Watch Out – Fuel Can Change Colour!


Viswa Lab has reported that it has received a peculiar fuel sample for testing from one of its customers, which was marked as RMD 80 grade and classed as ULSFO.  The sample sent for analysis was from the bunker manifold collected throughout the bunkering operation as per standard procedure.

Upon receipt of the sample, it was visually inspected before analysis.

Visual Appearance:

  1. The color of the sample when poured into a beaker was similar to golden yellow and smelled completely different from regular heavy fuels.
  2. The fluidity was not as good as it appears and neither was it a wax at room temperature.
  3. Actual images are posted below for your reference.



Visual Appearance After Heating:

  1. After heating for about 30 minutes, the visual appearance of the sample changed from golden-yellow to dark green color.
  2. Below are actual images of the sample after heating in the oven at 60 degree Celsius for 30 minutes.

The ambient temperature where the sample was kept before heating was around 25 degree Celsius.



Test Results:

Wax sample test results

It is to be noted that the Pour point is very high which is at 21 degree Celsius. This means at approximately 21 degree Celsius, the oil will cease to Pour. Heating the fuel and maintaining it well above the pour point will appease the problem with pour point. Viswa Lab – has a specific alert system incorporated with the fuel oil reports – to alert the fuel user and highlight the importance of such parameters though it is within the specifications.

Have a fuel problem – write to

Source: Viswa Lab – FPS (Fuel Problem Support) Team.


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