Section 10 Materials

1001. General

1. Rolled steels, steel castings and steel forgings used for hull construction and equipment are to be in accordance with the requirements in Pt 2, Ch 1 of Rules for the Classification of Steel Ships. Where it is proposed to use steel or other material having properties differing from those specified in the Rules, the specification and properties of such material shall be submitted to the Society for consideration and special approval. Due consideration is to be given to the ratio of yield to ultimate strength of the materials to be used, and to their suitability with regard to struc- tural location and to design temperatures.

2. Consideration should be given to the minimization of hazardous substances used in the design and construction of the unit, and should facilitate recycling and removal of hazardous materials. (Refer to the Guidelines on ship recycling, adopted by the Organization by resolution A.962(23)).

3. Materials which contain asbestos should be prohibited.

1002. Categories of structural members of self-elevating units and column-stabilized units

Structural members are to be grouped into the following three material application categories ac- cording to the design.

(1) Primary structural members

Structural members essential to the overall integrity of the unit, such as columns, legs, bracings,

lower hulls, footings, bottom mats, shell platings of leg tanks, decks, main deck girders, and so on.

(2) Secondary structural members

Structural members of minor importance failure of which is unlikely to affect the overall in- tegrity of the unit, such as internal structural members of primary members specified in (1) and other members.

(3) Special portions of structural members

Special portions of the primary structural members specified in (1), such as junctions which are specially important in structural viewpoint or in way of stress concentration and so on.

1003. Categories of structural members of surface type units

1. Primary structural members

Sheer strake, deck stringer, bilge strake, hatch corner in way of stress concentration part which are outer 0.4 but within 0.6 amidship and primary structural members except those specified in Par

3 such as bottom plating, side plating, deck plating, longitudinals on deck, etc. within 0.4

amidship.

2.

Secondary structural members

Inner members of those specified in Par 1 and stern frame, rudder plate, etc., and sheer strake, deck stringer, bilge strake, hatch corner in way of stress concentration part which are outer 0.6 amidship and primary structural members such as bottom plating, side plating, deck plating, longi- tudinals on deck etc. which are outer 0.4 amidship.

3.

Special portions of structural members

Special members which are specially important in longitudinal strength viewpoint, such as sheer strake, deck stringer, bilge strake, hatch corner in way of stress concentration part which are within

1004. Definition of design service temperature of materials

Design service temperature of materials is the lowest of the daily average atmospheric temperatures, based on meteorological data, for any anticipated area of operation. If the data of the lowest daily average temperature are not available, the lowest monthly average temperature may be used. The

design service temperature, however, need not be lower than 0℃ for members which are below the

light draught.

1005. Application of steels

1. Application of rolled steels for surface type units is to be in accordance

Pt 3, Ch 1, Sec 4 of Rules for the Classification of Steel Ships.

with the requirements in

Table 3.5 Application of Steels for Primary Structure Members

Table 3.6 Application of Steels for Secondary Structure Members

Table 3.7 Application of Steels for Special Portion of Structure Members

2. Application of rolled steels for self-elevating units and column-stabilized units is to be in accord- ance with Table 3.5 to 3.7 depending on the categories of structural members, thickness and de- sign service temperature.