How to define clean room grades

How to define the clean room grade

Clean room grade description

When users provide the clean room grade to suppliers, there are several tips. First, the grade definition model is as follows:

Class X (at Y μm)

Where X is the clean room grade, such as 100 or 10000, etc., and Y is the particle size such as 0.2μm, 0.5μm, etc., which can be selected. This means that the user stipulates that the particle content of the clean room must meet the limit of the grade at these particle sizes. This can reduce disputes. Here are a few examples:

Class1 (0.1μm, 0.2μm, 0.5μm) Class 100(0.2μm, 0.5μm)

Class 100(0.1μm, 0.2μm, 0.5μm)

In Classes 100 (M3.5) and Greater (Class 100, 1000, 10000.), generally only one particle size is sufficient. In Classes Less than 100 (M3.5)

(Class 10, 1.), generally more particle sizes are required.

The second trick is to specify the state of the clean room, for example: Class X (at Y μm), At-rest

Suppliers know very well that the clean room must be accepted in the At-rest state.

The third trick is to set the upper limit of particle concentration by yourself. Generally, the clean room is very clean when it is As-built, and the particle control ability test is not easy. At this time, you can simply lower the acceptance limit, for example:

class 10000 (0.3 μm <= 10000), As-built

class 10000 (0.5 μm <= 1000), As-built

The purpose of this is to ensure that the clean room still has sufficient particle control ability when it is in the Operational state.

The following two tables are the grade definitions of fed-std-209e and ISO-14644.