Section 2 Materials

2.1.1 Materials and grades of steel are to comply with the requirements of Ch 3 Rolled Steel Plates, Strip, Sections and Barsof LR’s Rules for the Manufacture, Testing and Certification of Materials (hereinafter referred to as the Rules for Materials) and as required by the individual ship type Chapter.

2.1.2 Where steel, or coated or lined steel, used in the construction of the cargo tanks is unsuitable for the carriage of the commodity and stainless steel is required, it is generally to be of the austenitic type which is suitable for the purpose. The stainless steel is to comply with the requirements of Ch 3, 7 Austenitic and duplex stainless steels of the Rules for Materials. Other types of stainless steel will be specially considered.

2.1.3 Where stainless steel cargo tanks are arranged, only to preserve product purity, lower alloy stainless steels will be considered.

2.1.4 Mild steel fittings are not permitted in stainless steel cargo tanks.

2.1.5 The use of other materials will be specially considered, taking into account the properties of the commodities proposed to be carried.

2.2.1 The use of wood, aluminium alloys or plastic materials within the cargo area, as far as hull structural items are concerned, is prohibited, except for:

• chocking of cargo tanks which are independent of the vessel’s hull and chocking of installations and equipment;
• masts and similar round timber;
• lids of boxes which are placed on the deck;
• supports and stops of any kind;
• Machinery items i.e. pumps, motors, etc.

The use of plastic materials or rubber within the cargo area is only permitted for:

• coating of cargo tanks and cargo lines;
• all kinds of gaskets (e.g. for domes or tank hatches);
• electric cables;
• hoses for loading and unloading;
• insulation of cargo tanks and cargo lines.

2.2.2 Wheelhouses may be constructed of aluminium, provided they are located abaft the aft cofferdams or forward of the forward cofferdam.

2.2.3 Means are to be provided to prevent spark formation within the cargo zone. The paint used in the cargo area shall not be liable to produce sparks in case of impact.

2.2.4 Toggles and their securing bolts (for instance, eyebolts) within the cargo zone for securing hatchcovers are not to be made of steel and are to be manufactured from either stainless steel, brass or an equivalent non-sparking material.

2.3.1 All steelwork is to be protected according to Pt 3, Ch 2 Materials.

2.3.2 To avoid corrosive attack of the cargo tank structure by chemical cargoes, it is strongly recommended the structure be protected by suitable lining or coating.

2.3.3 The suitability of the lining or coating and its compatibility with the intended cargoes is the responsibility of the Builder and Owner. LR will, however, require the confirmation of the manufacturer that the lining or coating used to protect the cargo tank structure is compatible with the liquids mentioned in the List of Defined Chemical Cargoes.

2.3.4 Where stainless steel has been used for the construction of cargo tanks, brackish or salt water should not be carried in these tanks in order to avoid accelerated corrosion.

2.3.5 Where water ballast spaces incorporate both mild and stainless steel, special protective measures to avoid accelerated corrosion of the mild steel, such as the use of suitable coatings, are to be taken.