Basic Documentation

Page 4 of 8 Siemens Industry, Inc.
Document No. 149-224
The PEC must be located so that it is not affected by
air currents or streams from heating, ventilation, and
air conditioning (HVAC), personnel, or doors.
ISO 7 and ISO 8 rooms must be physically
separated, with walls and doors between them and
with controls to prevent the flow of lower-quality air
into the controlled area.
ISO 7 areas must have at least 30 air changes per
hour (ACPH), and at least 15 ACPH must be HEPA-
filtered fresh air.
ISO 8 areas must have a minimum of 20 ACPH.
There must be a D/P of at least 0.02 inches water
column (wc) between the ISO 7 area and the ISO 8
area. There must be a D/P of at least 0.02 inches wc
between the ISO 8 area and the pharmacy or
unclassified area.
Must have a differential pressure monitoring system
in place that continuously monitors differential
pressure.
Surfaces must be smooth, impervious, free of cracks
and crevices, and non-shedding. Walls must be
constructed of durable material.
Supply Air
Supply air is provided to the space through HEPA
filters which make the supply air virtually free from
contaminants. While HEPA filters are effective in
removing most particulate contamination, they are
not effective in removing gases and vapors. For this
reason, the National Institute for Occupational
Safety and Health (NIOSH) requires that BSCs and
isolators used for volatile drugs be externally vented.
Room Exhaust
Return openings from the room should be low on the
walls
3
to promote a downward flow of air from the
supply to return, sweeping contaminants to the floor
and away from the product. Perforated floors are not
recommended due to the difficulty in cleaning them.
The room exhaust should be sized to handle both
the room and all containment devices vented
through the system.
3. ASHRAE Handbook 2003, Chapter 16 Clean Spaces
Room Pressurization
A pressure gradient is used to minimize particle
migration into the clean space from a less clean
space. The pressure gradient causes the air
pressure in the buffer zone space to be higher than
that of the ante area, so air cascades or flows from
the cleaner area into the dirtier area.
Typically, the pressure differential between two
adjoining areas (ISO Class 7 and ISO Class 8) is
+0.02 inches wc.
To ensure minimum air changes, the supply airflow
volume must be compensated for filter loading.
Differential Pressure (D/P) Monitoring – A
differential monitoring system must be used to
continuously monitor the pressure differential or
airflow between the ante-area and the buffer area
and between the ante-area and the general
environment (corridor or pharmacy). This system is
used by the healthcare workers to verify that the
required room pressurization is being maintained
and warns them of any loss of the required D/P. A
momentary loss in D/P occurs when a door is
opened and then closed. Therefore, D/P alarms
should have an adjustable delay period to prevent
nuisance alarms during the time needed for normal
passage through the doorway and for the ventilation
system to restore the required D/P.
Temperature and Humidity
Maintain the temperature below 68°F (20°C) and the
humidity below 60% in the CSP compounding area.
Maintain humidity and temperature at a level
necessary for operator comfort in the compounding
area designated for the preparation of CNSPs.
Temperature and humidity must be controlled
through an HVAC system.