Page 13 - Contamination Control

GMP Training – Contamination Control in GMP Areas by www.gmpsop.com

AIRFLOW PATTERNS AND CONTAMINATION CONTROL

There are basically two types of cleanrooms:
a. those designed to exclude particles, dirt, bacterial and other products -

these are called positive pressure rooms where the room pressure is higher
than the outer rooms.

b. those designed to contain dust generated during product processing within
the room – these are called negative pressure rooms where the room
pressure is less than surrounding rooms.
These rooms often have a dust extraction system to trap product dust.
The effective operation of either room type is dependant on keeping doors

closed and ensuring inlet filters, air return vents and dust extraction
equipment is clean and operating properly.

GOOD TO KNOW - POSITIVE PRESSURE ROOMS

Positive pressure rooms are at a higher pressure than surrounding areas - if
the door is kept closed. The rooms are designed to clean the air by exchanging
it about every 3 - 5 minutes through air filters in the inlet vents. The air is
swept across the room to outlets (returns) near the floor and door. Provided
the doors are kept shut the room should be very clean.

These rooms are used when the exclusion of bacteria and particles from the
room and product is important.

Products that are processed in these cleanroom, where bacterial exclusion is
important, include creams, oral liquids, ointments and sterile products.

GOOD TO KNOW - NEGATIVE PRESSURE ROOMS

Negative pressure rooms are used when it is more important to trap or contain
any product dust in the room or dust extractor. This is done to prevent
contamination of other processing rooms and possible cross-contamination of
other products and equipment.

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