BIO SAFETY-CABINET
Bio Safety Cabinet Is Designed To Provide Both A Clean Work Environment And Protection To Operators Who Work With Biological Hazards. It Has Vertrical Laminar Airflow To Create A Barrier To Airborne Particles And Micro Organisms. High Efficiency Particulate Air (hepa) Filters Are Used To Provide Clean Air In The Work Area As Well As To The Environment Through Exhaust The Hepa Filter. The Air In The Cabinet Is Re-circulated Over The Work Area Through The Hepa Filter. Biosafety Cabinets Are Classified Into Three Categories: Class I, Class li, Class lii.
Class I: The Class I Biological Safety Cabinet Is An Open Front Negative Pressure Cabinet. The Exhaust Air From The Cabinet Is Filtered By A High-efficiency Particulate Air (hepa) Filter. It Provides Protection To Human Beings And Environment Only. Class I Cabinets Suitable For Work Shere No Product Protection Is Required.
Class li: The Class li Vertical Laminar-flow Biological Cabinet Is An Open-front, Ventilated Cabinet. This Cabinet Provides A Hepa-filtered Re Circulated Mass Airflow Within The Workspace. The Exhaust Air From The Cabinet Is Also Filtered By Hepa Filter. Thus, Class li Bio Safety Cabinet Provides Protection To Product As Well As To Human Beings And Environment. While Hepa Filters Are Effective For Trapping Particulates And Infectious Agents, It Is Suitable For The Containment Of Bio Hazardous Material Thereby Providing Sterile Environment For Cell Culture. Class li Cabinet Is Most Versatile And Economical Model There Are Four Types Of Class li Cabinets:
Class li Type A1 (formerly Designated Type A): It Exhausts Approximately 30% Air Back Into The Laboratory And Re Circulates The Remainder. May Have Positive Pressure Contaminated Ducts And Plenums That Are Not Surrounded By Negative Pressure Plenums.
Class li Type A2 (formerly Designated Type B3): It Exhausts Approximately 30% Air Through A Hepa Filter Back Into The Laboratory Or To The Environment Through An External Exhaust Duct. It Has All Biologically Contaminated Ducts And Plenums Under Negative Pressure Or Surrounded By Negative Pressure Ducts And Plenums.
Class li Type B1: It Exhausts 70% Air Through A Dedicated Duct Exhausted To The Atmosphere After Passing Through A Hepa Filter And Re Circulates The Remainder. It Has All Contaminated Ducts And Plenums Under Negative Pressure Or Surrounded By Negative Pressure Ducts And Plenums.
Class li Type B2: (sometimes Referred To As "total Exhaust"): It Exhaust 100% Air Through An Exhaust Duct After Passing Through A Hepa Filter And Contaminated Positive Pressure Plenums Must Be Surrounded By A Vacuum.
Class lii: The Class lii Cabinet Is A Totally Enclosed Ventilated Cabinet Of Airtight Construction. Operations Within The Class lii Cabinet Are Through Attached Rubber Gloves. When In Use, The Class lii Cabinet Maintains Negative Air Pressure. Supply Air Is Drawn Into The Cabinet Through Hepa Filter. The Cabinet Exhaust Air Is Filtered By Two Hepa Filters Installed In Series, Before It Is Discharged Outside The Facility. The Exhaust Fan For The Class lii Cabinet Is Generally Separate From The Exhaust Fans Of The Facilities Ventilation System.
