Clasification Society Rulefinder 2016 - Version 9.25
Clasification Society Rules and Regulations - Rules and Regulations for the Classification of Offshore Units, January 2016 - Part 10 SHIP UNITS - Chapter 1 General Requirements - Section 3 Materials

Section 3 Materials

Parent topic: Chapter 1 General Requirements

3.1 General

3.1.1 Steel should be manufactured and tested in accordance with the Rules for the Manufacture, Testing and Certification of Materials (hereinafter referred to as the Rules for Materials) or other acceptable standards. The strength and grades (notch toughness) of steel required will depend on the following:
  1. design temperature;
  2. thickness;
  3. substance being stored/processed;
  4. structural category;
  5. location.

3.1.2 Material classes and steel grades should comply with Pt 4, Ch 2 Materials unless indicated otherwise in this Section. Materials for the hull structure of ship units engaged in the production, storage and offloading of liquefied gases at a fixed location are also to comply with Pt 11, Ch 4 Cargo Containment and Pt 11, Ch 6 Materials of Construction and Quality Control .

3.1.3 Critical joints which depend upon the transmission of tensile stress through the thickness perpendicular to the plate surface of one of the members are to be avoided wherever possible. Where the stress perpendicular to the plate surface exceeds 50 per cent of the Rule permissible stress and the thickness exceeds 15,0 mm, plate material with suitable through thickness properties as required by Ch 3, 8 Plates with specified through thickness properties of the Rules for Materials is to be used. For certain critical joints with a restricted load path, these criteria would be subject to special consideration, for example, mooring fairlead attachments and anchor line or hawser connections.

3.1.4 Steel grades for special and primary structural components with thickness in excess of the limitations of Ch 3 Rolled Steel Plates, Strip, Sections and Bars of the Rules for Materials and Pt 4, Ch 2, 4.1 General 4.1.6 in Pt 4, Ch 2 Materials will be specially considered.

3.1.5 Where attachments/pads are located on special or primary components which are subjected to high stresses, the attachment is to be of the same material as the plating to which it is attached, with welding to the same standard as the main structure.

3.1.6 Steel having a specified minimum yield stress of 235 N/mm2 is regarded as normal strength hull structural steel. Steel having a higher specified minimum yield stress is regarded as higher strength hull structural steel.

3.1.7 For the determination of hull girder section modulus, where higher strength hull structural steel is used, a higher strength steel factor, k, is given in Pt 10, Ch 1, 3.1 General 3.1.7.

Table 1.3.1 Values of k

Specified minimum yield stress, N/mm2 k
235 1,00
265 0,93
315 0,78
340 0,74
355 0,72
390 0,68
NOTE
Intermediate values are to be calculated by linear interpolation.
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