Type of Chemical Tanker & Ship Design (Chemical Cargo in bulk)

The IBC Code divides chemical tankers into three types:

1. Type I

2. Type II

3. Type III

The ship type required for individual products is indicated in column e in the table of chapter 17.

Type I

A type 1 ship is a chemical tanker intended to transport chapter 17 products with very severe environmental and safety hazards that require maximum preventive measures to preclude an escape of such cargo.

Max Volume of Cargo can be filled per tank is 1250 m3

However, practically the tanks are made only up to approx 500 m3

The ship should be capable of sustaining collision or stranding damage anywhere along her length.

Tanks intended for the carriage of cargoes should be located outside the extent of the damage as per standard damage assumptions.

Type 2

A type 2 ship is a chemical tanker intended to transport chapter 17 products with appreciably severe environmental and safety hazards that require significant preventive measures to preclude an escape of such cargo.

Max Volume of Cargo can be filled per tank is 3000 m3

Practically the tanks are made only up to approx 2000m3

A ship > 150 meters in length

• Capable of sustaining collision or stranding damage anywhere along with her length

A ship < 150 meters in length

• Capable of sustaining collision or stranding damage anywhere along with her length except involving either of the bulkheads bounding a machinery space located aft

Type 3

A type 3 ship is a chemical tanker intended to transport chapter 17 products with sufficiently severe environmental and safety hazards which require a moderate degree of containment to increase survival capability in a damaged condition

Moderate float ability and damage stability requirement

No special requirements for cargo tank location

Length > 225 meters

• Capable of sustaining damage anywhere along the length

Length < 225 meters

• Capable of sustaining damage anywhere along her length except involving either of the bulkheads bounding a machinery space located aft

Damage Assumptions

Bottom Damage

Design Features

• The ship shall be so designed as to keep unsymmetrical flooding to the minimum consistent with efficient arrange

• If pipes, ducts, trunks, or tunnels are situated within the assumed extent of damage penetration, arrangements shall be such that progressive flooding cannot thereby extend to compartments other than those assumed to be flooded for each case of damage.

• In any stage of flooding the waterline, taking into account sinkage, heel and trim, shall be below the lower edge of any opening through which progressive flooding may take place.

• Such openings shall include air pipes and weathertight doors or hatch covers.

• The maximum angle of the heel due to unsymmetrical flooding shall not exceed 25°,

• This angle may be increased to 30° if no deck immersion occurs.

Cargo Segregation

Tanks containing NLS cargo shall be segregated from :

• Accommodation, service, and machinery spaces and from drinking water and stores for human consumption by means of a cofferdam, void space, pump-room, empty tank, oil fuel tank, or other similar space.

• Cargo piping shall not pass through any accommodation, service, or machinery space other than cargo pump-rooms.

• NLS Cargoes shall not be carried in either the fore or aft peak tank.

• No accommodation or service spaces or control stations shall be located within the cargo area.

• Entrances, air inlets, and openings to accommodation, service, and machinery spaces shall not face the cargo area.

• They shall be located at a distance of at least 4% of the length (L) of the ship but not less than 3 m from the end of the superstructure or deck-house facing the cargo area

• This distance, however, need not exceed 5 m

Cargo Pump-rooms

Cargo pump-rooms shall be so arranged as to ensure:

• unrestricted passage at all times from any ladder platform and from the floor; and

• unrestricted access to all valves necessary for cargo handling for a person wearing the required personnel protective equipment.

• Permanent arrangements shall be made for hoisting an injured person with a rescue line while avoiding any projecting obstacles.

• Guard railings shall be installed on all ladders and platforms.

• Normal access ladders shall not be fitted vertical and shall incorporate platforms at suitable intervals.

• The bilge system serving the cargo pump-room shall be operable from outside the cargo pump-room.

• One or more slop tanks for storage of contaminated bilge water or tank washings shall be provided.

• A shore connection with a standard coupling or other facilities shall be provided for transferring contaminated liquids to onshore reception facilities.

• Pump discharge pressure gauges shall be provided outside the cargo pump-room

• Where machinery is driven by shafting passing through a bulkhead, gastight seals with efficient lubrication shall be fitted in way of the bulkhead.