Prefab Stainless Steel ISO 5 CLEANROOM (CLASS 100 CLEANROOM) Turnkey Project

In theory, for a classified room (not just below a LAFW hood) to reach ISO class 5 air cleanliness, you need to enter the cleanroom via an ISO 8 (ante-room), then go through an ISO 7, followed by an ISO 6 to finally get into the ISO 5.

In reality, however, you can reach an ISO 5 cleanroom with 2 or 3 airlocks. The optimal layout depends on the process taking place inside the cleanroom, the size of the room, the number of people working inside, the equipment inside, etc.

In addition, an ISO 5 cleanroom needs to use unidirectional air flow. Unidirectional air flow cleanrooms use much more air than non-directional air flow cleanrooms. High efficiency filters are installed across the entire ceiling.

The filtered air sweeps down the room in a unidirectional way, at a velocity generally between 0.3 m/s and 0.5 m/s, and exits through the floor, removing the airborne contamination from the room. Cleanrooms using unidirectional air flow are more expensive than non-unidirectional ones, but

can comply with more stringent classifications, such as ISO 5 or lower.

ISO 5 zone | 240–360 air changes per hour
ISO 6 zone | 90–180 air changes per hour
ISO 7 zone | 30–60 air changes per hour
ISO 8 zone | 15–25 air changes per hour (ante-room)

WHAT IS THE DIFFERENCE BETWEEN POSITIVE AND NEGATIVE PRESSURE IN CLEANROOMS?

Most cleanrooms are held in positive pressure. When dealing with hazardous contaminants, cleanrooms are usually held in negative pressure, eg. hazardous drug compounding and airborne infectious isolation rooms.

POSITIVE PRESSURE

Positive air pressure will make the airflow leak out of the room, instead of in, thus preventing unfiltered air or air particulates from entering the cleanroom. Simply put, to achieve positive pressure, more filtered air is pumped inside the clean zone to create a greater pressure differential than the adjacent, less clean rooms. Positive pressure is used in cleanrooms where the priority is keeping any germs or contaminants out of the cleanroom, to protect the manufacturing process.

NEGATIVE PRESSURE

Negative pressure is used in cleanrooms to prevent potentially hazardous contaminated air, from escaping the room. Negative air pressure cleanroom means more air is pumped out of the room, rather than in, which makes the pressure lower than the adjacent environment, and serves to protect the user and the environment.