Q: How do the ISO/TC209 clean room class ratings compare to the Federal Standard 209E clean room class ratings?

A: ISO/TC209 clean room class ratings have replaced the Federal Standard 209E ratings. ISO/TC209 is based on metric measurements versus Federal Standard 209E which is based on imperial measurements.

See comparison chart: 

ISO FED STD 209E
3 1
4 10
5 100
6 1,000
7 10,000
8 100,000


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