ETC

tanker

Effective Tank Cleaning on board Oil Products and Chemical Tankers.

Print this page Save as PDF

Purpose

The cleanliness of cargo tanks is mainly a commercial issue. Except for the IMO Crude Oil Washing basic standard, there are only safety requirements related to cleaning standards for cargo tanks on Oil tankers and Chemical tankers. For Chemical tankers and compliance with MARPOL Annex II, there are requirements relating to the pre-wash and stripping performance that were modified at the beginning of 2007.

Cleaning the cargo tanks on product and chemical tankers is often a time- and labour-consuming process due to the internal structure, lack of hot water capacity, low number and/ or capacity of fixed tank cleaning machines and,
in general, too many shadows, and the ETC notation is an attempt to improve this process.

Benefits

An improved tank cleaning standard related to the arrangement of and equipment on board oil product and chemical tankers that may reduce the turnaround time in ports. This notation is an attempt to make it less likely that the cargo will be affected by insufficient cleaning.

Features

This optional Class Notation requires:

  • Cargo tanks that are made of stainless steel or coated, in general without an internal structure (corrugated bulkheads).

  • Cargo piping and heating coils to be of stainless steel or an equivalent material.

  • The cargo tank to be served by individual in-tank cargo pumps, and with suction wells that are located for optimum drainage results.

  • The opportunity to wash cargo tanks using hot water of min. 85°C with a capacity sufficient for washing at least the largest cargo tank.

  • Tank cleaning machines:

    • Permanently installed tank washing machines giving a minimum coverage of 96% based on DNV’s Certified Jet Length (DNV Type approval Program 785.70) at normal operating pressure and with a minimum jet hit angle of 10 degrees. Shadows caused by the pump stacks are to be included in the shadow area.
    • In addition, portable washing equipment and necessary access openings enabling the complete washing of shadow areas are to be provided.

Testimonials

So far more than 100 Oil and Chemical tankers in operation have been built according to the standard, and
many newbuildings to DNV Class have been ordered with this notation.

Process

Approval of documentation during newbuilding and a survey and testing on board during construction.