Share thisIronically, the term “art” has been an appropriate description for the fabrication, installation and subsequent end use of isolation cubicles. Though space and cost analysis of animal isolation cubicles has been well established, little documentation exists to describe their physical operation and effectiveness. And, while tools for micro-isolation of animals are the industry’s predominate interest, the state of the art of isolation cubicles has quietly been advancing.
Intelligent Automation
Vivarium managers are probably not unique when it comes to the constant demand to do more with less. The increasing cost of labor and elevated concerns for occupational health and safety are creating new demands for automated vivarium tools.
As a result, manufacturers are implementing PLC (Programmable Logic Controllers) systems into their isolation cubicles. The initial cost of PLC based systems can be more expensive than manually controlled systems, however several advantages of automated systems can result in long term direct and indirect cost savings to the research facility.
The returns on investment in automation can be measured in three areas:
1. Safety of scientific data - better cubicles result in better protection of research animals and the research facility.
2. Reduction of animal stress - better cubicles are addressing the challenges of temperature distribution, noise, and diurnal patterns that affect the enclosed research animal(s) and may have a direct effect on the subject study.
3 . Improved operator safety - better cubicles are addressing both the ergonomic challenges of daily animal care and the containment of allergens.
Reduced Cross Contamination
One of the primary criticisms of cubicles is that the isolation barrier breaks down when the doors are open. With PLC based systems, the potential for cross contamination between cubicles can be reduced by creating an interlock between the door-open push button and the air handling system. The PLC can be programmed to “ramp” the air handling system inside the cubicle in response to the door-open request.
For example, assume a cubicle is normally operated in negative mode (to protect the aisle and other cubicles from its contents). The user pushes the button to open the doors on the cubicle. Prior to enabling the door motor, the PLC increases the output of the exhaust loop to maximize the negative pressure inside the cubicle. This stronger vacuum reduces the exit of contaminates as the doors open (similar to fume hood design when opening the sash). The effect of the vacuum is maximized when used with vertically sliding doors, which create minimal air disturbances when moving, as opposed to hinged doors that swing open, drawing air from the cubicle into the room.