4.9 Materials
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Statutory Documents - IMO Publications and Documents - International Codes - 1983 IGC Code - International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk - Chapter 4 Cargo Containment - 4.9 Materials

4.9 Materials

  4.9.1 The shell and deck plating of the ship and all stiffeners attached thereto should be in accordance with Recognized Standards, unless the calculated temperature of the material in the design condition is below -5°C due to the effect of the low temperature cargo, in which case the material should be in accordance with table 6.5 assuming the ambient sea and air temperature of 0°C and 5°C respectively. In the design condition, the complete or partial secondary barrier should be assumed to be at the cargo temperature at atmospheric pressure and for tanks without secondary barriers, the primary barrier should be assumed to be at the cargo temperature.

  4.9.2 Hull material forming the secondary barrier should be in accordance with table 6.2. Metallic materials used in secondary barriers not forming part of the hull structure should be in accordance with Table 6.2 or 6.3 as applicable. Insulation materials forming a secondary barrier should comply with the requirements of 4.9.7. Where the secondary barrier is formed by the deck or side shell plating, the material grade required by Table 6.2 should be carried into the adjacent deck or side shell plating, where applicable, to a suitable extent.

  4.9.3 Materials used in the construction of cargo tanks should be in accordance with Table 6.1, 6.2 or 6.3.

  4.9.4 Materials other than those referred to in 4.9.1, 4.9.2 and 4.9.3 used in the construction of the ship which are subject to reduced temperature due to the cargo and which do not form part of the secondary barrier should be in accordance with table 6.5 for temperatures as determined by 4.8. This includes inner bottom plating, longitudinal bulkhead plating, transverse bulkhead plating, floors, webs, stringers and all attached stiffening members.

  4.9.5 The insulation materials should be suitable for loads which may be imposed on them by the adjacent structure.

  4.9.6 Where applicable, due to location or environmental conditions, insulation materials should have suitable properties of resistance to fire and flame spread and should be adequately protected against penetration of water vapour and mechanical damage.

  4.9.7.1 Materials used for thermal insulation should be tested for the following properties as applicable, to ensure that they are adequate for the intended service:

  • .1 compatibility with the cargo

  • .2 solubility in the cargo

  • .3 absorption of the cargo

  • .4 shrinkage

  • .5 ageing

  • .6 closed cell content

  • .7 density

  • .8 mechanical properties

  • .9 thermal expansion

  • .10 abrasion

  • .11 cohesion

  • .12 thermal conductivity

  • .13 resistance to vibrations

  • .14 resistance to fire and flame spread.

  4.9.7.2 In addition to meeting the above requirements, insulation materials which form part of the cargo containment as defined in 4.2.5 should be tested for the following properties after simulation of ageing and thermal cycling to ensure that they are adequate for the intended service:

  • .1 bonding (adhesive and cohesive strength)

  • .2 resistance to cargo pressure

  • .3 fatigue and crack propagation properties

  • .4 compatibility with cargo constituents and any other agent expected to be in contact with the insulation in normal service

  • .5 where applicable the influence of presence of water and water pressure on the insulation properties should be taken into account

  • .6 gas de-absorbing.

  4.9.7.3 The above properties, where applicable, should be tested for the range between the expected maximum temperature in service and 5°C below the minimum design temperature, but not lower than -196°C.

  4.9.8 The procedure for fabrication, storage, handling, erection, quality control and control against harmful exposure to sunlight of insulation materials should be to the satisfaction of the Administration.

  4.9.9 Where powder or granulated insulation is used, the arrangements should be such as to prevent compacting of the material due to vibrations. The design should incorporate means to ensure that the material remains sufficiently buoyant to maintain the required thermal conductivity and also prevent any undue increase of pressure on the cargo containment system.

Parent topic: Chapter 4 Cargo Containment
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