Lecture 6: Biological Safety Cabinets

Filters are replaced when resistance makes it impossible to deliver required ____

airflow

Name at least 3 things that could disrupt the BSC air flow

1. Walking pass to close to the BSC 2. Moving your hands in horizontal motion (sideways movement) 3. open windows 4. Open flames

When cleaning up after completing a procedure, what is the correct order of the clean up procedure. (Choose steps in appropriate order) 1. Clean and disinfect outside surfaces of all containers before removing them from the cabinet. Autoclave everything that may have come into contact with the organisms 2. Leave the cabinet per your facility's protocol 3. Seal up everything that's been in contact with the agent(s) in a biohazard bag or container 4. Remove your gloves and dispose of them, wash your hands 5. Disinfect the cabinet.

3 , 1 , 5 , 4 , 2

Minimum efficiency of HEPA filters

99.97% of removal of 0.3 micron particles

What happens when the view screen is raised higher than the recommended position. (Mark all that apply) A. An alarm may sound B. You may not be able to lower the screen C. It can disrupt air flow

A & C

How Does the BSC provide the three types of protection? A. The HEPA supply filter removes any particles in the air that might contaminate the product. B. Bi-directional air flow within the cabinet helps prevent product contamination. C. The outside air flowing into the front grilles keeps the cabinet air from coming out into the laboratory, where it could harm personnel D. Air passes through the HEPA filter before it is exhausted into the environment

A, C, D

When must a biological safety cabinet be certified? (Mark all that apply) A. When it is installed. B. When it is relocated. C. When the HEPA filter is replaced. D. At least annually E. Every 3 years

A,B,C,D

Which of these should not be placed in the BSC? (Mark all that apply) A. Bunsen burner B. Sterile loops C. Clipboards or pencils D. Labeled test tubes E. Items that are not needed in the procedure you are doing

A,C,D,E

A HEPA filter is least efficient in capturing particles that are A. Smaller then 0.3 microns B. 0.3 microns in size C. Greater than 0.3 microns in size

B

Overloading Blocking airflow elements BSC location in lab Bunsen Burners UV lamps

BSC Pitfalls

Personnel and environmental protection No product protection Requires exhaust blower to pull air out Applications Housing centrifuges, etc. Cage dumping

Class I Cabinet

Offers product, personnel and environmental protection. Minimum intake air velocity: Type A1 - 75 FPM Type A2 - 100 FPM HEPA-filtered downflow air is a portion of mixed downflow and inflow air from a common plenum. Biologically contaminated ducts and plenums: Type A1 under positive pressure to the room Type A2 under negative pressure or surrounded by negative pressure

Class II Cabinet

Gas-tight absolute containment All three protections—personnel, product, and environment Air must be exhausted to the outdoors (double HEPA filtered) Operation through rubber gloves

Class III Cabinets

Product Protection ONLY Discharges air directly into room Application: Any application where the product is not hazardous but must keep product clean Preparation of media Particulate-free assembly of sterile equipment and devices

Clean Bench

The random motion of small particles, also known as Brownian motion. This motion is caused by collisions with gas molecules, Particles in the size range of 0.1 micron and smaller do not tend to follow the air-stream.. The random path of the particle increases the chance it will strike the filter and be captured. Eventually small particles will be stuck by electrostatic force (opposites attract)

Diffusion

(opposites attract) Particles will hit other particles with opposite charge and eventually get stuck/clumped together

Electrostatic Forces

T/F: You can use BSC to store equipment or chemicals if you disinfect the items before storing them in the cabinet

False

T/F: Chemical fume hoods protect the product and environment, but not the personnel

False. Do not protect the product or environment Only protect personnel

T/F: HEPA filters filter out gasses, vapors, and particulates

False: HEPA filters do not filter out gasses and vapors, only particulates

T/F: IF the BSC malfunctions and an alarm sounds, you should turn off the cabinet before covering exposed product and closing any open containers

False: Leave BSC on

T/F: If there is a spill of infectious material in the BSC, you should place an absorbent towel on top of the spill, wet it with disinfectant, and immediately wipe up the spill.

False: Not immediately, the time varies depending on the infectious material (usually 20-30 minutes)

HEPA stands for

High Efficiency Particular Air

Also referred to as impingement, occurs as the air-stream passes through a random network of fibers. Some particles will impact onto the filter medium and be caught due to their inertia driving them into the filter media. i.e runs into the filter

Inertial impaction

The easiest filtration mechanism to envision. A moving particle is blocked when it encounters a passageway or hole smaller than itself. The larger the particle relative to the hole size, the greater the chance of interception.

Interception

Four ways that HEPA filter work

Interception Inertial Impaction Diffusion Electostatic Forces

Designed to produce products in a clean environment Air is HEPA filtered in and out of the unit Protection is specific to the design Applications: Pharmaceutical industry & Super clean manufacturing

Isolators

Do HEPA filters removed gases and vapors?

NO

T/F: Class II cabinets are more frequently used

True

T/F: Filters are replaced when repairs exceed the size allowable by standards

True

T/F: If there is a spill of infectious material in the BSC, you should remove your gloves inside the cabinet and dispose of them as waste, and then wash your hands

True

T/F: When a biological safety cabinet is certified, it is checked for balanced air flow and leaks in the HEPA filter.

True

You should organize your work space in the BSC with ____ items on one side, _____ items on the other, and you should work in the _____

clean dirty middle

As resistance increases, efficiency _____

increases

Three types of protection provided by a biological safety cabinet (BSC)

personnel, product, environment

T/F: The larger the particle relative to the hole size, the greater the chance of interception.

true