Biological Safety Cabinet Use
OSHA Fact Sheet: Laboratory Safety; Biosafety Cabinets (BSCs)
CCR Title 8 §5154.2. Ventilation Requirements for Biological Safety Cabinets

Biosafety in Microbiological and Biomedical Laboratories (BMBL) 5th Edition:

Appendix A – Primary Containment for Biohazards: Selection, Installation and Use of Biological Safety Cabinets

Biological Safety Cabinet Overview

A biological safety cabinet (BSC), often referred to as a tissue culture hood, is a ventilated cabinet that serves as primary containment for handling potentially infectious materials or aseptic tissue culture.

The majority of cabinets on campus are “Class II Type A2.”This type of cabinet provides HEPA-filtered downward air flow within the workspace, and HEPA-filtered exhaust air from the workspace. 70% of the airflow is recirculated back to the work surface, with the remaining airflow exhausted through the filter to the lab.

The Baker Company schematic

Working at a Biosafety Cabinet

  • The laminar airflow is based on the sash height and the front and back grills that lead to the HEPA filters. For this reason, keep elbows, forearms, notes, equipment, etc., clear of the front and rear grills.
  • The intake air velocity past the sash at working height is 100 linear feet per minute. It’s important to minimize foot traffic past the BSC when it’s in use; walking past a BSC is enough to disrupt the laminar air flow.
  • Move your hands straight in and out when necessary. Place a waste container in the back to one side to reduce the number of times that you take your hands in and out.
  • Conduct work 4-6 inches inside the BSC where the laminar airflow is at its most uniform.
  • Divide the work space into clean and contaminated sides, and make sure that work flows from the clean area towards the contaminated area.

Recommended Start Up and Shut Down Procedures for Class II BSCs

a)Start up

  1. Turn off any UV lights in the BSC
  2. Turn on the blower(s) and cabinet illumination lights
  3. Allow 5 minutes of operation to purge particulates
  4. Confirm that the BSC is currently certified for use
  5. Check airflow gauges
  6. Wipe down readily accessible interior surfaces with 70% ethanol

(b) Shut down

  1. Decontaminate items with 70% ethanol and remove from the interior work area
  2. Wipe down the interior surfaces with disinfectant followed by 70% ethanol
  3. Allow 5 minutes of operation to purge the system
  4. Turn off cabinet blower
  5. Lower the cabinet sash and turn on the UV light

Spill Procedures within a BSC

  1. Keep the cabinet blower on
  2. Replace gloves if they are contaminated
  3. Cover the spill with paper towels to prevent aerosols and splashing
  4. Apply afresh solution of disinfectant to the area
  5. Wait out the prescribed time for the materials involved and the disinfectant used
  6. Wipe down any equipment in the cabinet with paper towels dampened with disinfectant
  7. Collect the paper towels with more paper towels, working from the outside in; use tongs if sharps are involved
  8. Bag the clean-up materials as solid waste
  9. Remove gloves aseptically and wash your hands thoroughly

BSCs are not the same as Chemical Fume or Laminar Flow Hoods

Do not use volatile chemicals in recirculating class II BSCs. Be aware some chemicals may damage the HEPA filtration system. Use a fume hood for volatile chemicals.

Type of Protection / Class II type A2 BSC / Chemical Fume Hood / Laminar Flow Hood
Personnel / Yes / Yes / No
Product / Yes / No / Yes
Environment / Yes / No / No

Certification and Servicing

Biological safety cabinets must be tested and certified for proper function after installation, relocation, or maintenance, and at least annually. The University of California has negotiated a system-wide agreement with Technical Safety Services, Inc., outlining service expectations and pricing schedules. The Los Angeles branch serves UCSB and a field manager may be reached at 562-694-3626 or 800-877-7742. Lead times vary, but technicians can usually visit campus within a week.

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Revision date: 12/20/2016