389D000 Rev B
1
I – FUNCTION OF THE SterilGARD
e
3
The SterilGARD
®
e
3
is a Class II, Type A2, Biological Safety Cabinet (BSC) as classified by
NSF/ANSI Standard 49. This Class of BSC may operate with or without an external facility exhaust system.
The cabinet relies on the flow of air to provide personnel, product and environmental protection. Personnel
protection (containment) is provided by a minimum intake air velocity at the front access opening. Product
protection is provided by the HEPA filtered supply air in the cabinet work area. Environmental protection is
provided by the exhaust HEPA filter.
Room air enters the front access opening of the cabinet at a minimum of 100 FPM [0.508m/sec] then enters the
front work surface perforation. Most of the HEPA filtered supply air passes through a diffuser but some of the
air is directed down the back side of the view screen creating a high velocity air curtain at the front access
opening. The HEPA filtered supply air in the work area splits at the work surface. Some of the air enters the
rear work area perforation while the remainder of the air enters the front work surface perforation. The air is
pulled through the drain pan area, up the rear and side wall plenums, to the cabinet blower. The blower pushes
the air into the positive pressure plenum. At that point most of the air is pushed through the supply HEPA filter
while the remainder is exhausted out the exhaust HEPA filter and through a perforated filter protector at the top
of the cabinet. [Reference Figure1]
Figure 1: Airflow design
EXHAUST
INTAKE
(ROOM AIR)
WORK SURFACE
SUPPLY HEPA
FILTER
POSITIVE PRESSURE
PLENUM
= ROOM AIR
= CONTAMINATED AIR
= HEPA FILTERED AIR
EXHAUST HEPA
FILTER
DRAIN PAN AREA
MOMENTUM AIR
CURTAIN
