|
In the late 1960’s to mid 1970’s, scientists often
submitted their own Class II cabinet specifications and options to manufacturers.
In order to standardize cabinet design and performance used by governmental
researchers, the National Institutes of Health (NIH) developed a specification
for biological safety cabinets in 1973.
The National Cancer Institute also developed their own specifications
for biological safety cabinets the same year. The government specifications
were demanding and differed on several design criteria creating an impediment
to development by the manufacturers. In an attempt to develop impartial
specifications, NIH contacted the National Sanitation Foundation (NSF
International) in the early 1970’s. NSF International is an independent
organization that acts as a neutral agency serving the consumer, government
and industry in developing solutions for problems pertaining to public
health and the environment. After numerous meetings with government
officials, scientists, and manufacturers, NSF International published
its Standard Number 49 in 1976.
The NSF Standard Number 49, entitled Class II (Laminar Flow) Biosafety
Cabinetry, established minimum materials, design, construction and performance
requirements for Class II biohazard cabinets including the quality control
tests which the manufacturer must perform on every unit, and the certification
tests to be performed in the field. In addition, its policy established
requirements for initial testing and periodic retesting of cabinets
by the NSF International Laboratory in Ann Arbor, Michigan, and annual
unannounced audits of the manufacturer’s facility.
The standard requires three separate biological challenge tests to
be passed in order for the cabinet to be NSF listed. The Personnel Protection
Test measures the number of bacterial spores escaping from the cabinet’s
work area into the environment. The Product Protection Test established
the number of bacterial spores entering the work area from the outside
environment. Finally, the Cross Contamination Protection Tests are additional
biological challenges performed at various inflow and downflow velocity
settings. These tests ensure that the cabinet still functions properly,
even when it is not operating at the manufacturer’s recommended downflow
and inflow velocity settings.
These tests are performed at NSF International before a cabinet is listed,
and once every five years thereafter. Typically, most manufacturers
perform biological challenge tests while their cabinets are in the prototype
stage of development, and periodically during production, to ensure
that the unit protects personnel, environment and product. Domestic
Labconco Purifiers are built to meet or exceed minimum requirements
of NSF Standard 49 and bear the NSF Mark.
|
