CLASSIFICATION |
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Class – l | protection for the user and surrounding environment, but no protection for the sample being tested |
Class – ll | Protection for the user, environment and sample |
| Type A1/A2-re-circulate air back into the laboratory. A1 & A2 are similar but differentiated by the minimum average inflow velocity (FPM). |
| Type B1/B2-B1 re-circulates a percentage of air into laboratory. B2 cabinets are entirely hard ducted. |
Class – lll | Also known as glove boxes, provides maximum protection; the enclosure is gas-tight, and all materials enter and leave through a dunk tank or double-door autoclave. |