Biosafety Cabinets Guidelines
Biosafety Cabinets, or Biohazard Cabinetry are also known
as LAF's or Laminar Air Flow hoods. The ones in your
area are likely to be Class II, Type A/B3. This refers to the way in which
the air flows through the cabinet and the degree to which
the user is protected. Other LAF cabinets have an open front
and no sash. Air is HEPA-filtered and blown across the work
surface. They protect the product from particles and bacteria,
but do NOT
protect the operator. These are commonly called "clean
cabinets."
The Class II Biosafety Cabinets work most efficiently when they are uncluttered
and airflow is unobstructed. A Bunsen burner in the
hood creates air turbulence from the flow of gas and flame,
which disrupts the proper airflow. This compromises
not only the sterility of your samples but the safety of the
user as well.
- Remove the Bunsen burner. LAF's are designed
to maintain a sterile environment on their own.
Use small micro-burners if you need to sterilize loops between
different samples. Do not use flames!
Bring only those items into the hood, which are needed and
make sure they are clean. Only those items, which
would be entering the culture media, need to be sterile,
so the Pipettes and pipette tips should already be sterile;
everything else simply needs to be clean. If you use
good technique to open media bottles (use one hand to open
it and leave the cap in your hand), flaming the media
cap is not necessary.
- Remove any items that are not being used in the work
area. Allow the air to flow properly. Bringing
in items that are not absolutely necessary inhibit the
airflow and could allow contamination to occur.
- When not in use, the interior of the hood should be absolutely
empty. All interior surfaces are easily cleaned with
ethanol.
Do not use bleach as it will corrode the stainless steel
surface.
- When you are finished with your work and have cleaned
the surfaces, close the sash all the way and turn on the
light to UV (or germicidal). The interior surfaces
will be sterilized by the light, creating a clean working
surface for the next time.
- Keeping plastic items out of the hood when the UV light
on is a good idea because the plastic breaks down under
the intense UV light. When possible, leave all plastic
items out of the hood until you need them.
- Wear latex or vinyl gloves and lab coat when working
in the hood. This protects the user as well as the
samples. LAF's should be certified every year.
The pressure of the air and proper airflow is checked. The
filters are either replaced or cleaned. This work must be
performed by someone who has been trained and certified
to do this type of work. NSF International, who establishes
the standards for LAF's, have a web site with names of qualified
certifiers of these hoods:
http://www.nsf.org/Certified/Biosafety-Certifier/#svclocationand click on Biosafety Cabinets, then search by state.
- Check the certification sticker on the cabinet before
using to ensure that it has up to date certification.
Revised: 8/18/2008 SF