NSF Standard Number 49
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.