Chapter 1 - General
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Statutory Documents - IMO Publications and Documents - International Codes - OSV Chemical Code - Code for the Transport and Handling of Hazardous and Noxious Liquid Substances in Bulk on Offshore Support Vessels - Chapter 1 - General

Chapter 1 - General

 To provide an international standard for the safe carriage, by sea in bulk, of chemicals by setting the design and construction standards of vessels involved in such carriage and the equipment, so as to minimize the risks to the vessel, its crew and the environment, having regard to the nature of the products, including flammability, toxicity, asphyxiation, corrosivity and reactivity.

1.1 Application

1.1.1 The present Code applies to OSVs engaged in the carriage of the products identified in 1.1.9, regardless of size or voyage.

1.1.2 The present Code should also apply when the cargoes indicated in 1.1.9 are part of a blending or production process of cargoes used in the search for and exploitation of seabed mineral resources on board vessels used to facilitate such operations.

1.1.3 Unless expressly provided otherwise, the present Code applies to OSVs the keels of which are laid or which, on or after 1 July 2018, are at the stage where:

  • .1 construction identifiable with the vessel begins; and

  • .2 assembly has commenced comprising at least 50 tonnes or 1% of the estimated mass of all structural material, whichever is less;

1.1.4 Existing OSVs the keel of which were laid or which were at a similar stage of construction on or after 19 April 1990 and before the date specified in 1.1.3 may be permitted to carry products as assigned for carriage on a type 2 ship in the IBC Code, provided that those OSVs comply with the present Code, except for the stability provisions in chapter 2 of the present Code, and subject to the satisfaction of the Administration.

1.1.5 A vessel, irrespective of the date of construction, which is converted for the carriage of bulk liquids subject to the present Code on or after the date specified in 1.1.3 should be treated as a vessel constructed on the date on which such conversion commences. An OSV which transports a cargo subject to the present Code and undergoes modification for the transport of additional cargoes falling under the present Code should not be considered as a vessel which has undergone a conversion.

1.1.6 The present Code applies only in the case of bulk carriage involving transfer of the cargo to or from its containment which forms part of the vessel or remains on board.

1.1.7 For requirements regulating the transport of dangerous goods and marine pollutants in packaged form, including transport of dangerous goods in portable tanks, refer to the International Maritime Dangerous Goods Code (IMDG Code).

1.1.8 The present Code applies in addition to the Guidelines for the design and construction of offshore supply vessels (resolution MSC.235(82)), as amended. Where the present Code sets forth alternative safety standards, the standards in the present Code should be applied.

1.1.9 Products which may be carried subject to the present Code are:

  • .1 products which are listed in chapters 17 or 18 of the IBC Code and the latest edition of the MEPC.2/Circular (Provisional categorization of liquid substances in accordance with MARPOL Annex II and the IBC Code) and their related references to chapters 15 and 19; or

  • .2 oil-based/water-based mud containing mixtures of products listed in chapters 17 and 18 of the IBC Code and the MEPC.2 Circular; or

  • .3 liquid carbon dioxide (high purity and reclaimed quality) and liquid nitrogen; or

  • .4 contaminated backloads.

1.1.10 For a product proposed for carriage in bulk, but not listed in chapters 17 or 18 of the IBC Code, the Administration and port Administrations involved in such carriage should prescribe the suitable preliminary conditions for the carriage, having regard to the criteria for hazard evaluation of bulk chemicals. For the evaluation of the pollution hazard of such a product and assignment of its pollution category, the procedure specified in regulation 6.3 of MARPOL Annex II should be followed. IMO should be notified of the preliminary conditions for consideration for inclusion of the product in the IBC Code.

1.2 Definitions

The following definitions apply unless expressly provided otherwise (additional definitions are given in individual chapters).

1.2.1 Accommodation spaces are those spaces used for public spaces, corridors, lavatories, cabins, offices, hospitals, cinemas, games and hobbies rooms, barber shops, pantries containing no cooking appliances and similar spaces.

1.2.2 Administration means the Government of the State whose flag the vessel is entitled to fly.

1.2.3 Anniversary date means the day and the month of each year that will correspond to the date of expiry of the Certificate of Fitness.

1.2.4 Backload means contaminated bulk liquids, taken on board a vessel offshore, for transport either back to shore or to an alternate offshore site.

1.2.5 Blending additives means small amounts of liquid substances used during blending of products or production processes of cargoes for use in the search for and exploitation of seabed mineral resources on board vessels used to facilitate such operations.

1.2.6 Breadth (B) means the maximum breadth of the vessel, measured amid vessels to the moulded line of the frame in a vessel with a metal shell and to the outer surface of the hull in a vessel with a shell of any other material. The breadth (B) should be measured in metres.

