The Lubricant Quality Scan (LQS) Analysis Report

Understanding the Lubricant Quality Scan (LQS) Analysis Report

Viscosity:

Using the correct oil with the right viscosity is critically important for good machine operation as this will ensure that the mechanical operation of the systems and its components relative to one another remains within the intended design scope. Used lubricating oils may show an increase of viscosity due to oxidation/nitration or as a result of contamination with unburnt fuel components within diesel engine oil. LQS monitors for any unexpected variation. It is beneficial to check that the lubricant-grade in use is what has been recommended by the lubricant supplier.

Insolubles:

Lubricants are subjected to a wide range of environmental variations which lead to the production or inclusion of contaminants. The presence of contamination degrades the base oil and additive system, producing insoluble particulates which can cause serious problems. Such contaminants can include heat, entrained air, iIncompatible gasses, moisture, internal and externally generated contaminants, partially burned fuel compounds, other oils etc.

Regular monitoring for the presence of insolubles is especially useful for marine engines, providing an effective tool in safeguards against costly engine breakdowns.

Flashpoint:

Flashpoint is the lowest temperature at which a vapour produced by the liquid will ignite when a flame is applied under standard conditions. Below a certain value there is a high risk of very serious incidents in service, including crankcase explosions. Because of the low flashpoint of most fuels, a sudden drop in flash temperature within crankcase oil can usually be relied upon as an indication of dilution. Therefore the flashpoint must be monitored very carefully.

Water Content:

Water contamination can occur from various sources in new or used oils. Storage tanks encourage water condensation simply from ambient air changes, resulting in free water which collects at the bottom of storage tanks over many years. Failure to remove this water will lead to water being drawn into the engine lubricating operational system with potentially catastrophic results. Water is the most common contaminant present within lubricant oil samples. This can cause machine failure due to rust corrosion, bacterial growth, sludge formation and the formation of unstable emulsions.

Acid Number:

Acid Niumber measures the level of acidity within the lubricant. An increase in the Total Acid Number (TAN) often suggests oxidation of the lubricant, depletion of the anti-oxidants and contamination with acidic components which can cause reduction of machinery reliability due to the build-up of lacquers and corrosive materials.

Wear Metal Elements:

LQS testing reports the levels in of metals likely to be found within marine lubrication and engine systems. Increases in certain elements such as Iron (Fe) and Copper (Cu) are early warning signs of a potentially unacceptable wear metal problem. A secondary ferrography analysis can give a detailed analysis, providing the morphology of particles and the number present, an experienced analysis will indicate if a failure is in progress.

PQ Index:

The PQ technique measures the effect of magnetic debris such as iron and nickel on a known magnetic field. The degree of effect is proportional to the degree of ferrous material present. The PQ Index test offers a proactive approach to controlling contamination. In combination with spectrographic metals analysis, PQ index significantly enhance the LQS analysts advisory capabilities.

Particle Count:

Particle count tests count the number of particles present greater than a given size per unit of fluid. Test results reflect the contaminants present within that size range and are applied to assess fluid cleanliness and filter efficiency. LQS rigorously recommends the use of the particle count method for all systems which rely upon cleanliness to protect highly machined and close fitting components from abrasion and detriment caused by the presence of unwanted particulates.

Base Number:

Lubricating oils are designed to clean and provide protection from acidic and chemical corrosion. The Base Number represents the potential to neutralise acidic properties. Low sulphur fuels mean engines work at higher temperatures with longer oil change intervals, resulting in higher levels of oxidation and organic acids. Sulphur is oxidised which in part combines with water, forming sulphurous and sulphuric acids which are extremely corrosive to the engine’s components and need neutralising.

• Contact Intertek LQS for more information.
• Download the full technical paper on "Understanding the LQS Analysis Report"
• Marine Lubricants Testing