The area within a cleanroom at a height of 0.8～1.5m above the floor (except where special process requirements apply).

Local clean zone

A local area within a room where the dust concentration of the air reaches the specified cleanliness class.

[Reference] Depending on process needs, the clean area can be achieved for the whole room or locally. The critical process areas require the highest cleanliness class and the strictest control, yet the area to be controlled is often not large; achieving high cleanliness for the whole room for this reason would be quite unreasonable in terms of both construction cost and operating cost.

[Reference] A clean zone refers to a defined space in which the concentration of airborne suspended particles is controlled; it may be open or enclosed.

[Reference] A Class 100 local clean zone is an appropriate way to achieve high cleanliness (Class 100) locally, that is, an area with a cleanliness class of Class 100 established in a local area of the room by means of local unidirectional flow, so as to protect the critical area.