NAS 1638, JAN 1964

AEROSPACE INDUSTRIES ASSOCIATION OF AMERICA, INC.

CLEANLINESS REQUIREMENTS OF PARTS USED IN HYDRAULIC SYSTEMS

MAXIMUM CONTAMINATION LIMITS (PER 100 mls)

Size Range Microns	CLASSES
	00	0	1	2	3	4	5	6	7	8	9	10	11	12
5 - 15	125	250	500	1,000	2,000	4,000	8,000	16,000	32,000	64,000	128,000	256,000	512,000	1,024,000
15 - 25	22	44	89	178	356	712	1,425	2,850	5,700	11,400	22,800	45,600	91,200	182,400
25 - 50	7	8	16	32	63	126	253	506	1,012	2,025	4,050	8,100	16,200	32,400
50 - 100	1	2	3	6	11	22	45	90	180	360	720	1,440	2,880	5,760
over 100	0	0	1	1	2	4	8	16	32	64	128	256	512	1,024