Specification Example #3: ISO 8573-1:2010 [1:2:0 (0.001)]
This indicates Class 1 for particles, Class 2 for water, and Class 0 for oil with a limit of 0.001 mg/m3. When requesting filtration or analysis to Class 0, always provide a limit that is more stringent than Class 1.
The use of the term Class 0 is frequently misunderstood and misused. When specifying air quality that meets Class 0, the limit MUST be included in the designation, AND it must be more stringent than Class 1 (Refer to Example 3). Class 0 does not mean that there are zero contaminants.
Read about testing with ISO 8573-1:2010 in the manufacturing industry.