The American Club has analysed the importance of regularly performing lube oil analysis for shipboard machinery, and has provided measures to prevent potential problems in a useful guidance document.
Oil analysis is important as it can help identify problems in the machinery such as abnormal wear, lube oil degradation, contamination of harmful agents, etc. all of which can lead to the potential failure of the machinery and its components. Failures can lead to a loss of propulsion and/or blackouts that can cause consequential incidents such as groundings, collisions, or damage to third party property. Periodic oil analysis can help maintain a proactive maintenance strategy, thus maintaining component life, mitigation of premature component failure and improved Mean Time Between Overhauls (MTBO).
The economic impact of breakdown prevention could result in considerable savings mitigating repair costs, downtime, loss of hire, wasting spares and the improving safety of operations. The results of lube oil analyses are unique to every machinery system and can be compared against specified manufacturers’ standards and limits as specified by international standardization regimes. Such analysis establishes whether certain key performance parameters are within operational ranges and so certify the oil’s fitness for use. In certain instances, further investigation involving some advanced analysis may be required to determine whether the lube oil meets recommended fitness for use.
Modern lubricating and hydraulic oils are designed to operate under specified conditions and durations (running hours). Deviating from recommended limitations may harm vital properties of the lube oil that can lead to poor performance and/or potential damage of the lubrication film thus paving the way for potential failure of the machinery.
What to look for in lube oil analysis
Lube oil samples are normally tested by specialized laboratories to determine the following characteristics:
– The viscosity, as a main factor of lubricating oil to provide sufficient film thickness between the relative motion of the machinery parts;
– The closed flash point, as an indicator of oil contamination, blowby and dilution of engine fuels;
– Infrared spectroscopy, to determine the presence and concentrations of insoluble solid contaminants such as combustion soot, dirt, oxidation products and metal wear debris;
– The Total Base Number (TBN) as a measure of the reserve alkalinity of the oil and its ability to neutralize harmful acids;
– The Acid Number that shows the acidity of the oil, identifying its potential to cause varnish and harmful deposits on the machinery and indicating the presence of organic acids generated by oil oxidation;
– The level of oxidation that has occurred during the oil’s ageing process by an Infrared test to assess the change in the molecular structure of the lube.
– The water percentage (by volume) defining the total amount of water contamination;
– The PQ Index that measures the total ferrous (iron) particles present;
– The presence of asphaltenes, as an indication of heavy fuel derived components from raw fuel ingress and/or the products of combustion from blow-by;
– Levels of various metals in the oil sample determined through Elemental Analysis that may indicate accelerated wear and tear in certain components of machinery.
According to the American Club, it is recommended that each vessel and its managers have established procedures for sampling and analyzing lube oil samples, reviewing the results, monitoring the condition of machinery and implementing relevant and adequate planned maintenance. There are some simple things to do and not to do with lube oil sampling:
Things to do
– Sampling should be performed by qualified and trained personnel.
– Samples should be taken from machinery that has been running.
– Samples should be collected upstream of filters.
– Samples should be taken at regular intervals.
– Samples should be properly sealed and labeled with relevant information on the machinery (component or system), running hours and date the sample was taken. Proper documentation is imperative.
Things not to do
– Collect samples from drain plugs as sediments and other contaminants accumulate at those points.
– Wait to send samples for testing.
Download the guidance: The Importance of Lube Oil Analysis