1.2.7 Cargo area is that part of the OSV where:

  • .1 a pollution hazard only substance having a flashpoint exceeding 60C and not defined as toxic is likely to be present and includes cargo tanks, portable tanks used as deck cargo tanks, slop tanks, cargo pump-rooms, pump-rooms adjacent to cargo tanks and enclosed spaces in which pipes containing cargoes are located; areas on open deck are not considered part of the cargo area;

  • .2 a safety hazard substance having a flashpoint exceeding 60C and not defined as a toxic is likely to be present and includes cargo tanks, portable tanks used as deck cargo tanks, slop tanks, cargo pump-rooms, pump-rooms adjacent to cargo tanks, hold spaces in which independent tanks are located, cofferdams surrounding integral tanks, enclosed spaces in which pipes containing cargoes are located and the following deck areas:

    • .1 within 3 m of cargo tank installed on deck or portable tanks used as deck cargo tanks;

    • .2 areas on open deck, or semi-enclosed spaces on deck, within 3 m of any cargo tank access outlet;

    • .3 areas on open deck over an integral tank without an overlaying cofferdam plus the open deck area extending transversely and longitudinally for a distance of 3 m beyond each side of the tank;

    • .4 areas on open deck, or semi-enclosed spaces on deck, within 3 m of cargo manifold valve, cargo valve, cargo pipe flange, except spaces within the 3 m zone that are separated by an enclosed bulkhead to the minimum height as given in 1.2.7.2.6;

    • .5 areas on open deck, or semi-enclosed spaces on open deck above and in the vicinity of any cargo tank vent outlet intended for the passage of large volumes of vapour mixture during cargo loading, within a vertical cylinder of unlimited height and 3 m radius centred upon the centre of the outlet, and within a hemisphere of 3 m radius below the outlet;

    • .6 areas on the open deck within spillage coamings surrounding cargo manifold valves and 3 m beyond these, up to a height of 2.4 m above the deck; and

    • .7 compartments for cargo hoses;

  • .3 a substance having a flashpoint not exceeding 60C, or defined as toxic or vapours of such cargo, is likely to be present and includes cargo tanks, portable tanks used as deck cargo tanks, slop tanks, cargo pump-rooms, pump-rooms adjacent to cargo tanks, hold spaces in which independent tanks are located, cofferdams surrounding integral tanks, enclosed spaces in which pipes containing cargoes are located and the following deck areas:

    • .1 within 3 m of cargo tank installed on deck or portable tanks used as deck cargo tanks;

    • .2 areas on open deck, or semi-enclosed spaces on deck, within 4.5 m of gas or vapour outlet, cargo manifold valve, cargo valve, cargo pipe flange, cargo pump-room ventilation outlets and cargo tank openings for pressure release provided to permit the flow of small volumes of gas or vapour mixtures caused by thermal variation;

    • .3 areas on open deck, or semi-enclosed spaces on open deck above and in the vicinity of any cargo gas outlet intended for the passage of large volumes of gas or vapour mixture during cargo loading, within a vertical cylinder of unlimited height and 10 m radius centred upon the centre of the outlet, and within a hemisphere of 10 m radius below the outlet;

    • .4 areas on open deck, or semi-enclosed spaces on deck, within 3 m of cargo pump-room entrances, cargo pump-room ventilation inlet, openings into cofferdams;

    • .5 areas on the open deck within spillage coamings surrounding cargo manifold valves and 3 m beyond these, up to a height of 2.4 m above the deck;

    • .6 compartments for cargo hoses; and

    • .7 within the hose landing area.

1.2.8 Cargo control station means a location that is manned during cargo transfer operations for the purpose of directing or controlling the loading or unloading of cargo.

1.2.9 Cargo pump-room is a space containing pumps and their accessories for the handling of the products covered by the present Code.

1.2.10 Cofferdam is the isolating space between two adjacent steel bulkheads or decks. This space may be a void space or a ballast space.

1.2.11 Control stations are those spaces in which vessels' radio or main navigating equipment or the emergency source of power is located or where the fire-recording or fire-control equipment is centralized. This does not include special fire-control equipment which can be most practically located in the cargo area.

1.2.12 Conversion means a vessel in an unrelated service modified for use as an OSV. Special purpose ships (operated under the Code of Safety for Special Purpose Ships, 2008 (2008 SPS Code)) in support-related service configurations are not considered "in an unrelated service".

1.2.13 Dangerous chemicals means any liquid chemicals designated as presenting a safety hazard, based on the safety criteria for assigning products to chapter 17 of the IBC Code.

