Laminar Air Flow is commonly used for recombinant DNA and plant
tissue culture works under sterile conditions. Laminar air flow (LAF) was
developed by Whitfield for the prevention of microbial contamination. A variety
of horizontal (cross flow) and vertical (down flow) laminar airflow cabinets
are commercially available. Laminar air flow consists of units of ultra-high
efficiency particulate air (HEPA) filters. HEPA filters are composed of a mat
of randomly arranged fibres. The fibres are composed of fiberglass and possess
diameters between 0.5 and 2.0 micrometers. Room air is taken into the unit and passed through a
pre-filter to remove contaminants. The air is then compressed, and sent at
approximately 90ft/min through
the HEPA filter. The purified air flows out over the entire work surface in
parallel lines at a uniform velocity. Thus the filter prevents
the entry of contaminated air into the chamber. LAF also contains UV lamps for
surface sterilization by UV irradiation.