Hydraulic componentry


Hydraulic componentry

Optimum Cleanliness Level Codes for Hydraulic Componentry

Hydraulics systems by nature, can be very susceptible to contamination. As a result various components have different tolerances to contamination within an array of hydraulic systems. Extensive research carried out by dedicated hydraulic specialists have produced target cleanliness grades for operators to use as a guide to increase the reliability of systems across industry.

For example, a system that has gear pumps, poppet valves and hydraulic cylinders will not require the stringent demands that a system using piston pumps, servo valves and piston motors does.

Below is a chart with target cleanliness grades enabling operators to achieve high levels of reliability in their operations.


<2000 psi <140 bar
<3000 psi 2100 bar
>2000 psi > 140 bar


Fixed Gear20/18/1519/17/1518/16/13
Fixed Vane20/18/1519/17/1418/16/13
Fixed Piston19/17/1518/16/1417/15/13
Variable Vane19/17/1518/16/1417/15/13
Variable Piston18/16/1417/15/1316/14/12


Direction (solenoid)20/18/1519/17/14
Pressure (modulating)19/17/1419/17/14
Flow Controls (standard)19/17/1419/17/14
Check Valves20/18/1520/18/15
Cartridge Valves20/18/1519/17/14
Screw-In Valves18/16/1317/15/12
Prefill Valves20/18/1519/17/15
Load-Sensing Directional18/16/1417/15/13
Hydraulic Remote Controls18/16/1317/15/12
Proportional Directional (throttle)18/16/1317/15/12
Proportional Pressure Controls18/16/1317/15/12
Proportional Cartridge Valves18/16/1317/15/12
Proportional Screw-In Valves18/16/1317/15/12
Servo Valves16/14/1115/13/10


Axial Piston Motors19/17/1418/16/1317/15/12
Radial Piston Motors20/18/1419/17/1518/16/13
Swashplate Design Motors18/16/1417/15/1316/14/12

Hydrostatic Transmissions

Hydrostatic Transmissions (in-loop fluid)17/15/1316/14/1216/14/11

This information was taken from the Certified Fluid Power Electronic Specialist Study Manual dated 18/12/09 and is found on page 10-30.

The fluid targets should be used as a general guide only with Original Equipment Manufactures recommendations also taken into account when setting targets for hydraulic systems in specific settings.