1.2.14 Dangerous goods mean the substances, materials and articles covered by the IMDG Code.

1.2.15 Deadweight means the difference in metric tons between the displacement of an OSV in water of a density of 1.025 at the load waterline corresponding to the assigned summer freeboard and the lightweight of the vessel.

1.2.16 Deck spread means portable tanks, piping, equipment, processing equipment and control stations secured to the vessel by permanent means and used in the operation of the vessel.

1.2.17 Density is the ratio of the mass to the volume of a product, expressed in terms of kilograms per cubic metre. This applies to liquids, gases and vapours.

1.2.18 Flashpoint is the temperature in degrees Celsius at which a product will give off enough flammable vapour to be ignited. Values given in the present Code are those for a "closed cup test" determined by an approved flashpoint apparatus.

1.2.19 Hazardous substance is any substance either listed in chapter 17 of the IBC Code or having a hazard more severe than one of the minimum hazard criteria given in criteria for hazard evaluation of bulk chemicals as approved by the Organization.

1.2.20 Hold space is the space enclosed by the vessel's structure in which an independent cargo tank is situated.

1.2.21 Hose landing area means an area on the main deck, except those in compartments for cargo hoses, where cargo hoses of substances having a flashpoint not exceeding 60C and/or defined as toxic are located during cargo transfer.

1.2.22 Independent means that a piping or venting system, for example, is in no way connected to another system and that there are no provisions available for the potential connection to other systems.

1.2.23 IBC Code means the International Code for the Construction and Equipment of Ships Carrying Dangerous Chemicals in Bulk (resolutions MSC.4(48) and MEPC.19(22)), as amended.

1.2.24 IGC Code means the International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk (resolution MSC.5(48)), as amended.

1.2.25 IMDG Code means the International Maritime Dangerous Goods Code (resolution MSC.406(96)), as amended.

1.2.26 Length (L) means 96% of the total length on a waterline at 85% of the least moulded depth measured from the top of the keel, or the length from the foreside of the stem to the axis of the rudder stock on that waterline, if that is greater. In vessels designed with a rake of keel, the waterline on which this length is measured should be parallel to the designed waterline. The length (L) should be measured in metres.

1.2.27 Lightweight means the displacement of an OSV in metric tons without cargo, fuel, lubricating oil, ballast water, fresh water and feed water in tanks, consumable stores, and crew and their effects.

1.2.28 Machinery spaces of category A are those spaces and trunks to such spaces which either contain:

  • .1 internal combustion machinery used for main propulsion;

  • .2 internal combustion machinery used for purposes other than main propulsion where such machinery has in the aggregate a total power output of not less than 375 kW; or

  • .3 any oil-fired boiler or oil fuel unit or any oil-fired equipment other than boilers, such as inert gas generators, incinerators, etc.

1.2.29 Machinery spaces are machinery spaces of category A and other spaces containing propulsion machinery, boilers, oil fuel units, steam and internal combustion engines, generators and major electrical machinery, oil filling station, refrigerating, stabilizing, ventilation and air conditioning machinery, and similar spaces, and trunks to such spaces.

1.2.30 MARPOL means the International Convention for the Prevention of Pollution from Ships, 1973, as modified by the Protocol of 1978 relating thereto, as amended.

1.2.31 Noxious liquid substance means any substance indicated in the Pollution Category column of chapter 17 or 18 of the IBC Code, or the current MEPC.2 Circular or provisionally assessed under the requirements of regulation 6.3 of MARPOL Annex II as falling into categories X, Y or Z.

1.2.32 Offshore portable tank means a portable tank specially designed for repeated use for transport of dangerous goods to, from and between offshore facilities. An offshore portable tank is designed and constructed in accordance with the Guidelines for the approval of offshore containers handled in open seas (MSC/Circ.860).

1.2.33 Offshore support vessels (OSVs) are:

  • .1 multi-mission vessels which are primarily engaged in the transport of stores, materials and equipment to and from mobile offshore drilling units, fixed and floating platforms and other similar offshore installations; or

  • .2 multi-mission vessels, including well-stimulation vessels, but excluding mobile offshore drilling units, derrick barges, pipe-laying barges and floating accommodation units, which are otherwise primarily engaged in supporting the work of offshore installations.

1.2.34 Oil fuel unit is the equipment used for the preparation of oil fuel for delivery to an oil- fired boiler, or equipment used for the preparation for delivery of heated oil to an internal combustion engine, and includes any oil pressure pumps, filters and heaters dealing with oil at a gauge pressure of more than 0.18 MPa.

