What Is Hydraulic Oil?
Hydraulic oil analysis focuses on oil cleanliness, the most critical parameter of the system. The result determined by automatic particle counting according to ISO 11500 is expressed by a three-number cleanliness code according to ISO 4406. In addition, viscosity, water content, oxidation, wear metals and additive status are monitored.
Purpose of Hydraulic Oil
The aim is to keep particle pollution under control, which is the cause of the majority of malfunctions in the hydraulic system. Most valve and pump failures are caused by pollution.
Which Products Is Hydraulic Oil Applied To?
- Industrial hydraulic systems
- construction equipment hydraulics
- Press and injection machines
- Marine and offshore hydraulics
- Aviation hydraulic fluids
In Which Sectors Is Hydraulic Oil Used?
Standards Related to Hydraulic Oil
- TS ISO 4406 (coding of particle pollution level)
- TS ISO 11500 (automatic particle counting)
- TS ISO 4407 (microscopic counting)
- TS ISO 6743-4 (classification of hydraulic fluids)
- ASTM D6304 (determination of water by Karl Fischer)
- ASTM D5185 (ICP element analizi)
Hydraulic Oil Conditions
- sample point
- While the system is running, it must be removed from the pressure line and turbulent zone.
- Specimen container
- Cleaning class certified, particle-free bottles should be used.
- Hedef temizlik
- ISO 4406 code required by the component manufacturer (pump, valve) is essential
- Water
- Free and dissolved water are evaluated separately
Equipment for Hydraulic Oil
- Automatic particle counter
- Membrane filtration and microscope
- Karl Fischer titrator
- ICP-OES
- Kinematic viscosity bath
- Sample bottles with cleanliness class certification
Sample Requirements for Hydraulic Oil
- A particle-free sample bottle with cleaning certificate should be used.
- The sample must be taken while the system is running and from the same point
- System, oil type and filter information must be reported
- Hedef ISO 4406 kodu belirtilmeli
Duration of Hydraulic Oil
Particle counting and basic parameters results quickly; standard package will be reported within a few business days.
Hydraulic Oil Procedure
- 1The sample is taken into a clean bottle while the system is running.
- 2The sample is homogenized and degassed.
- 3Automatic particle counting is done.
- 4ISO 4406 cleanliness code is calculated.
- 5Viscosity, water and element analyzes are carried out.
- 6The results are compared to the target cleanliness class.
Hydraulic Oil Acceptance Criteria
The acceptance criterion is the ISO 4406 cleanliness code required by the manufacturer of the most sensitive component in the system. Limits for viscosity and water are determined by the oil specification and the equipment manufacturer's thresholds.
Evaluation of Results
Sampling is the biggest determining factor in particle counting: a sample taken from an unclean bottle or stagnant area is not representative of the system. If the result is poor, sampling should be questioned first. Water availability is also critical; free water accelerates both corrosion and oil degradation.
Hydraulic Oil Report
- System description, oil type and filter information
- Sampling point and conditions
- Particle counting results and ISO 4406 code
- Viscosity and water content
- Elemental analysis
- Comparison and recommendation with target cleaning class
Accreditation
EUROLAB holds internationally recognised accreditation obtained from accreditation bodies party to the IAF and ILAC multilateral recognition arrangements, under ISO/IEC 17025 for laboratory testing, ISO/IEC 17020 for inspection and surveillance, and ISO/IEC 17021-1 and ISO/IEC 17065 for system and product certification. This chain ensures the reports and certificates issued are accepted worldwide.
Whether this test can be offered within accredited scope depends on your product and the standard applied; since accreditation is method-based, the scope is confirmed in writing at the quotation stage.
Scope and authorisationsRelated Regulations
- Fuel and LPG market technical regulations (EPDK)
- EU 2009/30/EC (fuel quality directive)
- Communiqués on the placing of lubricating oils on the market
Petroleum, Fuel and Oil Analysis — What Does This Testing Field Cover?
The section below describes the field that the Hydraulic Oil test belongs to; the conditions and acceptance criteria of this particular test are given in the sections above. The scope specific to your product is confirmed in writing at the quotation stage.
