Question

What is the main role of airlock in pharmaceutical GMP area. How does it prevent clean rooms from contamination?

Answer 1

The main role of an airlock in pharmaceutical GMP area is to avoid the chance of cross contamination and to separate or isolation of different process areas. It helps to protect the classified area from the contamination that occur during entry and exit of personnel and material.

Airlocks are closed rooms having two or more doors between two different controlled areas having different cleanliness level as Class B and Class C, Class C and Class D areas.The two doors should be interlocked to avoid being opened at the same time.These airlocks prevent direct airflow between these areas during the entry of material or personnel.

To prevent contamination and keeping the room clean airlock spaces are typically designed to maintain certain pressure relationships with respect to controlled environment and corridors. An airlock area is often ventilated with filtered supply of air, with return or exhaust air to exit. Based on the airflow directions and pressure differences between the controlled environment they are categorized as

1. Cascade airlock
2. Bubble airlock
3. Sink airlock

Cascade airlock:These airlocks have higher pressure on one side and lower pressure on another side.The positive air pressure flows from the higher pressure internal zone to be airlock and from the airlock to lesser lower pressure grade area.This prevents to entry dust and contamination from outside to airlock and from airlock to inner side.

Bubble airlock :These types have higher pressure inside the airlock and lower pressure both outside.It creates a barrier where contaminants within either area pushed back into theirown respective areas.

Sink airlock :These airlocks have lower pressure inside the airlock and higher pressure on both sides of the airlock. This airlocks pulls air from both adjacent areas creating a low pressure barrier and reduces the opportunity of contaminations passing to the internal zone.