Contamination Control

Contamination Is Costing Your Equipment More Than You Think

Dirt, water, and poor lubricant handling can reduce oil life, accelerate component wear, increase downtime, and shorten equipment life.

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Sample bottle of oil visibly contaminated with dark particles, resting on industrial equipment

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How Contamination Impacts Equipment

Accelerated Wear

Particles create abrasion and fatigue that shorten component life.

Higher Maintenance Costs

Contamination increases repairs, replacements, oil changes, and troubleshooting.

Moisture Damage

Water contributes to corrosion, oxidation, additive depletion, and reduced film strength.

Unplanned Downtime

Poor oil cleanliness increases the risk of unexpected equipment failure.

What Is Lubricant Contamination?

Contamination occurs when unwanted materials enter or develop inside a lubricant or hydraulic fluid. These contaminants compromise lubricant performance and increase the risk of equipment failure.

The Four Sources of Contamination

New Fluid

Oil can arrive with particle levels that are not suitable without proper filtration.

Dirty Components

Hoses, reservoirs, transfer containers, and system parts can introduce contamination.

Ingressed

Dirt, dust, moisture, and airborne particles enter through vents, seals, ports, and handling.

Internal Wear

Operating equipment naturally creates wear debris that can circulate and cause more damage

Contamination control must begin before the lubricant ever reaches the equipment.

Water – One of the Most Damaging Contaminants

Water in hydraulic and lubricating oils is a major contaminant that can cause serious equipment damage and reduced lubricant performance. It can enter the system through condensation, leaks, or improper storage. Even small amounts of water can lead to oxidation, corrosion, reduced load-carrying capacity, and increased wear due to loss of film strength.

Water contamination can exist in three forms:

Dissolved

(invisible at low concentrations)

Emulsified

(milky appearance)

Free water

(separates at the bottom)

Effective filtration, dehydration, and proper oil storage are essential to minimizing water contamination and maintaining optimal equipment performance. The water concentration in a hydraulic fluid is marked as RH percentage (relative humidity), ppm (parts per million) or % (percentage weight or volume). Most common saturation points will be between 200 and 600 ppm (0,02– 0,06 percent) depending on the temperature of the oil. At a higher temperature the oil will be able to hold more water. Water also becomes harder to manage as operating conditions change. Temperature, humidity, washdowns, outdoor environments, and frequent reservoir breathing can all increase moisture exposure and condensation risk.

Each form creates reliability risk.

Chart of water concentration in ppm against fluid temperature, showing the saturation curve separating free water from dissolved water, with a system design point marked

Water contamination can lead to:

Corrosion and rust inside components
Oil oxidation and shortened lubricant life
Additive depletion
Reduced film strength
Increased wear on bearings, gears, pumps, and hydraulic components
More frequent maintenance and oil changes

Small Particles. Big Consequences.

Particles that are too small to see can still damage seals, bearings, pumps, valves, and gears. ISO cleanliness codes provide a measurable way to track fluid cleanliness.

What is Cleanliness?

Particles that are too small to see can still cause serious damage inside lubricated equipment. When we speak in terms of cleanliness, we often refer to the ISO particle count of the oil. ISO cleanliness codes help quantify the number of particles in oil and provide a measurable way to understand fluid cleanliness. Maintaining the right cleanliness level is critical because particle contamination can damage seals, bearings, pumps, valves, and other precision components.

Particle Count Data
Size in Microns	Number of Particles Larger Than Size per ml
4	1,654
6	495
10	122
14	52
20	21
50	1.3
75	0.22
100	0.05

Number of Particles / ml	Range Number
80,000	160,000	24
40,000	80,000	23
20,000	40,000	22
10,000	20,000	21
5,000	10,000	20
2,500	5,000	19
1,300	2,500	18
640	1,300	17
320	640	16
160	320	15
80	160	14
40	80	13
20	40	12
10	20	11
5	10	10

Target Contamination Control Levels

Not all machine types have the same tolerance to contamination. Systems with precision components such as piston pumps, servo valves, and piston motors require significantly cleaner fluid than systems using gear pumps, poppet valves, and cylinders.

Cleanliness Targets:

Machine Type		Particle Target Level	Moisture Level
Hydraulics1,500 - 2,500 psi	With servo valve	15/13/11	125 ppm
	With proportional valves	16/14/12	150 ppm
	Variable volume piston pumps	17/15/12	150 ppm
	With cartridge valves or fixed piston pump	17/16/13	150 ppm
	With vane pump	17/16/14	150 ppm
Gearbox		19/16/13	300 ppm
Paper Machine		18/14/11	200 ppm
Steam Turbine		18/14/11	100 ppm
Pumps		17/14/12	150 ppm

Industry research has established recommended cleanliness targets for different component types, helping organizations determine the appropriate fluid cleanliness level for each application.

A system's cleanliness target should be based on its most contamination-sensitive component. For critical applications, highly sensitive components can be protected with dedicated filtration solutions that deliver cleaner fluid exactly where it is needed most. This targeted filtration approach helps reduce component wear, extend equipment life, improve system reliability, lower maintenance costs, and minimize unplanned downtime.