Petroleum, fuel and oil analysis determines whether a fluid meets its specification and how it behaves in use. Standards in this field consist largely of ASTM and EN publications, with a separate method defined for each parameter.
What distinguishes this family is that product specifications are written as PARAMETER LISTS. Specifications such as EN 590 (diesel), EN 228 (petrol), EN 14214 (biodiesel) and ISO 8217 (marine fuels) state for each parameter both the limit and the method by which that limit is to be measured. If the method changes the result may change too; the specification therefore binds the method as well, and the use of an "equivalent method" is possible only where the specification allows it.
On the fuel side, parameters describe three different properties of the product. Physical properties (density, viscosity, distillation curve, pour point, cloud point) determine pumpability and cold weather behaviour. Combustion properties (cetane number, octane number, calorific value) indicate performance in the engine. Contaminant and stability parameters (sulphur, water, sediment, oxidation stability, copper strip corrosion) affect both emissions and storage life.
Oil analysis is carried out for two different purposes and the two must not be confused. Analysis of NEW oil verifies the conformity of the product to its specification: viscosity index, additive content, flash point. Analysis of USED oil, by contrast, is done to read the condition of the machine — elemental analysis shows wear metals (iron, copper, chromium, aluminium), water and fuel contamination point to leaks, and oxidation and acid number determine the remaining life of the oil.
Used oil analysis is therefore a PREDICTIVE MAINTENANCE tool. The trend of samples taken at regular intervals is followed; it is the trend rather than a single result that is meaningful. Iron levels climbing over the course of months allow intervention before a failure occurs.
Marine fuels are the most active sub-body of the field. The global tightening of sulphur limits has brought new blended fuels onto the market; for these fuels stability, compatibility (whether two fuels form deposits when mixed) and catalytic fines content have become critical parameters.
Sampling is part of the result in this family too. A sample taken from the bottom of a tank shows different water and sediment content from one taken from the upper level; in commercial deliveries the sampling point and method are set by contract.
Method groups in this field
Physical properties
Density (oscillating U-tube and hydrometer), kinematic viscosity, distillation, pour and cloud point, flash point.
Combustion properties
Cetane number and cetane index, research and motor octane number, calorific value.
Sulphur and elements
Sulphur by UV fluorescence and XRF; elemental analysis and additive content by ICP.
Stability and corrosion
Oxidation stability, copper strip corrosion, water and sediment, filter blocking tendency.
Composition analysis
Boiling range distribution by gas chromatography, hydrocarbon types (FIA), benzene and aromatics content, fatty acid methyl ester content.
Used oil
Wear metals, contamination (water, fuel, soot), oxidation, acid and base number, change in viscosity.
Commonly confused in this field
- The specification binds the method as well; a result measured by a different method may not be accepted for specification conformity.
- A single result on used oil is not meaningful; the decision is made on the trend.
- The sampling point determines the result; the tank bottom and the upper level show different water and sediment.
- The cetane index is a calculated value and is not the same thing as a measured cetane number.
- Fuels blended with biodiesel behave differently in terms of storage life and microbial growth; classical diesel parameters are not sufficient.
- Mixing marine fuels from different sources can cause deposits; compatibility is assessed separately.
Which decisions these results support
- Conformity of a fuel lot to specification and commercial delivery
- Predictive maintenance decisions based on used oil analysis
- Determining parameters for customs and tax classification
- Quality verification after storage, blending and transport
- Compliance with sulphur limits under emissions legislation
Related Tests
Frequently Asked Questions About Hydraulic Oil
Our cleaning code turned out to be bad, should we change the filter?
It must first be verified that sampling has been done correctly. If the result is correct, filter efficiency, filter bypass status, tank ventilation and system entry points are evaluated. Simply changing the filter will not eliminate the source.
ISO 4406 kodu ne anlama geliyor?
The three numbers represent particle number ranges over certain sizes. The lower the code, the cleaner the oil; Each digit means approximately a twofold difference in the number of particles.