SECONDARY CONTAINMENT

In general, secondary barriers (containment) are those features associated with the facility which surround the primary barriers.  These features provide varying degrees of isolation between the laboratory and the outside environment, as well as from other spaces in the same building.  Examples of secondary barriers include floors, walls and ceilings, air locks and self-closing doors, differential pressures between spaces (positive pressure and negative pressure designs to ventilation system), exhaust filtration, as well as devices for treating contaminated air, liquids and solids. 

The function of these barriers is to prevent both the release of micro-organisms into the environment in the event of a failure in a primary barrier and to prevent environmental organisms from contaminating the workspace.

The primary function of the facility is to provide a physical environment in which work activity can be undertaken efficiently and safely.  A well-designed facility will facilitate good laboratory practice, contain equipment necessary to protect the worker and provide for the protection for those outside of the laboratory or building.The most important element of containment is strict adherence to standard microbiological practices and techniques.  Persons working with potentially hazardous materials must be aware of hazards and be trained and proficient in the practices and techniques required for handling such material safely.  

PHYSICAL CONTAINMENT LEVELS

While NIH and CDC have described four levels of physical containment, LBNL permits research at only BL 1 and BL 2. These levels of containment are to be regarded as adequate for most laboratory uses of the particular agents.