Tests Performed
Filter Testing
A leak test is performed on the supply filter and, in the case of the biological safety cabinet, the exhaust HEPA filters. A high concentration of polydispersed liquid aerosol of dioctyl phtalate, DOP, is introduced upstream of the filters. The downstream side of the filter face is then scanned with an aerosol photometer having a threshold sensitivity of at least 10-3 micrograms-liter of air. Where scanning is not feasible the probe method is used for detection.
These tests ensure 99.97% filter efficiency at 0.3 nanometer particle size and will detect filter and filter gasket leaks.
Air Velocity
Using a precision thermoanemometer, inflow, supply and exhaust air velocities are checked to ensure proper balance. These velocities are critical to proper operation and, if required should be adjusted to manufacturers recommendations.
Air Flow Patterns
Airflow patterns over the work surface and around the work opening are checked with a smoke source. This ensures that no reflux is present that might endanger the work, or in the case of biological safety cabinets the personnel.
Decontamination
Because of the nature of the work involved, Biological Safety Cabinets must be decontaminated when:
Any service work is performed within the contaminated portion of the caginet, i.e. HEPA filter change.
Moving the cabinet from one location to another.
After initiating a totally different work program.
After a gross spill of a highly concentrated research agent.
Decontamination is accomplished by depolymerizing paraformaldehyde in controlled temperature and humidity to form a gas. The gas is then circulated throughout the cabinet and is then externally vented or chemically neutralized after an appropriate decontamination period.
Records and Reports
PASS or FAIL labels are installed on date of certification.
Documentation of results are available 24/7 through our website's password protected delivery system.
Once reports are ready an e-mail with your password and login information will be sent.
Biological Safety Cabinets
Biological Safety Cabinets (BSC) were developed because of the need for personnel protection not afforded by horizontal and vertical flow clean benches.
Like the clean bench, the BSC utilizes High Efficiency Particulate Air (HEPA) filters which have a 99.97% efficiency on particles of 0.3 micron size. There are three classes of Biological Safety Cabinets.
CLASS I
The Class I Safety Cabinet is a modification of the chemical fume hood and provides protection to personnel and the environment, but little, if any, to the product.
Air is drawn through the work opening at a minimum average rate of 75 linear feet per minute (LFPM). The air is then exhausted through a HEPA filter. The Class I Cabinet can be used for low to moderate risk biological agents.
CLASS II
The Class II Safety Cabinet was designed to provide personnel, environment and product protection. Product protection is achieved with the use of a supply HEPA filter, an exhaust HEPA filter and laminar (unidirectional) downward air flow. This minimizes air turbulence which prevents cross contamination in the product work area. Personnel protection is provided through a cabinet design that always maintains containment at the window opening.
There are four TYPES of Class II Cabinets. TYPES A1 & A2 and B1 & B2 are designed to recirculate a percentage of filtered air with the remainder being exhausted. TYPE A Cabinet is exhausted into the laboratory or externally. The TYPE B Cabinet must be exhausted through an external blower system. The third TYPE of Class II is a Total Exhaust Cabinet which, like the TYPE B, can be used with chemical carcinogens and low level radioactive materials. All three TYPES can be used for low to moderate risk biological agents.
CLASS III
The Class III Safety Cabinet is a totally enclosed, self-contained, ventilated cabinet that operates at a negative pressure to the laboratory environment. Rubber gloves are attached and air enters through filters and is then exhausted through one or more HEPA filters. Incinerators are sometimes employed to provide greater protection to the environment.
Unlike the Class I and Class II Safety Cabinets, the Class III can be used for high risk biological agents, chemical carcinogens and low level radioactive materials.