MarineLine® E-Newsletters

Profitable Tanker News about Marine Cargo Tank Coatings
Issue 05
Intertanko Advocates a Unified Tank Cleaning Standard
Just recently, Advanced Polymer Coatings focused its issue of ‘Profitable Tanker’ on good practices for tank cleaning of MarineLine® 784 cargo tanks. To further this discussion, APC would like to present an article on Intertanko’s proposed standards on tank cleaning so you can be aware of industry discussions at this point. APC contacted and received permission from Tanker Shipping & Trade magazine to reprint this information article from its February/March 2013 issue.

Intertanko logoAs Intertanko states on its website, the reason for this exercise among others in discussion is: “Increasingly strict tank cleaning standards required by charterers are also being addressed. Such requirements result in over-cleaning and a subsequent waste of fuel, energy and time, as well as increased costs and an impact on the environment. The Committee is working on the production of a set of cleaning standards which could be deployed as an industry standard.”

Unclear and inconsistent tank cleanliness standards lead to unnecessary ship delays. As a result of these inconsistencies, customers are often exposed to demurrage claims that could be avoided if the standards and test methods were made more consistent.

In response, Intertanko, through its Chemical Tanker Committee, has compiled a list of ‘five tank cleanliness standards’. These new standards, if adopted by industry, would replace most of the standards used today and would be applicable for almost all cargoes loaded.

The standards range from a ‘visually clean standard’ to an ‘ultra-clean standard’. The visually clean standard would typically entail a simple hot water flush and ventilation. The ultra-clean standard, as the name implies, would involve extensive tank cleaning.

Intertanko says that having a consistent and well accepted tank cleanliness standard across the industry would mean:

Fewer delays related to tank surveys and tank approvals in ports (i.e. reduced surveyor and demurrage costs)
Tanks cleaned to the correct standard, but not over cleaned (less applied cleaning detergents, less use of energy)
Crew familiarity with the ‘five standards’ instead of the multitude used today

Intertanko’s PROPOSED tanker standards are intended to simplify both the commercial and technical dimensions of tank cleaning. (These 5 standards are proposed.)
1 Visually clean
Definition Tanks Suitable for Additional comments
Dry, free of visual residues of previous cargo and/or foreign matter Phosphoric acid, caustic soda, FAME, veg oils after CPP/veg oils, CPP after CPP/veg oils  
2 Water white standard
Definition Tanks Suitable for Additional comments
Dry, odour free, free of visual residues + Wall wash with suitable solvent shows
• colour PtCo (ASTM D 1209) less than 10
Styrene monomer, acrylonitrile, MTBE, ETBE, hydrocarbon solvents, chlorinated solvents, isopropyl alcohol, acetone, MEK, MIBK Methanol is a suitable solvent for wall-wash tests in most cases
3 BTX standard
Definition Tanks Suitable for Additional comments
Dry, odour free, free of visual residues + Wall wash with toluene
• colour PtCo (ASTM D 1209) less than 10 Acid wash*
• colour (ASTM D 848) less than 2
Benzene, toluene, xylene, sulphuric acid Acid wash colour is affected by unsaturated products, such as all inhibited cargoes, veg oils, olefins, pygas and gasoline
4 Methanol standard
Definition Tanks Suitable for Additional comments
Dry, odour free, Free of visual residues + Wall wash with methanol confirms to: Water miscibility test (ASTM D 1722) passes
• colour PtCo (ASTM D 1209) less than 10
• Chlorides less than 2 ppm
• Permanganate time test above 50 min
• UV spectrum passes
Methanol, ethanol, MEG fibre grade, food grade and pharmaceutical grade cargoes (acetic acid, MPG - USP grade) IMPCA specification is the international methanol standard and includes strict UV specification. Readings:
• Max 0.25 at 220 nm
• Max 0.10 at 250 nm
• Max 0.02 at 268.5 nm
• Max 0.01 at 300 nm
5 Ultra clean standard
Definition Tanks Suitable for Additional comments
Passes methanol standard + Wall wash with suitable solvent:
• Non-volatile matter less than 10 ppm*
• Last cargo by GC* or other suitable method less than 2 ppm
Highest purity chemicals, such as 1-hexane, 1-octene, HMD, acetic anhydride Tank is completely free of residues as detectable by modern instrumental methods

*Acid wash test, Gas Chromatography (CG) and non volatile matter can not be tested onboard.

If you have more questions/comments Intertanko’s proposed standards, you can contact Intertanko, or visit their website at

If you have questions regarding MarineLine® 784, contact your Advanced Polymer Coatings’ representative.