ISO International Standards Organization Particle Count Classification

ISO Class			Number of Particles per 100 ML

	1				0 - 2

	2				2 - 4

	3				4 - 8

	4				8 - 16

	5				16 - 32

	6				32 - 64

	7				64 - 130

	8				130 - 250

	9				250 - 500

	10				500 - 1000

	11				1000 - 2000

	12				2000 - 4000

	13				4000 - 8000

	14				8000 - 16,000

	15				16,000 - 32,000

	16				32,000 - 64,000

	17				64,000 - 130,000

	18				130,000 - 250,000

	19				250,000 - 500,000

	20				500,000 - 1,000,000

	21				1,000,000 - 2,000,000

	22				2,000,000 - 4,000,000

	23				4,000,000 - 8,000 000

	24				8,000,000 - 16,000,000

	25				16,000,000 - 32,000,000

	26				32,000,000 - 64,000,000
	

Typical Hydraulic Components Requirements

ISO  14/11 - Servo Control Valves

ISO  16/13 - Vane and Piston Pumps	
							 			
ISO  16/13 - Directional & Pressure Control Valves				

ISO  17/14 - Gear Pumps

ISO  18/15 - Flow Control Valves & Cylinders

Suggested Contamination Levels for Various Hydraulic Systems

 Target Class		Sensitivity		    System
------------------------------------------------------------------------
	13/9            Super Critical	    Silt sensitive control system.
                                            Laboratory or Aerospace.

	15/11           Critical            High performance servo and
                                            high pressure systems.

	16/13           Very Important      High quality systems. General
                                            machine requirements.

	18/14           Important           General machinery & mobile
                                            systems. Medium pressure &
                                            medium capacity.

	19/15           Average             Low pressure industrial systems.

	21/17           Main Protection	    Low pressure with large
                                            clearances.