Procedures for the Proper Use of a Class II Biological Safety Cabinet
Any laminar flow BSC is only a supplement to good microbiological techniques, not a replacement. If users do not properly understand or operate cabinets, they will not maintain an adequate protective barrier between the operator and the experiment. Listed below are procedures for proper use of BSCs.
- Turn the cabinet fan and the fluorescent light on. Turn off the UV light. Confirm that the drain valve is closed.
- Wipe the work surface with 70% ethanol or other appropriate disinfectant. Let the unit run for 5 -10 minutes to clean itself before beginning work.
- Plan the work operation in advance. Place everything needed for the complete procedure in the cabinet before starting. Nothing should pass through the air barrier, either in or out, until the procedure is complete. Arrange materials in a logical manner such that clean and contaminated materials are segregated. Remove from the cabinet all materials or equipment not necessary for the particular procedure.
- Avoid placing materials on the air intake grille, at the front of cabinet as this disrupts the protective air barrier.
- Keep equipment at least four inches (10 cm) inside the cabinet work area. Perform manipulations of hazardous materials as far back in the work area as possible.
- After the procedure is completed, decontaminate all equipment in direct contact with the research agent with an appropriate disinfectant. Run the cabinet at least three minutes with no activity to purge airborne contaminants from the work area.
- After removal of all materials and equipment, wipe the work surface with 70% ethanol or other appropriate disinfectant. Clean any spilled culture media that may support fungal growth and cause contamination in subsequent experiments.
- Turn off the cabinet fan. Some researchers prefer to let the cabinet run continuously. You may turn on the UV light if the BSC is so equipped and there are barriers in place to prevent inadvertent UV exposure to other lab personnel.
- Limit access to BSC to one person at a time. Two people simultaneously moving and working in a BSC can disrupt the protective air curtain at the face of the BSC. This can compromise the safety of the individuals working in the BSC, others in the room as well as product protection, thus negating the engineering control.
- Do not use an open flame in the cabinet as it disrupts airflow and could damage the HEPA filter.
- Conduct research in a ‘clean to dirty’ (left to right) work pattern.