Table 2.

ISO-14664, cleanrooms, and associated controlled environments (particles/m³).

ISO classification number (N)	Class limits
	≥0.1 µm	≥0.2 µm	≥0.3 µm	≥0.5 µm	≥1.0 µm	≥5.0 µm
1	10	2
2	100	24	10	4
3	1,000	237	102	35	8
4	10,000	2,370	1,020	352	83
5	100,000	23,700	10,200	3,520	832	29
6	1,000,000	237,000	102,000	352,000	8,320	293
7				3,520,000	83,200	2,930
8				35,200,000	832,000	29,300
9					8,320,000	293,000