and environmental protection • BSCII + This course has been supported by the President’s Emergency Plan for AIDS Relief (PEPFAR) through Centers for Disease Control &Prevention (CDC) under the terms of U2G/PS002710-02

9. Biohazard Safety Cabinets CABINET SELECTION • Minute Amount • Small Amount • In no instance should the chemical concentration approach the lower explosion limits of the compound. • Type A2 cabinets used for work with minute quantities of volatile toxic chemicals and tracer amounts of radionuclide’s required as an adjunct to microbiological studies must be exhausted through properly functioning exhaust canopies. This course has been supported by the President’s Emergency Plan for AIDS Relief (PEPFAR) through Centers for Disease Control &Prevention (CDC) under the terms of U2G/PS002710-02

10. Biohazard Safety Cabinets Major International Standards for Biological Safety Cabinets : • American Standard NSF/ANSI 49 • European Standard EN 12469 • Australian Standard AS 2252 • Japanese Standard JIS K 3800 • Chinese Standard SFDA 440569 • SABS VC 8041 This course has been supported by the President’s Emergency Plan for AIDS Relief (PEPFAR) through Centers for Disease Control &Prevention (CDC) under the terms of U2G/PS002710-02

11. Biohazard Safety Cabinets VALIDATION HEPA Filter Teak Test This course has been supported by the President’s Emergency Plan for AIDS Relief (PEPFAR) through Centers for Disease Control &Prevention (CDC) under the terms of U2G/PS002710-02

12. Biohazard Safety Cabinets VALIDATION Down-flow and inflow velocity. This course has been supported by the President’s Emergency Plan for AIDS Relief (PEPFAR) through Centers for Disease Control &Prevention (CDC) under the terms of U2G/PS002710-02

13. Biohazard Safety Cabinets VALIDATION Airflow Visualisation This course has been supported by the President’s Emergency Plan for AIDS Relief (PEPFAR) through Centers for Disease Control &Prevention (CDC) under the terms of U2G/PS002710-02

14. Lighting Noise Vibration Biohazard Safety Cabinets VALIDATION Secondary Tests This course has been supported by the President’s Emergency Plan for AIDS Relief (PEPFAR) through Centers for Disease Control &Prevention (CDC) under the terms of U2G/PS002710-02

15. Biohazard Safety Cabinets STANDARDS COMPARISON FOR CLASS II BIOHAZARD SAFETY CABINETS This course has been supported by the President’s Emergency Plan for AIDS Relief (PEPFAR) through Centers for Disease Control &Prevention (CDC) under the terms of U2G/PS002710-02

16. Biohazard Safety Cabinets • INSTALLATIONRECOMMENDATIONS • Avoid Drafts Around BSC Cabinets • Non-Aspirating air inlets should project air away from microbiological safety cabinets (No Coander effect!) • Sidewall HVAC diffusers are unsuitable. • Personnel traffic generates local air movements and possible loss of barrier containment. • The sudden opening and closing of doors can disrupt cabinet airflows. This course has been supported by the President’s Emergency Plan for AIDS Relief (PEPFAR) through Centers for Disease Control &Prevention (CDC) under the terms of U2G/PS002710-02

17. Biohazard Safety Cabinets • INSTALLATIONRECOMMENDATIONS • Avoid Drafts Around BSC Cabinets… • Doors can cause local airflow disruptions and should be considered during cabinet placement. • If cabinet has to be exhausted to atmosphere, consideration should be taken in the placement to allow for exhaust connections. This course has been supported by the President’s Emergency Plan for AIDS Relief (PEPFAR) through Centers for Disease Control &Prevention (CDC) under the terms of U2G/PS002710-02

