![]() ![]() RG1, RG2, and RG3 biological material can be handled safely in a Class II BSC. Class II Type A are the most commonly encountered BSC in a microbiology laboratory. Some BSCs may recirculate air within the containment zone, while others may exhaust air directly to the outside atmosphere through dedicated ductwork. The main differences between the types are the ratio of air exhausted from the BSC to the air that is recirculated within the BSC, and the type of exhaust system present. Newer models do exist that can be configured as either a type A or a type B BSC during installation. Class II BSCs are further divided into four types: A1, A2, B1, and B2. 11.1.2 Class IIĬlass II BSCs provide personnel and environmental protection however, unlike Class I BSCs, they also offer product protection. BSCs that are used as cage changing stations may require more frequent filter replacement due to filter loading. Class I BSCs are suitable for work with Risk Group 1 (RG1), Risk Group 2 (RG2), and Risk Group 3 (RG3) biological material. Since the air is never recirculated within the BSC, it is possible to work safely with minute quantities of volatile toxic chemicals if the BSC is hard-ducted. Class I BSCs can recirculate exhaust air into the containment zone, or exhaust directly to the outside atmosphere when hard-ducted to the facility's heating, ventilation, and air conditioning (HVAC) system. Room air is drawn into the cabinet through the front opening, moves directly across the workspace, and is then discharged from the BSC through a HEPA filter. This type of cabinet is commonly used to enclose equipment (e.g., fermenters, homogenizers) or for procedures where product protection is not a concern (e.g., cage changing). Footnote 1 11.1 Classes and Descriptions 11.1.1 Class IĬlass I BSCs provide personnel and environmental protection, but offer no product protection ( Figures 11-1a and 11-1b). The physical containment requirements, operational practice requirements, and performance and verification testing requirements relating to BSCs in containment zones regulated by the Public Health Agency of Canada (PHAC) and the Canadian Food Inspection Agency (CFIA) are described in Matrices 3.7, 4.6, and 5.1 of the Canadian Biosafety Standard (CBS), 2 nd Edition. Different manufacturers may have unique design features and new technology in their BSCs. This chapter provides general descriptions of the different types and classes of BSCs. Some classes of BSCs also offer product protection by using HEPA-filtered downflow to flush the cabinet interior of airborne contaminants and to prevent unfiltered inflow air from entering the work area. ![]() The air that is exhausted into the surrounding containment zone or directly to the outside atmosphere is passed through high efficiency particulate air (HEPA) filters to protect the environment. ![]() Personnel protection is provided through a continuous stream of inward air, known as inflow, which helps prevent aerosols from escaping through the front opening. The various classes and types of BSCs operate under the same basic principles. Chapter 11 - Biological Safety Cabinetsīiological safety cabinets (BSCs) provide effective primary containment for work with infectious material or toxins when they are properly maintained and used in conjunction with good microbiological laboratory practices. ![]()
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