Ability to Clean Between Edible and Non-Edible Grades


To a large extent, the intended grade to be loaded onto any tank vessel will depend on three factors: (a.) the construction of the tank being used, (b.) the thoroughness of the cleaning of that tank prior to loading and, perhaps most importantly, (c.) the history of what has been loaded into the particular tank in the recent past.

Tank Cleaning & Inspection
Where a cargo tank has been used for non-edible materials, great care must be taken to adequately clean and then verify that the tank has been properly prepared for the intended grade. The latter task is best performed by a suitably qualified superintendent for every loading or unloading operation, usually hired by the charterer of the vessel.

Previous Grades
The three previous cargoes carried in a ship’s tank should be declared by the vessel to the charterer and the records made available to all parties involved. This provision should be made a part of all shipping contracts. A voluminous list of “banned” cargoes, more than 100 in total, describes grades which cannot precede some edible oils. Some of these cargoes are banned from being any one of the last two cargoes in organically coated tanks and as the last cargo in stainless steel and inorganically coated tanks.

Use Caution
The list of cargoes that immediately precede an edible cargo in any tank changes regularly. Your Soundtanker broker keeps abreast of all these changes and will be your best source of data when determining whether or not you can use a particular ship or tank to transport your bulk cargo.

Best Bets
As a general rule, it is best to load sensitive cargoes onto vessels that achieve segregation of tanks by using individual pumps and line systems, with a segregated “drop” and “discharge” valve. Mild steel tanks must be coated to prevent corrosion of the mild steel and subsequent contamination of the cargo and those coatings must be approved for contact with food. To that end, a stainless steel tank is your best bet. Your Soundtanker broker keeps a detailed record of which vessels qualify in either category.