This document discusses biological safety cabinets and their classification. It identifies the main types of open front biological safety cabinets as Class I, Class II, and Class III. Class I cabinets provide minimal containment and protect the user, while Class II and Class III cabinets provide higher levels of containment for infectious materials. The document describes the different classes and types of cabinets, including their air flow recirculation percentages and exhaust requirements. It also discusses HEPA and ULPA air filters used in the cabinets and how they capture particles of different sizes.

1. Biological Safety
Cabinets(BSCs)
Sudheesh N
Research Assistant
Department of Virus Research

2. Objectives
 Identify and distinguish the various types
of open front biological safety cabinets
 Describe how to effectively and safely use
biological safety cabinets
 HEPA and ULPA
2

3. HEPA Filters
 High Efficiency Particulate Air
 Filters particles at 99.97% efficiency at 0.3
microns
– larger and smaller particles are filtered at higher
efficiency
 Gases and vapors are not removed from the
air stream by HEPA filtration
3

4. HEPA Filter
4

5. 3 ways to capture the Particle
 Diffusion
 Interception
 Inertial Impaction
5

6. ULPA
 Ultra Low Penetration Air
 Filters particles at 99.9995% efficient in
removing particles 0.12 µm and larger
6

7. Biological Safety Cabinets
 Used to provide containment of infectious
splashes or aerosols generated-Primary
Biological
Containment
Safety
Cabinet
Class
III
Class I
Class
II
Type A1
Type A2
Type B1
Type B2
7

8. Class I BSC
A. front opening
B. sash
C. exhaust HEPA
D. exhaust plenum
8

9. Class II BSC
 Class II Type A1
• 70% re circulated air; 30 % exhausted into the room
• 75 fpm intake
Class II BSC
9

10. Class II BSC
 Class II Type A2
•70% re circulated air; 30 % exhausted into the room
• 100 fpm intake
10

11. Class II BSC
 Class II Type B1
• 40% re circulated air; 60 % exhausted
• 100 fpm intake
11

12. Class II BSC
 Class II Type B2
• 0% re circulated air; 100 % exhausted
• 100 fpm intake
12

13. Class III BSC
13

14. Primary Containment- Conclusion
 Are not substitutes for good practice
 Provide only partial protection; aerosols
can escape from the cabinet, especially
when rapid motion occurs through the air
curtain
 Should be retested and recertified
annually and when the cabinet is moved
14