Every ship bunkers fuel to extend its endurance and reach out to various parts of the world. It is well known that after bunkering fuel, a sample of fuel is sent for lab analysis to determine its suitability for safe operation of shipboard machinery. However when it comes to lubricating oils, which are the blood of every industrial machinery, most of the shipboard and shore staffs are not aware of the reasons to sample and test a fresh/new lubricating oil.
This write-up is completely aimed to throw some light on the three main reasons to sample and test a new lubricating oil.
Whenever a vessel load lubricating oil in bulk, either engine system oil or cylinder oil, it is never tested for quality against its specifications.
This is critical for several reasons, such as
- To ensure that the oil received is the oil ordered,
- To establish a baseline for subsequent testing and monitoring of the oil condition and
- Simply to verify lubricant cleanliness.
1. Ensuring the Lubricant Received is the Lubricant Ordered:
This may involve a simple viscosity comparison or a complete elemental analysis to ensure that the additive package meets the application’s requirements. At the very minimum, a viscosity comparison should be performed.
“Lubricants are blended by humans. They are inspected by humans. They are transported and packaged by humans. They are labeled by humans. When it comes to humans, there is one unalterable constant – we make mistakes.” It has to be noted that though the technology has developed and the blending process automated, the complete process till the oil sits in the ship’s tank is not error free.
It has been said that the industrial world rides on a lubricant film between 1 and 10 microns. This film thickness is determined by the speed of rotation, the load on the elements and the lubricant’s viscosity. Lubricants are purchased with a specific viscosity to maintain that lubricant film and eliminate boundary conditions or metal-on-metal contact for the particular application. While this applies for lubricants purchased in drums, buckets, bottles, etc., in the case of bulk deliveries, there is an additional consideration.
A delivery barge generally has tanks of different sizes and is loaded based on the delivery schedule. For example, the barge may have four to six tanks: a 50 m3 tank, 100 m3 tank, a 150 m3 tank and a 200 m3 tank.
The orders being delivered today may require 75 m3 of oil “A,” 100 m3 of oil “B,” 150 m3 of oil “C” and 50 m3 of oil “D.” Tomorrow’s deliveries may require 50 m3 of oil “D,” 60 m3 of oil “C,” 100 m3 of oil “A” and 75 m3 of oil “B”. With this type of delivery schedule, cross-contamination is going to occur.
Thus, it is essential to collect samples during bunkering and ensure that the loading and unloading hoses are cleaned. Remember, it is much less expensive to sample and test oil than it is to repair a failure and suffer the costs of downtime associated with that failure.
2. Establishing a Baseline for Subsequent Testing and Monitoring
In order to conduct accurate lubricant condition monitoring, a reference sample should be taken. This will allow subsequent tests to be compared to the reference parameters when the lubricant was new. After all, if you have no idea where you started, how can you tell where you are going? Once this reference sample has been obtained, it should be kept as a reference. You can then directly compare the lubricant’s color or smell to that of the reference sample. This basic observation of color and smell of a used oil sample and reference would reveal vital information with regards to oil condition. This will provide an immediate indication if there is a problem with the lubricant in your machinery.
3. Verifying Lubricant Cleanliness
A Lubricant cleanliness is usually measured and represented as ISO codes based on ISO 4406. For those who may not understand ISO cleanliness codes, it can be simply digested as a combination of numbers representing particles greater than 4 microns, 6 microns and 14 microns in the lubricating oil. The oil cleanliness is depicted as R4/R6/R14 and the same values can be compared on to the below chart. It has been said that the industrial world rides on a lubricant film between 1 and 10 microns. Thus, the critical parameters to be observed are R6 and R14 – which is the number of particles more than 6 microns and 14 microns.
If you are not presently tracking lubricant cleanliness, hopefully, this will prompt you to start. If you are tracking cleanliness but are not sampling your oil upon receipt, you are spending good money to clean up someone else’s mess.
Viswa Lab always emphasizes to land fresh oil samples along with used oil samples when sending them for analysis. There have been cases where the ordered cylinder oil is 70 BN and the bunkered oil was found to have a BN of 56.
Voice your views/share your experience if you have encountered any cross contamination or wrong delivery of lubricant grade. Don’t hesitate to write to us.