18. Biohazard Safety Cabinets • INSTALLATION RECOMMENDATIONS • There should be an allowance of at least 600mm in the direction of exhaust discharge (Filter Replacement) • Power Supply and access to power connections. • In Ventilated rooms where cabinets are place the cabinet should not influence airflow patterns • Exhausting Cabinets placed in unventilated rooms require adequate airflow to the cabinet. (≈0.48m³/s each!). • Location should allow adequate space behind cabinet for testing and cleaning. • Location should allow for system decontamination. This course has been supported by the President’s Emergency Plan for AIDS Relief (PEPFAR) through Centers for Disease Control &Prevention (CDC) under the terms of U2G/PS002710-02

19. Biohazard Safety Cabinets EXHAUST SYSTEMS • Solid connections (Canopy Connections) are used for class I, II B2 and Class 3 Cabinets and are connected to a dedicated leak tight extraction system. • Secondary Extraction fans to be interlocked with Cabinet and cabinet • Exhaust fitted with an automatic anti backdraft system • There should be volume flow controllers on the system • Gas tight dampers should be provided for decontamination • An alarm system should be fitted to indicate loss of exhaust flow • The exhaust stack should end at least 3m above the roof/parapet wall to avoid re-entrainment by the building • Redundancy should be considered This course has been supported by the President’s Emergency Plan for AIDS Relief (PEPFAR) through Centers for Disease Control &Prevention (CDC) under the terms of U2G/PS002710-02

20. Biohazard Safety Cabinets EXHAUST SYSTEMS • Thimble exhaust systems used for class I and II A2 Biohazard safety cabinets. • Because the unit is extracting from the room as well as the cabinet a second filter can be fitted to the exhaust system. • If required by a risk assessment • Decontamination provisions may needto be made. Image Dr PA Jensen This course has been supported by the President’s Emergency Plan for AIDS Relief (PEPFAR) through Centers for Disease Control &Prevention (CDC) under the terms of U2G/PS002710-02

21. Biohazard Safety Cabinets DECONTAMINATION. • BSCs must be decontaminated: • prior to decommissioning and salvage • before physically moving the cabinet and • whenever maintenance work, filter changes or access to contaminated portion of the cabinet. • Para formaldehyde 11g/m³ Cabinet volume -depolymerised via heating Mantle . • Ammonium bicarbonate at >10% is used to neutralize the Paraformaldehyde. • Humidity kept at 70% • Cabinet has to be sealed “leak tight”. • Duct connections should be isolated. • Decontamination minimum 6 hours • Clearly marked “Decontamination In Progress”. • Validation Methods Completed (chemical indicators) • A certificate is issued. This course has been supported by the President’s Emergency Plan for AIDS Relief (PEPFAR) through Centers for Disease Control &Prevention (CDC) under the terms of U2G/PS002710-02

22. Biohazard Safety Cabinets • Additional Methods of Decontamination. • Vaporized hydrogen peroxide. • System safe • Systems have no residue. • Comparatively Costly • Chlorine Dioxide. • Costly • Corrosive • Chlorine gas is potentially explosive. This course has been supported by the President’s Emergency Plan for AIDS Relief (PEPFAR) through Centers for Disease Control &Prevention (CDC) under the terms of U2G/PS002710-02

23. Biohazard Safety Cabinets • -MAINTENANCE AND VALIDATION • -Cabinets should be kept clean and dust free in accordance with the manufacturers specifications. • -Log filter pressures and note any dramatic changes. • -In South Africa BSC Class II A2 have to be validated Bi-Annually with calibrated equipment. • HEPA Filter leak tests. • Down flow Velocity and flow uniformity test. • Inflow velocity test. • If present pre-filters should be replaced. • Smoke test to confirm operator protection. • Visual inspection of cabinet to ensure it is free from cracks and defects. • Inspect extraction system if fitted. • Inspect alarm systems • Vibration • Lighting • Validation certificate should be issued with date and date of next due validation. • Copies of all equipment calibrations must be available. This course has been supported by the President’s Emergency Plan for AIDS Relief (PEPFAR) through Centers for Disease Control &Prevention (CDC) under the terms of U2G/PS002710-02