7. Operations and Equipment Manual
Clasification Society 2024 - Version 9.40
Statutory Documents - IMO Publications and Documents - Specifications and Manuals - Crude Oil Washing Systems - Revised Specifications for the design, operation and control of crude oil washing systemsResolution A.446(XI) Amended by Resolution A.497(XII) Amended by Resolution A.897(21) - 7. Operations and Equipment Manual

7. Operations and Equipment Manual

 The Operations and Equipment Manual must be to the satisfaction of the Administration and shall contain the following information and operational instructions:

  (a) The complete text of the revised Specifications for the Design, Operation and Control of Crude Oil Washing Systems.

  (b) A line drawing of the crude oil washing system showing the respective position of pumps, lines and washing machines which relate to the crude oil washing system.

  (c) A description of the system and a listing of procedures for checking that equipment is working properly during crude oil washing operations. This shall include a listing of the system and equipment parameters to be monitored, such as line pressure, oxygen level, machine revolutions, duration of cycles, etc. The established values for these parameters shall be included. The results of the tests carried out in accordance with 4.2.10 and the values of all parameters monitored during such tests shall also be included.

  (d) Details of the requirements of section 6 of these Specifications together with advice and instructions, where appropriate, in meeting these requirements such as:

  • (i) Recommended methods and programmes of crude oil washing in order to accord with all foreseeable circumstances of cargo discharge restraints and to obtain maximum trim during the completion of washing and draining of each tank.

  • (ii) The procedure on ships to avoid vapour emission in accordance with 6.8.

  • (iii) The method of draining tanks which shall include information on optimum trim conditions as required by 4.4.10.

  • (iv) The method of draining cargo pumps, cargo lines, crude oil washing lines and stripping lines, the identification of spaces into which they may be drained and procedures for discharge ashore of drainings and strippings via the small diameter discharge line on completion of cargo discharge.

  • (v) Typical washing programmes under various conditions of loading specifying:

    • (1) The tanks to be washed in accordance with 6.1;

    • (2) The method for washing each tank, that is single or multi-stage;

    • (3) The number of tank washing machines to be used simultaneously;

    • (4) The duration of the crude oil wash and water rinse where the latter is appropriate;

    • (5) The volume of water used for water rinse, which shall be at least equal to that used in the water rinse prior to the inspection required by 3.2 and 4.2.10; and

    • (6) The preferred order in which the tanks are to be washed.

  • (vi) The procedure for draining and stripping, where appropriate, cargo lines and pumps before being used for the loading of departure ballast.

  • (vii) The procedure for water washing lines before discharge of departure ballast and the loading and final discharge of arrival ballast.

  • (viii) The procedure for verifying by sound patterns that bottom mounted machines are operating shall be carried out towards the end of the wash cycle for each tank. When carrying out such verification all other machines shall be shut down if necessary.

  • (ix) Precise details of procedure to ensure compliance with Regulation 9 of Annex I of MARPOL 73/78 in the discharge of departure ballast, the water flushing of lines and the decanting of the slop tanks at sea.

  (e) The dangers of leakage from the crude oil washing system and the precautions necessary to prevent leakage and the action to be taken in the event of a leakage. Guidance shall be given on how the crude oil washing system is to be operationally tested for leakage before each discharge.

  (f) The method of preventing the entry of oil to the engine room through steam heaters as required by 4.1.6.

  (g) The personnel required at all times to conduct the dual operation of discharging cargo and crude oil washing. The numbers of such personnel shall include:

  • (i) The person meeting the requirements of 5.2 who will have overall control of the crude oil washing process;

  • (ii) Those persons meeting the requirements of 5.3 who will be expected to undertake the actual operation; and

  • (iii) At least one person on deck at all times during washing to keep watch for leaks and malfunctioning of equipment, to test the oxygen content of tanks before washing, to check tank atmosphere pressure, to sound tank bottoms if required, to lift ullage floats if necessary and to change drive units when this is necessary.

    The duties of such persons are not necessarily mutually exclusive.

  (h) An effective means of communication between the watchkeeper on deck and the cargo control position so that in the event of a leak in, or malfunctioning of, the crude oil washing system the washing may be stopped as soon as possible.

  (i) The typical procedures for ballasting.

  (j) A pre-crude oil wash operational checklist for the use of the crew at each discharge which shall include the checking and calibration of all instruments.

  (k) The recommended intervals for on-board inspection and maintenance of crude oil washing equipment in addition to statutory surveys. Reference should be made to technical manuals supplied by the manufacturers of the equipment.

  (l) A list of crude oils unsuitable for the crude oil washing process and their origin.


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