1.2.35 Open deck is defined as an open or semi-enclosed space on cargo deck or inside of the cargo rail. Semi-enclosed spaces are those spaces that either:

  • .1 are open at two ends; or

  • .2 have an opening at one end and are provided with adequate natural ventilation effective over their entire length through permanent openings distributed in the side plating or deckhead or from above, the openings having a total area of at least 10% of the total area of the space sides.

1.2.36 Organization is the International Maritime Organization (IMO).

1.2.37 Permeability of a space means the ratio of the volume within that space which is assumed to be occupied by water to the total volume of that space.

1.2.38 Pollution hazard only substance means a substance having an entry only of "P" in column d in chapter 17 of the IBC Code.

1.2.39 Port Administration means the appropriate authority of the country for the port where the vessel is loading or unloading.

1.2.40 Portable tank means a multimodal tank used for the transport of dangerous goods.

1.2.41 Propulsion shaft tunnel is the tunnel or space in which the mechanical transfer of power to a propulsion unit is run.

1.2.42 Public spaces are those portions of the accommodation spaces which are used for halls, dining rooms, lounges and similar permanently enclosed spaces.

1.2.43 Pump-room is a space, located in the cargo area, containing pumps and their accessories for the handling of ballast and oil fuel.

1.2.44 Recognized standards are applicable international or national standards acceptable to the Administration or standards laid down and maintained by an organization which comply with the standards adopted by IMO and which are recognized by the Administration.

1.2.45 Safety hazard substance means a substance having an entry of "S" or "S/P" in column d in chapter 17 of the IBC Code.

1.2.46 Separate means that a cargo piping system or cargo vent system, for example, is not connected to another cargo piping or cargo vent system.

1.2.47 Service spaces are those spaces used for galleys, pantries containing cooking appliances, lockers, mail and specie rooms, storerooms, workshops other than those forming part of the machinery spaces and similar spaces and trunks to such spaces.

1.2.48 SOLAS means the International Convention for the Safety of Life at Sea, 1974, as amended.

1.2.49 Underdeck access way is a passage passing through the underdeck cargo area without being part of the cargo area providing access to essential areas for operation of the vessel, such as thruster room, propulsion room or steering gear room. The access way may be used to route non-cargo piping and cabling.

1.2.50 Vapour pressure is the equilibrium pressure of the saturated vapour above a liquid expressed in pascals (Pa) at a specified temperature.

1.2.51 Void space is an enclosed space in the cargo area external to a cargo tank, other than a hold space, ballast space, oil fuel tank, cargo pump-room, pump-room, or any space in normal use by personnel.

1.2.52 Well-stimulation vessel means an OSV with specialized equipment and industrial personnel that delivers products and services directly into a well-head.

1.3 Equivalents

1.3.1 Where the present Code requires that a particular fitting, material, appliance, apparatus, item of equipment or type thereof should be fitted or carried on an OSV, or that any particular provision should be made, or any procedure or arrangement should be complied with, the Administration may allow any other fitting, material, appliance, apparatus, item of equipment or type thereof to be fitted or carried, or any other provision, procedure or arrangement to be made in that vessel, if it is satisfied by trial thereof or otherwise that such fitting, material, appliance, apparatus, item of equipment or type thereof or that any particular provision, procedure or arrangement is at least as effective as that required by the Code. However, the Administration may not allow operational methods or procedures to be made an alternative to a particular fitting, material, appliance, apparatus, item of equipment, or type thereof, which are prescribed by the Code, unless such substitution is specifically allowed by the Code.

1.3.2 Where the Administration allows any fitting, material, appliance, apparatus, item of equipment, or type thereof, or provision, procedure, or arrangement, or novel design or application to be substituted, it should communicate to the Organization the particulars thereof together with a report on the evidence submitted so that the Organization may circulate the same to other Parties to SOLAS or MARPOL, for the information of their officers.

1.4 Surveys and certification

1.4.1 Following a satisfactory initial survey of an OSV, the Administration or its duly authorized organization should issue a certificate, the model form of which is set out in appendix 1, suitably endorsed to certify compliance with the provisions of the present Code. If the language used is not English, French or Spanish, the text should include the translation into one of those languages. The certificate should indicate the cargoes regulated by the present Code that the vessel is permitted to carry with any relevant carriage conditions and should have a period of validity not exceeding five years.

1.4.2 The certificate issued under the present Code should have the same force and receive the same recognition as the certificate issued under regulation 7 of MARPOL Annex II and regulations VII/10 and VII/13 of SOLAS.

1.4.3 The validity of the certificate referred to in 1.4.1 should be subject to the renewal, intermediate, annual and additional surveys required by the IBC Code, the IGC Code and MARPOL Annex II.


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