eBook: Safe and Effective Research in the Vivarium - 7

personnel, as well as HEPA-filtered downflow modules/units. ATS's and BSC's protection principles are
comparable: both provide a laminar (unidirectional)
downflow of HEPA-filtered air in the work area where
the IVC cage is opened and animals are handled to
ensure product protection. However, an ATS is specifically designed for changing cages of non-infected rodents. An ATS only provides protection from
most allergens.

Use of a Class II BSC is required where a higher level of protection is needed, or the animal's status
is unknown. They are used typically when working with Biosafety level 2 (BSL-2) microorganisms
(wildtype as well as genetically modified) to protect the operator, the animals, and the environment. It can be advisable to use a BSC when the
risk of infection of the animals should be minimized, e.g., in case of immune-deficient animals
and other animal experiments that can easily be
disturbed by unwanted microorganisms.

In contrast, a Class II BSC is designed to provide a
high level of personnel protection (for you and those
around you), product protection (for your samples),
and environmental protection (for the room). A BSC
must meet Class II international standards for containment performance. To meet these high standards, a Class II BSC needs to be designed and manufactured to specific construction and performance
criteria. Historically, BSC's were primarily designed
for microbiological research, and not for lab animal
work. However, many BSCs described as " Animal
Handling BSCs " have been modified to meet the animal researcher's specific needs.

BSC's used for animal procedural work were initially
developed for in vitro procedures to protect personnel, product and environment. Later on, BSCs were
redesigned and modified to facilitate working with
animals and IVCs.

In contrast, when it comes to an ATS, there are no
specific standards they are designed to. Each manufacturer can approach the design of their cabinet as
they see fit. An ATS can be designed to be accessible
from one or two sides. This provides high ease-of-use
and allows for the cages/workspace to be accessed
from all sides, enabling a high level of productivity
(i.e., technicians doing cage changing often need to
change out hundreds of cages per week). For the
ease of bringing in larger cages, the sash opening
height of an ATS is typically 14 inches (356 mm),
whereas the maximum on a BSC generally is 12
inches (305 mm). Furthermore, an ATS has a smaller
footprint, is less cumbersome, offers height adjustability, and is mobile to enable movement between
IVC racks and animal rooms. This makes an ATS very
versatile and widespread for general (low-risk) use.

NuAire's LabGard® ES NU-677 Class II, Type A2 Animal Handling Biosafety
Cabinet can accommodate the largest mouse and rat cages.

A BSC, by definition, is only open on one side and
traditionally has an access opening height of 8 or
10-inches (203 or 254 mm). BSCs designed for animal handling need to offer a larger access opening
of 12-inches (305 mm) or more to permit the movement of IVC cages in and out of the work zone. The
larger access opening allows a technician to reach
over the tops of cages to remove lids easily and

eBook: Safe and Effective Research in the Vivarium

Table of Contents for the Digital Edition of eBook: Safe and Effective Research in the Vivarium