Basic Documentation

Siemens Industry, Inc. Page 3 of 8
Document No. A6V11520001
Equipment (Primary Controls)
Although the ventilation system designer does not
normally select the type of ventilated cabinets that
are used within the compounding area, the designer
must know the type of protection (personnel,
product, and/or environment) provided by the units.
This knowledge ensures that the ventilation system
design will address the exhaust and makeup air
requirements of these cabinets.
Cabinets provide a constant, even airflow that
creates a barrier across the face of the work area
while also maintaining a constant flow inside the
cabinet.
ISO Class 5 Environment
2
–USP <800> requires
the CSP work environment to be located in an ISO
Class 5 C-PEC. This requirement means that airflow
within the C-PEC uses HEPA filters to remove any
particles.
C- PEC
Types Description
BioSafety
Cabinet
(BSC)
A ventilated cabinet with unidirectional
HEPA filtered airflow and HEPA-filtered
exhaust to protect the worker from
hazardous drugs
Compounding
Aseptic
Containment
Isolator
(CACI)
A type of restricted-access barrier
system (RABS) that uses HEPA
filtration to provide an ISO Class 5
clean-air environment designed for the
compounding of sterile hazardous
drugs
CVE A full or partial enclosure that uses
ventilation principles to capture,
contain, and remove airborne
contaminates through HEPA filtration
Failure of Cabinet–The impact that a cabinet failure
will have on the room environment must be
considered during the design process. For example,
consider a system with the following cabinets:
Negative pressure barrier isolators, Class II BSC
Type B1, and Class II BSC Type B2. If the building
exhaust or cabinet exhaust fails, the cabinet will
become pressurized, causing airflow from the work
area to flow back into the room. Therefore, these
cabinets should have their exhaust ducted to the
outside.
2. Classification of air cleanliness; ISO Class 5 is equivalent to
100 particles per ft
3
or 3520 particles per m
3
of 0.5 µm per
m
3
or larger.
Continuous Monitoring–Typically, cabinet
manufacturers provide a magnehelic gauge to
provide visual confirmation of cabinet operation.
Failure of the building exhaust system will not be
apparent to the user because the cabinet supply
blower will continue to operate. Therefore, a
pressure-independent monitor should be installed to
sound an audible alarm and shut off the BSC supply
fan if a failure occurs.
Building Exhaust–Typically, cabinets that exhaust
air to the outside are connected to the building’s
existing exhaust system. To maintain steady cabinet
flow conditions, the pressure relationships inside the
cabinet and between the cabinet and the exhaust
ducts must be held constant. Cabinets will require
either a hard connection or a thimble connection to
the exhaust duct. The type of connection depends
on the type of cabinet.
BSCs and glove boxes require constant exhaust
airflow to contain contamination and protect
products in the cabinet. If BSCs are connected to a
central exhaust system that also serves variable-
volume fume hoods, the variation in total system
exhaust can upset the pressure relationships
between the airflows in the cabinet, allowing
contaminants either to escape the cabinet or to enter
the cabinet workbench area. To avoid this problem,
BSCs can be equipped with constant-air-volume
controllers. In situations where constant-air-volume
controllers are required, they should be integrated
into the building automation system (BAS) so that
historical data, alarms, and alarm
acknowledgements can be collected and archived to
document compliance with regulatory requirements.
Design Requirements for HD
Compounding Areas
USP <800> requires that CNSP preparation occur
within a C-PEC located in an area that has a
negative pressure relative to the adjacent areas.
USP <800> requires that CSP preparation occur
within a C-PEC that meets ISO Class 5.
• Category 1 CSPs: The C-PEC may be located
in a C-SCA (unclassified space) without a buffer
or ante-area.
• Category 2 CSPs: The C-PEC must be located
within an ISO Class 7 buffer area with an ISO
Class 7 ante-room.