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Classification of Chemical Tankers

As per IBC code, ships carrying chemical in bulk are classified under three category:

  1. A type 1 ship is a chemical tanker intended to transport chapter 17 products with very severe environmental and safety hazards which require maximum preventive measures to preclude an escape of such cargo.
  2. A type 2 ship is a chemical tanker intended to transport chapter 17 products with appreciably severe environmental and safety hazards which require significant preventive measures to preclude an escape of such cargo.
  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.
Thus a type 1 ship is a chemical tanker intended for the transportation or products considered to present the greatest overall hazard and type 2 and type 3 for products of progressively lesser hazards. Accordingly, a type 1 ship should survive the most severe standard of damage and its cargo tanks should be located at the maximum prescribed distance inboard from the shell plating.

If a ship is intended to carry more than one product having the most stringent ship type requirement. The requirement for the location of individual cargo tanks, however, are those for ship types related to the respective products intended to be carried.

What is Chapter 17?
Chapter 17- Summary of minimum requirements
Mixtures of noxious liquid substances presenting pollution hazards only, and which are provisionally assessed under regulation 3(4) of Annex II of MARPOL 73/78, may be carried under the requirements of Code applicable to the appropriate of the entry in this chapter for "noxious liquid, not otherwise specified".

Product name                     Specify the name of the product
Pollution category             The number relating to each product as                                               recommedations proposed by the                                                       United Nations Committee of Experts                                                 on the Transport of Danferous Goods.
Hazards                             "S" means that the product is included in                                             the Code because of its safety hazards;
                                          "P" means that the product  is included                                               in the Code because of its pollution                                                     hazards; and
                                           "S/P" means that the product is included                                             in the Code because of both its safety                                                 and pollution hazards.
Ship type                            1= ship type 1
                                           2= ship type 2
                                           3= ship type 3
Tank type                           1= independent tank
                                           2= intergral tank
                                           G= gravity tank
                                           P= pressure tank
Tank vents                         Open: open venting
                                          Cont.: controlled venting
                                          SR: safety relief valve
Tank environmental          Inert: inerting
control                               Pad: liquid or gas padding
                                          Dry: drying
                                          Vent: natural or forced ventilation
Electrical equipment         T1 to T6: temperature classes
                                          IIA, IIB or IIC: apparatus groups
                                          NF: nonflammable product
                                          Yes: flashpoint exceeding 60'c
                                          No: flashpoint not exceeding 60'c
Gauging                            O: open gauging
                                          R: restricted gauging
                                          C: closed gauging
                                          I: indirect gauging
Vapour detection               F: Flammable vapours
                                          T: toxic vapours
Fire protection                  A: alcohol-resistant foam or multi-                                                      purpose foam
                                          B: regular foam; encompasses all foams                                            that are not of an alcohol-resistant type,                                              including fluoro-protein and aqueous-                                                film forming foam(AFFF)
                                         C: water-spray
                                         D:dry chemical
                                         No: no special requirements under this                                               code
Materials of construction N
                                         A blank indicates no special guidance                                                 given for materials of construction.
Respiratory and eye        E
protection                        No: no special requirements under this                                              code


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